LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Dynoed car have problems.

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Old Dec 1, 2004 | 06:00 AM
  #31  
brain's Avatar
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From: Columbia, SC, USA
Re: Dynoed car have problems.

Hmm...sounds like its pulling good vacuum...I'll be honest, I've never seen an ecu retard timing that bad, even at idle. I do have obd1 though. Is your car tuned at all? It is kind of wierd though, the graph is saying -22 advance, but the chart says 0.0 KR. If you are on a stock tune, that could be the problem. Basically if our cars had a distributor, its as if your car has it retarded 20 or more degrees. That could make the power low across the board.
Old Dec 1, 2004 | 10:33 AM
  #32  
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From: Hayward, CA
Re: Dynoed car have problems.

I am on the stock tune...but we couldn't tune the car with the way it was running. I have to fix this problem(whatever the problem is) first before I can tune it.
Old Dec 1, 2004 | 11:02 AM
  #33  
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Re: Dynoed car have problems.

Are you certain what you were reading is spark retard and not spark advance? I can see where you might find 21 degrees total advance at idle and 44 degrees at 2500 but theres no way the PCM is retarding it that much... just isnt possible AFAIK.
Old Dec 1, 2004 | 11:16 AM
  #34  
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Re: Dynoed car have problems.

oops, according to the software its says spark advance. Thanks for catching that. turbo_Z, do you see anything wrong in those pics I posted?
Old Dec 1, 2004 | 02:59 PM
  #35  
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Re: Dynoed car have problems.

Originally Posted by sherwinZ28
oops, according to the software its says spark advance. Thanks for catching that. turbo_Z, do you see anything wrong in those pics I posted?
To be honest with you man I cant read a damn thing in those links. You need to get a datamaster file or something with multiple engine parameters in wide ranges of engine load and RPM.
Old Dec 10, 2004 | 08:26 AM
  #36  
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From: Ocala, Florida
Re: Dynoed car have problems.

My power was dropping off like a rock in the high RPM's and it turned out to be a bad coil. I replaced it with the MSD coil from Thunder Racing.
Old Dec 10, 2004 | 12:42 PM
  #37  
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Re: Dynoed car have problems.

I already have an MSD coil. I thought it might the coil as well so that was the first thing I changed. I have a feeling it might be the opti which is causing the miss at high rpms and the reason for the low numbers may be due to knock. I'm thinking the car should make ~350 ft/lbs of torque right from the beginning and be a smooth/flat line across the rpm range. I've had knock since I first swapped cams and have not been able to get rid of it. I also changed plugs and wires when I did the heads. Tell me your thoughts guys.
Old Dec 10, 2004 | 11:31 PM
  #38  
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From: New Bern, NC USA
Re: Dynoed car have problems.

How much retard are you getting?
Old Dec 11, 2004 | 12:22 AM
  #39  
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From: newton, kansas, USA
Re: Dynoed car have problems.

I had a low hp problem on my car. It was the fuel pump. The car was low on power all across the board. I didn't have the spikes like you did. Oddly enough it didn't show up as super lean my air fuel ratio was still pretty good too. I would look at the spark retard, and slap on a fuel pressure gauge. It sounds like your vaccum is good.
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