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Topic: ###!**** fuel pump.....running again !!! (Read 3378 times) previous topic - next topic

###!**** fuel pump.....running again !!!

awhile back I was having problems with my car,
http://www.foxtbirdcougarforums.com/showthread.php?t=20045

on the above post my last post was that she was fixed,,,,she was for about a week then she started going south on me again. So after reading all the posts i decided to throw in a new pump again. She was FIXED again ...........for about a week, what the he!!. I did some searching and found this thread,,
http://www.foxtbirdcougarforums.com/...86&postcount=3

I done all the above tests and i guess i will need another pump, there is no buzzing, priming sound what so ever!!!! :punchballs:
The question is...BUT WHY???? what could be making these pumps die so fast?  Walbro at that!!  It's not like they are THAT difficult to put in.............if anyone has an answer please advise.

Thanks, Joe
88 sport,TW heads, comp xe270hr, cobra u/Tmoss ported lower, 65 mm throttle body, under drives,smog delete,
1.7 roller rockers, cai, k&n, bbk adj regulator, 76mm Pro-m,all MSD ign. MSD dist,18° base timing, 3g alt.1 5/8 ceramic headers, 255lph walbro, 2.5" h-pipe, flowmasters, silverfox valvebody, 3.73 gear,
http://i216.photobucket.com/albums/cc154/flipnbird/DSCF0185.jpg ( RIP : ( )

###!**** fuel pump.....running again !!!

Reply #1
It might not be a real Walbro.

There are some knock-offs floating around that are IDENTICAL to the Walbro ones, down to the stampings on the cases.  The thing is, they aren't Walbros...
Long live the 4-eyes!  - '83 Tbird Turbo

###!**** fuel pump.....running again !!!

Reply #2
Not to play devils' advocate but what about the possibility of a short in the circuit or a faulty/intermittent ground issue putting strain on the fuel pump motor. Could be causing it to fail prematurely. Just a thought. Not a direct answer to your question. Just thought it might be something to check out after three fuel pumps. If they are real Walbro pumps I would start looking for other causes to your problem. Just me .02.

###!**** fuel pump.....running again !!!

Reply #3
If the pump you bought was not advertised as a REAL Walbro pump (i.e. it was listed as a "255lph" pump or the like, and it was CHEAP...it's not a Walbro.

As an example

http://forums.turbobricks.com/showthread.php?t=140796&highlight=walbro

I also second the wiring issue, perhaps check your fuses.  I just ran through a similar issue on my Volvo...a bad/old/corroded fuse was causing the intank to cut out.
Long live the 4-eyes!  - '83 Tbird Turbo

###!**** fuel pump.....running again !!!

Reply #4
Quote from: speeddemon31176;231915
what about the possibility of a short in the circuit or a faulty/intermittent ground issue putting strain on the fuel pump motor.


A short in the wiring would keep voltage from flowing to the pump. won't run, but won't damage it either... A poor connection/ground that's high resistance, may damage motor due to it not receiving enough voltage to run... Since the pump is submerged, the gas keeps it cool(good reason to not run the tank low), and I actually doubt a bad connection anywhere but on the pump it's self damaging it...

A friend showed me a S-10 pump he changed, that the electrical connector on it was a charred lump... Said it still ran but the truck had weak fuel pressure(was drivable as long as you didn't give it more than quarter throttle) ... Customer told him he'd been having problems for over a year and no other shop had been able to fix it... Amazing thing to me is it didn't catch on fire...

I'll never buy another Carter, the one I but in my Bird in '99 died in a little over a year, my real Walbro is still just fine...

###!**** fuel pump.....running again !!!

Reply #5
A short in the wiring would keep it from running if it was an open short. I was thinking more along the lines of a hot short to ground where the pump was still getting voltage but not enough to operate properly. I have seen it before in particular on the last generation of Chevy Caprices where the green(power feed) wire runs under the back seat on those cars and gets pinched from passengers and starts a short to ground but not enough to stop it from working. I spent several days tracking down that problem but when I found it I was able to stop replacing pumps(they weren't the problem). The feed wire was. Just a thought. I am not as familiar with these cars yet as I would like to be or as most of you are but I am working on it.

###!**** fuel pump.....running again !!!

Reply #6
Try bench testing one of your pumps that you pulled out. Apply power and ground to the appropriate terminals and see if it runs. A few seconds without it in the tank drawing fuel won't hurt it and since you said they weren't running at all this would tell you if it is the pump or wiring.

###!**** fuel pump.....running again !!!

Reply #7
Quote from: speeddemon31176;231935
Try bench testing one of your pumps that you pulled out. Apply power and ground to the appropriate terminals and see if it runs. A few seconds without it in the tank drawing fuel won't hurt it and since you said they weren't running at all this would tell you if it is the pump or wiring.


I did just that yesterday with the one before the one that is in it now and it was dead,dead!!! The one that is in it now ran fine for the 3-4 times that i drove the car then 2 days after she was parked i went out to start it, she fired right up then died after 15 seconds or so, started her back up and it ran for another 10 seconds then died, started her right back up and ran for 2 seconds and died after that i couldn't get her to start and the pump wouldn't even prime.
  I checked and checked about everything from the link in my first post, even put in a new relay(which you CAN here it click when the key is switched to on, had my son lay in the trunk to listen.
Tonight (if i get the chance--2 kids) i am going to try and drop the tank and see if i have power at the pump, check for any bad/broken/worn wires and such.

Thanks for all the replys, I haven' t really got to enjoy my ride for about a month1/2 now
88 sport,TW heads, comp xe270hr, cobra u/Tmoss ported lower, 65 mm throttle body, under drives,smog delete,
1.7 roller rockers, cai, k&n, bbk adj regulator, 76mm Pro-m,all MSD ign. MSD dist,18° base timing, 3g alt.1 5/8 ceramic headers, 255lph walbro, 2.5" h-pipe, flowmasters, silverfox valvebody, 3.73 gear,
http://i216.photobucket.com/albums/cc154/flipnbird/DSCF0185.jpg ( RIP : ( )

###!**** fuel pump.....running again !!!

Reply #8
I hear ya. I know all about the kids thing. I had to take the day off today cause one of mine are sick(read contagious). It's not too bad since I run my own company. If you were closer I would come and help you figure it out but NC is just a bit too far away for me. I know all about not getting to drive it too. I bought the car with it needing a head gasket. We took the head off had it surfaced and reinstalled it only to find out that I should have primed the oil system before I started it. I had changed the oil just to be safe and bye bye went the turbo in a matter of seconds. We tried to rebuild it but somehow got the wrong bushings in it and that didn't work. I just put it back together yesterday with a new center section. I am staring at the new oil lines from Stinger right now. Can't wait to put em in. Anyone know what the extra port is for on the feed line fitting?

###!**** fuel pump.....running again !!!

Reply #9
Kids are great, fun, but sometimes there is just not enough time to yourself!!!

What kind of company do you own/run?? When I get this tank down shouldn't i just be able to pull the plug off the top of the pump and probe them two wires to see if i have juce? (while key is on) or will i only have juice for the 2-3 seconds of prime time?
Thanks guys,,,,,,,,,,,,,
88 sport,TW heads, comp xe270hr, cobra u/Tmoss ported lower, 65 mm throttle body, under drives,smog delete,
1.7 roller rockers, cai, k&n, bbk adj regulator, 76mm Pro-m,all MSD ign. MSD dist,18° base timing, 3g alt.1 5/8 ceramic headers, 255lph walbro, 2.5" h-pipe, flowmasters, silverfox valvebody, 3.73 gear,
http://i216.photobucket.com/albums/cc154/flipnbird/DSCF0185.jpg ( RIP : ( )

###!**** fuel pump.....running again !!!

Reply #10
Quote from: Chuck W;231917

I also second the wiring issue, perhaps check your fuses.  I just ran through a similar issue on my Volvo...a bad/old/corroded fuse was causing the intank to cut out.


No such animal chuck.
THere is a fuse link but no fuse associated to the fuel pump.

###!**** fuel pump.....running again !!!

Reply #11
Quote from: speeddemon31176;231934
A short in the wiring would keep it from running if it was an open short. I was thinking more along the lines of a hot short to ground where the pump was still getting voltage but not enough to operate properly. I have seen it before in particular on the last generation of Chevy Caprices where the green(power feed) wire runs under the back seat on those cars and gets pinched from passengers and starts a short to ground but not enough to stop it from working. I spent several days tracking down that problem but when I found it I was able to stop replacing pumps(they weren't the problem). The feed wire was. Just a thought. I am not as familiar with these cars yet as I would like to be or as most of you are but I am working on it.


please stop,, I cant believe your posting up such polluted information.  You are the only one who knows what you mean by an "open short".  IT does little to help people with problems when people pipe up with trivial diagnostics like this. 

You need to know a little bit about the circuit layout or even what everyone else is talking about before you lay out the advice. 
Another thing, why would chevy use a green color as a primary for such a load bearing device.

sorry to sound rude.,,



locate yellow wire up at starter solenoid (feed to fuel pump relay)
locate fuel pump relay (upper rt side of trunk)
locate inertia switch (typically located just on the other side of your license plate area in the trunk)
  Inertia switch gets power from a splice and then back to the output of the eec relay via the black/yellow wire.
Loate EEC relay (upper right hand side of instrument panel)
Identify the wiring plugged into the fuel pump relay
    yellow (from solenoid to input relay contact)
    Pink / black (from relay output contact to fuel pump input)
        the fuel pump ground is obtained by the orange wire.
    Red wire (relay coil input from inertia switch)
    tan/light green wire (this wire is the key, ground supply to the fuel pump relay)
        the tan light green wire is supplied a ground from the eec alone and nothing else.
Note the feel of warmth or not on the fuel pump relay after the car has been running for a while.


How it works,,,,,,,,,,,
key is turned on, the eec relay contacts close and power is delivered to the inertia switch and the EEC.
The eec now sees power.
the inertia switch is passive (a little ball sits in a seat and pretty much shorts the switch closed)
power comes out the inertia switch and travels through the coil of the fuel pump relay.
the eec knows it has power so it provides a ground to the fuel pump relay tan/light green.
magnetism takes over and the relay contacts are sucked together.
Now the yellow wire from your starter relay delivers power up through the fuel pump relay and out to the fuel pump.
the fuel pump sees power and it gets a ground from chassis.

I time delay kicks in and if the car is not running , in 3-5 sec, the fuel pump will stop running.

TO BYPASS THE TIME DELAY>>>for trouble shooting reasons.....................
locate your eec self test connector up near the driver side strut tower.
have your key off
ground the TAN light green wire  (does this color sound familiar?)turn on your key
now your fuel pump will run full time without the engine running.

Turn your radio on to Any AM station that has very little static (try to not be in a garage with flourecent lighting)
wiggle the wire harness along the fuel tank, the inertia switch, the fuel pump relay, and possibly even the eec relay.
Listen for pops and crackle as you wiggle/pull test wiring.  If you hear pops in an isolated area, there is your high resistance problem.

turn radio off
mesure voltage up at the starer solenoid (yellow wire)
measure the voltage at the yellow wire back at the fuel pump relay (input power)
measure power at the red wire fuel pump relay coil input (from inertia switch)
measure the voltage at the pink/black wire (relay output to fuel pump in)
measure power on the input to the inertia switch (red)
measure power on the output of the inertia switch (red)
make sure no power exists on the tan / light greed wire., measure for resitance from the tan/light green to frame ground

dospoogeent your above voltage readings and let us know what you find.

your known good or "standard" voltage reading will be what was dospoogeented at the yellow wire at the starter relay.
Any voltage lower by 1.5v or more should be the focus of your troubleshooting.
your car should not be running during any of these tests.

see attached wiring diagram

###!**** fuel pump.....running again !!!

Reply #12
Doesn't everyone know what an "open short" is? :hick:

Actually, I catch the drift of what he was trying to say after reading more - you might want to call it a partial short or intermittent short or "high leakage" current to ground. Anyway, if the pump voltage measures low, then you know something's up. If the voltage is intermittent, something's up. Sounds like you'll know more with the tank on the ground and a voltage meter.
11.96 @ 118 MPH old 306 KB; 428W coming soon.

###!**** fuel pump.....running again !!!

Reply #13
see edit,, took about an hour but that should help

I took notes on the walboro pump info that, thats intersting and appears to be common just like chuck said.

###!**** fuel pump.....running again !!!

Reply #14
The relay controls the ground side. When I did testing in my car 84 T/c. the signal coming form the EEC to the relay was a ground circuit. So the EEC grounds the relay to make it switch.  So as my car had a hacked relay they spliced the wires coming from the pump to the relay directly to the wire from the EEC. So when the EEC send a GND Signal the fuel pumps turn on. I haven't dug up all my parts to fix it yet. But this is what I found on my car.
84 Turbo coupe 2.3T Modded with 88 upper and lower intake, 88 injectors, E6 manifold, T3-4 AR.60 turbo, 31X12X3 FMIC, Homemade MBC , Greddy knock off BPV.
4 eyes see better than 2! 
Da Bird!

FreeBird