C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

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Old Jun 14, 2007 | 12:37 PM
  #1  
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Default missing bad

Hello,
Yesterday my 1985 manual started to give me problems. After the car was warmed up I went to accelerate and the car bogged down. The Check engine light was on. The car began to regain power and I drove it to my mechanic friends house. He put his code reader on the car and it read "tps problem". Since I had not done it in awhile I changed the plugs, cap and rotor along with the tps. The car would intermitantly run ok then run really bad.Surging and everything. We kept trying to make adjustments to the tps. Black smoke and everything. Still running bad. Maybe worse than when we started.
Any help would be appreciated.
Thanks in advance.

MDred85
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Old Jun 14, 2007 | 02:17 PM
  #2  
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You should have trouble shooted (shot?) the code before you threw money at it. Until you trouble shoot, you have no way of knowing what went wrong on the TPS circuit. Never just shoot the messenger. Apparently it wasn't the TPS, itself. Now you can go back, start at the beginning, trouble shot the code, and see if you can find what went wrong.

RACE ON!!!
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Old Jun 14, 2007 | 02:20 PM
  #3  
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Originally Posted by MDred85
Hello,
Yesterday my 1985 manual started to give me problems. After the car was warmed up I went to accelerate and the car bogged down. The Check engine light was on. The car began to regain power and I drove it to my mechanic friends house. He put his code reader on the car and it read "tps problem". Since I had not done it in awhile I changed the plugs, cap and rotor along with the tps. The car would intermitantly run ok then run really bad.Surging and everything. We kept trying to make adjustments to the tps. Black smoke and everything. Still running bad. Maybe worse than when we started.
Any help would be appreciated.
Thanks in advance.

MDred85
Typical behavior of a bad MAF Sensor. Swap it out with another to verify my hypothesis.
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Old Jun 15, 2007 | 12:15 AM
  #4  
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MDred85
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Hello,
Thanks for the replies. CFI EFI you are right. When the code said bad TPS when took that to mean that the sensor was bad. I will try to find access to a good MAF to swap out. Again thanks for the replies.

MDred85
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Old Jun 15, 2007 | 12:26 AM
  #5  
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Originally Posted by All2kool
Typical behavior of a bad MAF Sensor. Swap it out with another to verify my hypothesis.
Had the same problem with black smoke,running rich and poorly and the MAF was bad.Be sure to check the relays to ensure theyre good too.
Theyre cheap enough to change them out.

Also,even though you installed a new TPS,if you messed around with the TB screw for the blades,its gonna be way OFF as well.

Never adjust the screw to the TB blades,without doing a proper minimum air speed,tps and iac adjustment.
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Old Jun 15, 2007 | 08:19 AM
  #6  
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You mentioned plug, cap and rotor. Did you check your igntion and coil wires, too?
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Old Jun 16, 2007 | 12:33 PM
  #7  
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MDred85
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From: Det.Mi.U.S.A.
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Hello,

Thanks for the replies.
We inspected the wires for obvious problems. Since they were decent quality from the beginning and not a lot of use on them , we gave them a pass for now.

Bills86, could you give me a little more info on the second part of your assessment. The adjustments that you were mentioning?

Thanks in advance.

BTW. I inherited an 86 shop manuel for my 85 (in rough shape) so if any one can point to certain areas of it that I need to addresss I would appreciate it.

MDred85
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