GEO Prizm

1994 GEO Prizm Fuel System Stalling When accelerating Always

Car will idle, can be accelerated gradually. Will always die at full acceleration under load. replaced filter and pump.

You should have good pressure now, has this been confirmed with a gauge?

You may have a sensor problem like the TPS or MAP/MAF (depending on engine size). Does the check engine light come on? If yes I'll give you a link with instructions for checking trouble codes.

I had diagnostic check through, reads and bypass. No fuel pressure test as there are no easy places to get onto. No check engine light. I'm still thinking this is fuel. Is there any other regulating device, or control that would keep the injectors from fueling at open throttle.

Yes the sensors I mentioned. These are rather difficult to check without diagnostic equipement.

Does this happen when the engine is cold or only at operating temperature?

1992 GEO Prizm Engine Vibration When idling When warm 

i have a 1992 geo prism lsi i did a complete tune up including a new o2 sensor. when i drive it its fine still has full power but when its idle i get a vibration. prev owner stated the transmission was rebuilt and when it was set back in the o2 sensor wire was crushed possibly shorting out the cars computer please advise thanhs!!!!

Check your motor mounts. As far as the shorting of a control module, this needs to be checked with a scaner. Check with your local parts supplers. I understand some offer the service free of charge or at a nominal fee. If a code is retrieved, see if they have access or information on how to get the correct flow chart to help pinpoint the problem. It may be a whole series of tests but it is important to follow the whole process or you may wind up just throwing parts at the vehicle before you find the right cure. As far as the motor mounts, I have seen from past experience with several different makes of vehicles that this can in fact be a major cause of vibration.
Good Luck,
Paul

1991 GEO Prizm Engine Tuning When idling Always

1.6L LSI 4AFE. Idle speed not stable. Not surging, just wandering. Too much drop in idle when put in gear. Have had to idle it up to 1,200rpm - drops to 700rpm when put in gear with breaks on. If adjusted to near factory spec (about 750rpm idle) it luggs and vibrates badly when put into gear (breaks on). This is in addition to the non-functioning A/C idle-up vacuum switching solenoid. (I can't use the A/C at idle as the speed drops to 350rpm - almost a stall condition - and it shakes like crazy. Part on order.)

Have not found any vacuum leaks. Most vacuum hoses are new.

Have you checked the TPS?It sounds like under load you're not getting either enough of a fuel demand or possibly air intake.Also check around the intake manifold itself.An air leak in the intake gasket can also cause this type of problem.You might try if you havent done so already have a diagnostic scan done to see if any problem codes are retrieved from the ECM.There are a few parts chain stores that are doing this for free or at a nominal charge.If it is in a sensor,a code should show up.The O2 sensor and injectors(if so equiped)come to mind here also.
Good Luck,
Paul