So in neutral, it was building boost? So, no boost up through the rpm range but when the car started to show it's issues the boost started to climb rapidly at that point, correct?
K.
Car noses over hard at 5K rpms and will not recover until the throttle it lifted?
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So in neutral, it was building boost? So, no boost up through the rpm range but when the car started to show it's issues the boost started to climb rapidly at that point, correct?
K.
gunslinger
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TurboBuRick, I tired unplugging the cam sensor and then going for a ride and the problem is the same.
NCTURBOS, When I am driving the car it builds boost fine and pulls well until about 5K then it noses over and the boost drops to zero. When I tried to get the log in neutral the engine reved to aprox. 4800 then started to cut out as if on a rev limiter and the boost began to build immediately and got to about 12 psi quickly then I lifted.
NCTURBOS, When I am driving the car it builds boost fine and pulls well until about 5K then it noses over and the boost drops to zero. When I tried to get the log in neutral the engine reved to aprox. 4800 then started to cut out as if on a rev limiter and the boost began to build immediately and got to about 12 psi quickly then I lifted.
I tried some new plug wires tonight but that did not help either. I am not really beginning to wonder about the valve springs. Nothing exotic in the valvetrain of my motor--Comp 212/212 flat tappet, Comp 980 springs, Comp lifters and stock rockers. It is possible that I got a bad set of 980 springs and they have gone away in only 1500 miles of street driving? It just seems strange to have a problem with new 980's because they are so common and you don't hear about problems with them.
Here is list of what has been done so far but has not helped the problem:
1) Tried differrent coilpack/module
2) New plugs with tighter gap
3) New plug wires
4) Tried different ECM
5) Tried different chip
6) Checked for vacuum leaks
7) Unplugged Cam Sensor to try batch fire
8) Tested fuel pressure at WOT
Any other ideas? Thanks for the help
Here is list of what has been done so far but has not helped the problem:
1) Tried differrent coilpack/module
2) New plugs with tighter gap
3) New plug wires
4) Tried different ECM
5) Tried different chip
6) Checked for vacuum leaks
7) Unplugged Cam Sensor to try batch fire
8) Tested fuel pressure at WOT
Any other ideas? Thanks for the help
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- Feb 18, 2006
- Messages
- 10,084
Something else to check is end play on the crank and also the balancer to make sure it's tight. Either one can cause the wheel to walk out the sensor. When that happens you loose spark.
A tell tale sign is the belt edge will show wear.
A tell tale sign is the belt edge will show wear.
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- May 28, 2001
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- 16,704
Just went..
thru a diagnosis of this problem w/ an LSX engine in a Moosetang. Crank walked forward so far, [>1/8"], that the crank sensor was no longer aligned w/ the reluctor.
The thrust had been fried by the t-400 trans pushing the verter off the stator support.
thru a diagnosis of this problem w/ an LSX engine in a Moosetang. Crank walked forward so far, [>1/8"], that the crank sensor was no longer aligned w/ the reluctor.
The thrust had been fried by the t-400 trans pushing the verter off the stator support.
jasjamz
THS Racer
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The parts changing way with these cars will lead you to the poor house wearing a coat with long sleeves and buckles.
You sure the starter power cable isn't grounding out when the motor torques over with the stress of 5000rpm and boost? Does the car blink out or try to stall? Checked your coolant? What head gaskets are you using? If the boost is dropping to zero it is losing cylinder pressure. So either it stops making power or can't hold what it takes in. Rick is right. The converter pushes the crank forward and with a worn thrust, and loose balanced it will shut down.
You sure the starter power cable isn't grounding out when the motor torques over with the stress of 5000rpm and boost? Does the car blink out or try to stall? Checked your coolant? What head gaskets are you using? If the boost is dropping to zero it is losing cylinder pressure. So either it stops making power or can't hold what it takes in. Rick is right. The converter pushes the crank forward and with a worn thrust, and loose balanced it will shut down.
Mike Licht
I was here first
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sounds to me like the valve springs went away
ML
ML
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About 20 years ago I had my original T at the track, and it would do the exact same thing?
My first thought was it was doing just what my carbed race cars used to do when there was insufficient fuel supply. My thought in that case was correct.
About a month ago, a customer's car was doing the same thing, and a new fuel pump corrected the situation.
I found out over the years, good fuel pressure does NOT mean adequate fuel flow.
About 20 years ago I had my original T at the track, and it would do the exact same thing?
My first thought was it was doing just what my carbed race cars used to do when there was insufficient fuel supply. My thought in that case was correct.
About a month ago, a customer's car was doing the same thing, and a new fuel pump corrected the situation.
I found out over the years, good fuel pressure does NOT mean adequate fuel flow.
I would think if you're logging fuel pressure you could see inadequate fuel flow as a drop in pressure as you run out of volume
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