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ECM is more of a possibility than the CCM.. but before you go there.
Are the injectors new? if not:
Have you ohmed out all the injectors?
With the plenum off have you turned key on to check for any leaks form injectors?
I replaced all of the injectors last year with Accel. There are no leaks. The car was running perfect until this happened. Mark called me back this morning. I'm going to ship the ECM to him this week for testing and probing. I'll try disconnecting the battery to reset the ecm tonight and try and start it again.
What are fuel injector relays? Never heard of such a thing.
You have a primary and secondary fuel injector relay. On the 91, the secondary is mounted to the drivers wheel well, under the ECM. The primary injector is located behind the battery, tucked into the door hinge area with the rest of the wires. Both are black, about the size of a deck of cards. I think only your primary injectors fire when starting, but I could be wrong. I don't know if you can swap one for the other to see if it makes a difference.
Are you following the field service manual procedures for a no start?
You have a primary and secondary fuel injector relay. On the 91, the secondary is mounted to the drivers wheel well, under the ECM. The primary injector is located behind the battery, tucked into the door hinge area with the rest of the wires. Both are black, about the size of a deck of cards. I think only your primary injectors fire when starting, but I could be wrong. I don't know if you can swap one for the other to see if it makes a difference.
Are you following the field service manual procedures for a no start?
i can't find any fuel injector relay parts online. Just fuel pump relays. I'll look around the car where you're saying to see if anything is there. As for the service manual, yes, I've been following the procedure... posting on the forum and calling Hailbeck.
In all seriousness, I've run all the test I can find and that have been suggested by the brain trust here.
Haibeck said I've tested everything he would do. He is going to test the ECM. That CCM info I posted says that it won't report ABS and some other traction errors on 90-91 dashes. So maybe there is an ABS error I can't see? Maybe one of the accel injectors went bad causing an error? But these cars still run with the injectors failing.
Last edited by darklordftt; 07-03-2018 at 09:13 PM.
If misinformation bugs you why did you post a scematic from a LT1 F body? Haha
Originally Posted by Tom400CFI
Ah haaa. That's what I thought. No such thing as "injector relays". Power goes ignition if mis switch,>fuse>injector>ECM>ground....just like "regular" cars.
Yeeaaahhhh......IDK about that. You should be able to drive the car w/an air bag issue. I could be wrong, but I don't think those things will prevent it from running. You should be able to see codes related to that through your DIC and/or C68, if they exist.
Based on my personal experience the car would not start with the AIRBAG fuse removed. Makes sense to
me. Airbag blown as the result of a collision,best solution make car inop.
Ah haaa. That's what I thought. No such thing as "injector relays".
Misinformation is frustrating.
They are secondary injector relays. That's what they are called in the service manual. Page 6E3-A-6 (vin J). However, as corrected above, these are for the secondary injectors (not 1 for primary as I stated earlier) and should not effect starting.
So of the Chart A-3 steps (page 6E3-A-23), 4 pages, which step are you on?
If misinformation bugs you why did you post a scematic from a LT1 F body? Haha
Because they all operate the same, fundamentally and that schematic was readily available to me. I could have pulled an LT5 schematic from MItchell, but that is a PITA and it would only make the same point; power for the injectors comes from ignition>fuse>injector and is grounded through the ECM. LT5, LT1, L98, L83....doesn't matter.
How about you post a schematic of the LT5 and show us those injector relays that might be causing the OP's no-start? Otherwise, you're just confusing the OP with made-up gobbldy-gook that don't exist and don't apply to his issue. Right?
How about you post a schematic of the LT5 and show us those injector relays that might be causing the OP's no-start? Otherwise, you're just confusing the OP with made-up gobbldy-gook that don't exist and don't apply to his issue. Right? .
I was mistaken in my initial thought that there is a primary and secondary injector relays. The fuel injectors relays are for the secondary injectors only. Your argument that there are "no" injector relays is FALSE. I referenced the page where you can see them, a picture was posted of them. As stated however, these would not be expected to cause a no start.
So, moving on to the OP, what steps are you on using the cranks but will not start trouble shooting steps in the service manual?
I was mistaken in my initial thought that there is a primary and secondary injector relays. The fuel injectors relays are for the secondary injectors only. Your argument that there are "no" injector relays is FALSE. I referenced the page where you can see them, a picture was posted of them. As stated however, these would not be expected to cause a no start.
So, moving on to the OP, what steps are you on using the cranks but will not start trouble shooting steps in the service manual?
I don't have a service manual. I sent the ecm in for testing. I've verified everything is working except the injectors. They were replaced with accel ones last year.
I was mistaken in my initial thought that there is a primary and secondary injector relays.
Copy that.
Originally Posted by Aaron71771
The fuel injectors relays are for the secondary injectors only. Your argument that there are "no" injector relays is FALSE.
Copy that too. Looks like both of us learned a thing, today.
Now let's try to help the OP with accurate info, get this thing started. I'll see if I can find a diagnostic flow chart on Mitchell that I can screen shot....
Unfortunately Mitchell doesn't have squat on the LT5. Every thing is for "VIN P". IDK why they even give you the option to select VIN J....then they give you flow charts, procedures and diagrams for LT1 engines only. Irritating. Sorry I can't add something further here.
Marc called me back. The ecm would not start a stock 91zr1 he had at the shop. Also, the place he used to fix ecms recently lost the ability to repair them. Marc just happened to be talking with someone about setting himself up to repair ecms. He said if it goes good, he might be able to start fixing them in a few weeks, otherwise it wouldn't be until the fall.
Well, at least l know what the issue is now. Thanks for all the debugging help bros. I hope this thread can help others in the future. I'll follow up with more info when I hear back from Marc on the repair situation. I think the odds of finding a replacement ecm are slim to none and $$$$.
Last edited by darklordftt; 07-09-2018 at 06:25 PM.
07-03-2018, 01:16 PM
I highly doubt that a failing injector would, either, on a sequential injection car.
