ICP location: inboard front of left (drivers) head.

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Here, this should help:

 

Ok thats what I thought it was just double, triple checking. All these acrynims I forget once in a while. Ya ever forget?

 

I had a simular problem that turned out to be the transfer valve getting stuck half way. I replaced it and problem was solved. The ford steelers took me for $700.00 before that and couldn't figure it out.

 

Well,checked System Pressure And Its Good.hooked Up My Otc Scanner On The Drive Home And The Only Thing That Wouldnt Register Is My Engine Oil Temp.just Showed Xxxx On Temp And Xxx On Volt Scale.i Dont Know If This Has Anything To Do With It But It Ran Fine Until I Got Off Freeway And Came To A Stop.then It Started To Idle Erratic Again And At Steady Speed Of About 50mph It Wants To Surge And Chug Slightly,enough To Feel Like A Tire Out Of Round.got Home,shut Truck Off Went In Ate Dinner Came Out About 30min Later Started Truck Ran Fine Until I Went Down The Road And Came To A Stop,then It Started To Run Erratic Again But Never Stalls.step On Acc To Take Off Its Ok,reach Speed Starts Doing That Surge Chug Thing,even In Cruise Control Mode.i Am Going To Work On It More Today Trying To Unplug Inj Harness One At A Time To See If It Changes Anything As Plowhand Had Suggested.i Filled Up With More Fuel Yesterday And Dumped In A Whole Bottle Of Diesel Kleen To See If That Made A Difference.thanks For All The Support,and I Will Let You Know Later.thanks A Ton Everyone!

 

Dan ~

Something I didn't mention before was that my mechaninc also found that there was a tube that provided exhaust feedback pressure of some sort to the waistgate solenoid. People help me out here with the proper terminology 'cause I don't know it. Anyway, he said he had to take it off and work a coat hanger thruough it because it was so clogged with carbon. I think that helped do the trick. Regardless, I'm convinced that you are NOT looking at a single source failure but rather a failure on many different parts within the fuel injection system.

Jon

 

i thought that was only on the newer 7.3's like 99-03

 

the tube you talked about is the exhuast backpressure sensor tube and it controls the exhuast backpressure valve. commonly mistaken for a waste gate. they are two very different things. the easiest way to cure a plugged EBPV tube it to unplug the EBPV solenoid on the turbo pedestal and forget your truck ever had one. when that valve malfunctions it restricts the exhaust coming out of the turbo. and kills the engine of any hope of power. unplug the two wre connector bolted to the intake side of the turbo right where the air filter tubing hooks to the turbo and you will never have that problem again.

 

Tim ~
You say to un-plug the sensor and forget I ever had it, which I'm cool with but before I do I'd like to know the purpose <b><i>of</b></i> the sensor and how it works with the rest of the system. Is there, somewhere an "Equipment Description and Theory of Operation" type of text that discusses all the various sensors under the hood and describes their workings? My thinking is that the engineers had a reason for putting that sensor there. Do you know of any links that can give me that info?

Jon

 

well let me give you the run down. your not actually unpluggin the sensor your unpluggin the soleniod that activates the hydrualic sylinder the actuates the valve. but that said the exhaust back pressure sensor serves no other purpose than to tell the computer when the valve should be open. when it malfunctions it allows the valve to stay closed when your trying to drive the truck. The reason the engineer installed this system for quicker warm up during cold weather starts. I have had two trucks and neither warmed any faster or any slower than whent he vavle was working. other than it was working incorrectly and would not allow the truck to get out of its own way.

I guess your just going to have to trust me and the 100 other people I have given this advice to and had no problems cause I don't have access to any of the proof you have asked for.

 

don't only the newer trucks have this though? like 99+? cause i know for a fact that our '02 excursion does (you can hear the difference when it's idling) but i don't think my '97 f350 does (no noticeable difference in sound)

 

nope all 94.5 to 03 7.3's have the exhuast backpressure valve unless the truck was ordered with a cold weather delete package from the factory. only late 99 to 03 7.3 trucks have wastegates but they all have EBPV's.

 

Could you post a picture of the connector please

 

ok,here goes. truck quit doing this chug/surge miss thing all week long.ran perfect started fine every time.friday nite leaving work started truck and ran like crap.idle was crappy felt like a miss on a gas motor until you rev it up and then its like a fouled spark plug that starts to clear up.got on freeway and as long as it was at 2000 rpm and up it seems to run ok.let speed come down to about 55-60 and its starts to chug/surge miss.sat morning ran ok all the way to work.left saturday and same s**t all over again.got home and let truck idle and it sounds like a miss until you rev up then it clears up but come back down to idle and it starts to idle crappy again.pulled valve covers off to check harness and no fried wires.i thought maybe injector is bad,but then i checked the fuel bowl and it was about 2 inches from the top without even draining it yet.i dont think its supposed to be that low,is it?i suspect maybe fuel pump as i changed this back in december and it kinda felt like a slight miss then.also she was weeping a little then too.no leaks this time though.does anyone think i may be headed in the right direction? am i missing anything else besides maybe a bad injector? i didnt think when an inj. went bad it would smooth out at higher rpms. i thank anyone and everyone for their help.

 

well next step is to check fuel pressure while running down the road. its kind of back wards from a lack of fuel issue. fuel issues usually show up in the high rpm high load times. not usually at low load/rpm. but its possible. check the pressures at road speeds.