Fried ECU?

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Sep 25, 2009 | 11:20 PM

chevynation

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Fried ECU?

Hey guys I want to get your thoughts on an issue my car is having. Long story short, my tuned H/C ls1 randomly won't start... as in sometimes it turns over fine, but won't get any fuel or spark.

Took it to a mechanic and he pulls up a code for a crank sensor. I personally replace both the cam and crank sensors and check the grounds, and it gives me the same ****. Wierd thing is, sometimes it will start, and when it does it runs great.

So I decide to man up and buy HPtuners so I can finally learn to scan and tweak the tune myself. While scanning and cranking the car (not starting), I'll get an RPM signal (along w/ everything else), so this means the crank sensor is working right? And the wiring is good? Which leaves a fried pcm? Thanks

Sep 26, 2009 | 07:34 PM

poconojoe

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Did you check for fuel pressure and injector pulses?
Since you most likely already used a license on your PCM turn off the Vats and see if that helps

Oct 2, 2009 | 10:47 PM

chevynation

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Well when I pulled a plug to check for spark (after I cranked it for a bit) the thing was bone dry and I couldn't even smell any fuel so I assumed it wasn't getting fuel either. Is the inj mist really that fine? Regardless, there was no spark either.

I thought a Vats issue wouldn't let it turn over at all?

Btw, it does have fuel pressure.

Oct 3, 2009 | 05:26 AM

poconojoe

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Is this in a stock vehicle with a BCM or a swap? If its a swap, the VATS will have nothing to do with it cranking. If its in a stock vehicle, it will depend on the model, if the BCM will not allow cranking, when the VATS is not satisfied.
Use a niod light to see if you have an injestor pulse

Oct 4, 2009 | 06:46 PM

chevynation

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Stock pcm ('99 camaro). I'll see if I can track down a noid light (whatever that is). Thx

Oct 4, 2009 | 07:36 PM

donman

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ChevyNation,

I had a 96 firbird that did the exact same thing you aretalking about. However the fuel pump relay would chatter. When it di that I knew the car would not start.

I finally got fed up with it and bought my TA. As I was getting the firebird ready to sell my buddy and I were trying to get it to start. I tried wiggling the wires on the pcm, nothing. So I tapped it with my 1/2 inch ratchet, the fule pump relay stopped chattering and the car started. From then on I knew it was a bad conenction in the pcm. I bough a used one off ebay and the person who bought my car has not had a problem with it since..

Good Luck..

Don