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

What next??????

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Old May 27, 2010 | 10:58 PM
  #1  
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From: Van Horn Tx
Default What next??????

Okay, here we go. 1989 Coupe. Was running great. Then it felt as though I had gotten some bad gas. Started getting sluggish. Filled tank and added Lucas. Not much help. New plugs, cap, rotor, fuel pressure regulator, gutted cat conv. Running extremely sluggish. Now power under load. Seems to get weaker and weaker the further I go. ECM? Pre cats? I'm at a loss.
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Old May 27, 2010 | 10:59 PM
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From: Van Horn Tx
Default oops

oh yeah, new O2 sensor.
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Old May 27, 2010 | 11:19 PM
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Check fuel pressure. Also tape the gauge to the windshield and check under load.

Possible injector issue, try to ohm injectors hot and cold.
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Old May 28, 2010 | 12:51 AM
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From: Van Horn Tx
Default oh yeah

another symtom, as it gets worse, it seems to be backfiring, not from exhaust, but from under the hood. ???
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Old May 28, 2010 | 01:08 AM
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Spark control unit or distributor sensor.

Probably dist. Craps out in the heat.

Check FSM for troubleshooting
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Old May 28, 2010 | 01:26 AM
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distributor sensor?
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Old May 28, 2010 | 01:38 AM
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Your symptoms are identical to what my 86e encountered.

The dist was my culprit. Could be the same for yours.
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Old May 29, 2010 | 12:02 AM
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tested ignition control module (distributor), it started faulting once it was tested a few times and heated up. I replaced it today. The car ran better, but still no where near as good as it should. It threw codes 13 and 22. oxy sensor (which has already been replaced) and TPS circuit. Tested .55 volts (within specs). Could the ECM make it behave this way? Can an ECM be tested?
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Old May 29, 2010 | 01:49 AM
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Just ohm tested all injectors. the engine was not cold, not quite warm. not driven for apporx 3 hours. most hit .012 or .013. one hit at .010 and one at .005. could this be bad enough to make it run this poorly?
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Old May 29, 2010 | 08:18 AM
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Originally Posted by bigasswop
Just ohm tested all injectors. the engine was not cold, not quite warm. not driven for apporx 3 hours. most hit .012 or .013. one hit at .010 and one at .005. could this be bad enough to make it run this poorly?
Yes.
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Old May 29, 2010 | 08:32 AM
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Look at the injector sticky at the top. You probably have other issues, but I would start with a new fuel filter and injectors. Get them from Jon at FIC!
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Old May 29, 2010 | 08:38 AM
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When my Catalitic converter broke apart inside and started to clog up my power started to go down also.. Just a thought since you may have more then one problem going on at the same time..WW
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