Electrical 93 5.0 No Injector Pulse

[machinermac]

Just picked up a 93 5.0 because the seller was not a car guy and just wanted to drive it. I have run down as far as I understand the fuel system pulled the intake and checked fro 12v at each injector all good did continuity test from each injector ground back to the ecu plug all test good. None of the injector wires will flash a noid light. If I have the intake on and shoot starting fluid at it it does run (not perfectly) so I do have spark and timing seems right.

The next previous owner did some mods like a cam and suspension/frame stabilizers but the ECU and fuel look mostly stock. Looking for some direction on where to look to next before I start talking about a new ECU or just installing a standalone.

 

[Noobz347]

Pull codes:

OBD1 readers are cheap on Amazon or you could pull codes with a paperclip if you are so inclined.

Electrical Thread 'How To Pull Codes From EEC-IV In 86- 95 5.0 Mustangs'

Jan 27, 2016

@Noobz347 - The code dump procedure isn't in the sticky - you may want to add it...



Dump the codes: Codes may be present even if the Check Engine Light (CEL) isn't on.

Dumping the computer diagnostic codes on 86-95 Mustangs

Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.

Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.

Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for...

• jrichker
• Replies: 10
• Forum: Fox 5.0 Mustang Tech

• 

 

[machinermac]

Pull codes:

OBD1 readers are cheap on Amazon or you could pull codes with a paperclip if you are so inclined.

Electrical Thread 'How To Pull Codes From EEC-IV In 86- 95 5.0 Mustangs'

Jan 27, 2016

@Noobz347 - The code dump procedure isn't in the sticky - you may want to add it...



Dump the codes: Codes may be present even if the Check Engine Light (CEL) isn't on.

Dumping the computer diagnostic codes on 86-95 Mustangs

Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.

Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.

Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for...

• jrichker
• Replies: 10
• Forum: Fox 5.0 Mustang Tech

• 

As of yet I cannot find a STI or loose cable that should be in that connector anywhere near the self test connector. There is a similar connector near the starter solenoid but its just black wires. I do have a reader but I dont want to fry a possibly good ecu connecting the wrong thing.

 

[AeroCoupe]

My guess is the PIP but need to pull codes first.

 

[machinermac]

Was able to trace the line back from the ECU plug it got moved into the STO but when jumpered I get no codes not even 11. Got to do some more testing but if I can't get codes out of it the former owner was screwing with the ECU and it might be shot.

 

[JD1964]

Can you hear the fuel pump prime when you turn the key to the run position? The pump should run for a couple seconds and then automatically stop.

 

[Mustang5L5]

TPS issues can also cause this. Essentially if the TPS returns full 5V sensor ref the ECU will not fire the injectors.

But, sounds like you might have some ECU issues. I second the "do you hear the pump prime" when you cycle the key question

 

[machinermac]

Pump runs continuously in koeo.

Can you hear the fuel pump prime when you turn the key to the run position? The pump should run for a couple seconds and then automatically stop.

 

[DadLife0724]

Pump runs continuously in koeo.

Shouldn't run continuously. I'd pull the ecu and crack it open and inspect it. Look for anything out of the ordinary. Corrosion, swollen and/or loose capacitors. I am by no means an expert at these ECU's but when I opened mine up I found the issue pretty quickly.

 

[JD1964]

If you do need an ECU, don’t risk buying a used one. Send yours in to the repair service for exchange

 

[Mustang5L5]

Continuous pump good sign the ECu need a rebuild. You can likely open it up and take a peek at the capacitors, or test the pin 46 trace

 

[JD1964]

Also, considering this car is new to you, you need to make sure which ECU service tag belongs in the car because they are not all configured the same. This includes the possibility that someone re-pinned the harness for a transmission swap. If that was done and the wrong ECU was used, it might explain a failed ECU. You want to avoid installing a replacement and having it fry the moment you turn the key on. The most common service tags are A9L and A9P. I’m not sure which one it is but one is interchangeable with harness modification and the other is not. I think the A9L is the interchangeable one but don’t quote me on that. If I’m wrong then someone please correct me.

 

[JD1964]

Here’s the ECU exchange service that some of on here have previously used. I’ve heard no complaints about then thus far

https://ebay.io/m/9o6AEY