Any input on this? Good Compression...
09-07-05, 02:12 AM
#1
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Any input on this? Good Compression...
Car started running crappy on boost. over 5 psi it still ran, but was stumbling and not acting happy.
Did a compression test today and got three even pulses on both rotors, front was 80-80-80 and the rear was 70-70-70.
it has been idling rough but seems to smooth out as temp gets warm, it kind of lopes for the first 6 minutes or so at idle.
Swapped the plugs out, and they were fouled, especially the lower two, but that didn't help.
Oh, and I guess this would help. 94 Fd, med. street port, T04R and all the trimmings, D&D ignition amp, PFC w/ commander.
there is only about 4k on the rebuilt motor.
Also my knock readings stopped working when I put the ignition amp in, so I am getting no help there.
Idle vac is 10 in HG.
Before I run out and swap plug wires, any other ideas? Check the coils? The ignition amp?
I am silently praying this isn't a "buy a new motor" day...
Did a compression test today and got three even pulses on both rotors, front was 80-80-80 and the rear was 70-70-70.
it has been idling rough but seems to smooth out as temp gets warm, it kind of lopes for the first 6 minutes or so at idle.
Swapped the plugs out, and they were fouled, especially the lower two, but that didn't help.
Oh, and I guess this would help. 94 Fd, med. street port, T04R and all the trimmings, D&D ignition amp, PFC w/ commander.
there is only about 4k on the rebuilt motor.
Also my knock readings stopped working when I put the ignition amp in, so I am getting no help there.
Idle vac is 10 in HG.
Before I run out and swap plug wires, any other ideas? Check the coils? The ignition amp?
I am silently praying this isn't a "buy a new motor" day...
09-07-05, 06:39 AM
#2
Banzai Racing
There is something seriously wrong with your engine to have such low compression and only 4k on the rebuild. Who did the rebuild?
At least they are even which tends to mean that you have not cracked any apex seals.
The last time I saw these exact same symptoms, the customer had just purchased an engine from a builder on the west coast. When I cracked it open we found that they had used damaged rotors. The rotor faces were dented like someone had taken a ball peen hammer to them.
At least they are even which tends to mean that you have not cracked any apex seals.
The last time I saw these exact same symptoms, the customer had just purchased an engine from a builder on the west coast. When I cracked it open we found that they had used damaged rotors. The rotor faces were dented like someone had taken a ball peen hammer to them.
Last edited by BlueTII; 09-07-05 at 06:45 AM.
09-07-05, 12:20 PM
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I am going to redo the compression test with a different gauge today. There is a possibility it was bad. The motor was rebuilt on the west coast, but I want to call the builder and see what he says.
What are the symptoms of coils going bad?
What are the symptoms of coils going bad?
09-07-05, 08:30 PM
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We've all seen worse compression numbers with no apparent impact on the drivability. I agree with BlueTII, because the values are equal across all three faces, I don't think your engine integrity is the issue.
The problem seems to revolve around boost levels, and vacuum of only 10 psi, I'd be looking at your vacuum lines, check valves, assuming you have any of that left with the T04R.
Also, what about your commander? Was it tuned for your setup? How is your fuel pump/fuel filter? How are you controlling air flow with that T04R? One last idea, how is flow through your CAT? Those are simple checks that should be eliminated first before tearing into turbo control system. That would be my next option.
The problem seems to revolve around boost levels, and vacuum of only 10 psi, I'd be looking at your vacuum lines, check valves, assuming you have any of that left with the T04R.
Also, what about your commander? Was it tuned for your setup? How is your fuel pump/fuel filter? How are you controlling air flow with that T04R? One last idea, how is flow through your CAT? Those are simple checks that should be eliminated first before tearing into turbo control system. That would be my next option.
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