1998 3.4L SR5 4WD - Fuel/Starting issues

Hey fellas, I got a good one for you, hopefully some guru/expert here can clear the fog in my head and lead me to an answer...

I have this 98 3.4L 4WD since 99, but its been sitting for a few years. Had a no-start issue when I started getting it road worthy again, but resolved that with a park/neutral switch, drove it for a week, then it mysteriously stalled while driving, would idle, but die when given gas. Got it home, pulled the bed off (with the help from a friend) replaced the fuel pump, but still can't hear the pump come on when the key is 'On'. When I try and start it, it acts like it wants to run, then dies. You can hear the pump run after it dies for a couple seconds, then stops. When cranking, you can hear it start to run, starter stops, and then it sounds like its starving of fuel. We checked at the pump and its getting battery voltage when cranking, so the pump is good (it should be, its new).

So here is where I'm at... either its the Circuit Opening Relay (Fuel Pump Relay) or the ECM. I think its the COR because I don't think its keeping the pump running, even though you can hear it for a second. Maybe I just don't want it to be the ECM, I dunno... Any ideas? I've beaten my head against the wall for a good long while on this one...

I don't have an OBD reader, was told I could check codes without one, maybe someone can show me how to do that, but I'm not sure this will result in 'the answer'... If you do happen to find the answer, I'll buy you a beer or two at the local virtual bar, lol

Any comments are welcomed, have a wonderful day

 

These newer Trucks the fuel pump only is energized when cranking or the engine is running when the ECM sees everything is good to go If the ECM is not seeing all systems are go it will shut off the fuel

You really need to see what they are.

You did install a new filter just did not mention it ??

You can`t pull OBII codes without something to interface to the OBII system.

The codes are your friend they can point you in the right direction

 

I suspect that the computer is not letting your truck run and if that is the case then there is a reason.
Verify spark
check for wetness on spark plugs
If this passes the smell test and you think that the computer wants to start the truck then..
Check ECT engine coolant temperature sensors for connectivity. I think that there should be two on your 3.4L

 

Pull the MAF sensor and make sure it's not dirty, you can also try unplugging it and seeing if the truck runs (I can't remember if the 1st gens will run without it, most vehicles will).

 

The truck is immobile, so how can i get/find/rent/borrow a reader? I've always managed to get by with driving it to the reader, but not this time....

 

Hmmm, never thought of that, but some squirrels stored their acorns in this box, but it was thoroughly cleaned out prior to running, and ran for a week after... I'll pull it tomorrow and try, but do you really think that may be it? A buddy of mine, who is very smart, began with gotta be another sensor flaking out, not letting ECM agree to let the pump run... I thought relay, but he thinks sensor...

Thanks for the tip, will update with results

 

If the ECM doesn't see a MAF signal within seconds of the engine starting it's not gona give the engine any fuel.
I have seen a small leaf get in a MAF sensor before and stop an engine from running.

 

Mine had similar symptoms when the MAF was bad. Intermittent no start or would not idle after turning over, and occasionally stalling while driving. Replaced with a Denso sensor and haven’t had a single occurrence in months.

 

I feel real sorry for you not having any family or friends to give you a ride or stop by and help you out.

Then I can`t get by with only one vehicle now days .

good luck

 

If the bed is still off you can apply constant power to the pump and see if she starts. I hope that the crap gas hasn’t created any additional issues. I might be worth it to pull the fuel filter and see if it is plugged before you start throwing parts at her.

 

A MAF sensor can have lots to do with fuel delivery/fuel management with a host of running/not, stalling and performance issues easily mistaken for "no/intermittent fuel". It has nothing to do with actual "fuel pump control".
The crank position sensor/circuit (V6) and the "start" signal are the inputs the ECM looks for. Cam position sensor on the 4cyl.

The diagram below is a little misleading in that the ECM will allow the pump with the CPS (NE) or the starter signal (STA) alone/separate. It does not need both inputs at the same time. Theory of operation being that the start input instantly wakes up the pump for quick starting and the CPS signal maintains operation.
Also note the EFI relay contact circuit and the COR relay are in series.

Jumping the COR contacts or hot wiring the pump wire at a convenient point after the the COR will eliminate any pump control issues. The "pump" wire will be solid blue heading for the door sill from the COR.