Inj 1 fues keeps blowing

[LGAFF]

A month or so ago I had the plenum off my 1991 368. I noticed an electrical smell coming from the valley. One of the coils was very hot...so I pulled the coils off the coil housing and swapped them.
I also had the Inj 1 fuse blow. It now blows any time the ignition switch is turned on, except when I disconnect the two wire plug that goes onto the coil housing.(pnk/blck)

So is the coil housing possible the culprit? It all encased wiring

Thoughts?

Its CKT 639

[LGAFF]

I did not see any pinched wires on the injectors

[-=Jeff=-]

Bent pin in a connector?

otherwise without me having a ckt diagram it is hard to troubleshoot

[LGAFF]

I checked all of the pins, no issues.....the coils, DIS, and the primary injectors are on this circuit. As the initial issue with the coil was with them plenum off I wonder if its the Coil housing.

[XfireZ51]

I checked all of the pins, no issues.....the coils, DIS, and the primary injectors are on this circuit. As the initial issue with the coil was with them plenum off I wonder if its the Coil housing.

Lee,

You should be able to check the housing for short as improbable as that may be.

[-=Jeff=-]

what changed on the car from when it was not popping the fuse to when it started popping the fuse

[LGAFF]

Pulled Plenum to address a coolant leak...when the plenum was off I noticed the electrical smell from the coil

[A26B]

I would suspect the bad coil that overheated rather than the base. If the base were to short, then there wouldn't be any voltage to the coil to cause the overheat.

http://i190.photobucket.com/albums/z224/A26B/Coil%20Pak%20Base%20Schematic_zpstvlao56s.jpg (http://s190.photobucket.com/user/A26B/media/Coil%20Pak%20Base%20Schematic_zpstvlao56s.jpg.html )

[LGAFF]

:confused:Coils changed, problem continues

[secondchance]

Bad injector? Wouldn't coils be on separate ignition circuit and injectors on injector circuit?

[LGAFF]

So with the plenum off, and Ignition module and coil housing connected, I could not get the fuse to blow...has to be an inj wire...but I see nothing


tested with power on, all inj had power to the wire

[-=Jeff=-]

Ohm out the base with the coils off and base disconnected form car. check each line for shorts

where do the 4 hot coil wires go from the base, follow and check those. Since the fuse pops on key on, engine not running. disconnect the injectors try again.

What about the injector modules? is there one form primary and one for secondary?

electrical is not as easy as swapping parts, might be in the wire

[LGAFF]

checked all of the fuel injectors, going to replace all of the coils this weekend, will also go through the injector harness.

[cvette98pacecar]

checked all of the fuel injectors, going to replace all of the coils this weekend, will also go through the injector harness.

Lee, the plunger inside the injector is jammed. It is not moving with the PWM which is creating a large load on the circuit which is blowing the fuse.

[tpepmeie]

Lee, the plunger inside the injector is jammed. It is not moving with the PWM which is creating a large load on the circuit which is blowing the fuse.

There would be no PWM or plunger activation with Key on, Engine Off. That's when he said the fuse is blowing.

[cvette98pacecar]

Dah, Read first comment second. For whatever reason I thought the car was running.

[LGAFF]

INJ 1 fuse issue is back; It is tied in the coil plug ins/DIS somehow....at first it seemed to be the Crank sensor as the fuse only blew with the crank sensor was plugged into the DIS....then it suddenly stopped:(

Wonder if the wire is grounded out were it travels around the engine/frame

[-=Jeff=-]

you have a chafed wire that is shorting.. doesn't always happen, but sucks when it does.

I hate looking for those, good luck

[GOLDCYLON]

INJ 1 fuse issue is back; It is tied in the coil plug ins/DIS somehow....at first it seemed to be the Crank sensor as the fuse only blew with the crank sensor was plugged into the DIS....then it suddenly stopped:(

Wonder if the wire is ground out were it travels around the engine/frame

You may need to pull those harnesses apart like Cliff did in his write up. However his issue was in the injector harness Lee. I spoke with him last night about it. Since he has done that his problem in his 95 has went away. GC

[LGAFF]

You may need to pull those harnesses apart like Cliff did in his write up. However his issue was in the injector harness Lee. I spoke with him last night about it. Since he has done that his problem in his 95 has went away. GC

Did that already on the inj......but its not the injectors its in the DIS/Crank sensor

[GOLDCYLON]

Did that already on the inj......but its not the injectors its in the DIS/Crank sensor

Understood I meant you will need to pull that harness apart

[Dynomite]

First........Block TB Coolant so you can remove plenum quickly and use less torque on plenum bolts.....nothing on plenum gasket.

What I did is................ with ohm meter connected downside of INJ1 fuse with black ohm meter wire grounded......I slowely loosened plenum and tipped it up slowley. I then wiggled/discomnected connectors to DIS. I found the 14 pin (8 pins used) connector to plenum blew the fuse as I wiggled it (got zero ohms on ohm meter).

I went further down into wire harness and replaced 4 mechanical splices (soldered with heat shrink). I then wrapped each individual DIS connector and harness with split wire loom (I think 1/4, 5/16, and 3/8 inch). No more issues so far.

That is a tough issue and let us know your cure.

Oh........I did gain length on the various wire harneses by re wrapping which may have contributed to the cure.

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

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

[LGAFF]

Might have found the source

Took a test light and lightly probed around the harness.....got one primary that lights off the light pretty easy when pressing against the insulator.

[Dynomite]

Might have found the source

Took a test light and lightly probed around the harness.....got one primary that lights off the light pretty easy when pressing against the insulator.

Can you take a photo so we can tell exactly where that is?

Primary Injector?
Insulator?

Great Information if that be the case but am not sure what insulator is?
I am assuming this is the Electrical Harnesses going to the Injectors on each side?

Who is to say for sure.....this may have been my issue as well as I did re-wrap the Injector Harnesses both sides.

[LGAFF]

Will post a video....I am going to coat each injector harness connector with liquid tape as well

[LGAFF]

This is a test light running at the top of the rubber grommet on the primary injector with key on.....not backprobing pressing against the wire with the side of the test light

http://i134.photobucket.com/albums/q115/lgaff/th_DSCN66351.mp4 (http://i134.photobucket.com/albums/q115/lgaff/DSCN66351.mp4)

[Dynomite]

This is a test light running at the top of the rubber grommet on the primary injector with key on.....not backprobing pressing against the wire with the side of the test light

http://i134.photobucket.com/albums/q115/lgaff/th_DSCN66351.mp4 (http://i134.photobucket.com/albums/q115/lgaff/DSCN66351.mp4)

I am not sure how the test light circuit is set up? Are you measuring stray voltage? Is the Test Light Grounded on one lead?

I am not sure what top of the rubber grommet is......is that on top of Injector electrical connector?
One of the Injector Wires?

So the Injector electrical connector to Injector was shorting or one wire could be shorting if it contacted other metal (grounding out)?
With Key ON......is there suppose to be a HOT wire to each injector?

With INJ1 Fuse removed and an ohm meter probe on the downside of that fuse (current to Injector Circuits) and other probe to ground on chassis......press against the wire one more time and see if the Ohms goes to zero on the meter (the wire shorting within the injector connector).

The Ohms went to zero for me when I wiggled/pulled on the DIS Connector harness.

It seems to me that if we follow Marc's concept of measuring Injector Resistance Plenum in Place we would find that the resistance in your situation would go to ZERO on that Injector as you wiggle the wire? Checking Injector Resistance with Plenum in Place TIPS (http://www.zr1specialist.com/HAT%20Web/articles/Measuring%20Fuel%20Injector%20Resistance%20with%20 the%20Plenum%20in%20Place.pdf)

In my case the Resistance would go to ZERO no matter which Injector I was testing when I wiggle the DIS Connector?

I guess I have to study that Injector Circuit some more ;)

[LGAFF]

It was right were the two wires enter the injector connector, I believe the plenum often makes contact with this area when seated. With the key on the pink/black wires are hot

[LGAFF]

I am not 100% certain this is the cause, just noting that this is something that has the potential to ground out

[Dynomite]

I installed new individual red wire looms on all wire harnesses. I replaced the two individual wire looms for each Injector Harness as well. After the New Wire Looms were installed I have not had the INJ1 Fuse blow since.

[zrfast1]

Not sure how Lee's problem was finally sorted but to anyone who has this problem that just pulled the plenum, crossing the two ign. connectors on the front of the DIS module will give you the same problem. Very easy to do when they are not marked. Just a fyi[-X

[LGAFF]

That only goes on one way......unless tab is broken?

[zrfast1]

It was on the car i was helping with.