2002 GMC Yukon XL won't start

[cfell]

I know this is a MC forum, yet, there are similarities in car and LT systems... any help is appreciated.

Sunday, My 2002 GMC Yukon XL (yes, it's mine now that it is broken), fails to start.

Before I returned home, the fuel pump was diagnosed as having croaked and my sons have the tank partially dropped, and had the pump out. the new one did not quite seem right.. but what do I know.

Since I'm fighting the flu and respiratory distress, I go inside and await their frustration level to threshold..

An hour later they step up and say, "They gave us the wrong pump"... hmmm

Another 1.5 hours and they have returned with another "new pump" and start assembly into tank.

I go outside to make sure my prodigy are not smashed under the vehicle and ask them... "did you hook it up to make sure it runs?" .002 seconds later I get the "WTF???" look, so I just shut up and go back inside.

Another 1.2 hours and they are about to set fire to the tank because they can't get the retaining ring in place.

.1 hours later I (stupid old man) get the ring in place with a light touch of silicone spray between the ring and gasket...

.5 hours later it's all back together, Battery connected.... ready to crank... Turn igniton "on"... no fuel pump noise... no fuel gauge reading.... (there was about 1/8 tank before replacement)

We "swapped" relays around, checked fuses.. etc... noting "obvious"....

So, I'm still laid up, trying to keep breathing.. my oldest borrows a "test" device and checks the car.. there are NO errors.. zero. But, still no "vroom".

Before I pull the tank completely...again... when I get over a little bit of this illness, what do you guys think the problem is?
1- Faulty "new" pump
2- problem with wiring to pump
3- ECM
4- "other"?

[jzeiler]

Cycle the pump a few times and check the schreader valve on the fuel rail - should be about 40 psi if you have a gage - if not it should squirt out of there like gang busters. If that is OK check for spark. Pull a plug wire and insert a screw driver and hold close to ground look for arc. I had a similar problem with my 96 lincoln and it defied me with no spark. I was ready to change out the crank sensor when a buddy suggested a hard reset of the ECM. Did the old "LT radio reset" by disconnecting the battery to hard reset the ECM and it fired right up. Hope you are as lucky.

[sheldan2]

Some cars have a safety shut off to the fuel pump, or something to that effect. might be something worth enquiring as to whether yours has one installed. I know my ford has one, just never bothered to look for its location.

[jzeiler]

Oops I see you have a fuel pump not running situation. I have traced that to a melted wire (BMW sedan under rear seat) to corroded connector up under the hood on a ford explorer. Aside from the requisite fuse checks - try to trace the wiring back and look for corrosion on all the connectors. The fuel cut off switch is usually and impact type unit to shut off fuel flow in a wreck, but can some times be triggered by a lesser event. Good luck and hope you feel better.

[cfell]

all good ideas... thanks, gents... for the help and health thoughts

[Morley]

Well since you say there is no fuel level reading or pump prime I would have to say they forgot to hook the wiring harness to the tank back up. Failing that, look for a fuse near the battery with a pigtail going to the positive cable. That is the fuel pump/ECM fuse. If they didn't disconnect the battery before undertaking the job, they may have shorted one of the wires while removing the pump. If that is the case, be glad it didn't cause the mostly empty fuel tank to go BOOM!

[bigbear]

Channing,
If there is a connector outside of the tank can you carefully check to see if you are getting voltage to pump. Otherwise possible use a stick pin to pierce the wire insulation to get a reading. Not sure how a Yukon is made but on a Ford Crown Vic you can put the fuel pump in sideways or backwards and the sending unit will not work. I know this from experience, ya know stupid is as stupid does....

No power then start checking for the cut off switch normally located in the back of the vehicles buy the wheel wells, fuses etc.

Good luck

Roy

[JPSpen]

The motor won't start until you hear that fuel pump run.

Check the fuse, and the shut off switch. Your manual can tell you where that is.

Mine's on the passenger front kick panel.

Sounds like you're pulling the tank again.

Been there , done that..

Did they just replace the pump or the whole assembly ?

Check wiring to pump and sender. Fuel pumps are a PITA.

Good Luck

John

[Dick]

all good ideas... thanks, gents... for the help and health thoughts
Huuuh - what? You didn't teach them boyz about the BFH??? :eek: ;)

Git well, Bud - full strength Oregano liquid; one drop under the tongue every mornin'. Works for me - most of the time. Cold, flu, and allergies all. :cool:

[zippy_gg]

On Kathy's Rover there was a safety shut off valve that was triggered when the car was put on the tow truck (big lean angle). It is designed to shut off the fuel pump if the vehicle rolls over, etc... In her case that safety shut-off vales was in the engine compartment, and all I had to do was to reset it.
You may want to check a Yukon forum and ask the question there, you will probably get more hits...

[Morley]

According to my research the Yukon does not have a fuel cutoff switch (I don't know of any GM vehicle that does). As suggested, get a meter and check for power down at the connector. If there is no power there, go to the pump relay and check for power coming out of it, no power, check for power going into the relay. The relay is controlled by the ECM providing a ground to it.

[cfell]

Thanks for all the input.

I have verified there is power at the Relay. I will verify tomorrow that the relay is working.. I swapped with others and they function in those locations.

Just need to make sure I'm getting power at the pump wiring.

Since I'm not getting fuel to register on the gauge, I'm guessing something is fouled there.. so, I'll be pulling the pump tomorrow.

Here was the way we left it this evening.....

Notice.. no hammers were hurt during removal..

[bigbear]

Daddy, we there yet...... :D

One match and I bet she will light up :eek:

[cfell]

oops.. forgot to post the update... and resolution..

Turns out there are several "choices" for fuel pumps... some come with "new"/replacement electrical connectors to "upgrade" your existing.

Well, when all the pump swapping happened, there was confusion and the plug was not considered being a problem.. surely they are all "wired alike".....

They are not.

So, when I started feeling better I was able to find wiring diagrams, then figure them out on the car.... and yes, they were wired correctly on the car, but the pump was different....

FIX...... I had to purchase a new "connector" with attached wiring ($58 at dealer, $36 through my "locally owned" jobber) ....then figure out the correct circuit.... once I did that, I plugged in the pump BEFORE installing into the tank and verified it ran.... also verified the fuel gauge worked...

Installed all including tank and everything workie fine!!!

Lesson(s) learned...