Can anyone tell me what the stock injectors are in an 88 Cougar? Are they 19's? I have converted my son's mustang to mass air and it will barely run. The car was originally a 2.3 L and it was converted two years ago with an 88 Cougar 5.0.
I just installed the mass air meter, computer and harness. It still has the stock throttle body and injectors form the Cougar.
Car also seems to start with a fairly high RPM and then comes down to
500 and of course stalls shortly there after. It doesn't seem to idle at all. I have also noticed some light backfires into the TB.
You took the wiring harness off of a 90 something with an A9L computer. This would almost definately be a Mustang 5.0 H.O. computer and wiring harness.
You put that harness onto an '88 Cougar engine and EFI system. If I remember correctly... and I could be *way* off base here... the 1988 Cougar
5.0 engine was *not* an H.O. I have a parts '88 Cougar 5.0 and I'm pretty sure it's just a standard (non H.O.) 5-liter. If this is in fact true, and you tried to put a computer on that was set up for an H.O., you would most likely have problems.
H.O. engines have a different firing order... 1-3-7-2-6-5-4-8 by memory. The non-H.O. starts out 1-5. The problem here is that the injectors are supposed to be fired when the intake port is giong to be open and drawing air in. If your cam is a non-H.O. grind, you will be spraying fuel onto a closed valve on the power stroke. You won't get a proper air and fuel mixture.... you could get some backfiring out of the throttle body perhaps due to a bit of ponding of fuel. Considering that you used the entire harness from the '90, that would take care of the thermactor wiring change that was needed, the speed sensor wiring addition, and the fuel pump relay monitor #2 wiring addition. The car ran and idled before, so I'd rule out EGR + IAC at least for preliminary. I'd start with the things you changed.
Again, I'm not a mechanic. I've read a book on fuel injection (specifically the EEC-IV system that you're running but it also covers fuel injection theory) but that's about it. It makes sense to me though. I'm pretty sure the injectors are timed with the valvetrain to spray gas only when needed. Some cars have crank sensors, I believe the TFI module takes care of that on these cars, but I'm not sure.
How would I proceed? First thing I'd do, scan the codes to see what the computer is trying to tell you. Perhaps you missed a plug... or a wire in the harness is broken. If that doesn't lead you anywhere, I'd check the MAF to ensure that it seems to be working properly. Voltage changing for more air coming in... which is hard if the car won't stay running, but you can at least ensure that it's varying.
You've removed the vacuum line from the MAP sensor, correct? The car will not run correctly with the vacuum hooked up to the MAP sensor anymore. This was the way it was on speed density cars, but on mass air systems, it needs to measure the ambient air pressure.
After all of that, perhaps you could try test wires to swap the injector order. Obviously there isn't enough wire in the harness to put the #3 injector plug to the #5 injector, so you'll have to improvise, but I'd try to transpose the injector firing order to trick the computer into thinking it's running an H.O. engine when really it isn't.
Or you could find a computer set up for a mass air non-H.O. and try it, but that might cost a bunch more.
what car did you get the wiring harness from? if the wiring harness is from an H.O motor & the motor is not an H.O then the firing order is diferent & it will not run correct
Here is a quote from the cool cats website.This may answer your question.
For Converted or Transplanted 5.0 HO Cougars
This section is for converted or transplanted 1987-88 HO 5.0 motors ONLY. It is not intended for the stock Cougar/Thunderbird 5.0 motor. Any attempt to convert a stock non-HO motor to mass air can result in serious damage to the engine
Crap knew that I'd forget something important. I have an HO cam in it. It has the 1-3 firing order now. The only thing that is original on this car is the lifters, rocker arms, crank and rods.
Here's everything.
Bored 30 over HO intake but stoke Throttle body (I just haven't changed it yet) HO cam E7TE heads
90 Harness
90 Mass Flow meter
The motor was run with the stock Cougar intake, harness (speed density, cam and heads for 2 years, but it ran really rich and had poor fuel milage (IMO).
Bob I haven't read the CoolCats site as of yet but........
Then my next suggestion would be oxygen sensors, perhaps the MAP sensor that I'd mentioned earlier, etc.
If you changed the cam and the computer all at the same time, cam timing could be off, ignition timing could be off, etc, causing severe running issues and backfires as well.
What was the sequence of events since the last time it ran good?
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