1988LXCoupe

Greetings,
I was hoping some of you fine folks could help me out with an issue concerning a 1988 LX Coupe. The car was originally a four-cylinder car, which has been converted to an eight-cylinder car. I purchased the car during the transition period. I have the V8 engine harness in place with the appropriate computer (speed density), but I’m not able to get the car to start. The fuel pump is not turning on when I turn the key on. I have checked both the pump and the relay, both check out fine. Here’s another issue, I can turn the fuel-pump on to pressurize the system, by just adding a jumper wire in place of the fuel pump relay, but I don’t believe the computer or the fuel injectors are working because the engine will turn over, but will not run on its own. I am able to spray carb cleaner in the throttle body and get the engine to fire, still the car will not run on its own. I do have fuel at the fuel rails and I have spark, which is what leads me to believe that my injectors aren’t working and/or the computer isn’t working. At this point, its hit or miss for me, I’ve been checking wiring diagrams and really just racking my brain here and I keep coming up short of success. Any ideas or suggestions would be greatly appreciated!

Thanks!!
Glenn

Daysleepin

When sitting in the car and turning the
key to the on position are you getting an unusual beep or beeps from the cars pc?

If yes, Than there is something electricle from the original V8 body that is needed to be trans planted as well.

I would guess that when the V8 wire harness was installed just about everything plugged in easily with the exception of one or two things .
These exceptions maybe the problem.

joker

Just a bit of info. I have an 88 v8 coupe (original 4 cylinder car) that I converted to fuel injection and have the exact same issue. I have replaced the engine harness, computer, and headlight harness, but have the original dash harness and chassis harness back to the fuel pump. We have also tried a known good computer and verified that the issue is not with the computer.

What year car did your engine harness come out of? Mine was out of a 1990. My next step was going to be to replaced the dash harness. Just because of the fact thtat whoever changed my car to a carbed setup hacked the dash ahrness up and it now has about 20 splices where I put it back together. Is your dash harness all original and not hacked? Hearing you have the exact same problem leads me to believe that mine may not in fact be a problem with a splice but rather a pinout issue.

1988LXCoupe

Sorry I haven't updated the post with my progress. I was able to solve the problem. Ultimately, it was a ground wire for the ECM that was screwing me over. It has a proprietary connector at the negative battery cable that connects to the engine harness. I was using a generic auto parts cable and didn't realize that I was missing the connection. Once I found the issue (after viewing dozens of schematics) I just made a connection to the frame and all was well. Now, my 88 coupe was originally a 4-cyl car that I converted to a V8 car, the dash, body, and trunk wiring are all original to that of the car, the only difference, I purchased an engine control harness for a V8 from an 1988 hatchback from ebay. The harness was a direct plug in to my 4-cyl dash harness (as the dash harnesses are the same, mostly). Now, Ford did change the harnesses in 1989 due to the addition of mass air to the mixture, which changed the pinout on the 60 pin connector going to the computer. If you are going to use the dash harness out of your 88, I would recommend you checking wiring diagrams for the 88 and the 90 engine and dash harnesses, you may have to make wiring modifications to make everything work. Alternatively, you could change the dash harness to that of a 90 model, as well as the body harness (or you change modify the body harness to adapt to the 90 dash harness...then you will run into other problems (like the electric fuel door, which doesn't exist and isn't wired in the 90 models) that you will have to overcome. Ideally, your situation is not that bad, its just going to be a headache in matching up the wiring differences and making the appropriate changes. Let me know if there is anything you need. Feel free to e-mail me: trustyoleblue@gmail.com if you have questions and I'll try to help you out. I spent almost two weeks in troubleshooting my car, not to mention I probably spent a couple hundred bucks for parts that I didn't need, some of which I could return, some I couldn't. Best of luck to you. -Glenn