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1988 Mustang 5.0 No spark or fuel

6854 Views 30 Replies 5 Participants Last post by  Paul in LKY
Hey, everyone. I have an 88 Mustang 5.0 5 speed. It's my daily driver and it's still speed density. Today it cut out on me while driving and when I started checking things, I found that the fuel pump wasn't priming. I checked the inertia switch and it wasn't popped, however there was no voltage going to it. I jumped the relay for the fuel pump and got the fuel pump priming, but it still only cranked. I checked for spark and there is nothing. Tomorrow, I'm going to pull some codes after work. Does anybody have any idea where to look? I'm thinking it could be the ECU or Ignition Controle Module. Thanks in advance!
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I think your guesses are good places to start. If it is your ECU I had good luck with Ecuexchange on Ebay.
So I attempted to pull the codes, but could not get the light to blink. Maybe I'm doing something wrong, but I cannot get it to work. Also, there are only three wires going to my diagnostic port. Anyway, I found a guide to test the Ignition Control Module. Part 2 -Ford Ignition Module Test. Distributor Mounted Module (ICM). Using that guide, I verified that I have power and ground. However, in Test 3, the test light should blink when the engine is cranked. Mine was a solid light. I moved on to Test 4 and when the engine was cranked there was no light at all. That being said, should I replace the whole distributor and ICM or do some more tests? Any advice would be great. Thanks.
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http://forums.stangnet.com/attachment.php?attachmentid=58312&stc=1&d=1242744354

Your diagnostic port should have four wires going to it, at least mine does with two wires going into the fuel pump test wire (tan/green).

It seems like a strange coincidence both your fuel pump gets no power and your pick up isn't firing at the same time. Although, according to that test, it should have light but not pulse if the pick up were bad. So, it may be premature to replace the distributor yet. It sounds like there may be an underlying problem. Anyone you can trade computers with to see if that clears things up before you invest in one yourself, or start arbitrarily replacing things?
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Make sure the computer is powered up first. Turn key on, and check for 5v between the TPS orange and black wires.
check your TFI Module mounted on the side of the distributor, change it out
or the fuel pump relay under your driver seat
89coupe, that was some excellent advice. I checked for voltage between those two wires and got .02 volts with the key in the on position. But now what? Here's the list of what I know:

12V to coil
12V to Ignition Control Module at distributor
Ignition Control Module is getting ground
Only .02V between the orange and black wire at the TPS, not 5V.
No power to inertia switch
Fuel pump will only run if the relay is jumped
During Test 3 of the link posted, my test light was solid, and not blinking on and off the way it should.
During Test 4, the test light did not light up at all.

I do have another ECU and everything needed for a mass air conversion. I feel that if that's not to the solution to the problem, it may make things even more confusing. Thanks again for all your help, everybody.
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Also, I haven't checked the ignition switch for voltage yet. I took a picture because it appears there is a wire missing from the bottom right port. Is that supposed to be like that? Also, does anybody know how to check the switch? Auto part Vehicle Automotive wheel system Wheel Automotive exterior
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It would take a few minutes to swap out ECUs. Why not rule that out?
I only have a mass air ECU laying around and my car is speed density. I've been trying to find someone willing to let me swap ECUs, but I don't know anyone around here with a foxbody.
Since the fuel pump runs when jumped, I'm going to assume you have 12v at the injectors? But check anyways first. 12v there, let's you know the ECM relay is working. See what you find.

Need to check all the ECM power and grounds before you throw any money at. You may not have to spend a dime!
So I attempted to pull the codes, but could not get the light to blink. Maybe I'm doing something wrong, but I cannot get it to work. Also, there are only three wires going to my diagnostic port. Anyway, I found a guide to test the Ignition Control Module. Part 2 -Ford Ignition Module Test. Distributor Mounted Module (ICM). Using that guide, I verified that I have power and ground. However, in Test 3, the test light should blink when the engine is cranked. Mine was a solid light. I moved on to Test 4 and when the engine was cranked there was no light at all. That being said, should I replace the whole distributor and ICM or do some more tests? Any advice would be great. Thanks.
If you cannot get the test light to blink during the code test then thats a good sign the ecu is toast. But then again check the ecu relay by the ecu. Also check the ecu ground under the carpet up along the firewall area.
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Tomorrow morning I'll check to see if I have 12V at the injectors and get back to you. On the note of the ECU, is the relay underneath the kick panel with the ECU? And I'm guessing the ground is in that general area as well.
ECM ground is not beside the ECM. That's a case ground. The ECM ground is beside the battery. Mounted to the inner fender well. Black wire, green stripe usually. Has a black connector on it, and its round.
I checked the injectors and there is no voltage going to them. Also, the ground next to the battery is fine. MY buddy was swearing up and down it's the ignition switch, so I went ahead and changed it, but no luck. Now, I've got the kick panel off so I can see the relay, I just need to know how to test it. Thanks again for all the help.

Edit: I checked the ECU relay connector with a test light and I do have power in two ports.
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With key on, you should have power on 3 ports. Can you get me the wire colors that have power, and list the colors that dont?
MY buddy was swearing up and down it's the ignition switch, so I went ahead and changed it, but no luck.
Lol...your buddy owes you for one ignition switch :winks
I'll get the colors as soon as I get home from work. So is it looking like a fusible link went?
Its a possibility. I can give you a better answer once you have the colors and voltages. But if you have 2 with power, then it sounds like a ground issue, or a bad ecm relay. :bigthumbsup
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