These are the things I've replaced/modified over the last 50,000 miles:

- replaced fuel pump
- installed fuel pressure gauge
- replaced valve cover gaskets
- replaced glow plugs and relays
- replaced #8 injector (500 miles ago)
- replaced IDM (did that just today)

Thats what I can come up with off the top of my head. I know there's more.

I have a 2001 F250 with the 7.3 Diesel with 300,000 miles - manual transmission. About 1000 miles ago it started feeling a little sluggish while I was towing and it was having a hard time starting in the mornings. I cleaned the air filter and checked the fuel filters ect. I have a fuel pressure gauge installed and it's running about 70 PSI. I've already replaced the fuel pump a few thousand ago so I know it's good. I have bypassed the screens in the fuel tank. Basically I'm positive the problem isn't fuel related.

I got completely frustrated and took it to a shop, which is something I hate doing. The shop did a buzz test and told me #8 injector was bad and that the IDM was possibly bad also (it was throwing the IDM code). So I ordered a new injector and a new IDM and replaced them both. I read up on the issues with the loose connectors under the valve cover but since the valve covers had recently been replaced I figured it couldn't be that problem. After the injector was replaced it started to idle more more smoothly but it still had hard start issues sometimes.

I was towing a trailer the other day and it started missing. A few miles later it got worse and worse until finally it got so gutless I could only go 40 MPH. I pulled off the side of the road and turned the key off for 5 minutes and it seemed to run fine for the 10 more miles until I got home. I've been driving it around town and it seems to do fine over short distances but once it's ran a prolonged time it starts acting up.

Today after replacing the IDM I took it for a drive and I didn't notice any change. The SES light comes on and off randomly throwing the IDM code. When I get on the highway and give it the throttle it takes a long time to get completely spooled up and I can tell that it's missing on one cylinder. The local diesel shop can't figure it out and I can't figure it out. Today I decided to just double check and see if the wiring harnesses were loose under the valve covers and tore into it only to find them both tight and secure.

So I'm pretty much out of stuff to try. Anyone have any ideas? I don't want to go and get raped by a dealer to have them figure it out.

 

70 psi is about the max fuel pressure these trucks like. Above that and they often start acting funny. What did you do to get the fuel pressure up to 70?

Sounds like you've thrown quite a bit of money at it already. Any reason you haven't spent a few hundred on buying an AE so you can scan it and run some tests yourself?

What IDM code do you keep getting? P1316? I'd ignore the fact that the under valve cover wiring was new and ohm the connection from outside the valve covers anyway. Did you replace the valve cover gaskets too, or is there a chance the pass thru connector is bad?

 

70 PSI is just what it has run at since I've gotten it. The gauge may be off 5 PSI or so.

I've thrown alot of money at it just as maintenance over the last few years. The truck has always been very well maintained. I'm kinda a noob but what's an AE?

P1316 is the code I'm getting. I did replace the valve cover gaskets with new ones about 20,000 miles ago. The shop ran a buzz test and assured me that the wiring under the valve covers was good but it was the IDM that was the problem. Quite naturally I decided to check the wiring under the valve cover anyway and it was good.

I do have the valve covers removed already so before I put it back together is there any other testing I can do under there? If not I'll throw it back together and do OHM the connectors.

 

This is AE Riffraff Diesel: Total Ford Enhanced Bundle

Stands for autoenginuity. It's a scan tool that can help you diagnose your problems. If you've still got the valve covers off, plug the 42 pin connector back in and start the truck. Watch for the amount of oil discharge from each injector. Each one should spit about the same amount of oil.

 

I'll for sure look into the AE as I'm responsible for looking after several of these 7.3's.

I'll do the injector thing in the morning. Will the truck even run with all the stuff unhooked like it is?

 

You say you don't think it's the UVCH, but I'd still make sure and eliminate that as a possibility, just to make sure.

Stewart

 

You've got to plug the wiring back together, but you can leave the valve covers and intercooler tubes off for a quick visual.

 

Be sure there are no rags under the hood when you start it. It will suck them up quicker that you can say, "OH CRAP!".

 

Subscribing.
I agree with Chris, get the AE package and get some readings.

 

oh SNAP! I just broke the clip under the valve cover that holds the wiring harness to the valve cover gasket while I was attempting to do the "50 cent mod". I called Ford and they don't sell just the clip, they only sell the whole wiring harness. AHHHHH! Oh well. . . maybe the wiring harness is my problem. Unless someone has a good idea I'll probably be off to Ford to buy one for $100.

 

Got an International truck dealer nearby? They sell the same harness for less. You just have to tell them you have a 444 engine.

 

Just got back from Ford with 2 new injector wiring harnesses. I figure while it's apart I might as well do both of them. I'll hook them up and check back. . .

 

Okay. Hooked up the wiring and checked all the oil coming from the injectors. The drivers side one closest to the radiator isn't spitting out any oil. . . . I assume that means that injector is bad? And if it is WHY didn't the shop's buzz test catch it?

 

The buzz test only checks the electrical side of the injector. Since you don't have a scanner to watch rotational velocity numbers (yet), staring at the injectors was about the only test you could perform.

If the injector is not spitting any oil, and the wiring is good, then I'd say it's time to replace that injector.

 

That's what I was thinking. . . I guess I'll get another one on the way. Thanks for the help. When the injector gets here I'll let you know how things are going.