Engine Intermittent no start

claypoolxx

Member
Oct 13, 2013
42
7
19
I have a 93 gt 5 speed. A buddy and I just swapped the heads and now we have an issue. Installed gt40x heads that I had checked out my a machinist friend. First time starting the car after the heads it started right up. Turned it off, cleaned up some stuff, went to start again and it won't start. Fuel pump won't stop priming. Tried a few times, didn't start. Next day started right up many times. I drove it about 20 miles home, put it in the garage. Next day no start.

I started reading all the threads with similar issues that I could find. Some seemed to be the computer and others the fuel pump relay. I turned the key forward to get the pump to prime and then tapped the relay with a screwdriver. Fuel pump turned off. Went to start the car and it fired right up. I let it idle and it died. Since I don't have AC, I switched the relays, but that did nothing.

Went to parts store to get a relay since its cheap. Turned the key forward and the pump primed for a couple seconds like usual. Let the car idle for a minute and then it died. But here's thew weird part. With the new relay if I turn the key forward the pump doesn't prime at all. I put the old relay in and it primes forever like before. Not quite sure what's with the new relay.

I took the computer out and opened it up. I did find what looked like a leaking capacitor with one wire broken. I took some pics and zoomed in, I think that what I saw, my eyesight isn't what it used to be.

So this would leave me to believe that its the computer. I found a place the fixes them for $120 and if they check everything and nothing is wrong, its half price. Sounds like a deal to me. However, I am a bit worried about the new relay that is acting differently that the original. If they were both good, I'd expect them to behave the same way. If the new one went bad, why.

It seems that I need the computer fixed anyway, but I am concerned that there is another problem.

When I wasn't there and the car first started this. My buddy checked for fuel pressure and spark, both were good. He didn't check to see if the injectors were firing though. I don't think it can be anything mechanical, because it will start and run sometimes. Does anyone have any other ideas, or does it seem like I'm on the right track? Thanks
 

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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Get the computer worked on, in the mean time make sure you have the grounds installed and the connections you dealt with are good, when the computer comes back use the old relay first, let us know what it does or does not do.
 

claypoolxx

Member
Oct 13, 2013
42
7
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They received it Friday and got a message about it today.

The power supply in your computer was defective causing distortion on the system voltages. we also replaced the power supply along with the capacitors and voltage regulators. which are common to fail and this will prevent future defects.
we also beefed up a couple other areas known to fail while we were in there.

Hopefully I'll have it by the end of the week and I'll give an update.
 
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limp

wrap a little cheese around it and its a done
Oct 4, 2020
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They received it Friday and got a message about it today.

The power supply in your computer was defective causing distortion on the system voltages. we also replaced the power supply along with the capacitors and voltage regulators. which are common to fail and this will prevent future defects.
we also beefed up a couple other areas known to fail while we were in there.

Hopefully I'll have it by the end of the week and I'll give an update.
Always a good thing when faulty things are found... Nothing worse than hearing " everything looks good" when your car doesn't run right.....
 

85GTStangGuy

Active Member
May 19, 2021
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They received it Friday and got a message about it today.

The power supply in your computer was defective causing distortion on the system voltages. we also replaced the power supply along with the capacitors and voltage regulators. which are common to fail and this will prevent future defects.
we also beefed up a couple other areas known to fail while we were in there.

Hopefully I'll have it by the end of the week and I'll give an update.

Sounds like a great company you sent it to...... going the extra mile to not only fix it, but cut-off potential future problems.
 
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claypoolxx

Member
Oct 13, 2013
42
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Put the computer in today and all seems well. Pump primes for a couple seconds and it starts right up. Only took a small test ride because it is raining, but I think it's fixed. Ecuexchange is the name of the company that fixed the computer, they were great.
 
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