T O P I C R E V I E W
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MistaFosta
Member # 4068
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posted
First off, this is a 90 LX 5.0 (Ex CHP) It has a mac cold air, and a set of underdrive pulleys, otherwise it is stock.
A little while ago, I developed a strange missfire over 3000+ rpms under full or almost full throttle. It acts pretty much like a rev limiter, causing a complete loss of power (Can't even get past 3200 rpms). It only does it once the car warms up, and only under heavy throttle above 3000 rpms. Otherwise the car runs absolutely perfect.
I have either swapped with known good, or replaced these parts. Distributor, module, coil, plugs, wires, cap, rotor, fuel filter, fuel pump, MAF, intake air temp sensor, water temp sensor, put the stock intake piping back on, TPS, and I checked all my grounds. Also tried another computer. I gapped the plugs at 50 and 45, no difference.
If anyone has ANY suggestions, please let me know. This car is really pissing me off..
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nitrous_bob
Member # 77
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posted
hook up a fp guage to rule that out for sure... watch the fp when it starts to stumble.
if it's good...gotta be spark.
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FasterDamnit
Member # 442
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posted
Codes?
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MistaFosta
Member # 4068
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posted
It has a EGR code, but it throws that when it is cold, and has done that for about 6 months now...
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PunkINa5.SLOW
Member # 10
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posted
How did swapping out the cheap ass plug wires you have on that thing work for you?
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PunkINa5.SLOW
Member # 10
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posted
oh my bad I see that you swapped out the plug wires.
Tell you what hook that MSD box up and see if it makes any difference just for GP
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PunkINa5.SLOW
Member # 10
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posted
awww screw it come back over in the morning and Ill actually go for a ride in it with you this time to try to help you isolate
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six 5.0
Member # 3153
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posted
I have an 86, It does the same the shit mine does it when it's cold. It fuccin pisses me off, I can not figure it out either. I have had suggestions to change my cats and my mufflers (stock). Maybe you yau should look in to doing the same, if thier stock.
good luck
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MistaFosta
Member # 4068
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posted
quote: Originally posted by PunkINa5.SLOW: awww screw it come back over in the morning and Ill actually go for a ride in it with you this time to try to help you isolate
Lol, I gotta work 730 to 430. Id be happy to lend you the car to feel the problem yourself. I trust you with it. I have my brother's car for the next 3 weeks, so Im trying to fix the problem soon. Could it be plugged cats? Maybe I will try running open header...
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HungryHippo
Member # 537
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posted
bad grounds on the back of the heads?
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DaveG
Member # 1606
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posted
With a DVOM, sweep the TPS and look for a bad spot. I'd double check for a TPS code.
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MistaFosta
Member # 4068
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posted
quote: Originally posted by DaveG: With a DVOM, sweep the TPS and look for a bad spot. I'd double check for a TPS code.
Put in a TPS last night... No change. I also checked those grounds, they look fine, no corrosion, no opens.
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PunkINa5.SLOW
Member # 10
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posted
I think somehow you did something wrong when you put the fuel pump in just my .02
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MistaFosta
Member # 4068
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posted
quote: Originally posted by PunkINa5.SLOW: I think somehow you did something wrong when you put the fuel pump in just my .02
I guess i will pull it and check it again then. Its not really hard to pull, so no biggie...
What could I have done though, since it has the problem with a full tank also?
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MistaFosta
Member # 4068
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posted
K, checked fuel pressure, when stumbling is happening. Rock solid 41 psi...
So, Im guessing its the wiring for the ignition, primary or secondary. Any ideas still?
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forced331
Member # 1270
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posted
If you have an aftermarket ignition, that would cause the problem your dealing when an igition is bad.
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MistaFosta
Member # 4068
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posted
quote: Originally posted by forced331: If you have an aftermarket ignition, that would cause the problem your dealing when an igition is bad.
Stock ignition. Tommorow Im going to try puttin in an MSD just for fun...
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forced331
Member # 1270
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posted
Check for a pinched fuel line?
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MistaFosta
Member # 4068
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posted
Wouldn't I see a loss in pressure?
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DaveG
Member # 1606
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posted
Pinched / kinked fuel line you wouldn't necessarily loss in pressure, but a loss in volume.
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