strange problem

[usp55]

ok so here is my problem, when i go to accelerate my car seem to go in and out of power. my foot is steady on the gas but the power drops for a second or two and then comes back. sometimes the car stumbles ata red light if i go to launch. also i can never start the car on first turn of the key unless i drive to the store and its warm and then go to start it back up. Mornings usually take 3 tries to start it. i have been dealing with this for ever and i thought the power coming in and out might have been my trans slipping from gear to gear but i just had it rebuilt 2 weeks ago ( new stall, rebuild, shift kit)

the hard starts were before i had the engine rebuild and after. new starter, newish fuel filter. New fuel pressure regulator.

i have no idea what it is

oh also the other day i went to the gas station and put $20 in the tank and then i went to start it back up and had a good crank btu wouldnt start. wouldnt start for 10 min and 8 tries.

now i have had a fuel pressure meter hooked up and when i run the car or prime the pump i get a reading but as soon as the either the pump starts its prime or i shut it down the pressure drops to zero instatly.



WTF it is.....fuel pump? prob the only think i have not replaced on the car. would that cause drops in power and hard starts even though i hear it prme for 2-3 seconds.?


oh one last thing sometime its like i dont have any pop from a red light, but after it runs for a mile or two and i shut it down and restart it i instatly get my power back and can easily chirp my 315s from the next red light....explain that. haha


sorry for the rant and random thought but this is really bothering me

[hockeyman]

Re: strange problem

Sounds to me that it's either a tuneup issue or the fuel pressure regulator is bad...or maybe both. Could also be a clogged injector.

Hard startups shouldn't have anything to do with your trans. You say that it stumbles at a launch, but how does it idle? If it idles okay (in gear), then that leads me to believe that you don't have any issues with the torque converter.

Do you have a check engine light at all?

[usp55]

Re: strange problem

no check engine light

this has been a problem for 2 years now atleast with the hard starts. i dont see how its a tune up problem as i has=d the entire engine rebuild and still had the problem. trans is rebuilt with new stall, less than a 1k miles. stumbles at some launches but not often, today i went to launch and it almost stalled on my it stumbled so bad like it just had no fuel or something. i checked the old fuel pressure reg and there was no fuel getting by nor holes in the diaphram etc. I replaced the regulator with a holley adjustable reg so i know that new and working properly.

i seafoamed the car (one can in the tank for the injectors) and no change in the problems.

i have no idea


oh all brand new msd wires, plugs arm fairly new.

[tkoforpresident]

Re: strange problem

crank sensor/sensors

didn't you say you were getting a code for that not too long ago :poke:

[usp55]

Re: strange problem

i had that code after i changed my tensior for some reason, but then never came back. right after i changed the tensior i had catostophic water pump failure, trany lost 1rst gear, and something else happened but i cant remember. I have not seen that code in weeks and i drive my car 80 miles a day.

also these hard starts have always been an issue (going on 2 years now)

im reading about the rlief valve on the pump that should hold pressure in the lines, and i know i drop to zero pressure seconds after it stops so im thinking it has to be the pump

[Blizzard242]

Re: strange problem

Now, hopefully someone will correct me if I'm wrong, but don't Fuel filters have check valves in them??? That'd be a quick easy inexpensive fix. Other than that, I'd guess the pump is on it's way out.

[flamingchicken]

Re: strange problem

its fuel or air...fix the easy stuff first. IAT, air filter, fuel filter, and the like.

[Blizzard242]

Re: strange problem

air wouldn't have anything to do with him loosing fuel pressure. He could run his car with his IAT sensor disconnected even. I did it by accident for a day.

[speedingturtle]

Re: strange problem

what about the TPS? i've had a few cars that gave me the same problems. changed the TPS, and cleared it up. may be wrong, but just a thought.

[steddy]

Re: strange problem

A few years back, I grabbed one of those hoakey little doo-dads from Summit, where you plug it in between the lead to the TPS and the TPS itself. Car did the same thing. When I got it out of there (it was supposed to stop the lag at WOT, BTW). Car ran FAR better. You wouldn't happen to have one of those in there, would you? The symptoms just sound strangely similar.

[Rob Bell]

Re: strange problem

Your fuel pressure immediately dropping to zero is a symptom of a bad regulator. Many other posters here have mentioned that faulty regulators cause quick drops in fuel pressure and hard starting. I would suggest checking that first. Just because it's newer does not mean that it's not faulty. I have not personally dealt with one, but others have stated that if you pull off the vacuum line and gas leaks out, the regulator is bad. However, no gas coming out does not mean that the regulator is NOT bad... Just that it's not leaking fuel to the vacuum side. Since it's immediately dropping to zero it sounds like it is stuck open.

Since your symptoms point to the regulator, and it's (I hope) not too expensive of a part, I would suggest further testing or just replacing it and see what happens.

[usp55]

Re: strange problem

ok so i driving to work today and the car is surging at highway speeds, acting realy strange. Almost dies if i give it gas from a redlight. get over the bridge and sit in some city traffic and it almost dies on my twice if i let it idle without some pressure on the gas.

finally make it to the parking garage and go to put it in reverse to back into my space and it dies. couldnt get it restarted and the crank was strong. i went to see if i could here the pump prime and i couldnt hear it the first time (maybe i just didnt hear it cause i had the cutout open and the radio blasting the entire way over and my ears might have been pissed at me). Im changing the fuel pump tonight and will hopefull be finished by tomorrow some time. ill let u know what happens if i make it home tonight.

no fuel on the vacum side of the AFPR

thanks for all the responses

Oh also im just gona pick up a new TPS if the fuel pump does not so the trick. How hard it that to change out, never delt with that sensor or even know where it is, im assuming the throttle body.

[steddy]

Re: strange problem

How about the vacuum poret on the throttle body? It'll be on the left side. I had problems when that elbow went bad.

[flamingchicken]

Re: strange problem

air wouldn't have anything to do with him loosing fuel pressure. He could run his car with his IAT sensor disconnected even. I did it by accident for a day.

i didnt read the part about him losing fuel pressure. i was going back to the basics of what you need for an engine to run-fuel, air, fire, and compression.

[usp55]

Re: strange problem

ok so i got the new fuel pump in and it took about an hour by cutting the door above the tank. but i have another problem i guess

hook it up go to see if it primes and it does...turn the keep and she started right up (never done that before unless it was sitting for less that a half hour) but looking back at the hole i start to notice smoke....wtf. i shut it down real quick.................

im an idiot....its late, had a long daym and i just realied what it was (i hope). i have a cutout open under the pass side seat, it was prob exhaust coming up out of the hole. gona go hook it back up and close the cutout and see if there is any smoke. give me a minute :rant:.