NEED HELP Crank no start 2002 envoy 265000km Slt swb

[tailor]

So i want to give a little back ground.( sorry that its long)
16 months ago the fuel sending/pump unit was replaced and the vehicle ran well.About four months ago we hit black ice and slid sideways into the highway wall, shaken and stirred for sure,but ok .Damage was a side impact (no deployment of airbags)to the drivers door,rear passenger door wheel arch back and front fenders.
The vehicle had to be towed to a shop and the front end drivers side was repaired.I have an abs kick in on gradual stop now which i did not have before.The front 1/4 panel metal and bumpers and doors i replaced from the U pull yard, finding matching colours.

I did not find exactly the same doors from an SLT but did swap out the wire harness which may have been over kill. The original drivers mirror has an amber indicator light which i was unable to replace so i used a standard one for now. The harness was not changed on the mirror, as far as functionality of the mirror is concerned, it appears to be ok and can be adjusted internally.

About 2 weeks after the front end suspension work was done, the vehicle stalled out,( after the doors had been replaced) i was getting an oil change.at the time The mech started the vehicle and reved the engine,( to my horror) as i happened to be standing there i noticed a low oil pressure light come on and the vehicle stalled and refused to start. That also spryed under the vehicle to clean it...so i am little suspicious of that too.

Attempts to start it thereafter were fruitless,
What we did.
1) starting fluid sprayed into Throttle body would allow the motor to catch and run as long as we kept spraying, whereupon it would stall.
2) I have viewed the videos ands posts listed on the site for no crank/no start, good info but does not lead me to a conclusion.

This leads me to confirm that :
a)There is spark
b)The ignition switch appears to ok- swapped those out too made no difference.
c)Definitely fuel starvation as I do not hear the fuel pump prime with the ignition on
d)after contorting , i can confirm that the relay clicks when the ignition is turned to on.
e)swapping out various other relays with the fuel pump really made no difference to the situation.
f)removing the fuel supply lines and cranking delivered no fuel and no smell of fuel either.

I towed the vehicle to the garage that did the front end repair, and he concluded that the fuel pump sending unit needed to be replaced again. Oddly enough he said that the unit he took out appeared to work.So here I am two weeks after the repair is done a 2nd unit in and the vehicle stalls out again. I have returned the vehicle to him again and he cannot find the problem, blaming the issue on the door replacement. His suggestion is that i go to the dealer to have it checked...which may be all that is left for me to do.

I am maybe a few cm's above a shade tree mech....but this sounds like a lot of rubbish.

What he claims is that there is power to the fuel pump.so he suspects that it is the computer that has an issue, i am not so sure and have been trying to locate and exact one from the Upick as i know that if they don't have the same part #, it will not work. To me it appears to be a an intermittent fault.

I have gone through all the same items as listed above from a-e with all the same results.
i have tried to clean the grounds,checked the fuses,used dielectric grease wherever i could get my grubby paws.
The casa( camshaft actuator solenoid assembly) had a huge amount of oil in the connector ( so it may be bad)which i cleaned out to no avail.I did not remove it from the engine.

The check engine light is on.but i cannot seem to pull any codes, i did have a p0135, but don't believe that this is the issue.

Questions:
1) how can i verify that power is indeed going to the fuel pump?
2)Are the additional tests that i could try to resolve this ?
3) Does the fuel regulator play into the fuel pump priming and is there a bypass to test?

Any other detailed help is most welcomed.

Thanks

tailor

 

[budwich]

Of course, the "easiest" way to get things going is provide some fuel to the engine ...
So if your "starting fluid" technique that you employed earlier in your "saga" still results in the same run condition, then you have confirmed you have the necessary "engine control" for it to run... big step.
Then, just "hot wire" the fuel pump relay position... basically remove the relay and use jumpers in the appropriate slot positions to provide the equivalent connection that the relay would be doing. what's the result? does it run?
IF it doesn't then some where along the powering path of the fuel pump there is an issue or the pump itself is not "pressuring" enough. Of course, check the regulator to ensure that it is not the issue.... by if necessary disconnecting the regulator and "hot wiring the pump" and see if you get fuel coming to / thru the regulator. Once you have done some of these things, you can go from there with further help based on the results.

 

[Mooseman]

Obviously (to me anyway), it's a fuel issue since it will run on starting fluid.

To answer your questions.
1) Turn the key without starting and listen to the fuel pump prime. It will run for a couple of seconds and stop.
2) Fuel pressure check with a gauge. @MAY03LT has a video on Youtube on how to do this.
3) Yes and no. If the pressure regulator is completely bad, it will not hold pressure from the prime but it won't prevent the pump from running. Fuel pressure test will confirm this.

Door wiring having an effect is total BS. Hell, you can even cut power completely to the rear (i.e. the mega fuse) and it will still run.

If the fuel pump died after only a couple of years, he probably used some cheap Chinese knockoff or it was fine and it's something else. Sounds like an incompetent either way.

 

[MAY03LT]

Oddly enough he said that the unit he took out appeared to work

If he bench tested the pump and it worked, it points to a problem with power and/or ground to the pump. If you have the means to do your own electrical tests, the gray wire in the fuel pump connector is the power and the black wire is the ground. Remember that the power wire will only have power for two seconds after the key is turned on. I can't fit my hands in between the top of the tank and the body to access the connector, so I have to drop the tank a couple of inches to do these tests.

 

[mrrsm]

From reading your description of the damage areas as being fairly spread out along the Driver's Side of the vehicle... and after looking over the diagram for the 2002 GMC Envoy Driver's Side Under-Carriage... It seems like there is a chance that some areas of the Fuel System Wiring Harness-Loom are exposed enough to have been at risk of either being cut, stretched or pinched under there in some way ...as suggested in @budwich 's diagnosis:

Having watched @MAY03LT 's Fuel Pump Repair Video many times... it looks like if the problem(s) are situated down there, pulling the Gas Tank to perform the wiring inspection because it has to remain with the underside of the Truck Body might be the only way in which to gain enough inspection access to be sure. Fortunately for us all... He shows how this is done and if @Mooseman is right about the Cheap Chinese Pump being the culprit (and usually he is...) then that would be the time to install the OEM AC-Delco or Delphi Fuel Pump and kill two birds with a single stone:

 

[tailor]

Gentleman , thanks to you all for your thoughtful replies. I am suspicious of the wiring and grounds along the way to the fuel pump and will try get to this to have a look, as well as following all the good advice here.