Correct injectors?

[Jaap]

Hi,

Need some help, we`re working on the LT5 engine and have some doubts about the injectors. Is type number 2631 01D36B the correct injector? They`ve been replaced in 2013 but the engine just run 300 km since the engine had an overhaul en injector replacement. Some how the injector from cilinder two gone bad.

01D36B is correct, but what means 2631?

should we replace them or clean ultrasonic and test them?



thx
Jaap

[XfireZ51]

Hi,

Need some help, we`re working on the LT5 engine and have some doubts about the injectors. Is type number 2631 01D36B the correct injector? They`ve been replaced in 2013 but the engine just run 300 km since the engine had an overhaul en injector replacement. Some how the injector from cilinder two gone bad.

01D36B is correct, but what means 2631?

should we replace them or clean ultrasonic and test them?



thx
Jaap

Jaap,

Are these Bosch? What year ZR-1 is it? Any chance you have picture?

[Jitse]

They are Delphi , the car is a 90. # id on the injector is 01D036B. On the info I could find they are produced by Lucas in 1988.

[XfireZ51]

Does it look like this?

http://delphi.mycarparts.net/products/Delphi-FJ10024?product_application_id=5319126919

[Jitse]

Yes looks similair

[XfireZ51]

Same number. I wouldn't worry about the 2631. Could be date code or something else. Can you have them flow checked?

[Jaap]

Jaap,

Are these Bosch? What year ZR-1 is it? Any chance you have picture?

No Bosch injectors, it`s a 1990 ZR1
4117

4118

4119

4120

[XfireZ51]

Yes, I understand. The Jegs parts catalog shows that the FJ10024 injector is the correct injector for the ZR-1. http://www.jegs.com/webapp/wcs/stores/servlet/FitsApplicationView?storeId=10001&langId=-1&productId=2413192

[Jaap]

Same number. I wouldn't worry about the 2631. Could be date code or something else. Can you have them flow checked?

Tommorow they will be flow checked and ultrasonic cleaned.
The strange thing about it is dat some of the plastic has been filed of, you can see it in the first picture..

Is that a commom thing to do?

Jaap

[XfireZ51]

The question is what are the correct voltage offsets for them.

[XfireZ51]

Tommorow they will be flow checked and ultrasonic cleaned.
The strange thing about it is dat some of the plastic has been filed of, you can see it in the first picture..

Is that a commom thing to do?

Jaap

Depends. When we use Accel injectors here, we file down the "pegs" so the harness connectors fit properly.

[Jaap]

Injectors have been cleaned and tested and there all bad. so i need some new ones.
It is a standard lt5 engine.
What do you guys recommend?
FIC, Bosch, accell?

gr. Jaap

[Paul Workman]

I've got a ported LT5 running on the Accel #150821 injectors (from Summit Racing), recommended to me by the ZR-1 Specialist, Marc Haibeck. I've been very pleased with them for the past 5 seasons and approx 32,000 km

The electrical guide peg on one of the (either primary or secondary(?)) injectors has to be removed in order to allow the stock (male portion) connector to be pressed on. And, also, on the 1990s, the "O" ring at the tip end of the primary injector is NOT used and the "O" ring is removed.


Fuel Injector Connection (http://www.fuelinjectorconnection.com/shop/index.php?_a=product&product_id=108) (FIC) carries the stainless Delphi injectors for the LT5, two sets: one for the 90-92 model years and one for the 93-95 model years (LT5). And, I believe new "O" rings are included in the 'kit' (but you should ask to be sure).

Both the Accel 150121s and the FIC's stainless injectors have very good reliability, according to those that are using them.

[XfireZ51]

The correct # for the Accels is 150121.
Will U be doing any tuning?

[Jaap]

I've got a ported LT5 running on the Accel #150821 injectors (from Summit Racing), recommended to me by the ZR-1 Specialist, Marc Haibeck. I've been very pleased with them for the past 5 seasons and approx 32,000 km

The electrical guide peg on one of the (either primary or secondary(?)) injectors has to be removed in order to allow the stock (male portion) connector to be pressed on. And, also, on the 1990s, the "O" ring at the tip end of the primary injector is NOT used and the "O" ring is removed.


Fuel Injector Connection (http://www.fuelinjectorconnection.com/shop/index.php?_a=product&product_id=108) (FIC) carries the stainless Delphi injectors for the LT5, two sets: one for the 90-92 model years and one for the 93-95 model years (LT5). And, I believe new "O" rings are included in the 'kit' (but you should ask to be sure).

Both the Accel 150821s and the FIC's stainless injectors have very good reliability, according to those that are using them.

Thnx Paul.
That`s very helpfull:)

[Jaap]

The correct # for the Accels is 150121.
Will U be doing any tuning?

Thx,
I`ll keep the engine orinal, no tuning..don`t feel the need to.

[Billy Mild]

Accel injectors here. I bought them through Amazon.

[Jaap]

Just orderd the FIC injectors.
keep you informed

Gr Jaap

[XfireZ51]

Thx,
I`ll keep the engine orinal, no tuning..don`t feel the need to.

If you use injectors other than stock, you would re-tune the calibration, IMO. Doesn't mean they won't work ok, but the metering won't be as precise as it can be. Ask FIC if they can provide you with the Injector Offset Bias for Battery Voltage. Most manufacturers do.

[Jaap]

If you use injectors other than stock, you would re-tune the calibration, IMO. Doesn't mean they won't work ok, but the metering won't be as precise as it can be. Ask FIC if they can provide you with the Injector Offset Bias for Battery Voltage. Most manufacturers do.

Tnx, good tip:thumbsup:

[Jaap]

so the injectors have been replaced by FIC injectors, oil pressure sensor as been changed and the CO meters have been replaced.

Now we have a new challenge the car runs only good above 4000 rpm when it gets under the 4000 rmp the car starts to shock in every gear when the pedal is put to the mettal.. and it`s way to slow.

Do you guys have any idea what it could be?

[XfireZ51]

Check the fuel pumps.

[Billy Mild]

Check the fuel pumps.

I have noticed my car doesnt run smooth under 2000 RPM or around that RPM. It feels almost like a misfire, but doesnt sound like it is misfiring. Kind of weird.

[XfireZ51]

I have noticed my car doesnt run smooth under 2000 RPM or around that RPM. It feels almost like a misfire, but doesnt sound like it is misfiring. Kind of weird.

Don't know enough about the car to comment.

[Jaap]

Check the fuel pumps.

Fuelpumps have been replaced fuel pressure is as it should be

[Jaap]

when i put te pedal down very slowly it runs reasonably but when i put the pedal down hard it shakes back and froward.

[Paul Workman]

I've been following along too. Please, let me ask: When did this "misfire" situation begin? Was the problem there before you replaced injectors and other parts, or is this a new development (symptom)?

It doesn't sound too serious (yet), but do you suspect it is something related to work you have done or maybe the parts that were installed?? (Sooner or later, we all run across a bad "new" part. In statistics analysis they call it "infant mortality" - the new period when most products fail, not related to wear.)

[Jaap]

I've been following along too. Please, let me ask: When did this "misfire" situation begin? Was the problem there before you replaced injectors and other parts, or is this a new development (symptom)?

It doesn't sound too serious (yet), but do you suspect it is something related to work you have done or maybe the parts that were installed?? (Sooner or later, we all run across a bad "new" part. In statistics analysis they call it "infant mortality" - the new period when most products fail, not related to wear.)

Hi Paul,

The "misfire"has been there since i bought the car back in november, the "engine service soon" light jumped on when i bought it and has been there eversince. My mechanic put it on the computer and it said that fuel pumps where bad.
So we changed the fuel pumps, when the Z was ready and it had it`s test drive all of a sudden de injectors failed (injectors 3 years old) so we changed the injectors.

Next thing we changed was a new pvs system, oils, fuel filter, oil filter, LF pipe injector hosing, battery, oil pressure gauge sensor, oil pressure indicator, oxigen sensors, new gaskets. cleaned the tank and fuel lines, replaced the fueltankgasket. etcetc.

When i bought the Z there was a constant white fog behind the car, that`s now gone so that means that the work done sofar is properly done. The mechanic is a very serious guy and im absolutly sure he didn`t make any mistakes.

Three years ago the engine has been rebuild with new crankshaftbearings, new pistonrings, ingnition coils and sparkplugs.

BTW, engine service light is gone

[XfireZ51]

when i put te pedal down very slowly it runs reasonably but when i put the pedal down hard it shakes back and froward.

Do you keep your foot down when this is happening or do you lift right away?
It could be the secondaries. Try keeping your foot in it for longer than 2 sec. and see if SES light comes on.

[Jaap]

Do you keep your foot down when this is happening or do you lift right away?
It could be the secondaries. Try keeping your foot in it for longer than 2 sec. and see if SES light comes on.

I keep my foot down, SES light didn`t come on.

[XfireZ51]

Fuelpumps have been replaced fuel pressure is as it should be

Are you checking FP while driving and going to WOT?

[Jaap]

Are you checking FP while driving and going to WOT?


What do you mean with FP and WOT?

[FU]

FP = Fuel Pressure
WOT = Wide Open Throttle

[Jitse]

He means the fuelpressure, and how the pressuregauge is acting when going wide open trottle. ( under load)
FP at idle 46, and dont go's really lower when driving, with both pumps on testconnector FP is around 52.

[Jaap]

FP = Fuel Pressure
WOT = Wide Open Throttle

No, we didn`t test Fuel pressure at wide open throttle while driving.
At idle, fuel pressure is 45 psi and on both pumps 52 psi with testconnector.

[Paul Workman]

He means the fuelpressure, and how the pressuregauge is acting when going wide open trottle. ( under load)
FP at idle 46, and dont go's really lower when driving, with both pumps on testconnector FP is around 52.

52 psi at (WOT) too - just to be clear.

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/FPtestLarge.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/FPtestLarge.jpg.html)

[Jitse]

Did nog drove with the test power supply connected, used it only for testing the primairy and secondary fuelpumps by pulling each fuse. Jaap his car is always running on full power. a previous owner lost the power key and they bypassed the powerkey in always on mode.
But when I drove with the car in the street I did not see much deviation in the fuel pressure, it was stable.

[Jaap]

Did nog drove with the test power supply connected, used it only for testing the primairy and secondary fuelpumps by pulling each fuse. Jaap his car is always running on full power. a previous owner lost the power key and they bypassed the powerkey in always on mode.
But when I drove with the car in the street I did not see much deviation in the fuel pressure, it was stable.


Well, i gues you now know who`s my mechanic;)

Are there some people here who have more suggestions?
Drove the Z this afternoon and the problem is still not fixed.

All help is welcome

[XfireZ51]

Well, i gues you now know who`s my mechanic;)

Are there some people here who have more suggestions?
Drove the Z this afternoon and the problem is still not fixed.

All help is welcome

If this started after you swapping injectors, I guess I'd pull the plenum again and check everything under there one more time.

[Hib Halverson]

Now we have a new challenge the car runs only good above 4000 rpm when it gets under the 4000 rmp the car starts to shock in every gear when the pedal is put to the mettal.. and it`s way to slow.

Do you guys have any idea what it could be?

I think there might be a little language barrier issue, here...when you say it "shocks" what do you mean by that?

1) Misfire?
2) Throttle response problem?
3) Total engine cut out?

This thread is not exactly clear on fuel pressure, either. Make SURE you are testing it properly. Do not test it with the engine idling. Test it with the key-on/engine-off.

If you have 52 psi fuel pressure key-on/engine-off, it holds when you turn the key off and you have that pressure at WOT 4000 rpm or higher with the secondaries enabled--all of which you should have with two new pumps and a new fuel filter--you likely don't have a problem with fuel pressure.

The images of the injectors on the first page do not show the whole injector but they do not look like OE injectors. We'd have to see the whole injector to know for sure.

There are a lot of crap injectors on the market but there are, also, few good ones, too. The stuff that Marc sells is good. The stuff you buy really cheap on the Internet...maybe not so good.

The best on the market--admittedly somewhat pricey--are RCEngineering's LT5 injectors. I discovered them in 1997 when I did my a project series on my engine for Vette Magazine and, since then, RCEngineering has sold hundreds of sets of them to ZRoners. See www.rceng.com.

Reading all these posts, and assuming your fuel pressure readings are 52 psi key-on/engine-off, has me thinking that the misfire might not be fuel related.

Also, the sensors you are talking about are "oxygen sensors" or "O2 sensors" not "CO2 (carbon dioxide) sensors". You said you replaced them...what sensor did you use to replace them with?

Finally, it's a bit hard for me to tell but it sounds like this problem might be misfire at part throttle not misfire at WOT high rpm. Is that true? If so, I'd sure like to see some scan test data of what the fuel trims and O2S readings are in normal driving.

Part throttle misfire can be lots of different things.
1) Wrong injectors
2) Weak ignition
3) Improper calibration

Good luck!

[Paul Workman]

A little more information...

Hib mainly is referring to static fuel pressure test conditions.

Under dynamic (under load) testing without the secondaries being signaled ON, as you saw the pressure was around 46 psi, which is GOOD.

The secondary fuel pump is switched ON by the ECM when rpm AND throttle position parameters are met. At that time, dynamic fuel pressure should jump to approx a steady 52 PSI. (This test assures the delivery to the fuel rails under load is good.)

Even if the FULL POWER switch is always on, (mine it too, by the way) the secondary fuel pump is NOT turned on until BOTH the RPM and minimum THROTTLE POSITION requirements are satisfied. (Testing the dynamic fuel pressure is what my photo was attempting to show).

Note: At this point I'm almost sure we can dismiss the fuel delivery to the rails, at least, as probably OK...for now.

With regard to injectors, they must be alcohol resistant if ethanol is mixed with the fuel. (Mine were initially replaced with standard, non-alcohol resistant injectors, but they began to go bad after only a couple years of exposure to ethanol.)

The Summit Racing part number for the 21# Accel part no. ACC- 150821 (for 8, but 16 required for the LT5. Note that Summit part number ACC-150121 is for a single injector purchase.) or FIC sells the Delphi injector sets, complete with injector housing gaskets. Recommended new upper O-rings for the primary (1990) injector housing. But, regardless of which injectors are used, refer to the manufacture's recommended voltage off-sets for best results.

Note: Injector resistance must be checked when the engine is at or near operating temperature. They should all read (compare) within range of 1.5 Ω, average between 12 and 14.4 or so, depending on manufacturer. A reading about 3Ω+ lower is suspect; 4+Ω lower than the average is trouble!

Throttle Position Switch: Switch on, engine not running, refer to the schematics, but the signal voltage should range smoothly from idle to WOT. If it is erratic, that WILL cause issues!

Other items include ignition issues. Each of the 4 coils fire two plugs at the same time. If one cylinder is miss-firing, chances are the mating cylinder is missing some as well.

Like to spend more time on this, but leave for now. Good luck. Let us know your progress.:cheers:

[XfireZ51]

Agree w Hib that the description of the issue is really not clear. Can Jaap describe exactly what's happening and when? Scan data would also be very helpful.

[Jaap]

Agree w Hib that the description of the issue is really not clear. Can Jaap describe exactly what's happening and when? Scan data would also be very helpful.

Well let`s give it a try.
First of all my apology for my poor englisch, it`s complicated to explane from dutch to Englisch..

First an update of the work we have done so far.
The injectors have been replaced with FIC injectors.. after that the engine ran mutch better, but not as it should be because of misfire.

The previous owner changed with the engine rebuild 2 ingnition coils so we decided that we should change all 4 of them and the sparkplug wires. After that the engine ran pretty good but only above 4000 rpm.
Under 400 rpm it felt like misfire

Today i pulled the plugs and cilinder 2,4 and 6 where very bad, i didn`t had the right tools to pull plug 8 (that i do tomorow) the plugs show a nice light brown color that indicates that the injectors work well. despite the right color it shows some sort of welding pits in the electrode. The sparkplugs will be changed for new plugs

But.... to make it more complicated there is another issue and that is:
The exhaust mufflers where removed by the prevous owner for more sound.. as it turns out the mufflers are for a LT1 or L98 engine and they where welded on the exhaust, so there is a hughes restriction in the exhaust. Probably the catalatic converter is damaged because of the resriction.

Thats how far we are right now, what i`m planning to do is cut open the catalyc convertor and remove the material inside of it. and of course change the sparkplugs.

I hope i explaned it well and understandable.

All help and advise is welcome

Gr Jaap

[XfireZ51]

No apologies necessary. Your English is fine. Can u give more detail on the misfire. Doubt it's the mufflers.

[Franke]

Also, when you pull the plugs can you get a compression test done on all 8 cylinders just to make sure they are balanced?

[Jaap]

We have done a compression test. the compresssion for
Cil 1#220 psi
Cil 2#235 psi
Cil 3#220 psi
Cil 4#230 psi
Cil 5#210 Psi
Cil 6#230 Psi
Cil 7#215 Psi
Cil 8#195 Psi

[Franke]

Jaap, I would check that cylinder #8 again. I believe that the difference between the highest reading cylinder reading (235) and lowest cylinder reading (195) cannot be more than 15% to have a good balance. Based on these numbers #8 is at approximately 17%. I would do a wet cylinder test to verify.

[XfireZ51]

Jaap, I would check that cylinder #8 again. I believe that the difference between the highest reading cylinder reading (235) and lowest cylinder reading (195) cannot be more than 15% to have a good balance. Based on these numbers #8 is at approximately 17%. I would do a wet cylinder test to verify.

Agree. #8 looks suspect.

[mike100]

My lowest cylinder was more like 205 and the rest were 210 on my gauge (and not cranking it forever to get a peak number). It still sounds like maybe one of the newer injectors went bad because it it runs ok over 4000 rpm, maybe the secondary injector is providing good fueling enough to feel ok on power and smoothness.

I guess there is a small chance the injector driver or wiring to that injector is bad- maybe scope the injector signals or check for a broken wire right at the injector connector. It might be hanging by two or three wire strands with an intermittent contact.

[Jaap]

Hi,

I just don`t understand why and how but the probem is solved and i`m very happy about it.

This aftenoon i changed the new ac spark plugs for the old Bosch super plus sparkplugs. And the LT5 ran inmediately very well and smooth.

When my son and i took it for a test drive it scared us both how fast the zr1 rides. Great fun.

thx for all the help.

Gr Jaap

[XfireZ51]

Hi,

I just don`t understand why and how but the probem is solved and i`m very happy about it.

This aftenoon i changed the new ac spark plugs for the old Bosch super plus sparkplugs. And the LT5 ran inmediately very well and smooth.

When my son and i took it for a test drive it scared us both how fast the zr1 rides. Great fun.

thx for all the help.

Gr Jaap

OMG! If only we knew. Yes the Bosch plugs are crap. We have run into that same issue here.
Or are you saying you re-installed the Bosch plugs?

[Franke]

Jaap, that's good news. My opinion is that you should drive it awhile and then pull the plugs again especially on the 2,4,6,8 cylinders. (Funny how that's the right engine side.) You mentioned that those plugs 2,4,6 showed deteriorated electrodes and in an earlier post you said "When i bought the Z there was a constant white fog behind the car, that`s now gone". Sometimes a white fog is an indication of a coolant leak which you may have fixed. So it may be wise to inspect the plugs after awhile to see if all is well.

[Jaap]

OMG! If only we knew. Yes the Bosch plugs are crap. We have run into that same issue here.
Or are you saying you re-installed the Bosch plugs?

Yes that`s what i`m saying XfireZ51, i reinstalled the Bosch plugs and it runs perfect. (don`t know for how long)

The new AC R41lt SP we installed broke down and i just don`t understand why..
I really would like to know.. but then again i shouldn`t worry about it too much and drive the ZR1:-D

[Paul Workman]

Yes that`s what i`m saying XfireZ51, i reinstalled the Bosch plugs and it runs perfect. (don`t know for how long)

The new AC R41lt SP we installed broke down and i just don`t understand why..
I really would like to know.. but then again i shouldn`t worry about it too much and drive the ZR1:-D

Spark plugs breaking down?? That doesn't sound so good. Here is some information on evaluating spark plugs and heat ranges.

http://www.gnttype.org/techarea/engine/plugs.html

Upon the recommendation of Pete's (a well respected ZR-1 mechanic and racer) I installed the AC Delco 41 602 and have been using that plug for over 6 years with NO problems at all. (And, they cost much less than some more exotic plugs do - less than 1/2 a tank of gasoline; cost is low enough they can be replaced often to keep them always like new.

Also, compression checks should be done with the battery fully charged, and a battery charger connected to keep the battery at full charge between each cylinder test. Otherwise, what might look like low compression on some cylinders might be because the battery is becoming discharged.

I run my compression checks by taking my reading after equal number of compression strokes (5 to 7 compression strokes is usually enough to reach the peak, I find). And, I wait until the charging current from the charger drops down to 3 Amperes or less (fully charged) before testing again. That way I feel if I get a low reading it is NOT due to the battery being discharged.

Glad to hear it is running well. I'd want to keep an eye on those plugs for a while, to be sure there is nothing wrong with them.

[Jitse]

What about if the Catalytic converter is blocked/ damaged on the even bank....., and on the uneven bank not. Abnormal things are going to happen than. Like unstable engine load, more heat, which can damage the engine. He needs to look at his exhaust manifolds.

[XfireZ51]

Yes that`s what i`m saying XfireZ51, i reinstalled the Bosch plugs and it runs perfect. (don`t know for how long)

The new AC R41lt SP we installed broke down and i just don`t understand why..
I really would like to know.. but then again i shouldn`t worry about it too much and drive the ZR1:-D

Jaap,

We've had the opposite experience happen here. Some installed exotic Bosch plugs and developed a miss. Not only on LT-5 but also BMW. AL-ZR1 can tell you about his experience w them. Installed stock plugs and bingo. I run NGK6E plugs on my LT-5 and never think twice about them,

[Paul Workman]

Jaap,

We've had the opposite experience happen here. Some installed exotic Bosch plugs and developed a miss. Not only on LT-5 but also BMW. AL-ZR1 can tell you about his experience w them. Installed stock plugs and bingo. I run NGK6E plugs on my LT-5 and never think twice about them,

Q: Dom, did the plug heat range change with the big cams?

[XfireZ51]

Q: Dom, did the plug heat range change with the big cams?

Paul,

Actually made the change after porting.