Engine Crank but no start 1990 LX 5.0

[ty50650]

I’ve been having issues with my fox for about a week. 1990 LX 5.0

It is cranking but won’t start. The first thing I noticed was that the fuel pump won’t stop priming when the key is turned to on position. Usually it would prime maybe 2-5 seconds then turn off. I looked it up and saw it could be the fuel pump relay that was faulty, so I replaced it. Pump still stays priming with no start. I noticed a small hissing noise around my throttle body/fuel rail. Not sure if this is normal.

Some things I’ve tried also is adding fuel to a vacuum hose. It started, but was rough , then eventually died and wouldn’t idle. Then I tried removing the idle air control valve. I had a friend help by covering the holes with hand while I tried to start the car. It started maybe a little too fast, but began to idle just fine. So I bought a new IAC valve and replaced the old one. Then after replacement, the only way it would start is when the gas pedal was all the way to the floor. It wouldn’t do this before the IAC replacement. Fast forward to the next day, car cranks but won’t start at all, even with gas down.

I also pressed on the schrader valve, and it spit out a stream of gas.

I’ve tried checking codes, but my obd1 is showing 000 and when I tried to manually show codes with paper clip, check engine light wouldn’t blink it would just stay on.

I also removed the MAF and cleaned the small wires with MAF cleaner. Let the part dry completely before reinstallation. Crank but no start.

I made sure there is gas in the car, so that’s not an issue.

I’m not the most knowledgeable person when it comes to cars, so if someone could tell me some suggestions that would be great. Thanks for your help

 

[JD1964]

Abnormal fuel pump priming can sometimes be related to a problem in the ECM. With the age of these cars, the capacitors in the ECM leak and cause corrosion on the circuit board. With a little care during the process it’s not too difficult to remove the ECM, remove its cover and visually inspect the capacitors.

 

[AeroCoupe]

Agree with JD1964. Also, just for grins have you checked the ignition switch (not the cylinder you put the key in but the switch it moves) under the steering column covers to see if it is coming apart. Another known issue on these cars that causes all kinds of random and weird problems.

 

[Mindseye007]

I’ve been having issues with my fox for about a week. 1990 LX 5.0

It is cranking but won’t start. The first thing I noticed was that the fuel pump won’t stop priming when the key is turned to on position. Usually it would prime maybe 2-5 seconds then turn off. I looked it up and saw it could be the fuel pump relay that was faulty, so I replaced it. Pump still stays priming with no start. I noticed a small hissing noise around my throttle body/fuel rail. Not sure if this is normal.

Some things I’ve tried also is adding fuel to a vacuum hose. It started, but was rough , then eventually died and wouldn’t idle. Then I tried removing the idle air control valve. I had a friend help by covering the holes with hand while I tried to start the car. It started maybe a little too fast, but began to idle just fine. So I bought a new IAC valve and replaced the old one. Then after replacement, the only way it would start is when the gas pedal was all the way to the floor. It wouldn’t do this before the IAC replacement. Fast forward to the next day, car cranks but won’t start at all, even with gas down.

I also pressed on the schrader valve, and it spit out a stream of gas.

I’ve tried checking codes, but my obd1 is showing 000 and when I tried to manually show codes with paper clip, check engine light wouldn’t blink it would just stay on.

I also removed the MAF and cleaned the small wires with MAF cleaner. Let the part dry completely before reinstallation. Crank but no start.

I made sure there is gas in the car, so that’s not an issue.

I’m not the most knowledgeable person when it comes to cars, so if someone could tell me some suggestions that would be great. Thanks for your help

100% the Ecu, take it out open it and show us what it looks like inside...

 

[JD1964]

For the record, when my ECU took a dump I tried to change the capacitors myself but was not successful. After failing to repair it myself I sent it for exchange. This service takes your ECU as a core and gives you a replacement refurbished unit. There’s more than one of these ECU service vendors out there. All I can say is I had a good experience with this particular vendor. That was a couple years ago so I don’t know if that good quality that I had gotten is still there or not.

A9L A9P C3W A3M X3Z MUSTANG ENGINE COMPUTER ECU PCM ECM 5.0 REPAIR & RETURN | eBay

Mustang ECU Repair Service. Quick turn around after the computer is received. Easy repair process. If we are unable to repair your computer, WE CAN HELP! 701 La Veta Dr. Crank, no start?.

www.ebay.com

 

[AeroCoupe]

That’s the one pretty much everyone uses and they do great work.

 

[Mindseye007]

That’s the one pretty much everyone uses and they do great work.

https://www.theecuexchange.com/prod...-service/50?cp=true&sa=true&sbp=false&q=false
TheEcuExchange did an amazing job with my ECU too, highly recommend them.

 

[ty50650]

100% the Ecu, take it out open it and show us what it looks like inside...

ECU has been removed and after a second opinion from an experienced Mustang mechanic, a couple of the capacitors have failed. Also noticed a bad smell coming from the ECU when taken apart. I’ve ordered replacement capacitors and will try to replace the failed ones. Thank you for your help

 

[limp]

ECU has been removed and after a second opinion from an experienced Mustang mechanic, a couple of the capacitors have failed. Also noticed a bad smell coming from the ECU when taken apart. I’ve ordered replacement capacitors and will try to replace the failed ones. Thank you for your help

Based on the hit and miss do it yourselfers doing the same thing as you, comments on here, You would be much better off sending it out to ECUexchange..

 

[Mindseye007]

ECU has been removed and after a second opinion from an experienced Mustang mechanic, a couple of the capacitors have failed. Also noticed a bad smell coming from the ECU when taken apart. I’ve ordered replacement capacitors and will try to replace the failed ones. Thank you for your help

I would highly recommend you send it out to ECU exchange they did a nice job fixing my ecu and the car runs sweet and purrs like a kitten.

 

[General karthief]

And the cost is very reasonable, my last one (I've had several done there) I think it was like $150?