OK yall, I have read and read and read and still need help. My 99 started having problems ever since I hit a big pothole about 3 weeks ago. It was so hard that it broke my exhaust where it coupled into the next pipe back by the spare tire. I have replaced: all glow plugs, icp, ipr, cps, idm, intake air heater, intake air heater relay. It is totally intermintent, thought I was fine until the other day driving down the road and it had no power & would idle like crap when slowing to a stop. Almost thought it was going to die. Then about 5 minutes later it was just fine. It threw these codes when that happened:
P1249 Wastegate fail steady state test
P1211 ICP not controllable - pressure above/below desired
P0542 Manifold intake air heater
P0640 Manifold intake air heater

And this one about a week ago:

P0478 Exhaust pressure control valve high input.

I also have an exhaust leak somewhere below/ behind the turbo. I think it is just from the connection from the drive side exhaust manifold to the y pipe that goes to the turbo. But that wouldn't make it run like crap would it? What now???? Fuel pump? HPOP? Loss of turbo/boost from the leak making it do this? As always, any and all help would be greatly appreciated!!!

 

Exhaust least can cause some loss of boost pressure, but it sounds like you could have some chafed wires at the large square connector on the driver's side VC. These chafed wires could be causing intermittnet problems. This connector/harness carries most of the wiring to the engine sensors and relays.

 

I agree.... check the main harness that sometimes rubs on top of the driver's side valve cover.. You could use a mirror to see beneath the harness..

 

Wow, quick replies. Thanks guys I'll check right now.

 

Well I pulled the black rubber accordian air intake hose off for better view, then went ahead and took the harness completely off with the 10mm bolt, saw no chafing on any wires. re-intalled, checked for clearance & there is about a fingers width so I don't think it was ever rubbing. I did snug that 10mm down fairly good just in case that was it & loose zip tied the wire loom to the air intake hose for a little extra clearance. What about the fuel bowl heater or the computer maybe? Last time it was at the Ford house they said my IDM just "went bad", could have the main cpu gone "bad" too? Thanks!!

 

Sounds like the impact cracked something and/or you have a loose electrical connection somewhere.
I would continue in your search, remove the ECU and check for damage.
The IDM, too, if needed.
Look for a loose/broken engine ground.
Double check every connection for the engine by unplugging and examining.

 

My truck did the same thing ( without hitting the pothole). It would act up for about 2 months, then it died. Turns out my fuel pump and my cam sensor both went out at the same time. I don't why it acted up intermittently, But I replaced them both along with both batteries and haven't had a problem. I'm getting my 6637 today!!!

99 F-350 4 door dually, 4" exhaust from the turbo, superchip programmer.

 

Where is the ECU & how would I check for damage? Isn't everything silicone sealed inside of a metal case?

 

MX, I was thinking fuel pump too, how long has it been since you replaced the fuel pump?

 

sounds kinda like the uvh guys. what do you think?

 

I would check IDM connection (inside of fender well on drivers side and yes...shoot the engineer who put it there) and the PCM (inside behind the e-brake but the elec connector is on the other side of the firewall) make sure the bolt / connector is tight on both of these. Maybe the jolt knocked one loose. But...if you haven't already, I would also check the the under valve cover gasket connection.

 

But...if you haven't already, I would also check the the under valve cover gasket connection.[/QUOTE]


You beat me to it!
I would also consider checking the batteries.

 

Did you check the wires coming out the back side of that box for chaffing as well? That's where mine rubbed.

I agree with the posts above. If you hit a pot hole hard enough to brake the exhaust, it's time to unplug, and plug back in everything you can think of, then give every other part the wiggle test and see if you can find something loose. I've hit some pretty rough patches before, but never anything hard enough to break the exhaust. I can only imagine what kind of hole that must have been.

 

I replaced my fuel pump and CPS about 2 months ago. No problems since. The code P 1211 is what makes me think we have the same problem. I was spitting out the same code. But not anymore.

 

[quote=F350-6;7180344]Did you check the wires coming out the back side of that box for chaffing as well? That's where mine rubbed.

F350-6, I checked the wires on the side going torwards the driver side fender well, that is where it easily appeared that they could have been rubbing on the driver side vc. You are refering to the side that goes torwards the HPOP & pass side vc, right? I didn't check those as I didn't see anywhere those could have been rubbing on something.

I agree I'll have to start unplugging, plugging, torqueing (sp?), & wiggling as it does seem to be an electrical issue because of the intermittance. Hopefully I'll get some time this week to check before it acts up again.