3.8L - No Start Condition

[96RS Alex]

1996 3.8L V6, 305,000 on the odometer.

Motor ran flawlessly last night.

This morning I get in to go to work, key in... no start !

New coils last summer, new MSD wires, new Optima.

I have full juice to my battery. Fuel tank refueled from a 1/4 tank last night.

It's not the pesky VATS. Security light goes away.

I turn the key to ON and the only obvious thing I do not hear is the fuel pump priming, it's absent. 2 things came to mind; fuel pump or the relay.

I suspect the fuel pump relay first but I need to know where exactly to find this part and buy a new one.

Questions:

1: How do I retrieve a code if the SES light never lit the night or 2 years before?

2: If it is the fuel pump relay, what's the part number and how do you test it? I'll just buy another for simple troubleshooting.

3: I'm pulling all the fuses besides the drivers door sill and underhood fuse compartment box to visually check for any breaks. I've read it could be the PCM fuse here, where would I find that?

I disconnected my negative battery post just for the hell of it to clean it. Maybe this time I can start clean slate with the codes but I never seen the SES flash since 2 yrs ago.

Search performed. I have taken the next 2 days off to fix this problem so I'll be online to troubleshoot with your help!

[96RS Alex]

Re: 3.8L - No Start Condition

Still no start, keeps cranking as usual though...Question #3 resolved.

Pulled all fuses, visual check is all good and reseated them.

[96RS Alex]

Re: 3.8L - No Start Condition

Keeps cranking but still no start. All fuses check out good here. Reseated the small black boxy ones...

[Andy H]

Re: 3.8L - No Start Condition

well the "black boxy ones" are relays. You could temporarily swap out the fuel pump relay with another one if it is the same and see if that fixes it.

[Andy H]

Re: 3.8L - No Start Condition

my fuelp pump relay is under the hood on my 2000. your 96 may be loacted here:

http://shbox.com/1/fuel_pump_relay.jpg

[96RS Alex]

Re: 3.8L - No Start Condition

Andy, thanks for the link! I didn't know where to find that fuel relay. I'll pop that out and find another hopefully at AutoZone or Advance Auto.

Removed the coil assembly and here we have the original Ignition Coil Module ( ICM ) to have it tested at one the auto retailers mentioned above. This is gettin down & dirty "fun".... will post back soon on my findings.

[Rob Bell]

Re: 3.8L - No Start Condition

If you have the schematic and/or a multimeter you may be able to jumper the contacts in the wiring harness to bypass the relay and force the pump to start. The relay may show what each contact does.

[96RS Alex]

Re: 3.8L - No Start Condition

Installed new ICM, only because the original was 14yrs old.

Then the new fuel pump relay was replaced.

Battery connected.

Turned the key to ON, finally heard the fuel pump prime but it was a slight and muted hum I noticed, not the whirring sound of a healthy pump like before.

Key to ignition, motor fired for about 2 seconds then it dies. Not good I thought... :mad:

2nd attempt: Key to ON, I do not hear the fuel pump prime at all like before. Motor cranks but will not fire. Now I'm dreading it's the fuel pump. Key off.

3rd attempt: Key to Ignition, motor fires. Surprisingly, it idles for 30 min and I revved it like there was no tomorrow. I decide to shut it off and was almost satisifed until I restart it and the problem repeats itself.

What could the problem be? ( Fuel pump has 305,000 miles on it. )

[scream97]

Re: 3.8L - No Start Condition

if you find out whats wrong let me know cuz sounds like the same problems iam having but i getting ready to replace the fuel pressure regulator to see if that help and i only had 5psi at the fuel rail whats yours

[96RS Alex]

Re: 3.8L - No Start Condition

I don't know what my fuel pressure reading is yet. I am a complete newbie on measuring fuel pressure with a gauge, a tool I have not purchased yet because how can I read fuel pressure when the engine does not fire but crank repeatedly?

I say this with the fact I tried to start the motor after a 4 hour break and the fuel pump prime hum is not there now. After I replaced the fuel pump relay and ICM, it ran beautifully until I shut it off for a test restart and the problem is still evident. :rant:

Another Search has provided me 5 avenues to troubleshoot. Many variables!
1- Fuel Pump Replacement: Going with Walbro 255
2- Fuel Pressure Regulator
3- Crank sensor
4- Cam sensor
5- Fuel Filter ( which I replaced last summer )

[Fred]

Re: 3.8L - No Start Condition

I'm betting thats it gonna be the fuel pump.

[travis5049]

Re: 3.8L - No Start Condition

This happens to us........Check this out A year and a half ago I thought I had a bad fuel pump and took it into the shop after already trashing a fuel pump that I bought, (long story). Anyway, I had cut out the back floor pan to get to the pump. They replace the pump for me but 2 days later I've got the Vats thingy. Bought a bypass module online and cleared the light. Ran fine for 4 months. Now it will occasionally die in the middle of the street or not start after parking. The fix is to walk back and lift my little cover I made that conceals the fuel pump access and unplug both wires to the fuel pump. Starts right up. Could that be the relay?

[travis5049]

Re: 3.8L - No Start Condition

Sorry of course I have to plug the pump back in first and then it starts right up................sorry just woke up.

[96RS Alex]

Re: 3.8L - No Start Condition

I just woke up feeling refreshed to attack this fuel pump R&R.

Travis, if you have to unplug your wires at your homemade trap door flap you described above then I'm making a wild guess it could be your relay not switching at all. The relay was an easy find thanks to Andy in the previous posts.

[96RS Alex]

Re: 3.8L - No Start Condition

Got the fuel pump out, what a pain in the A$$, :P !

Taking a break while I'm high on fumes....here's my progress so far.

Took measurements and started cutting the hatch panel. Took me almost 2 Dremel cutting discs to complete the hole as you can see.


Rectangular hole complete. Tank cover nuts are 8MM FYI.


Hard part here was removing the rubber lines but some long screwdrivers and penetrant made things easier. The metal lines were not as fun either. I'll suggest widening the hole a little wider on the drivers side of the hole where the the CRC can was in the previous pic.