C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

1990 Stalling, MIL Flashing

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Old Apr 22, 2017 | 03:01 PM
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Default 1990 Stalling, MIL Flashing

My father-in-law is considering buying a 1990. Car is really clean, obviously well cared for, about 85,000 miles. Seller has only owned the car about a month.


FIL took the car for a test drive. It started and idles fine. Ambient temp about 90 degrees F. About 15 minutes into the test drive, the car stalled multiple times. He had to restart it several times to limp it back. Malfunction Indicator Lamp (MIL, SES) was flashing, indicating potential for serious engine damage if car continues to be driven.


FIL lives a couple thousand miles away, so I can only diagnose over the phone. He likes the car well enough, and price is good enough, he is considering buying the car as is.


Any suggestions as to cases and solutions. I know that with the car in front of you, it is difficult to diagnose.


It sounds like a fuel system problem to me - fuel pump, filter or injectors. I have read here on the forum that the Multec injectors are problematic, and the solution is rebuilt Bosch injectors.


What should he expect to pay for parts and labor to install rebuilt injectors?


Are fuel pumps prone to failure? What should he expect to pay to have the fuel pump replaced?


Just trying to get an idea of what repairs could cost.


Also, does anyone have a pocket guide on how to read codes, shorting the ALDL to flash codes on the MIL? Which terminals to short, and how to count the flashes?


Thanks
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Old Apr 22, 2017 | 05:33 PM
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Since the SES light it flashing, a quick diagnostic check will pin point the problem. Have him do the "paper clip" jump test on the ALDL ports A and G and that will engage the CCM.

From there, he will have a pretty good idea on what faults the car is throwing prior to purchase.

Or, he can low ball the guy with a known problem, go home, jump the terminals and fix it himself.

Either way someone will have to run the diagnostic.
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Old Apr 22, 2017 | 05:54 PM
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MIL? Malfunctioning Indicator Light or Mother In Law? Coincidence?

Any reason why he doesn't want to take it to a dealership for a PDI?

Without testing, it is hard to say that the pump is failed. Injectors are a different story. Multecs are garbage so it is about $200 for a "rebuilt" set and whatever they charge for labor.

Without proper testing, I'd say replace everything from "stem to stern" if you want to be sure. Obviously that is cost prohibitive so get a mechanic with the proper tools to do a PDI that consists of identifying the problem, check trans, check rear end, brake flush, etc, etc.
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Old Apr 22, 2017 | 09:23 PM
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Pics of mother-in-law flashing?
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Old Apr 22, 2017 | 09:29 PM
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Originally Posted by Railroadman
Pics of mother-in-law flashing?
That was my first thought but I didn't know how good the relationship was.
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Old Apr 23, 2017 | 08:45 AM
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Originally Posted by aklim
That was my first thought but I didn't know how good the relationship was.
I've spent too much time in Off Topic. ANY mention of a wife, GF, female neighbor, female sales clerk or great-great-grandmother brings forth a demand for pics! In this case the title was just too much of a set-up to resist!
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Old Apr 23, 2017 | 09:25 AM
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If the car has only been owned for a month & is being sold there are probably other issues.

Injection is "batch fire" = non sequential, if one injector shorts the rest may not work.
Injector issues normally begin as engine temps rise. Miss fire, stalling, hot engine will not restart but will start after cool down.
Have the Bosch 3's in my 90 am pleased with them.

Air bag: SIR is one year only no parts are available. Red INFL light should appear at start up then go out. If INFL does not go out there is a SIR issue or if INFL does not illuminate
the bulb has burned out or has been removed = air bag inoperative.

RPO codes are under the center console lid its a coded list of everything on the vehicle.
J55 = 13" front brake rotors = HD brakes, standard front rotor size is 12"
Z51 = handling package
RPO code list is available on line.

Jump terminals A & B in the ALDL to read stored CEL (your MIL) codes.
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Old Apr 23, 2017 | 09:38 AM
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Originally Posted by Railroadman
I've spent too much time in Off Topic. ANY mention of a wife, GF, female neighbor, female sales clerk or great-great-grandmother brings forth a demand for pics! In this case the title was just too much of a set-up to resist!
For Great-great-grandmother, would she still be alive? IF not, flashing for a corpse? Pass.
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Old May 3, 2017 | 03:07 PM
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Originally Posted by aklim
MIL? Malfunctioning Indicator Light or Mother In Law? Coincidence?

Any reason why he doesn't want to take it to a dealership for a PDI?

Without testing, it is hard to say that the pump is failed. Injectors are a different story. Multecs are garbage so it is about $200 for a "rebuilt" set and whatever they charge for labor.

Without proper testing, I'd say replace everything from "stem to stern" if you want to be sure. Obviously that is cost prohibitive so get a mechanic with the proper tools to do a PDI that consists of identifying the problem, check trans, check rear end, brake flush, etc, etc.

Thanks for the info on the injectors. It confirms what I had read elsewhere.
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Old May 3, 2017 | 03:14 PM
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Originally Posted by Churchkey
If the car has only been owned for a month & is being sold there are probably other issues.

Injection is "batch fire" = non sequential, if one injector shorts the rest may not work.
Injector issues normally begin as engine temps rise. Miss fire, stalling, hot engine will not restart but will start after cool down.
Have the Bosch 3's in my 90 am pleased with them.

Air bag: SIR is one year only no parts are available. Red INFL light should appear at start up then go out. If INFL does not go out there is a SIR issue or if INFL does not illuminate
the bulb has burned out or has been removed = air bag inoperative.

RPO codes are under the center console lid its a coded list of everything on the vehicle.
J55 = 13" front brake rotors = HD brakes, standard front rotor size is 12"
Z51 = handling package
RPO code list is available on line.

Jump terminals A & B in the ALDL to read stored CEL (your MIL) codes.

Thanks for the info on the injectors. I either didn't know or didn't remember that they were batch fire. Sequential was introduced with the LT1 I assume?


And thanks for the info on the SIR. I wasn't aware that parts are not available. Do you know what year C4 to buy that does not come with unobtainium systems? As cheap as the C4's are, I am considering buying a coupe for a track day car. My '93 convertible is not really suitable.
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Old May 3, 2017 | 03:24 PM
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SO here is the rest of the story. We weren't about to start throwing parts at the car hoping to fix it. In one of my careers, I did vehicle troubleshooting, so I know the downside of that (it must be the computer, let's change that).


I was trying to determine if what the specific issues to be concerned about. Injectors? No. Relatively inexpensive. SIR? Whole 'nother story.


Anyway, the seller took the car to O'Reilly's. They read the code and diagnosed it as IAC valve. Seller bought and installed an IAC, and fixed the problem.


Father-In-Law bought the car at a very reasonable price, below market actually.


Thanks for the help.
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Old May 3, 2017 | 03:40 PM
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Originally Posted by Procrastinateur
Thanks for the info on the injectors. I either didn't know or didn't remember that they were batch fire. Sequential was introduced with the LT1 I assume?


And thanks for the info on the SIR. I wasn't aware that parts are not available. Do you know what year C4 to buy that does not come with unobtainium systems? As cheap as the C4's are, I am considering buying a coupe for a track day car. My '93 convertible is not really suitable.
I have a 91 and the ABS sensors, regardless of what others say, I can't get. The front has to come with the hub and the rear is obtainable from NAPA as far as an entry in the system goes. We checked and there no availability.
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