Glad I am not alone ;-(

No I have not and the nightmare continues... I have just posted a new thread about ECM swapping as I am thinking that could be the culprit of our problems.

Lets keep in touch

 

I feel your pain. I started searching this forum for help and came across your post.

Heres my story:
Ive changed knock sensors twice, within 2 months, new wiring harnessss each time, cleaned out intake, codes still come back.

The strange part about my situation, the knock sensor codes don’t activate unless I do some highway driving. If I’m doing normal city/in town driving....45mph or less.....the codes do not activate. Once I drive 70mph plus, then the codes activate. It takes 45 mins or more of driving at 70mph plus for the cel to come on.

Judt thought I would share my woes. After reading your posts and the response, there are many other things to check. It just gets old trying to track down the culprit.

I will report back once I’ve spent more time checking this out.

 

Thank you very much for sharing this!

Same here, only hwy driving will trigger the KS codes.
How is you engine running? Are you also experiencing lack of power and hesitation or just getting the codes?

 

It doesnt seem to have a lack of power. Hesitation....not really.

I have a 6” lift with 38” tires....so a “lack of power” seems very subjective. I will floor the accelerator today and let you know more.

I don’t drive the H2 hard at all bc of the size/weight. Going fast just isn’t the point for me in this tonka toy. Now, I do run over curbs, speed bumps, etc without concern.

When I press the gas pedal, the H2 instantly begins to move. I don’t feel any sluggishness or as if it were bogged down.

I’m surprised you’re having the same trigger....highway driving. Most of my driving is in the city....i have gone 3 or 4 weeks without hwy driving and NO CODES. Then, I take the Hummer out for 30 min drive one way....and on the way back, cel comes on.

 

So....from zero to 40mph, throttle is very responsive, no hesitation at all. Truck drives great!

Now, once I’m driving over 40mph, I’ve got NO power. Even pedal to the floor and nothing, rpms kinda revved up a small bit, but nothing noticeable. The next lower gear definitely did not kick in automatically. H2 just slowly builds up speed. I even let off accelerator and pressed to the flooor again and nothing.

If I floor it from 0, then the H2 roars like crazy and rpms hit 4K before going into then next gear.

 

What was the pressure in the exhaust?
Can you monitor the fuel trims both long and short?
What is the exact codes you were getting?

Neal

 

Hello Neal,

Do you know what values should normal fuel trims read? I can bring my scanner with me tomorrow for a 30 mile drive... In my case I only get codes P0327 and P0332, KS 1 and KS2 low frequency.

 

I have a scanner that can read fuel trims. Not sure what I’m looking at though. I glanced at it today and the graph was very erratic. Don’t recall if it was the short or the long.

Regarding exhaust pressure.....Not sure if my scanner can measure that. Am I looking for “exhaust pressure reading?” The scanner has a variety of sub menus that I can play around with. I didn’t realize it was possible to measure the exhaust pressure through a scanner.

My codes are p0327, p0332, p0455

 

Fuel trims should be within +/- 10 under normal driving for both long and short term trims. If more than that there could be an issue if no major modifications have been done to the engine. The closer to 0 they are the better

 

The scanner will not read the exhaust pressure you will need to remove one of the O2 sensors and install a pressure gauge.