Well it happened again - driving along and it stalled. Pulled over and tried to restart it - no joy. Holding the throttle >1/4 open and cranking produces a surge to high RPM, but then it dies.

My brother had me disconnect the MAF - it would idle roughly, but as soon as I touched the gas, it would die. He then had me unplug the throttle position lead - nothing would happen then. He thinks it might be a fuel pressure regulator issue - he says when they fail, they produce abnormally high pressure.

I've had the fuel-pump-hose-came-off problem a couple years ago and solved it with new pumps with barbs on the nipples. No fuel problems since.

EEEERRRRR Any thoughts would be helpful.

-DHF

 

did you pull the chip if you have one ?

DId you remove neg battery terminal to reset computer ??

Doug

 

Chips been out for a couple years.

My brother just left. He ran a scanner and found a 'P1288 - Cylinder head temperature out of range' code. ??? Everything else checked out.

Then we hooked up a fuel pressure gage to the Schrader valve. Pressure fluctuated between 0 and 40 psi, up and down, with both key on engine off and engine running (it will only idle with the MAF disconnected).

So then he disconnected the vacuum from the fuel pressure regulator - no change.

?????????????

He left a message with the drivability tech at the local dealer and told me to replace the fuel filter, just in case it's clogged.

We'll see...

 

Sounds similar to the problem 20"SVT was having, did you check the resister under the front bumper to see if was open? Just a thought.

 

I need help, fellas

Worked on this all weekend and still no joy.

I bought a fuel pressure regulator (part# XR3Z 9C968 AA - $49.30 list), but it looked like a b!tch to R&R, so my brother suggested restricting the return line to see if consistent pressure could be maintained before we dug into the fuel rail. This took all Saturday as I couldn't get the connection apart at the back of the fuel rail, or next to the fuel filter. EEEERRRRRRR!!!!!! I bought 3 different tools, and sprayed and blew out the connections, but they wouldn't budge. Finally my brother was able to do it yesterday and clamp it off, which raised fuel pressure. So we thought it was definitely the fuel pressure regulator.

Mitchell On Demand 5 said it came off with two screws, but posts on another thread here said it was part of the fuel rail and the whole thing had to be replaced. After much aggravation we found that it was held on by a cir-clip hidden underneath. After another struggle to R&R it, we found it would produce another 10 psi, but it still bled off within a second and wouldn’t run for more than a couple seconds. The truck still only idled with the MAF disconnected, and hog rich (clouds of half burned fuel filled my garage).

So then we went looking for the leak. My brother wanted to pull the tank to see if one of the hoses came off again, but I reasoned that if one had, we wouldn't be able to build 40psi. Then he thought maybe the PCM had a bad injector driver that was holding an injector open. We disconnected each injector, one at a time, to feel for the 'click' and to see if it still lost pressure while disconnected. Everything checked out.

We're at wits end. It's a $100 tow to a competent dealer and $90/hour + parts after that, and I’m cheap!

Any thoughts?

 

Have you checked the fuel pump relay under the hood in the High Output Fuse Box? With the key on the fuel pressure should read 40psi then switch to about 34psi after pumps shut off. If you pull the vaccume line off the regulator it will hold a steady 40psi. If its jumping around, you either have a bad relay or low pressure fuel pump.

 

I switched the two relays in there (they both have the same part number), and nothing changed.

 

Did you check the coils? (I had the same problem as you, and fixed with a new coil).

Did you check the vacum lines (Specially the ones behind the supercharger)?

Just some ideas.

 

At the suggestion of another tech I know, I pulled the fuel tank night before last. The 'running' rich threw us off and had us chasing things under the hood. Found that one of the fuel lines between a pump and the 'Y' had burst. EEEERRRRRR!!!!

When I dropped the tank (2/3 full), the fuel sloshed and it fell off the jack and snapped off the nipple on the vapor recovery valve... EEEERRRRRR!!!! Chasing a replacement from the dealer.

I also may have goofed my PCM when I tried to run the fuel pumps by jumping the power at the relay box as the pumps run all the time now. Anyone know of a good, used, inexpensive CUX1?

I'm not having fun yet. And it's supposed to be single digits this weekend...

BBBBUUUUURRRRRRRRRR!!!

 

Here's the problem:



Replaced fuel lines and then the tank (a lot of fun at 8 degrees!).

Makes good pressure consistantly now, but it cranks without starting. I need to figure out if I goofed the PCM, but how? My dealer says CUX1's are ~$350 with a core. I hate to spend that much to find out, but how do I figure out what I broke?

 

Do you have a fuel gage verify pressure it should be about 30 if I remember if you don't it would be best to drop the tank again I bet the fuel line in the tank popped off. Or check the MAF meter cable if you didn't put back on tight your truck will not start.

Good Luck,

Peace,

Suavy