seems that my car is having a fuel problem. i drive a 96 pontiac trans am. the car has a heavy hesitation top end, and now it's got a low-end stumble or hesitation. from all of my observations, the only conclusion that i can come to is that it's a fuel problem. my instructors at school have suggested that the problem is most likely the fuel pump and the fact that i need to install some rear o2 simulators where i removed the o2's when i did my header install. anybody know where i can get a good fuel pump that's not OUTRAGEOUSLY priced? the cheapest "quality" aftermarket pump i found was a holley pump but it suggests that it will need some alterations to make it fit... and that's not usually a good sign. i found a couple of others, but most are in the $200-$300 range. i found the OEM replacement part, an AC-DELCO pump, but it says that it shouldn't be used on any modified car.

any suggestions?

- jay

 

depends on how much power you are running through your car if you want to run a Delco replacement pump. or how much power do u WANT to eventually run through it

i'm in the midst of replacing mine and wasnt' able to afford a new one until just recently (cause i wanted to do a genuine delco replacement and the dealership wanted over $500 for one). however, i found one on ebay, brand new in the box for $150. i just sent the money today for it. the guy says he had several in stock, so if u want one send him an email. i dont' have his address handy on me right now, but his eBay ID is: klova
so u can get in touch with him through there. btw, the Delco part number is MU19. hope that helps

 

I'm suprised "teach" didn't suggest you put a fuel pressure gage on it and tape it to the windshield and drive it around. I'm also surprised he didn't suggest that you take care of the O2's before you start throwing money at the problem. I would also clean the EGR if you still have one. Clean the IAC and at most replace or at least test the TPS. But definately check the pump before you go to all the trouble and money to change it.

 

if you get a new fuel pump, thunderracing's racetronix kit is awesome. i JUST finished installing it maybe ten minutes ago, and the car pulls much harder up top. my old pump was hurtin pretty bad. anyways, its a walboro 255 lph and was only $150.00

 

actually, "teach" did suggest that i put in the o2 simulators before doing anything else. i've never heard anyone suggest using a fuel pressure gauge taped the window while driving down the street to diagnose anything, and i sincerely doubt that the instructors would let me borrow their fuel pressure gauge to go hauling *** down the street

i don't have an EGR anymore, but i will clean the IAC. i'm sure i'll feel like an idiot later for asking this... i think i know what it means, but rather than go off sounding like more of a dumbass, i'll just ask... TPS?

the o2 simulators will be first. and i fully plan on testing the pump before i replace it. but, from my understanding, that's where my problem lies... i could be wrong, wouldn't be the first time.

i'm not really looking for the OEM replacement pump because i'm already modded, and i'm getting ready to add on... so the factory replacement probably isn't a good idea. i will check out that pump from thunderracing tho.

any more help is greatly appreciated.

- jay

 

If you are into HP you should seriously consider owning your own FP gauge. Using a FP gauge under WOT is common practice for testing a fuel pump's capacity to keep up.

You can also perform a volume test by running the FPR return into a fuel can and timing how long it takes to fill it to the 5 gallon mark. This test assumes you know what the healthy spec should be and what your motor's fuel requirements are.

In most cases the WOT test is much easier and better as it lets you see the big picture.

 

next time i get an extra $40 i'll buy one... until then, i'm pretty much stuck with the basic fuel pressure test that i can do at school. problem is... i could buy one for myself... but then i'd be shorting myself some extra cash that i'm gonna need to fix my car with lol

btw... i checked out that racetronix fuel system on thunderracing, and assuming i'm gonna be replacing my fuel pump, that looks like it's definitely gonna be the route i go. thanx man.

anymore info is still appreciated.

- jay

 

For those that don't have a gage in the car, that's the only way to really test certain conditions. Many people have hauled hiney down the highway with a lot flimsier S@#$ on their car then a fuel pressure gage taped to the window.

The TPS is the throttle position sensor. And if your money is that tight, you may want to reconsider owning a near decade old F-body with a LT1.