INJ1 Fuse Blowing

[Dynomite]

I am looking for information on the INJ1 circuit (1995) to determine where I might have a short. I have no injector wires caught between the plenum and Injector Housing. This all started all of a sudden and the 10A INJ1 fuse keeps blowing. At least it is that circuit and not the Crankcase Sensor that is the issue I am thinking.

When the INJ1 Fuse blows you are DONE with NO spark on any of the 8. At least this happened in my driveway and not a thousand miles down the road :p

[WVZR-1]

I am looking for information on the INJ1 circuit (1995) to determine where I might have a short. I have no injector wires caught between the plenum and Injector Housing. This all started all of a sudden and the 10A INJ1 fuse keeps blowing. At least it is that circuit and not the Crankcase Sensor that is the issue I am thinking.

When the INJ1 Fuse blows you are DONE with NO spark on any of the 8. At least this happened in my driveway and not a thousand miles down the road :p

I think the terminology of the fuse is maybe misleading. Maybe! I'd think you have no choice but to start at what GM seems to want to call the IGNITION COIL PACK (the component that all of the coils are mated to). Do you have the FSM for your '95 or are you attempting to work from a previous year?

[Dynomite]

I think the terminology of the fuse is maybe misleading. Maybe! I'd think you have no choice but to start at what GM seems to want to call the IGNITION COIL PACK (the component that all of the coils are mated to). Do you have the FSM for your '95 or are you attempting to work from a previous year?

I do not have the FSM. Was thinking/hoping it would be a simple short associated with the Injectors as this has happened to at least one other individual that pinched the Injector hot wire between the Plenum and Injector Housing :p

If I install a new 10amp fuse everything starts and runs perfectly.......for about 5 minutes then nothing. Actually....now if I insert a new 10amp fuse, the fuse blows immediately upon starting.

[WVZR-1]

I do not have the FSM. Was thinking/hoping it would be a simple short associated with the Injectors as this has happened to at least one other individual that pinched the Injector hot wire between the Plenum and Injector Housing :p

If I install a new 10amp fuse everything starts and runs perfectly.......for about 5 minutes then nothing. Actually....now if I insert a new 10amp fuse, the fuse blows immediately upon starting.

The primary injectors are just a "splice" off of the circuit to the Ignition Coil Pack - try 8A-22-10 for '94/'95 years I think, 8A-22-8 for a '90. I can send you a .pdf for your '95 if you need.

[Dynomite]

The primary injectors are just a "splice" off of the circuit to the Ignition Coil Pack - try 8A-22-10 for '94/'95 years I think, 8A-22-8 for a '90. I can send you a .pdf for your '95 if you need.

A .pdf of 8A-22-10 to Dynomite07@prodigy.net would be superb :handshak:

[XfireZ51]

Dyno,

Definitely an issue w the coil packs. That "injector fuse" feeds 10amps to the ignition coils. I know because that's what blew when I ran CnP on my motor a few years ago.

[Dynomite]

Dyno,

Definitely an issue w the coil packs. That "injector fuse" feeds 10amps to the ignition coils. I know because that's what blew when I ran CnP on my motor a few years ago.

Yes.....from what Dave sent me it appears the INJ1 10 amp fuse feeds the coil packs.......but now what exactly am I looking for (what to measure to verify the issues)?

This issue started with the INJ1 fuse only blowing after the engine was warmed up for about 5-10 minutes. If I then (after engine is warmed up) replace the INJ1 fuse it blew immediately upon starting. Now the INJ1 blows with engine cold or warm and immediately upon trying to start the engine.

Also.....the INJ1 10 amp fuse does feed the Primary Injectors it appears and would also blow INJ1 if you pinched an Injector Wire or otherwise grounded an injector wire as others have done.

It appears the Plenum comes off (a 10 minute job) and then the coil packs...but again....what and where to measure?

Are you saying the coils themselves may be shorted out?

Anyway.....it also appears any pinched wire between the fuse block and coil packs/injectors could be involved (DIS and ECM may not be involved since neither would warm up within only 5-10 minutes)?

I think I can measure ohms backwards to INJ1 fuse (the hot wire) to verify if any path from the coil packs or Injectors is grounded which would indicate a short. But in this case I would not find any issues unless the components I am testing were warmed up.

I do not wish this issue on anyone who has driven the ZR1 some distance from home base.....;)
For me....I just got done with a 2,000 mile round trip to the Canadian Border to get a Customs report for the 95' ZR1 with NO issues as this issue happened a couple days after that trip backing the ZR1 approximately 100 feet from my garage, lift, and tools :D

I tested out (on the 2,000 mile road trip) ZFdoc rebuilt black label Transmission that I installed in my 95' along with new throw out bearing, new pilot bearing, and new U-Joints installed in the main drive shaft. Have to say......everyone should get a ZFdoc rebuild....those transmissions ARE THAT GOOD especially with the short throw Shifter.

Thanks guys...appreciate the information :handshak:

[WVZR-1]

Do you maybe just start at the DIAGNOSTIC CONNECTOR PIN G? 8A-22-11 I've no idea Cliff BUT ...

Have you been in the car around and behind the IP on the Right side? Maybe check C237

How about at the PASS THRU P101 to the right of blower housing/evap? Should be an image 8A-201-3 (page 1262 BOOK 2)

[XfireZ51]

Cliff,

The issue causing my fuse to blow was due to the fact that the LSx coils require 20amps for charging. I was ignorant of that fact when I put things together. The motor ran for 30-45sec. (Idle was really smooth I might add, even at first start),
but then it started to stumble and it finally died. I traced the shutdown to the Inj.1 fuse. Once I put things back to stock, motor ran fine.
So my suspicion for u is that as the coils warm up, the current draw is blowing the fuse. That's why I posted what I did.

[GOLDCYLON]

Cliff,

The issue causing my fuse to blow was due to the fact that the LSx coils require 20amps for charging. I was ignorant of that fact when I put things together. The motor ran for 30-45sec. (Idle was really smooth I might add, even at first start),
but then it started to stumble and it finally died. I traced the shutdown to the Inj.1 fuse. Once I put things back to stock, motor ran fine.
So my suspicion for u is that as the coils warm up, the current draw is blowing the fuse. That's why I posted what I did.

So the issue is the coil base or the coils in the pack or?

Any possibility of bent pin on the DIS connector ? But that cant be he just drove back and forth to Canada so this has to be a new failure like a coil. Ok I see it now Dom

[WVZR-1]

Cliff - if you have and I'd think you do, I might just swap the coils and the module/coil pack as a package and see if the issue goes away. For you that's likely possible and maybe the easiest first step beyond the "head scratch" and "now what"!

[Dynomite]

So the issue is the coil base or the coils in the pack or?

Any possibility of bent pin on the DIS connector ? But that cant be he just drove back and forth to Canada so this has to be a new failure like a coil. Ok I see it now Dom

Cliff - if you have and I'd think you do, I might just swap the coils and the module/coil pack as a package and see if the issue goes away. For you that's likely possible and maybe the easiest first step beyond the "head scratch" and "now what"!

Checked this morning and on a cold engine blew a INJ1 10 amp fuse immediately when trying to start the engine. Yesturday the fuse blowing was heat related as the fuse would not blow until the engine warmed up. This seems to me like it is an issue progressively getting worse and would indicate a coil pack and not a pinched wire.

Got Top End all apart and everything checks out fine. I even disconnected DIS from Plenum and plugged it in (with ground wire) and also plugged in Coils and could not blow the fuse. All injectors check out at 12 ohms but measuring back through ECM found one injector connector with 1/10 resistance of others but after fooling around found same on another ECM I plugged in...then the resistance disappeared on the injectors. Right now I have 4 new coils coming from Summit and will install them and connect things up including DIS without installing Plenum and turn on the switch. If INJ1 does not blow will install Plenum. I think I can plug in everything without installing the Plenum that might have impact on INJ1 fuse.

If I accidently hit start and the LT5 fires up without a Plenum I will definitely post up a photo. It might be a moon shot with direct air to the Injector Housings :D

Lee did not follow up on this ;)
INJ1 Fuse keeps blowing TIPS (http://www.zr1.net/forum/showthread.php?t=26054&highlight=ignition+coils)

[WVZR-1]

Were you able to OR did you even try to locate the "splice" for the INJ wiring? Years ago that was the first place a tech might head towards if there was a known splice in the circuit.

[Dynomite]

QUOTE=WVZR-1;245966]Were you able to OR did you even try to locate the "splice" for the INJ wiring? Years ago that was the first place a tech might head towards if there was a known splice in the circuit.[/QUOTE]

I am assuming that is inside the car.....I figured I would see if I can eliminate the fuse blowing as above by installing everything but the Plenum and if not....will then start from the fuse panel and work through the fire wall.

This could be as simple as a temporary short in one of the connectors on each injector that if you move the connector around with key on would short out...I will try that also. I will wiggle, twist, push, pull on each and every connector and wire to see if I can blow INJ1 fuse.

The BIG Problem is accidently fixing this issue of INJ1 Fuse Blowing without knowing for how long. This started all of a sudden so must/most likely is a component rather than a pinched or worn wire but could be one of the injector electrical connectors as they can move a bit.

[WVZR-1]

See 8A-22-19 - Splice is S127 and I'd think it "in the vicinity" of where you're working. Search should work quite well with that .pdf, try S127 and G106.

[Dynomite]

See 8A-22-19 - Splice is S127 and I'd think it "in the vicinity" of where you're working. Search should work quite well with that .pdf, try S127 and G106.

Yep.......I will check that......and thanks again.
Should I not be able to see zero ohms INJ1 fuse to ground any time I do have a short without the power on? And next time that fuse blows I will connect up the ohm meter downside the INJ1 fuse and have someone watch as I mess with wires.

It is one thing to have a short and associated fuse that blows and you let it go to be fixed later or limp home. This, on the other hand, stops you dead in the water :confused:

It is also one thing to have this happen hundreds of miles from home base. This, on the other hand, happened 100 feet from my garage :-D

[Demps]

Yep.......I will check that......and thanks again.
Should I not be able to see zero ohms INJ1 fuse to ground any time I do have a short without the power on? And next time that fuse blows I will connect up the ohm meter downside the INJ1 fuse and have someone watch as I mess with wires.


That's where I would start.

Key off and no resistance-->you can trace the culprit.

Key off and resistance-->wiggle &/or inspect wires & junctures.

Still resistance with analysis, key on:
--If no resistance, suspect a powered source in the tree--relay, ECM (itself or injector drivers),etc.
--if resistance, intermittent...heat it up, back to wiggling, pray...?

Ted

Ted

[Dynomite]

Got the 95' back together and installed 5 amp (#22) INJ1 fuse (requires 10 amp). Blew the 5 amp in five minutes....installed 10 amp correct fuse and been running for 30 minutes.

Took it for a spin and still running :D

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/IMG_1059.jpg
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/IMG_1061.jpg

Did install new MSD 8224 Coils and checked and rechecked all wiring.

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/IMG_1067.jpg (http://s287.photobucket.com/user/dynomite007/media/Dynomite17/IMG_1067.jpg.html)

Since the LT5 is now running as long as it has I suspect the issue of blown INJ1 Fuse was associated with something I monkeyed with:

Injector Connectors (16)
Injector Wiring Harness (2),
Coils (4),
DIS Connectors (5),
Coil Connectors (two),

I was going to monkey with the wiring from the Fuse Block through the Fire Wall but at this time appears not the issue.

I did re-install the DIS. And I have to say again.....with TB Coolant blocked at the Injector Housings I did not need to apply a lot of torque to the Plenum bolts and can reuse the Plenum gasket many times.

Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

[32valvesftw]

Good luck Cliff, I don't like those types of problems where there is more than one possible solution. Have you thought about putting the old coils on another Z to see if you can replicate the problem.

[Dynomite]

No....... The other Zs are running perfectly and these coils had a lot of miles so will just toss them. Like Lee said in our duscussion (he had same issue with INJ1 fuse) he re-loomed injector wires and issue was solved. He does not know how exactly he fixed the issue (INJ1 fuse blowing) ;)

I am in same boat as Lee :D
I have a clue but do not know exactly.


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

[XfireZ51]

Cliff,

I've had the MSDs in my motor for 8 years. Never skipped a beat.

[Dynomite]

I have MSDs in my 91' and besides I like RED :D

MSD Ignition Coil 8224

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite9/ef10af17-42d4-42e3-bbe0-4fcda8df889e.jpg


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

[GOLDCYLON]

I have MSDs in my 91' and besides I like RED :D


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

And tan interiors :p:p:p:p

My money is on the injector wires

[Dynomite]

And tan interiors :p:p:p:p

My money is on the injector wires

I am thinking that also as I really gave each Injector Connecter the "once over" as did Lee. Both of us installed new Coils as I recall. Lee removed the Injector Wire Loom and installed a New Loom (the corrugated black plastic with longitudinal opening). I did considerable manipulation of that Injector Wire Harness also. I will be doing some more testing tomorrow.

It was interesting that I blew the 5 amp fuse which I installed just for testing purposes as I wanted to get an indication at what amperage the fuses were operating if in fact I solved the issue. The 5 amp fuse did last for about 10 minutes which indicates that the INJ1 circuit is operating right around 5 amps.

Tan Interiors are very nice and I really like the 95' seats as they are considerably different than the earlier 90'-91' seats (A bit more flimsy looking but more comfortable). And the 95' seats do not have that arm on door Side of the seat that I keep sitting on getting into and out of the Z ;)

[Racinfan83]

^^^^ Exactly why I put '95 seats in my '90.. ;)

[Dynomite]

^^^^ Exactly why I put '95 seats in my '90.. ;)

Yes...... Differences between 90', 91' and 95' ZR-1s and Engines (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1583614819)

One thing I did was install a Black Label Trans rebuilt by ZFdoc into my 95' :p
Rebuilt Black Label Transmission Installed (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-13.html#post1592505462)

I really like the Reverse lock out feature in the Black Label and of course have ZFdoc Short Shifter in the Rebuilt ZF S6-40 Transmission :thumbsup::thumbsup:

The 95' is my favorite if you can find one at a reasonable price :handshak:

[GOLDCYLON]

^^^^ Exactly why I put '95 seats in my '90.. ;)

X2 but I'm running 96 sports in mine. My wide rear does not like bolster button butt

[Dynomite]

Ok boys and girls. I did some more testing on the INJ1 issue. Took a 15 mile drive and INJ1 blew again.......so......not fixed.

Resistance after fuse blew downside fuse was .5 Ohms.

Took top end apart watching dowside resistance. I disconnected three front plugs from DIS and no change in resistance. Disconnected large rear plug and resistance jumped much higher. Connected everything back and INJ1 downside resistance settled at 1200 Ohms. Put back Everything with three Plenum bolts each side and runs perfectly ;);)

I think I am zeroing on something. Will run till INJ1 blows again and repeat diagnosis. First thing when fuse blows again or if does not blow is to check all pins in large rear DIS connector.


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

[LGAFF]

could an injector be shorted?

[LGAFF]

bad ecm?

[Dynomite]

Lee........I am starting from fuse panel downside to engine. When fuse blew I measured .3-.6 ohms and now after I disconnected DIS large wire connector with 1/4" bolt resistance came back to 1200 ohms on downside. But.....I was in middle of disconnecting lots of stuff and wiggling electric connectors so have to repeat that experiment. I put it back together again and fired the LT5 up perfectly and now cannot get fuse to blow again. I will try tomorrow and if I can or cannot get fuse to blow I will take a serious look at DIS connector as this seems heat related (most of the time).
And every time I remove the Plenum and monkey, I can drive the car a few miles before the fuse starts blowing again. Tomorrow I will wiggle, jiggle, pull, push every wire I can with the ohm meter attached to the downside of the fuse panel to see if the resistance moves at all from 1200 ohms.

What I know......it is NOT the Coils which are NEW MSD 8224s.
I did switch ECMs but did not run it with switched ECM.....I was checking back resistance from injector connectors to the ECM and found same on both ECMs.

I am now determined to find the cause one way or other.

Are DIS same for all years?
I am aware that ECM are the same for all years functionally as long as you have the appropriate years chip.

I am now down to about 6 minutes removing and 6 minutes replacing Plenum. And for those of you that have difficulty getting that throttle cable off the TB wheel......I rotate the wheel clockwise and place a screw driver between TB and wheel holding the wheel at full throttle and that cable (the cable/cables that have the end that has to be inserted through the little hole and wire inserted through the little slot) slips into place very easy ;)

I am thinking there might be a pinched pin on the DIS which I will look closely for.

And yes Lee......at the moment anything is possible. The INJ1 fuse has blown cold immediately upon starting, warm ten minutes after starting, hot after 15 mile drive. I am just waiting for that fuse to blow when I open the doors :D
The injector being stuck does not seem possible given this happened under so many different conditions. And then it always unsticks itself even without the engine running. BUT....anything is possible.

What is of interest is the fact after I monkey under the Plenum it always comes back to life which would indicate the issue is under the Plenum. As erratic as this is it seems to be a component or connector that has or can move or the DIS. The trouble is that this issue fixes itself each time I start testing.

Today I was doing 80 a mile from the house and the fuse blew. I put it in neutral and coasted 3/4 mile into my driveway :p

Again.....I do NOT tighten the Plenum bolts very much at all and I have TB coolant blocked at Injector Housings........that is a MUST for this kind of work :dancing

[GOLDCYLON]

Lee........I am starting from fuse panel downside to engine. When fuse blew I measured .3-.6 ohms and now after I disconnected DIS large wire connector with 1/4" bolt resistance came back to 1200 ohms on downside. But.....I was in middle of disconnecting lots of stuff and wiggling electric connectors so have to repeat that experiment. I put it back together again and fired the LT5 up perfectly and now cannot get fuse to blow again. I will try tomorrow and if I can or cannot get fuse to blow I will take a serious look at DIS connector as this seems heat related (most of the time).
And every time I remove the Plenum and monkey, I can drive the car a few miles before the fuse starts blowing again. Tomorrow I will wiggle, jiggle, pull, push every wire I can with the ohm meter attached to the downside of the fuse panel to see if the resistance moves at all from 1200 ohms.

What I know......it is NOT the Coils which are NEW MSD 8224s.
I did switch ECMs but did not run it with switched ECM.....I was checking back resistance from injector connectors to the ECM and found same on both ECMs.

I am now determined to find the cause one way or other.

Are DIS same for all years?
I am aware that ECM are the same for all years functionally as long as you have the appropriate years chip.

I am now down to about 6 minutes removing and 6 minutes replacing Plenum. And for those of you that have difficulty getting that throttle cable off the TB wheel......I rotate the wheel clockwise and place a screw driver between TB and wheel holding the wheel at full throttle and that cable (the cable/cables that have the end that has to be inserted through the little hole and wire inserted through the little slot) slips into place very easy ;)

I am thinking there might be a pinched pin on the DIS which I will look closely for.

And yes Lee......at the moment anything is possible. The INJ1 fuse has blown cold immediately upon starting, warm ten minutes after starting, hot after 15 mile drive. I am just waiting for that fuse to blow when I open the doors :D
The injector being stuck does not seem possible given this happened under so many different conditions. And then it always unsticks itself even without the engine running. BUT....anything is possible.

What is of interest is the fact after I monkey under the Plenum it always comes back to life which would indicate the issue is under the Plenum. As erratic as this is it seems to be a component or connector that has or can move or the DIS. The trouble is that this issue fixes itself each time I start testing.

Today I was doing 80 a mile from the house and the fuse blew. I put it in neutral and coasted 3/4 mile into my driveway :p

Again.....I do NOT tighten the Plenum bolts very much at all and I have TB coolant blocked at Injector Housings........that is a MUST for this kind of work :dancing


Cliff the DIS is the same for every year.

[Dynomite]

Cliff the DIS is the same for every year.

Every time I check injectors they ALL measure 12.4 Ohms. If I can get the INJ1 fuse to blow or not......I will check the pins on the DIS and if OK....I will change DIS. I have wiggled the Injector Connectors many times with no changes in Ohm Reading. Will also wiggle Coil bracket connectors. The Coils are New...so what is left could be ECM which I can change after I run it and if the fuse fails tomorrow I will change ECMs first since that is simplest without removing Plenum.

Then if all fails......no pun intended......I will look inside the car for a short. just in case. I just wish it would not fix itself so often in between failures.

[XfireZ51]

Cliff,

For grins, check the Diag Connector by the firewall or have u done that already?

[WVZR-1]

I mentioned the connector many posts ago and I also suggested "coils/module" AS A PACKAGE if he had and I thought he might have had. He didn't hint that he has or has even considered it.

[Dynomite]

I mentioned the connector many posts ago and I also suggested "coils/module" AS A PACKAGE if he had and I thought he might have had. He didn't hint that he has or has even considered it.
I switched coil base just to test that out as both original and switched coil bases measured the same but I installed alternate coil base just for kicks in case the original coil base responded to heat differently than the one I installed.

I figured I would exhaust by back measuring the resistance from fuse panel to items under plenum first and then when I exhaust that and switch everything (as it appears heat related to start with) I would go to the fire wall and inside the car. It appears that upon cool down the resistance goes back up and I will try to confirm that today. If after I switch everything and wiggle everything and check when exactly resistance goes less than an ohm on the INJ1 circuit as it relates to heat and when it comes back to 1200 ohms I figure is a BIG clue. And if that is in fact engine heat related then most likely under the hood but yes....I will get to it when I get to it today.

Regarding DIS substitute by years.......I have two additional Experts helping me (Marc and Anonymous) who have pointed out that the first 500 or so 90's used a DIS module that has a part number that ends in 37. Those units only function with a brass shim under the crankshaft sensor. These modules will work in later cars as long as the crankshaft sensor is modified with the brass shim. After that initial run of 500 or so the DIS are interchangeable with later year LT5s. Crankshaft Position Sensor Shims (http://www.zr1.net/forum/showthread.php?p=163130#post163130)

Also it was pointed out by Marc regarding installation of a new Crankshaft sensor....some new crankshaft sensors have manufacturing faults. One new manufactured crankshaft sensor had the magnet installed backwards in about 2005. There is no spark with that magnet installed backwards. Some currently available new crankshaft sensors have a metal bracket that prevents the sensor from seating correctly in the LT5 block. This sensor is positioned in the block in such a way that the LT5 is difficult to start at times.

I have to say....these guys and guys on this Forum are super and the LT5/ZR-1 technical knowledge base is absolutely exceptional and only gained from these guys being involved and having to fix everything and anything over a number of years. Their learning curve developed through running into these very unique issues themselves experimenting with what is first thought to be good working components. Kind of like the NEW water pump I installed with a cracked impeller :D

I digress but firing up the LT5 with a water pump impeller spinning on the shaft (who would have guessed) is a strange/rare issue. Of course I thought it was Air Lock and after trying to develop ALL SORTS of Coolant Installation Techniques that did not work in this case, finally just changed Water Pumps. What Marc is saying and what I have also experienced......New parts do not always function correctly with design flaws or manufacturing flaws. ANYTHING IS POSSIBLE and when you have excluded the impossible, what remains must be the truth.

[Paul Workman]

*... What Marc is saying and what I have also experienced......New parts do not always function correctly with design flaws or manufacturing flaws. ANYTHING IS POSSIBLE and when you have excluded the impossible, what remains must be the truth.

Statistics of failure rates determining the "MEAN TIME BETWEEN FAILURE (MTBF) for any device shows the the most likely period in a device's lifetime for failure, other than after it has reached it's practical life expectancy, is immediately after it is put into service for the first time! The term (from statistics) to describe this phenomenon is "INFANT MORTALITY".

For that reason alone, it makes sense to determine by testing, verifying whether a component is actually bad or not before installing a replacement. And, to test the newly installed component to verify it is functioning properly.

I know you know that, Cliff (and others). But, every now and then someone has a problem and starts "changing stuff until the problem goes away...maybe", and often winding up without fixing the issue, or worse introducing another problem (besides lightening his wallet!).

I'll shut up now...:dancing

[Dynomite]

Never shut up Paul.......Yes.....the issue is replacing things and inadvertenly fixing the issue without realizing it and ending up having a bad component on the bench without knowing it. I actually am having fun and about ready for another drive hoping to blow INJ1 fuse again lol lol

I have established Ohms down stream of fuse is 1,300 Ohms with engine off and key off. When fuse blows Resistance is .6 Ohms more or less. And stays that way untill engine cools down or I mess with components and connectors. I will now determine if cooling down does the trick by itself.

Will disconnect DIS to see if resistance goes up and stays up like yesturday.

I cannot get fuse to blow :D


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

[GOLDCYLON]

Never shut up Paul.......Yes.....the issue is replacing things and inadvertenly fixing the issue without realizing it and ending up having a bad component on the bench without knowing it. I actually am having fun and about ready for another drive hoping to blow INJ1 fuse again lol lol


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

Cliff you can do it! Gawd I hate electrical issues.

[Dynomite]

I cannot get the INJ1 Fuse to blow....went on 30 mile ride and perfect all the way.
Downside Resistance from INJ1 stays at 1200 Ohms. What did I do yesterday....just took Plenum Off and put back on with less bolts. I will take Plenum off again and prolly change DIS for the heck of it after checking ALL pins. Will check ALL connectors one more time.

I will take a couple photos of some new Plenum removal techniques along the way as I got Plenum removal down to 6 min and Plenum Installation down to 6 min......

I will relax a couple electrical looms/connectors since they seem to not have enough slack under the Plenum.

Next time this happens I will at least know it is NOT DIS or Coils or Coil Base. Or some other things..........

When the INJ1 fuse blows it appears the downside resistance does not creep down from 1200 Ohms but just drops to almost zero immediately. That is a clue also. I am not sure the resistance came back up because things cooled down or because I disconnected the DIS as it happened (got 1200 Ohms resistance downside INJ1) exactly when I removed the rear main DIS Connector with 1/4 inch bolt.

[Paul Workman]

No....... The other Zs are running perfectly and these coils had a lot of miles so will just toss them. Like Lee said in our duscussion (he had same issue with INJ1 fuse) he re-loomed injector wires and issue was solved. He does not know how exactly he fixed the issue (INJ1 fuse blowing) ;)

I am in same boat as Lee :D
I have a clue but do not know exactly.


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

Wooohohohoo... That sounds like a Lukas Electronics kind of peoblem, Cliff! It is a Lotus, after all...;)

[Dynomite]

Wooohohohoo... That sounds like a Lukas Electronics kind of peoblem, Cliff! It is a Lotus, after all...;)

Well......this Lotus just will not quit now as I have been trying for several days to blow INJ1 fuse. It maintains 1200 Ohms on the down side and the LT5 runs perfectly.

Of interest and indicating where the INJ1 issue might be......... was last time watching the Ohm meter measuring down stream electrical resistance from INJ1 fuse while disconnecting electrical under the Plenum (INJ1 had failed and showed zero ohms on down side) the Ohms came back as I disconnected the 14 pin DIS connector.

The 14 Pin DIS connector (8 pins are used) has 4 wires with original (stock) mechanical crimped splices down by rear of block just before large Wire Loom. I disconnected the large Loom clamp and raised the loom just even with the windshield wiper motor. I cut those mechanical splices and slipped heat shrink on the cut wires and then soldered the wire ends. Heat shrink slips over the soldered splice and with some heat will insulate the splice. I then put it back together temporary and took a ride with no issues. I then removed the Plenum one more time and installed new wire looms on all electrical wires.

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/c890472d-90fd-45df-bb11-635abc44f223.jpg

Installed New Red Wire Looms on Coil Driver wires, EGR wire. secondary MAP wire, and the Crankshaft sensor wire connected to rear of DIS. Just cleaning up all wiring (Some of the New Wire Looms contained multiple Connector Wiring). Installed new wire looms on Injector Wires as well.

The key is to install the wire looms such that no connector is under any kind of tension at any time and with the wire looms on each wire there should be no wire contact with anything under the plenum.

The INJ1 Fuse issues are summarized here INJ1 Fuse (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-13.html#post1592505475)

Did check secondary operation by grounding Pin 17 on the ECM Green plug. With key on and with finger over vacuum line going to secondary Map sensor the secondary canisters functioned perfectly.

New Coils............................................. ...........................New Wire Looms (Red)
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/bfded784-d8a6-4935-bf6c-01f9c0ab4984.jpghttp://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/0ee9232c-dbe0-404f-96e5-9e91a90cabe2.jpg
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/7cf29450-2dcc-422a-a473-5f05bca4234a.jpg
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/667c563d-16c1-4a24-b2d8-27576d79c3ca.jpg


See Also:
Under the Plenum (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-13.html#post1592505477)
The Four Minute Plenum Installation (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-13.html#post1592505479)

[Paul Workman]

Well......this Lotus just will not quit now as I have been trying for several days to blow INJ1 fuse. It maintains 1200 Ohms on the down side and the LT5 runs perfectly.

Of interest and indicating where the INJ1 issue might be......... was last time watching the Ohm meter while disconnecting electrical under the Plenum (INJ1 had failed and showed zero ohms on down side) the Ohms came back as I disconnected the 14 pin DIS connector.

The 14 Pin DIS connector (8 pins are used) has 4 wires with original (stock) mechanical crimped splices down by rear of block just before large Wire Loom. I disconnected the large Loom clamp and raised the loom just even with the windshield wiper motor. I cut those mechanical splices and slipped heat shrink on the cut wires and then soldered the wire ends. Heat shrink slips over the soldered splice and with some heat will insulate the splice. I then put it back together temporary and took a ride with no issues. I then removed the Plenum one more time and installed new wire looms on all electrical wires.

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/c890472d-90fd-45df-bb11-635abc44f223.jpg

Installed New Red Wire Looms on Coil Driver wires, EGR wire. secondary MAP wire, and the Crankshaft sensor wire connected to rear of DIS. Just cleaning up all wiring (Some of the New Wire Looms contained multiple Connector Wiring). Installed new wire looms on Injector Wires as well.

The key is to install the wire looms such that no connector is under any kind of tension at any time and with the wire looms on each wire there should be no wire contact with anything under the plenum.

The INJ1 Fuse issues are summarized here INJ1 Fuse (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-13.html#post1592505475)

Did check secondary operation by grounding Pin 17 on the ECM Green plug. With key on and with finger over vacuum line going to secondary Map sensor the secondary canisters functioned perfectly.

New Coils............................................. ...........................New Wire Looms (Red)
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/bfded784-d8a6-4935-bf6c-01f9c0ab4984.jpghttp://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/0ee9232c-dbe0-404f-96e5-9e91a90cabe2.jpg
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/7cf29450-2dcc-422a-a473-5f05bca4234a.jpg
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/667c563d-16c1-4a24-b2d8-27576d79c3ca.jpg


See Also:
Under the Plenum (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-13.html#post1592505477)
The Four Minute Plenum Installation (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-13.html#post1592505479)

Nice write-up, Cliff!

BTW, I never saw a mechanical splice that I liked. And, I never looked at a pin/cylinder connector that wasn't gold flashed with less than suspicion. (I use dielectric grease on them to retard oxidation.)

[Dynomite]

Nice write-up, Cliff!

BTW, I never saw a mechanical splice that I liked. And, I never looked at a pin/cylinder connector that wasn't gold flashed with less than suspicion. (I use dielectric grease on them to retard oxidation.)

Just for your additional information.......I also found original stock mechanical splices on the Drivers side Injector Wire Harness between the last injector by the fire wall and main wire loom captured in the Clamp attached to rear of block. I did not replace those original Injector Wire Harness splices simply because it is NOT an easy job to get down in that area with a soldering gun, wire stripper, Heat gun, or electrical tape. The mechanical splices on the Injector Harness did look well separated.

I did manage to replace four of the 14 Pin Connector Splices between the 14 Pin Connector and the main wire loom captured in the Clamp attached to rear of block. I removed the mechanical splices and used Solder, Heat Shrink, followed by electrical tape to connected the exposed ends of each wire (overlapping the bare wire ends about 3/8 inch on each side of the splice). The solder took very well saturating the two bare wire ends.

[32valvesftw]

Cliff,

Do you think we all have these suspect splices on our cars?

[Dynomite]

Cliff,

Do you think we all have these suspect splices on our cars?

Interesting question....I checked another LT5 wire harness I have on the wall (from a 90 or 91) and yes....it also contained these splices. The splices are interesting as they are swedged/crimped metal clips that are crimped over overlapping ends of bare wire as you can see in the photos. These Crimped wire ends are in turn wrapped with a silly cloth wrap about 1.5 inches long that is relatively loose and can be removed by cutting lengthwise with razor blade. Keep in mind this is a 95' with more going on under the Plenum (EGR and MDP).

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite18/a297d98e-c7ea-42ba-b3c8-c5011ba0c382.jpg

I am not saying these splices caused INJ1 to blow as it appears only a shorted wire could do that. The spices although in somewhat poor condition did not appear to be in contact with associated spliced wires. I will say when I got done soldering the overlapping ends and sliding heat shrink over the splice with some heat it is like night and day on the continuity of the resulting splice compared to the original mechanical splice. And.....most importantly, the stripped wire ends (stripped 3/8 inch on each overlapping wire) took solder very well saturating all strands of the bare wire ends.

One more point........These four splices on the 14 Pin Connector Harness each had two wires coming from the main wire harness within the clamp attached to the rear of the block going into one wire going on into the 14 pin DIS Connector. The only way to do that is to splice the wire.

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/c890472d-90fd-45df-bb11-635abc44f223.jpg

[XfireZ51]

First of all, great work and documentation on this Cliff. Second, are u suspecting these are OEM splices? Do the appear to match the splice methodology illustrated in the FSM?

[Dynomite]

The splices are definitely OEM splices and the FSM does not seem to indicate where splices are located but I recall Dave suggesting to check splices inside the car or maybe outside also. Further, the only wires spliced are those wires where two wires are spliced into one.

I rechecked my on the wall 90'/91' wire harness and the 14 pin DIS connector wire harness does have identical appearing splices but did not check if identical wires within the harness.

Again I am suggesting these splices did not appear to contribute to a short blowing INJ1 fuse but could contribute to a discontinuity in electrical signals.

And...... The Drivers side Injector harness (and maybe passenger side also) contains similar splices between last injector and main wire harness.

I doubt anyone has peeked inside the wire looms of these wire harnesses :D


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

[GOLDCYLON]

CLiff is she good to go?

[Dynomite]

CLiff is she good to go?

Seems that way....good to go....and NEW Plates :p

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite18/33cb18fa-1f00-43d3-a267-8a825259d641.jpg
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite18/eb0a9877-52fe-4e61-a4d9-ad85faad0aae.jpg

[GOLDCYLON]

Congrats. You think it was those spices or the connectors to the DIS or ?

[Dynomite]

Congrats. You think it was those spices or the connectors to the DIS or ?

Lee nor I really know for sure but we both replaced all wire looms on Injectors and I actually replaced or added wire looms on ALL under Plenum Wiring. I also loosened up some wires under the Plenum such that no Connector to the DIS was under any kind of tension. Same with Injectors.

1995 ZR-1 Plenum and associated DIS
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite18/a297d98e-c7ea-42ba-b3c8-c5011ba0c382.jpg

When I unscrewed the 1/4 inch nut from DIS with Ohm Meter connected to that INJ1 Fuse downside I actually got the resistance back to 1200 ohms which is normal with switch off. This was after INJ1 fuse blew (zero ohms on that circuit). The resistance went from near zero to 1200 Ohms during the disconnection of the 14 pin Connector.

From that I expect the issue resided in that DIS 14 pin connector or wire harness or maybe in those splices. That DIS 14 pin actually has only 8 pins functioning and 4 of those 8 are splices between the main wire harness and the DIS wire connector. Those 4 splices contain two wire each coming from the main wire loom spiced into a single wire going to the DIS 14 pin connector. I guess you can then say that there are 12 wires going to the DIS Connector from the main wire loom.

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite17/c890472d-90fd-45df-bb11-635abc44f223.jpg

It was kind of a mess from the main wire loom as the two Coil connectors and associated wires, the 14 Pin DIS connector wires and associated splices, the Coil Drivers, the EGR, the Crankshaft sensor wires, and the MDP wires were all kind of tangled. I actually spliced a couple of wires so I could untangle the mess and separate ALL connectors and associated Wiring separately to each connector.