Cranks, no fuel pump, relay is good!

jrichker · Mar 15, 2006

The key element here is that there is no power on either
side of the inertia switch. It should have 12 volts on at
least one side. That means the EEC power relay is not
suppling power to the computer or fuel pump circuits.
There is either a blown fuse link in the EEC power circuit or
the EEC relay has failed.

See the following website for some help from Tmoss
(diagram designer) & Stang&2Birds (website host) for
help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Diagram courtesy of Tmoss & Stang&2birds

Saleen0679 · Mar 15, 2006

DNeinstadt said:
Will do, otherwise I'll have to make my own ground from the pin 22 from the ECM to chassis and test the EEC 12v switched, but what if that's not going? Put it with a relay to ignition switched 12v??

Testing the EEC switched 12v is where I'm leaning. Since you don't have 12v at one side of the inertia switch the EEC relay is either not energizing or you have a faulty connector or splice.

Edit: Looks like JR beat me to it.

tragikcomic · Mar 15, 2006

I know the last 2 guys said this, but this is the exact same Gremlin that I had to track down on my buddies 88. I went through all of this, and found that the EEC relay had gone bad. We picked up a new one at the zone, and it fired right up. Good luck to you.

DNeinstadt · Mar 15, 2006

Ok, I can't seem to get my fat butt to the EEC relay, I pulled the speaker panel and glovebox and it's a tight squeeze in there but I tried to get to it.. I checked via Hissin50's post and I get no power to the WOT red wire either, so now I suspect power to the EEC is bad.

Then I go under the hood. I follow the wiring diagram I downloaded earlier in the week, and decide to check the dark blue fuse link. Seems "rubbery", like there's no wire inside. OK so the dark blue fuseable link looks bad. I cut it out of the harness, it matches up with an orange/black wire. I cut the fuse link away and temporarily jumpered it over to the solonoid stud. I get sparks, melting wire, and smoke immediately.

I'm guessing I'm not getting a good ground somewhere. Do you still think the EEC relay is still the issue?

Help?

Dan

DNeinstadt · Mar 15, 2006

JR - those are the same diagrams I printed out Sunday night in color to troubleshoot... been staring at those things for hours already..

Dan

HISSIN50 · Mar 15, 2006

Dan, I'm no JR or Saleen, but it sounds like a short-to-ground in the power feed wire (Or/Blk) from solenoid to the the EEC relay.

Wait for others to comment in case I'm way off target.

DNeinstadt · Mar 15, 2006

Well, here's a little more confession, as I just found a thread re: injector wiring trapped under intake after VC swap. That's what I was doing under the hood that day..

I'm going to check injector harnesses and any wiring that may have gotten trapped under the intake...

Obviously there's a short somewhere...

Dan

DNeinstadt · Mar 16, 2006

EXACTLY WHAT IT WAS!!! Red wire trapped under intake!!!

Removed, reconnected red wire that was smashed, hooked up orange/black to stud and "grounded the test" plug and the car starts and runs!!!

OK. Now, since I'm still not getting a ground from the ECM unless I jumper the test port, does that mean I have a bad ECM ground or is it still something else?

Dan

Saleen0679 · Mar 16, 2006

I didn't think you would have anything at the WOT relay since you didn't have anything at the inertia switch. I'm betting that anything connected to the output of the EEC relay and the splice won't have any power either.

I think Hissin is on track with the BK/O short. I would check both paths for that wire from the solenoid to the EEC relay and from the EEC relay to the computer.

If you can manage to remove the EEC relay it would be easy enough to check out of circuit. Just connect a 9v battery across the coil and listen for the relay to energize and verify contact closure with a meter. With the relay out it would also be an ideal time to see if there is a problem with the relay socket or other wiring in that area.

Edit: I guess I'm a little late.

Saleen0679 · Mar 16, 2006

DNeinstadt said:
OK. Now, since I'm still not getting a ground from the ECM unless I jumper the test port, does that mean I have a bad ECM ground or is it still something else?

Dan

Have you checked the T/LG wire at the EEC module itself for a good connection?

BTW, major thumbs up for finding the crushed wiring.

DNeinstadt · Mar 16, 2006

I will check that wire there, but I suspect it was a fuel pump wiring cutoff that was part of the alarm that was installed in the car. So now all I have to do is run a wire from the T/LG wire from the EEC to the FP relay and I'm set??

Dan

Saleen0679 · Mar 16, 2006

Since grounding the test connector works you know that there is continuity from the test connector to the fuel pump. Also check for continuity from the test connector to the EEC while you're inspecting the connection at the EEC. That should tell you if the path has been cut.

DNeinstadt · Mar 16, 2006

I'm sure it has, that's why my FP doesn't come on with key but will work with grounding the test plug.

I can run diagnostics so I imagine that works, but the ground from computer to ANYTHING doesn't seem to work. I suspect it was cut for the alarm system re-wiring, which I plan to fix.

I'm looking for the tan/gr wire as a EEC switched ground correct?

Saleen0679 · Mar 16, 2006

Yeah, I'm just trying to verify everything. If you don't have continuity from the test connector to the computer then the circuit has definitely been cut.

Referencing JRichker's post you're looking at the T/G wire going from the test connector to pin 22 on the computer. You've already verified the other half. Don't forget to check that pin if you don't find anything else obvious beforehand.

DNeinstadt · Mar 16, 2006

You got it, I'll try tonight when I get home from work, will update you guys. I suspect somewhere from the EEC pin 22 to the fp relay is cut due to the alarm system that was put in at the time. I may just splice in at the EEC (after testing of course) and run a wire up and over to the FP relay to complete the circuit. IF that's the problem.

Thanks guys, I'll update this thread and post the resolution so it can be searched later!

Dan

DNeinstadt · Mar 20, 2006

Going to fix it up tonight. Had a long weekend working on someone else's car!

Hopefully I can update/close this thread tonight!!

Thanks in advance for all your help guys!
Dan

DNeinstadt · Mar 21, 2006

OK, I tapped into the computer "ground" wire and got nothing to the FP. I swapped over a buddy's '89 4 cyl computer and the FP turns on (normally). Guess I'm in the search for an EEC too!

Dan

HISSIN50 · Mar 22, 2006

DNeinstadt said:
OK, I tapped into the computer "ground" wire and got nothing to the FP. I swapped over a buddy's '89 4 cyl computer and the FP turns on (normally). Guess I'm in the search for an EEC too!

Dan

Dan, if you dont have a FP ground pulse from the puter, it sounds like the ground strap thing-a-majig is at fault inside the puter. Talk with Saleen, JRichker, TMoss, et al about fixing it on your existing puter (if you are handy with opening a puter and playing with that stuff).

I would end up probably running an external ground a different way, but I would not recommend it.

Good luck.

Cranks, no fuel pump, relay is good!

jrichker

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