HELP...2001 7.3 starts but runs terrible...

[wingnut]

Nope...CPS not it

[wingnut]

ok, still working on this and was about to pull valve covers and check the harness...

...but i finally got the local ford tech on the phone and he doesnt seem to think that the UVCH would be an issue since there are no codes being thrown.

he does suspect the Injector Pressure Regulator though, does anyone else think this might be an issue?

[Houstonvett]

If the IPR was bad the PCM should have a code set, IMO. I would start with checking the fuel pressure first @ the regulator block. Make sure you have 20PSI @ idle and 30 to 70 Lbs @ WOT. Good place to start, might save you a lot of time.

The IPR circuit does have a relay inside the PCM which can go bad also. The PCM determines the amount of injection control pressure and then modulates the on/off time by shorting the signal to ground thru this relay. A real PITA to find this problem and doesn't happen that often, just to me. Good Luck on your quest.

[wingnut]

oh thank you for the pressure numbers!

...but sadly i cant get her to run long enough to check a dam thing anymore

[Houstonvett]

Originally Posted by wingnut

oh thank you for the pressure numbers!

...but sadly i cant get her to run long enough to check a dam thing anymore

The IPR circuit is 1 of the guys that will keep the truck from running. A real PITA if it is in the IPR relay that is in the PCM. Hopefully you can get the engine turned on to check fuel pressure before checking the IPR circuit.

[Codum]

I don't think you need the truck to run to check fuel pressure, not for your issue anyway. You are not having performance issues, your truck won't run. The fuel pump is electric, when you turn the key to on, you should here the electric pump run, it's under the drivers door inside the fram rail. I am going to suggest something that I just thought of, never tried or heard of it, but should work. On the back side of the fuel bowl is a yellow valve that allows you to drain the water/ fuel out. Pull that hose off the back of that valve. Get you some fuel line rubber tubing and connect to the back of that valve. Now connect a fuel gauge to that tubing, you will need to get some fittings to connect it together. Open the yellow handle on that valve, go turn the key to on and then check the fuel pressure on your gauge. Another quick way is to remove the tube of the yellow valve, turn the key to on, with on finger over the valve outlet, open the valve, you should feel good pressure, it may even be hard to hold the fuel back. This will tell you if you fuel pump is providing enough fuel for the truck to run.

[wingnut]

alright, i will check the bowl fuel pressure in the morning...

...thank you sir!

[PanhandlePS7.3]

My '01 Excursion was doing the same thing and it turned out to be the UVCH. It NEVER threw a code! I asked a local Ford mechanic to do a buzz test on the injectors to try and narrow it down to one side but they refused and wanted to trouble shoot it themselves. So, I checked the gaskets myself at the house and fixed it for the cost of two new gaskets.

As for the CPS, on my '99, when it went, it never fired back up. Swapped it out in a dirt parking lot and haven't had an issue since.

Hope you get it fixed!

[Turbostang500]

I forgot to mention, when i forgot to plug in the one uvch, i had a ses light. After i shut it off and plugged the connector back in, the light DIDNT come back on.

Hope this helps.

[wingnut]

SUCCESS...it was the passenger side UVCH, and after reading the last two posts i said "screw it" and tore into her, cause for the cost of two dam quarters i couldnt NOT try it

the drivers side was first, cause its obviously the easier of the two to get to. but after seeing the clip and slipping the quarter into place, i was not convinced there had been enough of a problem to try and start her up without tackling the other side

i also had been considering powdercoating the valve covers while i had them off, but time constraints were kicking my @$$, so they stayed factory colored

on to the passenger side, and i noticed the gap, gave the plug a nudge only to hear a satisfying "CLICK". quick dug up another quarter, ground her down and 20 minutes later the old beast fired right back up

big thanks to EVERYONE who suggested EVERYTHING...i was prepared to go down the fuel pressure road directly after this, but that CLICK told me the culprit had been found