Mechanics

88 WONT SMOG

1988 Pontiac Sunbird • 4 cylinder FWD Automatic •

I took my sunbird to get a smog test, and as I expected (due to californias new smog laws), I didnt pass. So I do a full tune up (oil change, oil filter, air filter, fuel filter, spark plugs and wires, flange gasket on exhaust manifold, oxygen sensor, reset timing. I also put a bottle of fuel system treatment in the gas tank before the 1st smog test and a bottle of octane booster before 2nd smog test.I even put the original muffler back on that the previous owner had replaced with straight pipe.
so, after all the repairs are made, I return to the smog shop for my free retest, feeling rather confident, I might add.
And the guy returns with ABORTED TEST written on my receipt. He said timing was accurate but he wasnt able to get my car to stay running at the 15mph or 25mph without "bogging" down and loosing power. Ive got no idea whats causing this to happen. I dont have any serious vacuum leaks but ive noticed that im burning through gas a lot faster than usual. Please help
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Demlshn
March 8, 2011.



Do you have a check engine light?

Bogging and lagging acceleration could be caused by one of the following below

Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Crankshaft position sensor
Knock sensor
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note: If it doesn't apply disregard it and keep testing.

Rasmataz
Mar 8, 2011.
Good advice but im way ahead of ya. I pulled each sensor individually and tested them as described in my manual(voltage, resistence, etc.). They all checked out fine. I even pulled my injector and replaced the seals on it. My timing is right on the money. I havent checked my fuel pressure regulator yet. I guess thats next. I had a friend plug his diagnostic code reader into my ALDL link and on the screen read "cannot communicate with vehicle computer system". Although, I was able to retrieve a code with a jumper wire from the test to ground link on my ALDL plug. The only code that displayed(by way of a flashing check engine light) was Trouble code 12. This indicates that the diagnostic system is working properly. Needless to say, the vehicle doesnt seem to realize its malfunctioning. According to the smog tech, the bogging down is not caused by any of the repairs ive recently made to the exhaust/emmisions system. He feels its not related, yet could have occurred while tinkering under the hood.

Tiny
Demlshn
Mar 8, 2011.