rogerdoger1993

As the title says. The car has a slight hesitation at part to full throttle at the lower rpm's. It happens for a split second then it goes away and the car accelerates normally. I have changed TPS sensor, opti, plugs, wires, fuel pump/filter and 02s. However, I tried disconnecting the TPS sensor and the problem goes away entirely. Other than the fact that the car has a SES light and a very slightly higher idle. The problem goes away. I have already replaced the TPS sensor and that did not help. Any suggestions?

tehcarguy

Are you sure you adjusted the TPS correctly? You could always ohm check your injectors.

rogerdoger1993

I don't think you can adjust the TPS on the LT1. As for the injectors I am running 36lb accels. And the ohm test is uniform across all the injectors.

rogerdoger1993

any suggestions?

ex-x-fire

I have heard of guys drilling out or slotting the tps holes to make slight adjustments.

dewfall

I have the same sort of problem with my '94 LT1. At idle and in park, if I stab the gas pedal quick and hard there is a delay or hesitation in the engine revving up. Like you say, it is only a split second hesitation, otherwise power seems strong and smooth throughout rpm range. Hopefully some good advice will emerge.

toptechx6

This is probably a stretch, but I'll toss it out since it seems like you have covered the bases. I notice in my 93 FSM there is an EBTCM relearn procedure for the ASR whenever the TPS is replaced, it must be performed using a Tech1 scan tool. The ASR system has the ability to reduce throttle opening and pull timing when functioning. Out of curiosity have you checked for hesitation with the ASR switched off? Just an idea, good luck.

FireRoc

This is a flyer....but just in case.

A lazy O2 sensor can cause a hesitation under light acceleration or revving the engine while stopped when running in closed loop. I've had this happen to me.

When you remove the connector to the TPS that may cause the engine to go to open loop which means it is no longer looking at the O2's and hence will rev normally.

Not saying this is it, but if nothing else works............

rogerdoger1993

I tried unplugging the O2 sensors and it still does the same hesitation thing.

rogerdoger1993

any suggestions?

TWISTERUP

Since you have a SES light--what code do you have ?

rogerdoger1993

Code 22.... but that is only because is disconnected the TPS. With the TPS disconnected the car accelerated really smoothly. I have already tried replacing it and that didn't help.

96GS#007

36# injectors? Is the engine otherwise stock? If it is, you're flooding the thing. If the engine is not stock, what are your other mods? You must be pushing some serious hp because I'm over 500 with 32# injectors.

GREGGPENN

I think you've hit the nail on the head. Even if a new tune has been burned, you may need to remove most, if not all, of the acceleration enrichment value. This controls how much fuel is "dumped" when you stab it.

dewfall

Could this problem also be caused by a faulty fuel pressure regulator? Also I just installed a set of FIC's rebuilt Bosch III 24lb. injectors and wondering if a tune is needed now. I was under the impression that they were direct stock replacements.
I'm not trying to hyjack this thread, but expand on the OP's original issue.

rogerdoger1993

You hit the nail on the head. I did a data log and sent it to PCMforLess and I am waiting to here back from them. Hopefully they can re-flash the chip they made me and get this solved.

rogerdoger1993

Ok I finally figured out what the problem was. Bad injector or injectors. I put on the stock injectors and the car ran great. The resistance on all 8 injectors is uniform across the board. But obviously one of them isn't flowing properly. I took a chance and bought them off of some kid on craigslist. And I got taken for $120. This time I am not going to be such a cheapskate airline pilot and just spend the money on new injectors.

bjankuski

The problem is the stock tune with 36 lb injectors. If you put the stock 24 lb injectors back in and the car runs fine with a stock tune then the car needs to be retuned to run the 36 lb injectors. If it is not retuned it will run very rich.

rogerdoger1993

The car was tuned for 36lb injectors. But one of them was bad from the get go. I didn't realize accel made crap injectors.

adamzane

i recently replaced my fuel pump. the old pumps strainer had gone bad at was torn and it allowed the pump to fail . Anyway the problem is now when i get on it there is a slight hestitation like it is fuel starved or something. never did this before with the old pump. So i am thinking i must have a pump that just can't keep up with the fuel demand. I tested the fuel presure and it was good . Not sure about under load . So i am thinking of going with another fuel pump any ideas????????