MooJohn

When I got my car I was told it had a Walbro pump. It's loud as hell sometimes and other times it's pretty quiet. Today was my car's first road trip and it started sputtering at part throttle after maybe 2 hours of driving. The pump was waay loud at this time.

I was at 1/4 tank but filled it up again in case it was an overheating issue. The pump was still loud and it still sputtered trying to pull away from a stop. I removed the 12v jumper wire in the underhood test connector and the car ran well enough to drive the 50 miles home. The pump was much quieter too. It still sputters at part throttle and only sometimes clears up if I go WOT. Today was the first time in my year of ownership that I've driven longer than an hour and only now has this problem shown up.

I think whatever pump I do have is failing. Jumpering it to 12v shouldn't hurt anything - I've done that for years on other cars. I think the pump was either a knockoff Walbro or a downright fake.

Anyway, my SC isn't a performance car. Is there any reason I shouldn't buy a stock-spec replacement pump on ebay for $40-$70? 90-100 lph is plenty of flow. I think it's hilarious that AutoZone wants $250 for a plain pump. Denso would be nice but even $150-170 is too much if $50 will do the job.

MooJohn

Really? Everybody is either running OEM or Walbro, with nothing in between?

I don't mind being the first then. $50 isn't much of a risk and it's not all that hard of a job in the SC.

This issue led me to do more research on my super-pressurized gas tank and I might have some useful info to post when it's all finished.

Retox

Are you sure its the pump and not the fuel pump ECU?

MooJohn

It's been wired for 12v since I got the car. That rules out the FP ECU. When I removed the jumper to get the car back home, it ran ok but is back to hard starting - I have to hit the gas pedal to get it to start.

I think the pump is overkill for my car and when given 12v it heats the fuel too much. Combine that with a inadequate evap canister setup my fuel system is just fubared. I'm nowhere near the only one with the pressurization problem and the fix looks pretty simple and cheap. That'll be a new thread when I verify it.

The car runs fine after sitting overnight so I think I'm on the right track. The other fun part of the trip is now I have proof of a leaking rear main seal. Yay! 3k rpm @ 80 mph really accelerates the oil loss. Right now it's cheaper to top off the oil than to fix

When I come up with the cash to get that fixed (too involved for me to handle) I'll try to get a torque converter upgrade at the same time.

MooJohn

Just for those searching in years to come...

The cheap pump works great. It fit fine, is almost silent, and the car runs fine. It came with a sock, short piece of hose, and worm clamps for $30 shipped.

I did find the cause of the Walbro's instability. The previous owner did not put a clamp on the rubber line between the pump assembly and the rest of the car. Fuel would spew into the tank and the Walbro would get super hot trying to keep up with the demand. It's a miracle the car ran at all.

The electrical connectors were also rigged. It looked like the factory connectors (small spade connectors) were shoved into the pump's plug that required large spade connectors and then electrical tape was jammed in to wedge it all in place. Yep, inside a fuel tank is exactly where you want sketchy electrical work!