Jess W

I put the battery back in and went through the motions again. When I shorted the pins for the diagnostics codes, I got the same 12 and 42. Interestingly, when I put the car in accessory, there's a slow clicking coming from under the hood. Trying to locate it, it seems to be coming from an injector. Unplugging the injector seems to make the click only happen once when I put the car in accessory afterwards. No significant changes to any lights or diagnostics thus far.

Alright, we're under the dash checking out the wiring, unplugging, cleaning, and re-plugging plugs as we go. We did find this though, a very thick pink wire with a black stripe that doesn't seem to be plugged in to anything. I've seen a few things in the wiring diagrams saying that the injectors are wired to pink/black wires, but I'm not certain this is the same. I also don't see a slot this can plug into, so I figured I'd ask - Can someone identify this? I'll keep y'all updated as we finish troubleshooting. Edit - sorry about the blur. I should also mention there's a cap that goes on the end of this wire too.

Sorry for the long pause here, but I haven't had a lot of time to work on the car. I unplugged and re-plugged the MAT sensor that was supposedly causing code 23 to flash. That really shouldn't have fixed anything, but code 23 no longer flashes. Instead, we are getting a new error: 42. I believe that means something is wrong with the ICM, but my guide isn't very specific on what this means. Any thoughts? The same issue is happening - engine runs rough for a second or two and stalls.

Here's an update on what we're checking. I've read the pressure at the test port and it's exactly 40psi, and its 45psi when the fuel pump is active, so it seems this is fine. I've checked the codes and it's showing us two: 12 (just telling me we're in diagnostic mode) and 23. 23 looks like it could be a number of things: MAT sensor voltage issue, throttle position sensor problem, mixture control solenoid is shorted or open, or the air intake temperature sensor is low. It would make sense that the mixture control is off, considering it runs rough and won't idle. I don't know where that is or how to check it however.

Responding to 60FlatTop - I'll definitely have to invest in an ALDL reader, thanks for pointing me in that direction. This car will probably have every error code in the book, but I'm determined to get it running. And about the MAF sensor - after removing it and trying to run it again, it seemed to do the same thing either way. It may be faulty, so I'll look for another one if only for peace of mind.

Thanks for the reply! The "Service Engine Soon" light is on, yes. I believe I know how to read diagnostic codes via the touchscreen climate menu, but there's one problem: I can't navigate to any other screen but the radio. I've managed to open the climate screen for a split second by pressing the button as I turned the key, but it switched back to radio instantly. So... not sure how to overcome that part. I don't know what the exact fuel pressure is but I will be testing that soon with a gauge - I'll get back to you on what that reads. The vacuum leak came from the vacuum manifold on the top of the engine. Of the four lines connected to it, the small one facing the rear of the car was severed (the plastic nozzle had broken off in the rubber hose) and has since been reattached. It's entirely possible that another one has sprung somewhere considering the age and brittleness of the vacuum lines. I'll look for the PCV line and check if there's a problem there too. The error message that said "electrical problem" was a light on the IPC. Since I can't read engine codes from the CRT, I don't know what issue it found. I've heard there may be a way to read codes from the ALDL port, but I'm not sure how.

I've been doing a lot of work on my '89 coupe recently, and getting it to start has been a pain. The engine will crank and start running a but rough for about two seconds before sputtering out. We know there's fuel pressure at the engine, the compression is good, the air flow should be fine, and there are no vacuum leaks anymore to the best of my knowledge. The engine was able to idle smoothly just one time for about 20 seconds the other day - then it eventually died again, and a new light on the dash came on saying 'electrical problem'. That was also the first time I've ever seen any part of the IPC come on, and that light is persisting. I have no idea what other problem this engine could have, especially considering it worked just fine once. After that one time it blew a vacuum leak again but I fixed that again immediately. Hasn't idled for more than 2 seconds since. Thoughts?

Alright, so this isn't entirely over. Tried powering the fuel pump using the green test connector and it started priming there as well (and sprayed fuel everywhere... no matter how tight we get the connection from the fuel hose to the tank, it seems to leak). The weird part here is that when I put the car into accessory or try to turn the engine over, the fuel pump won't prime then. No pressure builds and the pump won't start unless we use the green test connector. What kind of problem could this indicate? I'm fairly certain that the relay should be fine, but I'll try swapping that too.

Here's an update: I followed Barney's advice and after quite a bit of head scratching, I was able to figure out why power wasn't getting sent. The ground for both the fuel pump inside the tank and the connector outside the tank had gone bad. The wires are just crimped directly onto the metal casing, and both crimps had rusted and corroded to the point that neither of them were conductive. After finding that every other surface worked as ground, I soldered on new connections, applied heatshrink, and tested 12V from the battery again - the fuel pump primed! Now to get the fuel tank back in... my least favorite part.

Alright, we found the connector and sent power from the battery to it, and nothing happened. Might there be more than one of these connectors in here? The one we found is on the driver's side close to the brake master cylinder.

Will do, thank you for the quick response. I saw something similar to this on another post, but we're having trouble finding this green connector. Where under the hood is this located?

I am a new owner of an '89 coupe and I've just replaced the fuel pump. The engine cranks, but will not start. The pump doesn't seem to be priming, and the schrader valve doesn't have any pressure or gas in it. When the battery is plugged in, the park lamps are always on and I cannot turn them off - the security light on the dash also flashes and only the blower motor comes on when I put the car in accessory (not sure if this is relevant, but it could be possible that some anti-theft system is preventing my fuel pump from starting). I've checked the relay for it, and I'm not hearing it click when I turn the car to accessory or to crank it. I've tried swapping in another relay that I'm fairly sure works, and still no click. The tank has 4 gallons of gas that I just put in it, so I doubt it's a problem of the fuel pump not touching fuel. I can't seem to hear the fuel pump making any noise either. I thought we would hear a hum or something when it primes, but all I'm getting is silence. I'm completely out of ideas on why fuel isn't getting sent to the engine / the fuel pump is not doing anything. Is this a known problem? I know the fuel pump is a common part to fail on this car, but considering I just replaced it and all electrical connections / harnesses are new and should work, I don't know what the problem from here could be. Any guidance to help me get this car moving would be greatly appreciated!