What happened to"Stops making power after 4800rpm on dyno!! " by VINCE
06-16-2008, 05:44 PM
#1
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What happened to"Stops making power after 4800rpm on dyno!! " by VINCE Where did the thread go?? I was watching it to see what the problem was...
Having a similar issue with my car...
Having a similar issue with my car... 
06-17-2008, 07:04 PM
#2
My HP flatlines from 5500-6500 RPM. Cause is still under investigation, but my first finding is 23 pounds of back pressure in my exhaust system (post cat). Currently resolving my exhaust issues, then back to the dyno....
06-20-2008, 09:17 AM
#4
My issue is still unresolved. I have a turbo car Chris. I have found three other turbo cars who a similar issue and one had a bad turbo and that fixed their problem. The other two are still investigating.
So far I have changed plugs 2 times, brand spanking new plug wires, used a spare set of coil packs, changed the crank sensor, boost leak tested the car to death, pulled the wastegates off and inspected and they are fine, checked the turbos and they do have some side to side play, but they are not hitting anywhere. Called Turbonetics and they report if the turbos are not hitting they are fine.
On the dyno my car hits 4850rpm's and the power just falls off each time. Boost spikes up to 16lbs and then drops to 14lbs and holds off the WG spring. I am recording boost via my boost controller. It has a record function.
Logs on the street show right at 4550rpm the injector pulse width starts to slowly decrease, dynamic cyl air starts to decrease, injector duty cycle goes from steady upward trend to flattening. I did notice my injector duty cycle use to hit 78 percent off the WG spring and now peaking at 68 to 70, but that I would think is due to not making the same power as b4.
Ignition Voltage drops from 13.7 to 13.2 at the most.
So far I have changed plugs 2 times, brand spanking new plug wires, used a spare set of coil packs, changed the crank sensor, boost leak tested the car to death, pulled the wastegates off and inspected and they are fine, checked the turbos and they do have some side to side play, but they are not hitting anywhere. Called Turbonetics and they report if the turbos are not hitting they are fine.
On the dyno my car hits 4850rpm's and the power just falls off each time. Boost spikes up to 16lbs and then drops to 14lbs and holds off the WG spring. I am recording boost via my boost controller. It has a record function.
Logs on the street show right at 4550rpm the injector pulse width starts to slowly decrease, dynamic cyl air starts to decrease, injector duty cycle goes from steady upward trend to flattening. I did notice my injector duty cycle use to hit 78 percent off the WG spring and now peaking at 68 to 70, but that I would think is due to not making the same power as b4.
Ignition Voltage drops from 13.7 to 13.2 at the most.
06-20-2008, 09:48 AM
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My issue is still unresolved. I have a turbo car Chris. I have found three other turbo cars who a similar issue and one had a bad turbo and that fixed their problem. The other two are still investigating.
So far I have changed plugs 2 times, brand spanking new plug wires, used a spare set of coil packs, changed the crank sensor, boost leak tested the car to death, pulled the wastegates off and inspected and they are fine, checked the turbos and they do have some side to side play, but they are not hitting anywhere. Called Turbonetics and they report if the turbos are not hitting they are fine.
On the dyno my car hits 4850rpm's and the power just falls off each time. Boost spikes up to 16lbs and then drops to 14lbs and holds off the WG spring. I am recording boost via my boost controller. It has a record function.
Logs on the street show right at 4550rpm the injector pulse width starts to slowly decrease, dynamic cyl air starts to decrease, injector duty cycle goes from steady upward trend to flattening. I did notice my injector duty cycle use to hit 78 percent off the WG spring and now peaking at 68 to 70, but that I would think is due to not making the same power as b4.
Ignition Voltage drops from 13.7 to 13.2 at the most.
So far I have changed plugs 2 times, brand spanking new plug wires, used a spare set of coil packs, changed the crank sensor, boost leak tested the car to death, pulled the wastegates off and inspected and they are fine, checked the turbos and they do have some side to side play, but they are not hitting anywhere. Called Turbonetics and they report if the turbos are not hitting they are fine.
On the dyno my car hits 4850rpm's and the power just falls off each time. Boost spikes up to 16lbs and then drops to 14lbs and holds off the WG spring. I am recording boost via my boost controller. It has a record function.
Logs on the street show right at 4550rpm the injector pulse width starts to slowly decrease, dynamic cyl air starts to decrease, injector duty cycle goes from steady upward trend to flattening. I did notice my injector duty cycle use to hit 78 percent off the WG spring and now peaking at 68 to 70, but that I would think is due to not making the same power as b4.
Ignition Voltage drops from 13.7 to 13.2 at the most.
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07-28-2008, 08:19 PM
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unsolved problems hey I think you are talking about the post I had put up I have been eliminating so many options its crazy everytime we think we know it happens again. its not just power falling off its 400+ hp then hits about 4,800 and sits there tell I get out of it because at 100% throttle it wants more rpm before it shifts it is all power then a wall if anybody might have an idea or same situation, question anything give me a call at (303)856-8370 ask for shane or leave a message
07-29-2008, 03:48 AM
#17
I don't know if it applys to this situation, but I had the same sort of problem in my Starion, it ended up being a bad injector that was messing with the PCM so it wouldn't add fuel after a certain amount of boost. I found out when I swapped the injectors as a desperation move and it immediately started pulling again (it would drop out at like 3800rpm). Hope you find whatever it is.
07-29-2008, 04:49 AM
#18
