fuel pump nightmare.

[2door2wheel]

was driving on the long island expressway today at about 65 mph and my fuel pump quit (i think. but i will get to that) i pull off and go to check the fuel pressure. i don't have a gauge so i just poke the schrader valve by the firewall to see if fuel comes out. it just dribbles out with no pressure. so i tow the truck home ( with a Nissan altima. that was a white knuckle ride!) and drop the tank and swap out the pump. fast forward 3 hours later the truck drops dead again. same issue no pressure in the fuel line. it is extremely cold and im thinking this may be a factor? basically im wondering if their is any reason that this would happen again the same day. could it be the cold? some other problem? or do i just have the worst luck in the world.

 

[ccapehartusarmyINF.(ret)]

cold is probably not the issue unless you have a significant amount of water in your fuel it mite turn it slushy but assuming that isnt the case theres not many places on the planet that get cold enough to freeze gas
most gasoline starts to freeze at roughly -72c thats -97F some hydrocarbons in the fuel wont freeze until -184c wich is -300F outer space is roughly -454F thats at the point that molecules stop moving
have you replaced the fuel filter its possible the fuel filter is clogged allthough highly unlikely its direclty under the drivers seat usually
what kind of fuel pump did you swap it out with if its a refurb there is a chance you mite be that unlucky and the new pump shit bed 3 hours after you put it in

 

[2door2wheel]

the cold would not be a factor when your dealing with gasoline
gasoline has a freezing temperature of -150 dagrees below zero

yea thats what i figured. im thinking it may be a defective pump. its 11 degrees outside and doing the pump again is like unbearable to think of. i may be grasping at straws for a reason not to do the pump again.

 

[OR VietVet]

I think before changing pumps you need to hook a gauge to it. maybe a relay is bad and 10 pumps won't fix that. Your test was incomplete. You could be bleeding off pressure from a leaking injector that is not effecting the engine when running but bleeds pressure off when engine is not running. Start with the basics and report back.

 

[2door2wheel]

I think before changing pumps you need to hook a gauge to it. maybe a relay is bad and 10 pumps won't fix that. Your test was incomplete. You could be bleeding off pressure from a leaking injector that is not effecting the engine when running but bleeds pressure off when engine is not running. Start with the basics and report back.

would a relay or a leaking injector cause it to just drop dead like that? it was at 2500 rpms cruising on the highway no warning just dead. and came rigt back to life after the first pump. i will test the pressure and get back just to be sure

 

[OR VietVet]

would a relay or a leaking injector cause it to just drop dead like that? it was at 2500 rpms cruising on the highway no warning just dead. and came rigt back to life after the first pump. i will test the pressure and get back just to be sure

Ok, let start over in order. The relay can indeed kill the engine because it controls the pump. The initial dying could be from other things though like, an ignition switch shut down or interruption in the ignition components but I doubt that. The fuel pump, when it goes bad, typically has to burn off the fuel in the lines that is still there even if the pump stops and the engine will jerk and buck as it dies. An engine shutting off like a light switch is typically not a fuel pump. Ignition problems can cause that. The trickle of fuel you saw when you depressed the shrader valve could be from a leaking injector bleeding off or the existing fuel pump not holding the pressure after it shuts down but the engine can still run ok when it does fire up and you accel. I think you lost ignition, IMO, and the fuel pressure spit was just something else.

 

[2door2wheel]

Ok, let start over in order. The relay can indeed kill the engine because it controls the pump. The initial dying could be from other things though like, an ignition switch shut down or interruption in the ignition components but I doubt that. The fuel pump, when it goes bad, typically has to burn off the fuel in the lines that is still there even if the pump stops and the engine will jerk and buck as it dies. An engine shutting off like a light switch is typically not a fuel pump. Ignition problems can cause that. The trickle of fuel you saw when you depressed the shrader valve could be from a leaking injector bleeding off or the existing fuel pump not holding the pressure after it shuts down but the engine can still run ok when it does fire up and you accel. I think you lost ignition, IMO, and the fuel pressure spit was just something else.

thanks for the wisdom im going to check the pressure and verify its good (or bad) and verify that i have proper ignition function. also another note when i did the schrader test it was with the pump on (key in the run positon) im not sure if that makes a difference

 

[OR VietVet]

Ok, yea that does make a difference. Theoretically you should have had good pressure at that point with the original pump. I am now assuming you did not do the same test with the 2nd pump, or did you? Ok, I remember now that you said 3 hours later and no pressure again. You have a tricky one here. Get the pressure test done before you do anything else. have seen a decent test kit that you can pick up at Harbor Freight for about $25. It also has an extension hose that you can attach and that allows you to attach and snake out from under back of hood and tape to windshield so you can drive and watch the pressure to see what happens. That is key. You want to see what that fuel pressure does when you drive and it dies again, if it does.

 

[2door2wheel]

Ok, yea that does make a difference. Theoretically you should have had good pressure at that point with the original pump. I am now assuming you did not do the same test with the 2nd pump, or did you? Ok, I remember now that you said 3 hours later and no pressure again. You have a tricky one here. Get the pressure test done before you do anything else. have seen a decent test kit that you can pick up at Harbor Freight for about $25. It also has an extension hose that you can attach and that allows you to attach and snake out from under back of hood and tape to windshield so you can drive and watch the pressure to see what happens. That is key. You want to see what that fuel pressure does when you drive and it dies again, if it does.

yep both times it died i tested it with the key in the run position. my assumpion was with the key on it should have hAd 60psi when i opened it up but both times it was almost nothing

---------- Post added at 12:11 AM ---------- Previous post was at 12:09 AM ----------

it wont even start so checking it when it stalls again isnt an option.

---------- Post added at 12:12 AM ---------- Previous post was at 12:11 AM ----------

im still going to get a pressure gauge on it but im positive the reading is going to be 0

---------- Post added at 12:14 AM ---------- Previous post was at 12:12 AM ----------

im thinking maybe i have crustys in my gas tank that is killing these pumps. when i did the first pump the sock had some nasty stuff wedged in it

 

[2door2wheel]

the fuel pressure is 35 psi while cranking and when the key is first put in the on postion. its on the third fuel pump. every time a new one is installed it runs but shortly after it dies. i am at a loss.

 

[OR VietVet]

Holy crap. Let me run this by a friend or 2 that I know and see what they say.

 

[2door2wheel]

Holy crap. Let me run this by a friend or 2 that I know and see what they say.

thank you i appreciate any help i can get.

 

[OR VietVet]

I have private messaged 3 friends and they should get back to me either today or tomorrow so have some patience and we will see what happens.




I copied and pasted a lot of what is going on and one of them is really sharp with the 99 and older rigs so we shall see.

 

[2door2wheel]

that's great ! after doing 4 fuel pumps in the snow ive become a very patient man. waiting a little bit is easy compared to what ive been dealing with

 

[OR VietVet]

With each new pump did it start? Or just the first one you replaced and then with the next new pump it only cranked and then did not start?

---------- Post added at 04:06 PM ---------- Previous post was at 04:00 PM ----------

From an instructor friend of mine:

I have to believe crusties in the tank would be showing up on the screen if there was enough to kill the pump...a new pump isn't going succumb that quickly...it would be a visible problem if it did...the sock would look like a chia pet...I know he said the first sock was dirty but didn't mention it the second time...


bleeding injectors would more than likely lead to starting concerns and possible rough running when it is running....he isn't complaining about extended cranking or rough running....just quitting...

I would be looking for an electrical concern...we have a vehicle with some years on it and may have unwanted resistance in a fuel pump circuit that heats up and takes away enough voltage to kill the pump...

I am assuming he has replaced the filter and eliminated that as a concern...

careful examination of the electrical system and a voltage drop at the pump to determine that it is getting and using all 12 volts...if not hes got some detective work to do...the electrical integrity has to be there before moving on to any other concern...

I had a similar problem with a vehicle when I was with Saturn and ended up refunding a pile of money to a customer when we found a wiring problem the tech overlooked...they would have paid the bill willingly but right is right...

---------- Post added at 04:10 PM ---------- Previous post was at 04:06 PM ----------

Did you ever replace the fuel filter?

 

[sgtpoliteness]

I second checking for voltage drops. All that above was really good advice.


Sent from my iPhone using Tapatalk

 

[OR VietVet]

I will get back with you tomorrow with any new info.

 

[SunlitComet]

Can we assume that new new design of fuel is being used? As for checking the wiring the ground connection for it is on the left frame rail.

 

[2door2wheel]

Ok i don't have an answer to all of those inquires but let me tell you what i do know. yes the truck started every time i put a new pump in it . the only time it had a rough running issue was about ten minutes before the first pump quit. the 2nd - 4th where just working one minute and not working the next. ( they aren't stone dead just not enough pressure)
the injector leakage may be the culprit because while cranking the pressure is 35psi but when the key is released it quickly drops to 0
i will have to do the voltage tests and get back the results . hopefully tomorrow but there is a snowstorm here at the moment. thank all you for the info. i hope it works

---------- Post added at 08:24 PM ---------- Previous post was at 08:20 PM ----------

Can we assume that new new design of fuel is being used? As for checking the wiring the ground connection for it is on the left frame rail.

not sure what the new new design is . i have a 2 door tahoe and im pretty sure it has its own sender. Also i had the same idea that you did and thoroughly checked out that ground. i even ground it back to have a fresh metal on metal contact.

---------- Post added at 08:27 PM ---------- Previous post was at 08:24 PM ----------

ohh yea the filter is only about a year old but i bought one Aand hope to also swap that in the morning

 

[SunlitComet]

Is the pump connector an inline type or square with round corners. It sure sounds like it is an electric issue. Or maybe even the filter. Really leaning towards electrical tho.