2.9 GURUs....help me...rough idle, random stalling then dead for good. Fuel Problem?

UPDATE 2/13/14! 2.9 GURUs....HELP! rough idle, random stalling then dead for good....

UPDATE- 2/13/14

Trucks an 87 reg cab, long bed, 4x4 2.9 5 speed

I bought a new in-tank low pressure fuel pump, a new high pressure external fuel pump along with a new fuel filter and installed them all today. Well, everything but the fuel filter, but thats another story.

Before I go much further, here's what led up to this. 3 months ago, in November, I bought a new set of tires for this thing and was loving the hell out of driving it. It had sat for like a year before that, waiting on a clutch to be done on it. Twice, while driving, it would for no reason at all stall out completely like it was being starved of fuel. Usually if I let it sit for about an hour, it would start up then, after about 5-10 rotations of the key to prime the fuel system. It wasnt a huge deal to me, as I only drove the truck here and there, but it wasn't my DD.

Well a month ago, in the Harbor East section of downtown Baltimore (high falOOting snob area) while driving with my buddy, the truck dies right in the middle of the road. I loved it cuz it so easily pissed off these idiots down there. I'd been driving it for hours that day before this happened. And this time, it wouldnt fire at all. Buddy went and got a can of ether and when we sprayed that into the intake, it would run fine, but nothing else. Couldnt hear the pumps prime or anything. Had it towed back to my house and it sat until this past weekend when I got some time to pull the bed and do work.

I installed both the low and high pressure pumps but the filter they gave me doesn't match the one thats on the truck, so no bueno yet on the new filter.

Went to start it and all it does is crank. No fuel pump whine, no buzzing nothing. I can hear the relay engage, but no fuel pump buzzing or anything. I double checked all the wires running to the pumps and everything is hooked up where it is supposed to be.

Here is what I have done so far:

-I checked for spark (we are good for spark)
-I looked at the fuse panel under the steering wheel but didnt see anything for the fuel pump written on the diagram.
-I sprayed ether in the intake again with my roommate cranking and it fires up and runs on ether...

I don't want to run around and install a bunch of non-needed expensive sensors, etc that don't need to be done. I just want to track down the problem and fix it. I don't want to diagnose this problem by financial ruin (installing un-needed expensive parts). HOWEVER.....if there is a cheap sensor or something I can do that sounds like it may be the problem, I'm all ears. Never hurts to do preventative cheap part replacement every now and then....

I know I should do the filter at this time as well, and I fully plan on it, but I also know without a doubt, that this problem right now is electrical and not a clogged filter.

I have read about jumping wires from some relay to send power to the pumps 24/7.....I have no clue what this entails. Anyone know about this?

I'm also rather clueless when it comes to the electronics on this thing, or any vehicle for that matter, so any pointers or (more than likely fixes) are much appreciated, along with an idiots walk thru guide....that would be awesome.

Thanks a ton in advance.

The idle is controlled by the "Idle Air Control" which is controlled by the throttle position indicator. After setting for as long as it did the IAC may be sticking. It can be taken apart and cleaned. Also a quick way to find if the fuel pumps if you don't have a fuel pressuer guage ( there are two one is in the gas tank and the other on the frame driver's side) is to remove the small plug on the fuel rail and momentarily turn the key on. If gas squirts out then the pumps are working. There are losts of other things in the system that controls the engine like the engine coolant temp sensor ( different than the one that connects to the dash guage. It took me about a month to get my 2.9 running properly.

I updated this so hopefully someone can help me with my newfound issues....

Power for the fuel pumps goes like this:

Battery---Fuse(engine fuse box)----Fuel pump relay(passenger fender, Green base)---inertia switch(in cab, passenger kick panel)-------fuel pumps

Check fuse first, usually a 30amp fuse

The jumper place you are looking for is the OBD/DLC port in the engine compartment. usually passenger side, but......
Have a look here at the diagram, about 1/2 way down the page:
http://www.therangerstation.com/tech_library/OBD_I.html

Fuel pump connector will activate fuel pump relay if key is ON and that connector is Grounded, so jumper wire is NOT power.
Put jumper wire in that connector then touch other end to a good ground.
You should hear the Fuel Pump relay "click"

Inertia switch is just a 12volts in 12volts out switch that will disconnect fuel pump power if vehicle stops suddenly(accident), or rolls over, all electric fuel pump systems have an inertia switch to prevent fires.

In my old 88 it lost power to the pumps. not sure where between the relay and the hp pump. I ran a wire from the hot post on the relay down to the pumps and it worked fine

theres several connectors from the inertia switch to the sending unit....so hard lining power can be a worthy shortcut for testing purposes.....


i am laid off still ....too bad your in fawking china

zachis4wheeling said:

UPDATE- 2/13/14

Trucks an 87 reg cab, long bed, 4x4 2.9 5 speed

I bought a new in-tank low pressure fuel pump, a new high pressure external fuel pump along with a new fuel filter and installed them all today. Well, everything but the fuel filter, but thats another story.

Before I go much further, here's what led up to this. 3 months ago, in November, I bought a new set of tires for this thing and was loving the hell out of driving it. It had sat for like a year before that, waiting on a clutch to be done on it. Twice, while driving, it would for no reason at all stall out completely like it was being starved of fuel. Usually if I let it sit for about an hour, it would start up then, after about 5-10 rotations of the key to prime the fuel system. It wasnt a huge deal to me, as I only drove the truck here and there, but it wasn't my DD.

Well a month ago, in the Harbor East section of downtown Baltimore (high falOOting snob area) while driving with my buddy, the truck dies right in the middle of the road. I loved it cuz it so easily pissed off these idiots down there. I'd been driving it for hours that day before this happened. And this time, it wouldnt fire at all. Buddy went and got a can of ether and when we sprayed that into the intake, it would run fine, but nothing else. Couldnt hear the pumps prime or anything. Had it towed back to my house and it sat until this past weekend when I got some time to pull the bed and do work.

I installed both the low and high pressure pumps but the filter they gave me doesn't match the one thats on the truck, so no bueno yet on the new filter.

Went to start it and all it does is crank. No fuel pump whine, no buzzing nothing. I can hear the relay engage, but no fuel pump buzzing or anything. I double checked all the wires running to the pumps and everything is hooked up where it is supposed to be.

Here is what I have done so far:

-I checked for spark (we are good for spark)
-I looked at the fuse panel under the steering wheel but didnt see anything for the fuel pump written on the diagram.
-I sprayed ether in the intake again with my roommate cranking and it fires up and runs on ether...

I don't want to run around and install a bunch of non-needed expensive sensors, etc that don't need to be done. I just want to track down the problem and fix it. I don't want to diagnose this problem by financial ruin (installing un-needed expensive parts). HOWEVER.....if there is a cheap sensor or something I can do that sounds like it may be the problem, I'm all ears. Never hurts to do preventative cheap part replacement every now and then....

I know I should do the filter at this time as well, and I fully plan on it, but I also know without a doubt, that this problem right now is electrical and not a clogged filter.

I have read about jumping wires from some relay to send power to the pumps 24/7.....I have no clue what this entails. Anyone know about this?

I'm also rather clueless when it comes to the electronics on this thing, or any vehicle for that matter, so any pointers or (more than likely fixes) are much appreciated, along with an idiots walk thru guide....that would be awesome.

Thanks a ton in advance.

Click to expand...

you really need a fuel pressure gauge.


when you dropped the tank how did the sending unit connectors look? any green corrosion in there???? what about the frame pump?

did you reset the inertia(rollover/crash) switch....did it seem sticky?

unplug it and check for key on power as you cycle the key...or jumper it with a paper clip or something....


to run the pump manually you ground the fuel pump relay via the eec4 connector. on these it is up by the blower motor housing btween it and the airfilter box... it should have two wires slots in one row and four on the other.... find the tan/light green wire in the row of four.....and ground it. should be pin 22 on the eec... this should turn on the fuel pump relay even with the key off, its the little green bastard, and should aslo be on the passenger fender area by the airbox. if it dont then the fuse link may be bad....see if the yellow wire has power.

if the yellow wire has power and if it clicks but dont turn the pumps on check for power at the inertia switch orange and light blue wire.....if it does...then move to the pink and black......then out to the round pink/black wire under the master on the drivers side....not sure what setup you have.

if the pumps turn on...

pop the cap on the shrader valve and see if its wanting to squirt you in the eye with nice yummy blinding gasoline.....do this recklessly...your a fireman, it will be ok

if it dont turn on or click the green relay manually or with the key, it may just be a bad relay if it dont click...very possible...switch it with the wac relay if you have one...

otherwise its possible you just have bad computer grounds at the battery...make sure the little black ones are good...sometimes the pcm ground goes bad internally and it cant run the pump but all the other shit works...i just hook it to a mnormal relay in that case and let it run when the key is forward...


call me man....

One thing I would do if it runs on ether. Check the compression to all your cylinders-ether fires up at a much lower compression than gasoline will. Gas needs compression to spark. Low compression=no sparking gasoline. Just a thought because I have been there(on one big block and a 2.9) not because this is a definitive answer. Pull the fuel line off to see if it perhaps is pumping.

Well I've been logging on the site again quite a bit more often and decided to update this.....9 months later.

I ended up replacing both fuel pumps, both fuel filters and a section of fuel line. I also ended up bypassing the inertia switch. I unplugged it and cut the electrical connector off and twisted the wires together. And voila! She works great now.

Pulling the bed off was definitely the way to go....WAAAAYYY easier than dropping everything out from underneath.

Not to mention, I even talked to BobbyWalters for the first time in years about 8 or 9 months ago for a while too. Guy has changed a bit!

Thanks for all the help guys!