Fuel pump problems

[DirectConnection]

Just recently, my fuel gauge started moving more than normal on acceleration. I didn't think much of it at the time, until a few nights ago doing some street racing where I ended up starving the pump hard core with a 1/4 tank (never ever been a problem with this car). The car essentially bogged real bad on the 1st series of races when I floored it (very embarrassing... read my post in street stories under best VNT race yet! I won later on btw;-) The 2nd series that I won, I noticed that the car just stopped pulling at 130mph. Pulled hard at 120+ just peetered out at 130. I added a few gallons before those runs as I figured it was the pump having issues picking up the fuel. I have run the car hard at that speed before so I know it certainly was far from done at 130.

Can anyone tell me what is happening to the pump assembly? I figure something's loose now, pickup fell off, or...?

Also, I don't understand how my pistons made it through that.... 4 times!

I replaced the pump in thge car 2 times. 1st time... aftermarket oem type replacement and 5k miles later, pump won't hold more than 67psi at 4,000 rpms... and falling. The pump in it now is a back up correct application used pump that worked fine for the past 30,000 miles that I installed 4 years ago.

Thanx.
Steve

[SUPER60omni]

the pump is probly fine. the problem is most likely the power supply to it. this is a common problem with many older cars (DSM's ALWAYS have this issue!!!!) my friends GLHS had the same problem. We noticed it on the dyno on the under hood FP guage. it made it to like 68psi then dropped down to like 61psi still @ 30psi boost
To solve this problem get a heavy duty relay some 4 or 8 guage power wire for a stereo, and a distribution block and a fuse. run the power wire to the trunk or back seat (wherever the pump is) find the wire powering the pump (green on my omni) cut it and use it to turn on the relay then connect other side of relay which now uses the large power wire. this stops voltage drop to the pump and is the only way to max out a pump, even a 255. good luck.

[minimopar]

Quote:

Originally Posted by DirectConnection Can anyone tell me what is happening to the pump assembly? I figure something's loose now, pickup fell off, or...?

You may have lost the pickup sock or the plastic baffle around it popped loose from the bottom of the tank.

Quote:

Originally Posted by DirectConnection Also, I don't understand how my pistons made it through that.... 4 times!

Luck, probably. You probably went from running straight to miss-firing before it had a chance to really detonate hard. I would do a compression check, though.

Quote:

Originally Posted by DirectConnection I replaced the pump in thge car 2 times. 1st time... aftermarket oem type replacement and 5k miles later, pump won't hold more than 67psi at 4,000 rpms... and falling. The pump in it now is a back up correct application used pump that worked fine for the past 30,000 miles that I installed 4 years ago.

FPG would tell the tale.

[_9_]

don't ever just rely on fuel pressure, always measure fuel flow. I'll have to find my spec for good fuel flow.

-Courtney

[86Shelby]

With the engine at idle you should be able to get a bare minimum of 1 pint in 15 seconds. I prefer to see closer to a quart if the engine is anything above stock. This is done with your fuel pressure gauge hooked to the schrader valve and the botton or port open to measure the flow. Make sure your hose is long enough to get to a catch can on the ground. Also, take notice of the fuel pressure while doing this to make sure it doesn't drop much.

[DirectConnection]

Thanks for the input guys. I think Russ is on the right track, though. Seeing that fuel is sloshing around alot and showing on my guage tells me the fuel is being starved due to a physical situation at the pump.

I'll just steer away from running it real hard and keep more fuel in it at all times. Hopefully have my Intrepid back on the road again, soon. Then focus on the other VNT Shadow project and temporarily retire this one.

[DirectConnection]

I forgot to ask about the differences in tanks and the baffles. I heard the older tanks have a baffle, yet the ones from an R/T ('91+) don't? I think a later pump has a resivoir in place of using baffles?

So, whe the time comes, I need to look for the baffle in my tank? What secures it?
Thanx

[PARAZIT]

I have fuel issues with my Dodge Shelby Lancer. I was wondering if the turbo pumps are the same, because I have T1 pump installed right now. I am running 14 psi of boost and a larger Volvo intercooler.

Thank you for your information.

[DirectConnection]

I believe they are the same pump. I am speaking from my experiences which are for a '90 model VNT car. The stock oem pump has a sticker on it that says: TURBO/V6 Not sure if there was a difference in the earlier years like your Lancer, though. But, whatever you do... don't get a pump from the parts stores like I did. It will work, but mine was weak and couldn't sustain the fuel flow needed at even the stock 12psi my car came with. Get a Mopar unit, or one of the aftermarket Walbo ones. (Holley?)