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Walbro pump Giving up??


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Hey Guys. I havn't posted for a long time mainly cause my car has been Great!

But.. The other day I went for a regular trip to The Gap. While I was thrashing I had a few lean moments and then the car shut off. No restart. I snooped around and found my Fuel Pump fuse in my MS relay box had popped. Replaced the fuse and the car started. And then Died a couple minutes later. Popped fuse again. Let it sit for a bit and put a new fuse in. The car got me home but was pushing 15-30lbs of fuel pressure. I have a permenentally mounted Fuel psi gauge on my passenger incpection lid. It's tapped into my Aeromotive 1.1 regulator.

 

So today I started the car and took it for a drive. Still Very low fuel psi. Brought it home. Checked for proper voltage at the pump and relay box and all looks well. Drained the tank of gas, it was Clean. Disconeccted all the fuel lines, all are braided with AN fittings, Cleaned the Aero1 fuel filter, Blew through all the lines and put it all back together. My fuel supply lines connect to a rear sump box on the tank and it does not have a pre/sock filter.

Cranked the car. Fuel psi is back to good. I do notice the pump whinning a little more than usual but these Walbro pumps are loud always. Take it out for a spin. Boost it to 14-15 psi for 2-3 miles and all is well. Go to turn around to go home and fuel psi cuts to 10psi. Car doesn't die but barely idles. Pull over check the fuse and it's good. Restart and it runs fine. So I decide to drive some more. When the fuel psi starts to drop, if I put the car in neutral and shut it off and then restart it will run Great for a mile or 2 and then do it again. Over and over. Like something is abstructing the fuel line. But everything that came out of the tank was very clean and I had the tank cleaned and sealed about 1.5 years ago when I welded on the sump box.

I wonder if the fuel pump may just be crapping out or if it's something with MSII?

 

any suggestions?

 

thanks

tc

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Isn't this the second Walbro 255lph pump problem within the last few weeks? Who had the similar problem in the recent thread?

 

I need to hook a P gauge up to mine so I can watch it while driving. Mine began sounding funny sometime last Summer. AFR seem OK with mine and it never dies....knock on wood.

 

...try running some temporary wires to the pump to bybass what you are using just in case something is shorting out. See if that changes it.

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Yes.. Actually.

 

I ran a hot wire from my battery disconnect switch in the cockpit to the fuel pump. Altho the problem wasn't as bad it was still there. Shut the pump off momentarilly and restart and go again for a minute.

I guess it's time for a new pump??

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Yeah. Let us know if the new pum fixes it. The last thing I want to happen to me is to get stranded with a flatbed fee back home because of the damn fuel pump. Maybe I should keep a backup one in the car.

 

How is your ground wire?

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Think I'll try another ground wire just to see. All my wires are new, big and multiple but who knows?.

The stock replacement pump used a different connection than what my line fittings will connect to. On monday I'll get some and try the new pump.

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So you added a low psi pump at the tank to push fuel to the Walbro?

Still doesn't make sense. Why would the Walbro work fine for soo long and then all of a sudden need to be fed.?

I was looking at my setup and even tho I lowered the pump as low as I could with the stock pump hanger I think lowering the pump as low as the bottom of the tank may fix the problem. From what I have read the Walbro is not a good suction pump but a pusher pump.

Seeing as I have done alot of hard driving with 1/4 of a tank and the bottom of the pump hangs about 2.5" above the bottom of the tank, I think starvation is the culprate. I am going to make a pump hanger that puts the pump lower and see what happens. This pump may be already smoked tho. But worth a try.

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My Walbro pump is mounted inches from the tank outlet. The pump is about level with the bottom of the tank but it still makes gurgling sounds. So far it's working, but I dont like the gurgling. It might be feeding bubbles to my injectors which is NG.

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I hear ya.. or the Walbro.

I havn't worked on it yet but I will have too soon. I have a guy wanting to buy my car now so I must get it fixed.

Seems these Walbro pumps are notorious. Any Quality alternatives?

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^^^ me too

 

I plumbed in the stock pump and had the same problems. Upon better inspection it looks like the supply hose is in a compromise and folding shut. I am going to replace the supply today. I'll report back.

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So I drained the tank again. put a new supply hose on and went for a drive.

Same thing! I swear I can turn the car off for a split second and restart it and it's good for a couple hard pulls. then it starts loosing psi.

What the Hell??? I got a guy coming to look at the car for sale tomorrow. Hope this doesn't keep him from buying it.

This is the 3rd pump I have had in 3 years of boosting. I'm beginning to think the in tank pump setup is the way to go.??

HELP!!

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Somethin I wanted to add to this discussion.

 

Only days before I started having pump problems, my alternator took a dump. Killed the battery and left me having to get a jump start.

I believe the voltage drop during operation caused the Walbro to begin to fail.

 

Also I believe the stock pump I used is fine. It just can't keep up with the 1.1 fpr, causing the fuel psi to drop to around 35psi. Not enough on the boost.

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Update:

 

I bought Tony's car knowing the fuel pump was going out and was going to have it replaced within the month.

 

Drove to my buddy's house about 2 miles down the road and had to restart right before the driveway. Went and put a little gas in her and she ran fine for the next few days. The fuel pressure would drop a bit, and the AF would get toward lean, but the restart always seemed to cure it. I drive the car pretty leisurely anyway, so the problem didn't rear its ugly head too often.

 

Welllllllllll long story short, I was out for a drive and the car shuts off on me. Tried to restart to no avail. Zero fuel pressure. Haven't checked the fuses yet to see whether any have blown, but I had her flatbedded back home and now she's sitting up in the air waiting for a fuel pump after I changed the oil and tore out the turn signal switch trying to fix THAT problem ha.

 

I'll let you all know what happens. :burnout:

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Oh and also, the car was near impossible to start up. Usually took at least 10 tries to get her to run and idle. Would ALWAYS turn over though. Just never fire or would fire and immediately shut off.

 

Tony, looking elsewhere on here, the fuel pressure with the OE pump should be around 36 psi, so what you were reading from the gauge should be normal.

Walbro claims their pump is 255LPH @ 43.5psi, which is what the gauge usually reads ( ~40psi ) at idle.

 

Should have her back on the road in no time...or...about a week's time ha.

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