Possible bad ECM input needed.

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Vampcrist
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Possible bad ECM input needed.

Postby Vampcrist » Mon Apr 06, 2015 6:15 am

Been a long time since I've posted or had problems. I was driving and she started to sound a little rough at idle almost like a lifter was shot then it leveled out sounded great again for a minute abs then died. Here's where it gets interesting, check engine light comes on andi try to restart it with no luck then I notice that the break light is on with the ignition but the oil and check engine light are longer light. Turns over fine but does not turn on the fuel pump with direct power it does turn on. Any ideas?

Thanks



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Re: Possible bad ECM input needed.

Postby Money pit Beretta » Mon Apr 06, 2015 11:15 am

Check all connections at the ECM first.


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Re: Possible bad ECM input needed.

Postby Vampcrist » Mon Apr 06, 2015 3:05 pm

Oh I have even changed proms.



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Re: Possible bad ECM input needed.

Postby ronaconda » Tue Apr 07, 2015 2:31 pm

Process of elimination basically. And the ECM will rarely throw a code for a faulty ECM (even though there is one). Best way to tell is if you have another to swap it with. I chased a timing issue and, through process of elimination, determined that the ECM was the culprit. Grab one out of the yard. I have one i could sell you shipped for $40 out of an 89 GT if you want.



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Re: Possible bad ECM input needed.

Postby Vampcrist » Tue Apr 07, 2015 3:29 pm

The biggest thing they makes me think it's the ecm is that the check engine light won't come on, the fuel pump doesn't prime, and it cranks over with no issues it was driving just fine before this happened. And I can't check codes it won't enter diagnostic mode when I jump the terminals.



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Re: Possible bad ECM input needed.

Postby woody90gtz » Tue Apr 07, 2015 11:50 pm

When I have had a crank but no start with no fuel pump it was the ECM. Sounds like that's it.


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Re: Possible bad ECM input needed.

Postby ronaconda » Wed Apr 08, 2015 12:38 am

X2!!!!!!!!



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Re: Possible bad ECM input needed.

Postby 3X00-Modified » Thu Apr 09, 2015 2:41 pm

or the ECM isnt getting an ignition/turn on signal from the key.



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Re: Possible bad ECM input needed.

Postby Asylum » Thu Apr 09, 2015 6:23 pm

It has been proven over and over and over again that these ECU/ECM just DON'T go bad!!

Give it a clean 12 volts, and a good ground and they are absolutely 99.99% reliable.

Check for corrosion and un-plug, re-plug it all in and you may be surprised.

What happens is the corrosion and GM-Designed water leakage compromises these cars.

The electronics is actually very well designed, and hell, it worked for 20 years. Why would it fail now all on its own?

Just check everything first.

Good luck!

:beer:





.

Good luck with it.

:beer:


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'92 3500 GT gone and not really missed. It was fun. Documented 13.47 N/A.

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Re: Possible bad ECM input needed.

Postby woody90gtz » Thu Apr 09, 2015 11:10 pm

Sorry Eric, I disagree - 100%. I have personally had two 7730 ECMs die on me. At this age, they are no where near 99% reliable.


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Re: Possible bad ECM input needed.

Postby Asylum » Thu Apr 09, 2015 11:19 pm

But do you know why?

You have myriad mods to your car and anything along the way could take one out with a power surge.

But in my experience, they are pretty reliable.

I have never had one go bad.

Even the 3500 car still had the original unit, just with a very modified chip.

FWIW!


Eric

Asylum Motorsports
"Where we're not happy 'til YOU'RE not happy!






'91 California Quad
'92 3500 GT gone and not really missed. It was fun. Documented 13.47 N/A.

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Re: Possible bad ECM input needed.

Postby 88*Beretta » Fri Apr 10, 2015 12:54 am

Vampcrist wrote:makes me think


I'd be check wiring schematics, and confirming power is where its suppose to be.

Relay controls fuel pump....there's a test connector for priming fuel pump under the hood, on driver's side...on earlier Berettas.

No fuel, no go...is there fuel pressure in the rail?

Fuel pump relay shot craps...



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Re: Possible bad ECM input needed.

Postby 88*Beretta » Fri Apr 10, 2015 12:56 am

woody90gtz wrote:7730 ECMs


I've never looked at one, but on ECMs that can be opened up, sometimes its the capacitors that fail...replace them, VaRoom



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Re: Possible bad ECM input needed.

Postby Cliff8928 » Fri Apr 10, 2015 1:03 am

My failed one was presumably a bad solder joint. I could tap on it and it would act normal for a while.


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Re: Possible bad ECM input needed.

Postby Asylum » Fri Apr 10, 2015 8:17 am

Cliff8928 wrote: I could tap on it and it would act normal for a while.


Sometimes if you tap on ME, (with a big enough bat) I'm able to act normal for a while!

:beer:


Eric

Asylum Motorsports
"Where we're not happy 'til YOU'RE not happy!






'91 California Quad
'92 3500 GT gone and not really missed. It was fun. Documented 13.47 N/A.


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