P0470 - half idle - 40mph max

[arrowstrap]

96 f360 PSD 7.3L intermitently would bog down to low idle (almost enough to die), i'd loose all power the check light comes on and the engine shakes like i lost a cylnder.

no change when i flip fuel tanks.

the problem would occur for 1 to 10 minuites then it would run fine and the light would go out and i'd get all my power back. i pulled the codes and this is all it gives: P0470 Exhaust Back Pressure Sensor Circuit Malfunction.
i cleared the code and restarted the truck and it ran fine and threw no other codes till it bogged down again then only the P0470 code.

parked in my drive i turned it on and it ran fine then bogged for a min then ran fine. it did this for 10 min till i shut her down.

please dont tell me i've got a faulty injector! it would probably make me cry.

ant input would help. i need to get my rig back on the road for a roofing job.

thanks.

 

[95_stroker]

Sounds like your exhaust back pressure vavle (EBPV) is closing when it shouldnt. You may have to clean the tube that runs from the bottom front of the left exh manifold up to the EBPS (sensor) located on the front of the engine behind the HPOP. The tube tends to get clogged with soot. A drill with a short (15") length of small diameter cable chucked up works well when used in conjunction with copious amounts of carb cleaner.

Or, gut the vavle.

 

[arrowstrap]

ooooh, so youre telling me it's probably not a faulty injector? i like that! i'll take you up on your suggestion... if i can find the tube.

so the exhaust sensor can play that much on the engine? when i give it a liffle fuel the engine throws the truck arround quite a bit till higher RPMs then it mellows out a bit but it's still there. i wouldnt be pulling the exhaust code as a result of another problem without pulling another code right? i should pull and injector code if that were the issue?

also, if i unplug the EBPV sensor, wont the gate remain open and tell me if it is the problem?

 

[ACERATI50]

do you have an alarm installed on your truck or any auto start or perhaps have you checked on the valve covers the clips get loose and thats what happens tell me more of what you have checked or what you have on the truck.

 

[Frankenstien]

Another possibility.... when cold... start the truck... check your exhaust manifolds, If one side is staying cold, you may just have a bad Valve cover, if this is the case you may also have to cahnge the wiring harness under the cover.... not to bad a job..... parts all together should run less than 150.....
Hope this or the advice of my friends helps...

 

[arrowstrap]

i checked the tempiture of both sides of the engine. driver side is 30 degrees cooler than passenger. pulled the wires to the valve cover on the cooler side and no change in engine. i suspect its an electrical issue with the wiring under the cover. i plan on removing the cover but of corse its the hard-to-get-to side. i hope the problem is not further back cause i wouldnt know where to begin troubleshooting.

 

[arrowstrap]

i pulled the valve cover and the front wireing harness under the cover was melted, separating the terminals. a quick fix to replace the harness (2 per cover @ 50 bucks a pop) the plug on the inside is attatched to the plastic gasket and this also was melted. my question would be, "what would cause it to get that hot?"

 

[ACERATI50]

it happens on this trucks i really dont know but it has happened to mine and i think the passenger side needs to be replaced but its a pain so i'll do it when i have enough time.