NEED SOME HELP 94xlt still giving trouble

[jshg46]

hi guys i posted on this truck before but i have a engine light thats on now and i have ran test on this truck and what i get is (ept volts hi ) on diagnostic machine but this truck is running bad at idle and is using a ton of gas ,and acts like it want to stumble when you first press gas pedal ,smell ranky also , thanks for any help you guys can give me

 

[MrShorty]

Not sure what you mean by "ept." What was the actual code number? Your symptoms seem consistent with an EGR problem, so I'm guessing it was and EGR type code. I find it easier to help people if they not only give the code number, but also identify which part of the test the code is from (KOEO, KOER, or continuous memory). It can also be useful to know which, if any, of the portions output pass (111) codes.

 

[jshg46]

if i remember correctly the code was 336 on both test

 

[MrShorty]

if i remember correctly the code was 336 on both test

Which means that a) you got a 336 for both the KOEO code and continuous memory code and didn't do the KOER test or b) you got a 336 for the KOER test, and didn't distinguish between KOEO and continuous memory codes during the KOEO test. If you get a 336 for a KOEO code (sometimes I call them hard fault codes to better distinguish them from the continuous memory codes), then the fault almost has to be electrical. This is because the engine isn't running when the fault is triggered. The startegy would be to a) check the wiring between the computer and the EGR sensor for faults, and b) check the sensor inputs (if any) and output to see if it's what it should be.
Diagnosing a 336 where the code is a KOER and/or continuous memory code and it passes the KOEO test is a little more complicated, because you have additional potential causes that stem from the engine running. Still check the wiring, just recognize that an out of range EGR sensor could be caused by other things.

 

[410Fortune]

You didn't tell him that if the EGR code is apparent and the wiring checks out that the EGR sensor may very well need to be replaced along with a clean or new EGR tube.