Car not making near power it should??
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Car: 1986 Trans am
Engine: 5.3 LM7
Transmission: T56 6 speed
Axle/Gears: Dana 44 w/ 3.55's
Car not making near power it should??
Hi all. I have been playing with my car for a while now and it just doesn't have any "*****." It'll run good just driving it, but when you push the pedal, the RPM's just go up kind of slow and the car isn't anywhere near as fast as it should be. I have set fuel pressure and timing to every imaginable spot, and they have little to no effect on performance. No engine codes are coming on, and I have a chip burned by TPIS. Is there something internally that could cause this problem? I had a 305 TPI with just a cam that felt faster than this!!! The car will pop every once in a while too if you gradually push on the gas pedal, right around half way down.
TPS is set at .710 volts, fuel PSI is at 42 with vacuum sorce off, timing is at 8*, and I have no idea what could be wrong. This car has been a huge nightmare, and if I can't get it figured out, I may sell it, which I'd rather not do!!
TPS is set at .710 volts, fuel PSI is at 42 with vacuum sorce off, timing is at 8*, and I have no idea what could be wrong. This car has been a huge nightmare, and if I can't get it figured out, I may sell it, which I'd rather not do!!
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Re: Car not making near power it should??
Valve springs worn out? Car feels somewhat ok but never feels like it fully goes into the powerband?
Has the car been tuned?
Has the car been tuned?
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Car: 1986 Trans am
Engine: 5.3 LM7
Transmission: T56 6 speed
Axle/Gears: Dana 44 w/ 3.55's
Re: Car not making near power it should??
I'd really like to get it hooked up to a scanner to see whats going on, but I don't even know what to look for. Anyone by me have the equipment for that? I am at a total loss with this car, and would be willing to even pay someone if you found something out. I'm 15 mins from hartford.
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Re: Car not making near power it should??
Popping out the intake huh? Hmm.
That can be from a slightly bent intake valve, being that this isnt a constant thing, I would lean towards no.
Timing extremely advanced. Once again, not constant, so I am guessing no.
What kind of ignition do you have? Post specs on everything. From distributor, to rotor, to cap, wires, plugs...
That can be from a slightly bent intake valve, being that this isnt a constant thing, I would lean towards no.
Timing extremely advanced. Once again, not constant, so I am guessing no.
What kind of ignition do you have? Post specs on everything. From distributor, to rotor, to cap, wires, plugs...
#7
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Car: 1986 Trans am
Engine: 5.3 LM7
Transmission: T56 6 speed
Axle/Gears: Dana 44 w/ 3.55's
Re: Car not making near power it should??
Popping out the intake huh? Hmm.
That can be from a slightly bent intake valve, being that this isnt a constant thing, I would lean towards no.
Timing extremely advanced. Once again, not constant, so I am guessing no.
What kind of ignition do you have? Post specs on everything. From distributor, to rotor, to cap, wires, plugs...
That can be from a slightly bent intake valve, being that this isnt a constant thing, I would lean towards no.
Timing extremely advanced. Once again, not constant, so I am guessing no.
What kind of ignition do you have? Post specs on everything. From distributor, to rotor, to cap, wires, plugs...
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#8
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Re: Car not making near power it should??
Im wondering if youre getting spark scatter. Basically its when the spark is diverted to the wrong cylinder. That could be causing the huge intake backfire.
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Car: 1986 Trans am
Engine: 5.3 LM7
Transmission: T56 6 speed
Axle/Gears: Dana 44 w/ 3.55's
Re: Car not making near power it should??
Well the only thing that would point to is the wires, correct? I plan on getting new ones anyways, but it is a huge power loss, and I just don't know if thats all it would be. Me and a freind think my pushrod length may be a factor. I am using 7.1 inch pushrods and stock is 7.4. I have stock rockers, and stock roller lifters with the trickflow heads....anyone have a similiar combo and can tell me thier pushrod length??
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Re: Car not making near power it should??
Well the only thing that would point to is the wires, correct? I plan on getting new ones anyways, but it is a huge power loss, and I just don't know if thats all it would be. Me and a freind think my pushrod length may be a factor. I am using 7.1 inch pushrods and stock is 7.4. I have stock rockers, and stock roller lifters with the trickflow heads....anyone have a similiar combo and can tell me thier pushrod length??
You can always call Trick Flow and ask them what pushrod you would need.
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Car: 1986 Trans am
Engine: 5.3 LM7
Transmission: T56 6 speed
Axle/Gears: Dana 44 w/ 3.55's
Re: Car not making near power it should??
----------
I called trick flow but they weren't much help....they basically just said that pushrod length will vary with engine combos, and that what I was using they though was probably ok, but I dont like just "probably."
Last edited by whitedevilTA; 06-30-2008 at 10:25 PM. Reason: Automerged Doublepost
#13
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Car: 1986 Trans am
Engine: 5.3 LM7
Transmission: T56 6 speed
Axle/Gears: Dana 44 w/ 3.55's
Re: Car not making near power it should??
By the way, someone told me that if you have a big cam, you can't adjust valve lash by the method of adjusting half the valves at TDC, rotating the motor 360 degrees, and adjusting the other half?? is this true? I mean, it would explain the popping if a few of the valves were hanging open slightly due to being adjusted wrong.......they said you have to adjust one valve at a time while turning the motor to different spots.
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Car: '87 IROCZ
Engine: 395 ZZ4
Transmission: ProBuilt 700R4
Axle/Gears: 9 bolt 3.70s
Re: Car not making near power it should??
Valve adjustment: I have always done "one valve at a time" method. Also, I turn the rocker nut 1/4 turn after zero lash. Get the #1 cylinder at Firing TDC and adjust both #1 valves. Then turn the crank exactly 90 degrees and adjust the next cylinder in the firing order, and continue.
Fuel pressure should be set to give you 12.8:1 AFR at WOT. Just trying different fuel pressures is not the right way. Get a wide band on their and adjust it correctly.
The TPS should not be at 0.71V, thats too high; set it to 0.62V at closed throttle.
I was told that popping when you slam the throttle down is a lean condition. Timing can also affect this. Since you have a TPIS chip, you have no idea what timing that you are running. For kicks, install the stock chip and see how it runs.
A scanning could "see" alot about whats going on with your engine.
Fuel pressure should be set to give you 12.8:1 AFR at WOT. Just trying different fuel pressures is not the right way. Get a wide band on their and adjust it correctly.
The TPS should not be at 0.71V, thats too high; set it to 0.62V at closed throttle.
I was told that popping when you slam the throttle down is a lean condition. Timing can also affect this. Since you have a TPIS chip, you have no idea what timing that you are running. For kicks, install the stock chip and see how it runs.
A scanning could "see" alot about whats going on with your engine.
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Car: 1986 Trans am
Engine: 5.3 LM7
Transmission: T56 6 speed
Axle/Gears: Dana 44 w/ 3.55's
Re: Car not making near power it should??
Valve adjustment: I have always done "one valve at a time" method. Also, I turn the rocker nut 1/4 turn after zero lash. Get the #1 cylinder at Firing TDC and adjust both #1 valves. Then turn the crank exactly 90 degrees and adjust the next cylinder in the firing order, and continue.
Fuel pressure should be set to give you 12.8:1 AFR at WOT. Just trying different fuel pressures is not the right way. Get a wide band on their and adjust it correctly.
The TPS should not be at 0.71V, thats too high; set it to 0.62V at closed throttle.
I was told that popping when you slam the throttle down is a lean condition. Timing can also affect this. Since you have a TPIS chip, you have no idea what timing that you are running. For kicks, install the stock chip and see how it runs.
A scanning could "see" alot about whats going on with your engine.
Fuel pressure should be set to give you 12.8:1 AFR at WOT. Just trying different fuel pressures is not the right way. Get a wide band on their and adjust it correctly.
The TPS should not be at 0.71V, thats too high; set it to 0.62V at closed throttle.
I was told that popping when you slam the throttle down is a lean condition. Timing can also affect this. Since you have a TPIS chip, you have no idea what timing that you are running. For kicks, install the stock chip and see how it runs.
A scanning could "see" alot about whats going on with your engine.
And by the way, DOC, do you think by adjusting the valves the way I did, some are hanging open? Cam is a comp XR276 hydraulic roller, 112 LSA, 224/230 @ .50, .503, .510 lift.
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