Hey guys, long time reader, found a lot of great advice in here, but I'm getting at my wits end with this issue, so I thought I'd make a post, appreciate any advice. Sorry it's kinda long!

1999 7.3 Powerstroke E350 with about 350000 miles on it.

The truck ran perfect, then one day, right after a railway crossing, the thing lost almost all power, barely was able to putt the thing home and then it quit, would not start after. Started with checking fuel filter, made sure it had fuel to the fuel bowl. Got a diagnosis done and it it came up with a p1298 code - drivers side injectors not passed buzz test. Took apart, added the clip to the harness on that side and checked with a multimetre, everything had power. Replaced the IDM, and bam, the truck started. I was so happy and I put everything back together again. Well, I celebrated too quickly, when I went to drive it it had no power, will only go about 20mph.

The 1298 code went away, but it is now giving my the p1316 code for IDM.. I tried another IDM just to be sure the one I got wasn't faulty but it did the same thing. It's also showing a p0263 code for Cylinder #1 Contribution/Balance and a p0476 for exhaust pressure control valve malfunction.

It seems weird that the new IDM made the truck start but not entirely fix the problem, unless I damaged something before switching the idm when I was trying to get it to start.. Need to figure out where to go next!!

 

Is it smoking bad? exhaust pressure valve might be stuck closed on you and that would cause those symptoms, excessive smoke AND heat, be careful not to overheat your turbo and exhaust if that is the problem. You could also check all of your engine harness connections at the VC's and check that harness for rubbing through where is rubs on the driver's side VC. If you got an OBDII adapter and some scanning software it would be helpful.

 

Thanks Walleye Hunter! It's not smoking bad, and last night i let it run for a half hour to get it up to temperature and the heat gauge was normal. Was gonna dig back into the valve covers and check over everything. I did pick up a nice scanner that will run codes and live data.

 

Many scanners won't work on these trucks so if it doesn't work don't be too surprised. If you tell us what you have someone can tell you if it will work or not.

 

 

I suspect it is a wiring issue somewhere between the 42 pin and the injectors. I bet you "fixed" the problem when messing with the UVHC and then it rattled loose again somewhere. If you haven't done it I would replace both UVHC with OEM, check everywhere for chaffing and see where that gets you. From all my reading on here it is rarely the IDM.

 

It does sound like a UVCH issue to me as well. It also could be a lose tinnerman nut on the IPR. If a big bump jarred it loose, it might do the same thing as far as low power.

 

Yep so true. I have had the nut come loose on my several times. If it is loose the truck will cut in and out. One time it totally fell off. It would shut of, but then I was able to restart it. I suspect that the solenoid or whatever the tin nut holds on would slide back on enough to send a signal. The last time I was on a long overpass and it just died. It took me a little bit to realize it, but I finally saw it laying in the valley. I need to put some RTV on the backside of that booger!

 

 

My Pennies say UVCH Harness as well.....Replace them....

 

I agree...

I had this problem when I shorted out my IDM. The code was staring me right in the face too...."IDM Bad" but I didn't believe it since my truck ran. My truck ran but injector #1 would stick and barely operate. Biodiesel and seafoam would make it run right, but as soon as I swapped the IDM with a known working one, it fixed the problem.

You would need either AE or a Ford IDS to get that code, generic scanners won't pick it up.

Definitely check your UVCH on both sides and replace them with the Motorcraft parts only. The Dorman parts are nice, but cause more failures than they solve...

 

I'm kinda just taking my time at this now so I don't get frustrated. Getting used to life with just my car this summer, gah!

The strangest thing to me is that it ran great, then started running like crap and wouldn't start. Changing the IDM fixed the no start, but it's still running like crap.

It will drive, but maxes out around 25MPH.

I had already checked the UHVC's with a multimetre and they seemed fine but I bought a new motorcraft one for one side, and tried both my other ones on the other side. Unless they were both fried I think I'm safe to say that is not the issue.

Couldn't find that tinnerman nut Hkusp mentioned, but in theory I know where it should be.. maybe have to pull more stuff out to get to it.

I'm getting codes p1316, p1271, p1298, p0476, p0263

Also it seems to rev the engine up during the on demand self test a lot more than I am able to when I hit the accelerator, don't know if that means something.

Since I did IDM and UHVC, those codes make me think next is either having to change injector #1, change the the Exhaust Pressure Valve sensor, locate that IPR and possible change or tighten the nut, or possibly the PCM.

I guess what I'm wondering now before spending too much more money on parts, is there any live data I can look for that might lead me to which thing to try first? Am I missing anything in my list.

You guys have given me a lot to work with and I appreciate the tips!

 

Before doing ANYTHING else you need to verify that the tin nut is on the IPR. Get on top of the engine. Look/feel down below the back side of the oil reservoir that is below the fuel bowl. There is a sensor with wires going to it. You will find the tin nut, as shown in the picture below. If it is not there find it or get a new one. This could absolutely be your problem. It is a 5 minute fix and easy to locate.

 

okay, i located that tinnerman but today, it is in place and tight