on my 01. my fuel milage i think sucks, and it seems to be getting a little worse. what to check next??? exhaust backpressure was reading 14-15psi, map psi was 14/15 and baro vaccum was 30.

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just was poking around, and the sensor positioned under the turbo in the middle facing the front of the engine by the pedestal was unplugged! i cleared all codes, what sensor is this and would that have messed with my fuel milage and/or threw these codes???

 

What kind of mileage are you getting that has you worried?

That sensor sounds like the ebpv sensor. Unplugging it doesnt allow it to function but I have mine unplugged except during winter...

look thru the sticky post to find out what the codes are for, im not on my comp otherwise i'd look for you however I know the 1211 is icp related...

 

P0473 Exhaust Back Pressure Sensor Circuit High Input
P0476 Exhaust Pressure Control Valve Malfunction
P0476 Exhaust Pressure Control Valve Performance
there is no 0475. these codes are a sticky somewhere on this site.
P1211 ICP Not Controllable - Pressure Above/Below Desired
for the ICP, it could have gone out and the PCM is running on the default setting. with the engine running, unplug the sensor and if the idle changes, the sensor is good (the idle will get a little rougher.) if the idle doesn't change then the sensor is bad. OR just needs to be cleaned out. there is a sticky on here for removal and cleaning. the 0475 could be a 0476? that could be just because the EBPV wire was un plugged. but that shouldn't throw a code.

 

the sensor was unplugged for the ebvc causing the code to come on...i still am getting the p1211 code. i unplugged the icp sensor while running and it does change the idle a little but didnt really make it sound rough and the connector is free of oil. I haul commercially so its not a fair comparison as i get between 7-11mpg. 11mpg being the best with the empty 40' g/n trailer which i believe sucks. my 95 gets 13-14 empty pulling the same trailer. i was told to check the IPR valve and bought a socket to try that. other than that, i'm out of ideas.

 

ok well if the idle changed then your ICP is good. and no oil in the plug is good. and 7- 11? that's way low. i think the OBS get better mileage. but i'd check your IPR. those are kinda pricey tho.

 

i cleaned the exhaust tube and sensor of some sort on the front of the engine 2 days ago...so far, it actually seems to be helping with the fuel milage andi do notice that the truck doesn't blow the black smoke near as bad on the race setting and hardly any smoke on the tow mode.and after 2 days of running, no code has come back...would that thing being clogged cause that code to come on though? i just bought a socket to take out the ipr sensor, so thats on my list for the weekend!! off to vermont i go, so i'll report back to see what kind of milage i get this time....

 

that tube being clogged could very well be the problem. if the sensor is reading low then the PCM could say more fuel. and if it's not smoking as much it's not using as much fuel. black smoke is unburnt fuel.

 

hey, thats exactly my thoughts too and after running my vermont load yesterday, i can say it got a little better than it ever has. i got around 12.0 mpg empty with my 40' flatbed which is a little better than i ever got before. Since i already bought the socket, i'm going to take apart that idm sensor (think thats what it is) and clean it up...also, no codes since i cleaned that exhaust sensor tube too!!! thanks for the input...

 

i'm glad it helped! i'll have to try that on mine.

 

it DEFINATELY helped. i checked just yesterday my last 150 mile stretch home from vermont, and i put the chip on the number 5 position which i believe is 110hp, and i got 12.98mpg empty!!! thats over 1.5 mpg better than i ever got before. i'm excited!!! would haveing the chip turned up like that, cause the p1211 code to appear? it was gone for a little bit, but it did come back yesterday but i did flog on it a little bit so i'm just wondering if thats the case and does that code make the computer compensate and do anything differently or should i just erase it and go on or just let the code in there???