QuestionDear Kris:
My question concerns a 1989 Pontiac Grand AM with a 2.3L engine, code U. The car has 115 Kmiles and was aquired at 107K.
Under normal acceleration the car is fine; however, when accelerated to full throttle the enging lurches violently. The check engine light flashes and the speedometer drops to zero. Generally this will continue for 30 to 60 seconds and then the car accelerates normally again. I have been told it may be a speed sensor I think it was called.
The Haynes manual engine troubleshooting section, section(11), instructs to check: 1. plugs and wires, which were fine; 2. fuel pressure, which I skipped temporarly; 3. fuel filter, replaced since it was never done since we have had the car: 4. intake manifold leak, found loose TBI bolts, replaced gasket and tightened bots snugly, as I had to remove valve to replace valve cover gasket which was leaking badly; and 5. ignition timing, will check after fuel pressure.
I think fuel pressure and timing will be good as car generrally runs very well with the exception of the full throttle bogging and lurching.
Please give any advice you think is helpful so I can make this care reliable for my son's use. Thank you very much for any information you can provide.
Sincerely,
Joe
AnswerThe fuel pressure check may show an issue Joe, but TBI is a low pressure system not much higher than a carb. What you might have is a bad injector though. It will work fine till wot and then the delivery is not constant and is therefore causing problems. Also check to make sure that there is nothing electrical being disconnected or grounded or anything by the cable when you are hitting the gas. Check the harness going to the injector to make sure there is no messed up or shorted wiring that is causing a bad connection. It might also be a good idea to check all the grounds in the engine compartment and to the computer. This can cause huge problems. Hope this helps and good luck :)
