Thread: Fuel pump failing?

What are the symptoms of a failing fuel pump?

I have a walbro that would whine after driving for about 25-30 mins.
Seemed fine otherwise,car has been running great.
Then the other day,after driving for about an hour ,it started to bog intermittently while cruising.
It really fell on its face in VVL trying to pass a couple times too.
I had the happen when fuel was low before and just though maybe I was running out of gas....this last time I had a full tank,so there goes that theory.

Well,now the fuel pump whines all the time,noit just after driving a while.
Problem is that I can get in the car and run it hard or not most of the time,but theres a problem rearing its head slowly.....I am trying to get it taken care of before I get to AMP and have issues on track.
maybe the F pump is getting hot?? Maybe it was defective to start with?
The walbro was new in the package,but was in a box of parts that came with a car I bought for parts....I didnt actually buy it,so I cant return it for warr.

Do the walbros fail alot?
It seems like alot of guys complain about the whining.

Check your fuel pressure. It sounds like a failing fuel pump to me. I suppose it wont hurt to get a new fuel filter, and to top shelf fuel just to rule out a bad batch of gas. Also, if possible, check your afr. It may give you some indication as to what is happening.

Good suggestions.
Fuel pressure is good.I have a gauge,but its under the hood...LOL
I need to watch the wideband next time,thats a good idea.I was so caught off guard,I didnt really even look at it...DOH!
I did clean the tank and put a new fuel filter in and the pump when I put the motor in.It has been flawless since...including a 4.5 hour highway trip,20+dyno pulls and a 4.5 hour drive back just a couple weeks ago.
This problem has just started to rear its ugly head.
Once the tank gets low again,I am gonna pull the pump and look in there.Maybe the sock is getting clogged again or something.

Its weird like you are cruising along like normal,and it feels like a misfire,but I swear its fuel.
The car will idle rock solid all day.It seems like only after driving a long time,and then it comes and goes...weird.

Do you have an adjustable frp, or stock? with the key on engine off, jump the fuel pump to keep the system primed and check your fuel pressures. This simulates wide open throttle, and will help you narrow down what side of the fuel system the problem is on. Also, if you a an adjustable, make sure the lock nut is tight and its not coming out of adjustment.

stock VE ,non adjustable FPR.
So by jumping,you mean just keeping 12v straight from the battery to the pump,but leave the key on? I have never heard of this before....hmmm

Well, jump the relay so it does not time out. Or however you want to check your fuel pressure. Basically though, fuel pressure is set at WOT. Two ways to do this. Start the car, pull the vacuum line going to the regulator, in this case the one on the driver side. The fuel pressure will rise. This simulates WOT. The other way is to jump 12v at the relay to keep the pump from timing out. Same thing then, except you do not have to pull the vacuum line since, well the car isnt running. Then just look at your gauge. The pressure should be 43 psi, i believe.

OK cool.I will try that.
problem is,that I have to wait for it to mess up again.It seems to be fine until driven for a long while.I honestly wish it was a constant problem,so I could just fix tham darn thing.

Intermittent problems are the worst. Let us know what you find.

Update.
I pulled the hose off the FPR at idle(43psi),and it goes to 49ish and stays there until the hose is replaced....seems everythings good there.
Drove the car 35 miles to work,no issues.Didnt really go into VVL much,though.
I have been paying close attention to the wideband readings and it seems ok.

On the way home,I noticed that the AFR goes lean off the chart 16+ when it goes into VVL and starts to miss.
Cruising is aroung 14.7-15 ish.
WOT (no VVL) is still pretty good in the 12-13 range....it will stay there as I go into VVL and then...pegs the AFR meter lean.

Note...I did have to clean the tank in this car before I put the motor in.
The car sat for over 5 years so I had to replace basically everything in the tank due to rust/corrosion and trash in there.
I put the NEW walbro 255 in at that point,as well as a new Z32 filter.
I obviously could not get all the crap out of the tank,so it is possible that the sock is getting clogged from the remaining crap in the tank.This is what I keep thinking.I plan to pull the pump this weekend to investigate.

Whatever is going on is NOT gonna work for the convention/track day,so I gotta get this fixed ASAP

I will know for sure tomorrow when I puyt it all back together....but I believe I found the problem.