OK, I've had this horrible hesitation problem that happens intermittantly at all sorts of odd times and there is no rhyme or reason to it. I think I made progress though.... I ran all of wiring in the engine bay under the fenderwells recently and thats when this problem happened. Well I just looked under the pass fender and saw a relay dangling there banging against my wheel because I was apparantly too lazy to mount it correctly. I looked at it and the wires at the harness are all corroded and some are bare. Well I tucked it up where the wires were probably grounding to the chassy and took it for a spin. Man, my problem was 100 times worse all of a sudden! The car jerks and surges like crazy and revs up and down radically at idle. I found out the relay in question is the WOT relay. So I cut it off and reran the wires directly to the relay since the harness is junk. No change. My buddy did some checking and found out that in ex-aod cars you cant use a 5-speed computer because if there is 12v at pin 30 on the ecu harness then it will fry yer puter. Well my car is an ex-aod car and i threw a 5speed puter in it at the same time as when i reran the wires under my fenders. I havent had time to check for 12v at pin 30 yet. So, do you guys think my puter is fried, or maybe just the wot relay is bad, or something else in that circuit?? Please help.
ecu wiring gurus in here plz!
- Thread starter slick88GT
- Start date
The WOT relay is for the A/C. It turns the compressor off for 5-10 seconds when the throttle goes wide open.
And your buddy is right. A 5 speed computer will be damaged in an AOD car.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif
And your buddy is right. A 5 speed computer will be damaged in an AOD car.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif
Thanks for the info. I already have those diagrams and have spent A LOT of time looking them over to try and figure this out. I'm thinking that if that relay is for a/c only then it should have no effect on anything else. But, it seems to share power with other things and when I screwed with it my symptoms instantly became 100 times worse. I'm, kind of at a loss because from those diagrams the only thing I can think to do is replace that relay and throw in an aod computer. Anyone else have some thoughts on this?
86Cobra
Founding Member
jrichker said:
Can you explain why? I'm pretty familiar with 5.0 efi wiring and I don't see anything that would cause this. I ran a 5-speed EEC (X3Z) in an AOD car with no problems a few years ago.
86Cobra said:
I'm not familar with the X32 computer, so you may be correct about it. From what I know about the A9L, it isn't supposed to be compatible with auto trans cars. The voltage on pin 30 is different in an A9L from an A9P. I have personally used an A9P auto trans computer in a 5 speed car with no problems.
Hook a voltmeter up to the red wire on the WOT relay, it should be 12v. If it is, wiggle the harnesses and make sure it doesn't fluctuate. It may also be a good idea to do the same for all of the "legs" on that circuit. If you don't find anything that way do a voltage drop test on all of the "legs."
Have you checked for codes??
Have you checked for codes??
86Cobra
Founding Member
jrichker said:
The X3Z is basically the same EEC as the A9L just with different tuning. If anything it would be even more manual trans specific since it was the 93 Cobra EEC.
In my experience, this is just another internet rumor. Pin 30 goes to the neutral safety switch on autos and the clutch switch on manuals.
OK, I realized that at the same time I screwed with the wot relay, I replaced the tps. Well I checked it and it was at like 1.25 volts and I couldnt make it lower, so I bought a new one and now it doesnt surge and it idles fine, but I still have the hesitation problem where it bogs down for a few seconds then regains power. Codes are just the ones for the smog control junk (i took it all out) and I checked power and stuff at the wot relay and all is good. Anyone know of what sensors or anything would cause a very bad hesitation where it seems like I just lost 4 cylinders and then it kicks back in? It does this all the time, sometimes it wont regain full power unless I shift gears and ease into it. I'm still speed density by the way.
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