I'll give yall some background to get up to speed about my swap. Most of these parts were bought back in 08 and weren't used untill a month ago or so.

So I just recently started the car up and adjusted the Fuel pressure regulator W/Return (Keep the stock Fuel tank and installed a Grantelli 255lph Fuel pump) at 58psi. Today i start it up and the fuel pressure is all over the place, varying from 38-43psi and adjusting the screw in doesn't raise the fuel pressure. I hope it isn't the fuel pump biting the dust, now that i think of it maybe I need to replace the Fuel filter? If i have to drop the tank im going to be pissed. Thanks for yalls help in advance..

 

Anybody Bueller Bueller ?

 

could be the fuel lines. are they the stock ones? or the volts i had the same problem got from 60 all the way to 25 then cut off. i had a clog in my line and my wiring was f'd up. check those before you go changing fuel pumps

 

The first Walbro 255 I had lasted about for about an hours worth of run time before the fuel pressure dropped to around 33lbs. I think the Grantelli 255 and the Walbro 255 are the exact same pumps. I got my second pump from Racetronix and haven't had a problem with it. From what I’ve read some vendors have a cheaper less reliable version of the pump.

 

Now this is what I did and didn't want to hear lol. I figured I got a cheap fuel pump, cause now its fluctuating more than it was before. So right now i'll start the car and the pressure will be at the 58psi set and it will slowly go down from there. When I rev it up it goes up a bit but then falls down even lower. Im still going to drop the tank to check for anything abinormal.

 

You know im really glad i have an External Fuel pressure regulator, how would I of seen this coming ? I ran it alittle bit last night and it would jump up to 58psi when i started it then slower but surely as i revved it up bleed off the pressure till it got around 38-42, then it started flucatuating from 20-40psi.

I did swap out the 30# injectors for the stock ones and that made it idle a ton better on a stock tune.

 

I just thought of something else, I left all the stock TPI Fuel lines/EVAP vent line in place. I capped the EVAP Vent line, would that be causing this problem ?

 

They are all Walbro pumps. I don't think anyone else is making them. Racetronix is walbro. That's what I have in my car.

 

Just had my Walbro 255 pump take a **** on me about two weeks ago. I had only been driving the car for about a month and it went out on me while I was crossing a bridge. I can hear my pump run but it does not produce any pressure at all. I left my vent line open because under WOT the pump can produce a vacuum in the tank, and when the car is off it keeps the tank from pressurizing.

 

Thanks for the reply. Yea im really having these mixed reviews on the pump. I guess i'll just have to drop the tank and see wtf is going on, so i guess racetronixs is the best place to get a pump, what about anyfrom jegs ?

 

Bought mine from Jegs, it was an edelbrock drop-in but the pump had "Walbro" stamped on it. Good thing about buying from Jegs, I have 3 years to turn this pump in as a defective unit and they'll send me a new one free of charge. Some of us must just be getting a bad batch of pumps, kinda sucks because I hate taking my tank down.

 

having fuel pressure issues myself did the corvette filter and capped my vent to the purge canister going to swap filter first then check voltage to pump gosh i hate dropping my tank but we e gotta do it

 

Did you connect engine vacuum to your fuel pressure regulator?

 

Don't believe thats needed, only for boosted aplications. Of course I maybe wrong.

I uploaded a short video of what its doing on youtube. Please excuse the crappy HTC EVO Video clip quality.

http://www.youtube.com/watch?v=A6iZpdFgnJ8

 

So i dropped the fuel tank over the weekend, I didn't visible see any signs of failure. Of course the pump could be going bad internally. The one thing I noticed after the fact of install this pump is the wiring harness that connects from the factory harness to the pump is 18gauge wire, WTF. Why would you go from 14 to 18 guage wire ? When i get the new racetronixs pump im going to soilder in some 14awg wire if that harness doesn't have it.

 

Just ordered my Fuel pump kit from racetronixs, going to have to wait till Dec 1st to get my pump. I miss jegs shipping =(

 

Im debating on geting the Hotwire kit, suggestions or advice ?

 

I didn't need the extra copper on my '82, just have good clean grounds and positive crimps & solder on my harness connector pins.

The GSS340 gerotor pump uses less amps making 58psi than the factory Delco TPI turbine pump at 43psi, so unless your rear harness is trashed there's not much reason to upgrade the wiring IMHO.

 

Nope, you're right. Not only not needed, but will mess up the fuel delivery and cause leanness and high LTFTs.

 

Good news to hear, the Fuel pump i ordered is part number-GSS340M so its a older model. The pump i just pulled out was the F20000169.

My rear harness is in perfect shape visually, along we all know how copper stranded wire gets corroded after time. I do however find it strange that they go from 14awg wire to 18awg with the fuel pump harness in the gas tank.

 

I haven't had any problems with the smaller wire with either my Walbro 255, or a stock 4th gen tank/pump.

 

Also good to know, i guess i just had a bad pump from the get go. I guess im just trying to understand the logic behind doing it.

 

Did you remove the OEM intank regulator?

 

It's originally a tpi car so no intank regulator.

 

Here are some pictures of the new pump I installed last night, man what a difference between the two. The Racetronixs pump is almost 2x heaver than the Granettli walbro pump and check out that wiring, I knew i was on to something when i saw the gauge difference.

The First picture is the Granettli pump, next picture is the difference between the two wiring harnesses and the final picture is the new Racetronix walbro pump. Enjoy

 

Just checking in, The fuel pump was the problem. It not moving a bit now woo hooo !!!

 

guys u may want to drop ur tank even before ordering a pump mu rubber connection hose was the prob! i did however replace the pump while i was in there! just sayin may be a less expensive alternative i could have only replaced the hose for about 2 bucks but i had all the labor invested!