2002 2500hd Running Bad

Genuinefine409 · June 7, 2008

My 2002 2500HD w/ 6.0 is acting funny. Maybe someone can help. I searched around for a while and found some useful info however I'm getting an extra code I haven't seen on here yet.

Codes are:

P0101 - MAF

P0171 - O2 Lean

P0174 - O2 Lean

P0332 - Knock Sensor (I haven't seen anyone else with this code and having the other codes too, All four come back within 5 miles of driving)

It all started just after filling up with gas with may be coincidence but I thought maybe I got some bad gas at first. I ran tank very low and filled again only about 1/3 full in case I had to do something with the fuel pump but it still has same symptoms. While driving the truck surges and really lacks power. When first starting the truck, it fires up and shuts right off. it takes 2 or 3 times starting it and it'll run then but it runs rough. When its warmed up it starts back up fine. I even tryed cycling the key a few times to build the pressure think it was leaking down over night but it still starts the same.

Sometimes when starting up a hill you can really hear it pinging like crazy at first but stops then you can feel the power just die off then.(I assume its retarding the timing cause of the pinging) I read on a few threads about leaky intake gaskets being associated with the P0101 code and the P0171 and P0174 codes usually come along too and I think that changing the intake gaskets will be my first move unless having two little fuel pressure can cause this too.

I only have 47psi with the engine idling and 55psi with engine off and using scanner to run the fuel pump. while the engine is running, I take the vacuum line off the regulator and the pressure goes from 47psi to about 53-54psi. The book calls for 55-62( I think, don't have it in front of me) with the engine idling.

I have cleaned the MAF twice and I use a paper filter so there is no K&N crap on it. The intake is stock as well and I checked over the whole thing for air getting in past the MAF and everything is fine there. The truck is totally stock. Not a single mod of any type. From other threads I've been reading on here it is more than likey the MAF, MAP Sensor, or the intake gaskets. Anyone know anything else? perhaps about my fuel pressure?

BTW - I have a Snap-On MT2500 scanner so if there is anything in the sensor data or anything I can look for it would help. Thanks.

copenhagen · June 9, 2008

It really sounds like a plugged or broken cat converter, and just to add that bad gas plugs cats.

Find somebody with the same truck and rev up the engine so feel the difference of exhaust coming out or take out a o2 sensor and hook up a backpressure gauge, but the gauge dont really work if the cat is broken most of the time..

Genuinefine409 · June 11, 2008

I was thinking about the cat being clogged but it will rev fine and pull upper rpm's really good every now and then. I swapped out intake gaskets last night becuase they were the chepaest and it would give me a good idea of the buildup of carbon and crap in the engine. After doing the gaksets it's still the same.

I tested the MAF sensor and the hz on it were low compared to everything I've been able to find over the internet. I also tested the MAP sensor and it tested good, same with TPS and EGR valve. I guess I'll change the MAF sensor and see what happens.

The readings at an idle were 2200hz and pretty much every I found says they should be around 2900hz at idle. We'll see what happenes.

Genuinefine409 · June 15, 2008

The readings at an idle were 2200hz and pretty much every I found says they should be around 2900hz at idle. We'll see what happens.

I replaced the MAF sensor and the Hz at idle are now around 3000 or so. After doing so the truck ran better but still not right. Still throws all four codes. I changed the MAP sensor and Now the only codes I have are P0332 and P0101. So I have to pull the intake again to change the stupid knock sensors so I'm going to check the intake out more closely.

Genuinefine409 · June 21, 2008

I noticed that part of my wiring harness was tampered with. It was the wiring for the knock sensors. The previous owner must have had the P0332 code come up, and cut and rewire the sensors so they both read from the front sensor. I repaired it and thats went I got the P0332 code. I got a new sensor and new harness and fixed it up with the update your upposed to do with the rear knock sensor so thats all good now.

I replaced the MAF, MAP, and fuel pressure regulator and still had P0101. for whatever reason I fiddled with the EVAP solenoid and sure enough, thats were my problem was. I guess air was getting past the o-ring and rubber gasket. fixed that up and the truck runs like a champ and no codes.

jefferias · June 21, 2008

glad to hear it! wow im amazed at your knowledge of the "new gen" aka. vehicle with computers . i would have been pullin my hair out fo sure! If it dont have a carb i dont wanna fix it lol!!!!!!

whmayhew · June 22, 2008

You must have alot of patience. Good tracking down your problems.

tomo62 · June 23, 2008

Don't you love some of these 'fixes' that some clowns come up with! Great work tracking that down - Detective Columbo would be impressed!

P.S.

1. Since you are now an expert! - how long does it take to change the intake gasket? (for the first time! - second time is generally WAY quicker!)

2. Fuel pressure readings are taken with the vacuum tube OFF the FPR? (Just changed the fuel pump and reading is 45psi with vac line on FPR)

Thanks and good work!

Genuinefine409 · June 23, 2008

Don't you love some of these 'fixes' that some clowns come up with! Great work tracking that down - Detective Columbo would be impressed!

P.S.

1. Since you are now an expert! - how long does it take to change the intake gasket? (for the first time! - second time is generally WAY quicker!)

2. Fuel pressure readings are taken with the vacuum tube OFF the FPR? (Just changed the fuel pump and reading is 45psi with vac line on FPR)

Thanks and good work!

The first time it took me a lttle over two hours, I was taking my time and wanted to make sure i got it right. the second time was about 45 minutes- 1 hour. I think fuel pressure is supposed to be checked with the vacuum line on but i do not know for sure.

tomo62 · June 24, 2008

Thanks for the time estimate - always handy - I might have these jobs coming in my near future and wanted to have some idea as to duration.

great when these things work right isn't it!

Don't you love some of these 'fixes' that some clowns come up with! Great work tracking that down - Detective Columbo would be impressed!

P.S.

1. Since you are now an expert! - how long does it take to change the intake gasket? (for the first time! - second time is generally WAY quicker!)

2. Fuel pressure readings are taken with the vacuum tube OFF the FPR? (Just changed the fuel pump and reading is 45psi with vac line on FPR)

Thanks and good work!

The first time it took me a lttle over two hours, I was taking my time and wanted to make sure i got it right. the second time was about 45 minutes- 1 hour. I think fuel pressure is supposed to be checked with the vacuum line on but i do not know for sure.