Engine Help

udeleon · April 30, 2009

I've looked around a bit and I haven't seem to locate the exact answer to my current issue with the truck.

Currently when you first turn on the truck, I receive the typical "clatter" or I guess "piston slap"…it usually goes away…that's not really my issue. (Or at least I don't think it is.) My issue is that, after 1^st gear, my truck starts to feel sluggish, and I can hear what sounds almost like an exhaust leak (which has been checked). I hear my engine struggle and makes I had bad gas, denotation / engine knock type sound.

Any ideas? Again this only happens usually right after 1^st gear, and the engine is at around 1500 – 2000 rpm's…

Truck - 2007 - 5.3L Gas 4x4

FYI – I do not have a tune at the moment, and I have already tried fuel injector cleaners.

VR021302 · April 30, 2009

try this click me click me

udeleon · April 30, 2009

try this click me click me

I noticed that bulletin states that it's for a 2002. does this issue occure with the new models/5.3's as well?

Thanks for the info, as it's a good starting point to let the dealer know.

Would any of this have to do with adding headers to the truck...like I stated, it's not an exhaust leak, as it's been check already.

VR021302 · April 30, 2009

It might have to do with the headers, maybe they caused a cat problem

udeleon · April 30, 2009

It might have to do with the headers, maybe they caused a cat problem

Great...that's exactly what I DID NOT need. I guess I'll just have to take it to the dealer and see what they blame me for doing...

Thanks for the info Tex-Mex...

Anyone else have any ideas?

superjim · May 1, 2009

It might have to do with the headers, maybe they caused a cat problem

Great...that's exactly what I DID NOT need. I guess I'll just have to take it to the dealer and see what they blame me for doing...

Thanks for the info Tex-Mex...

Anyone else have any ideas?

Does it only do it after 1st gear...when it changes to 2nd gear?

Is it ok after you speed up a little and it changes to 3rd and 4th?

Or does it do it ALL THE TIME after it changes OUT of 1st?

Need more info.

udeleon · May 1, 2009

It might have to do with the headers, maybe they caused a cat problem

Great...that's exactly what I DID NOT need. I guess I'll just have to take it to the dealer and see what they blame me for doing...

Thanks for the info Tex-Mex...

Anyone else have any ideas?

Does it only do it after 1st gear...when it changes to 2nd gear?

Is it ok after you speed up a little and it changes to 3rd and 4th?

Or does it do it ALL THE TIME after it changes OUT of 1st?

Need more info.

jim,

after driving it this morning this is what i noticed.

when i start up in the mornings i hear what i guess people call piston slap? after about a min or so the sound softens but does not go away. in first gear taking off you can hear the clatter but not as much. its when you get to higher gears that you can really hear it. the sound reminds me of manual trannsmission car when you have it on a high gear and the engine calls for a lower gear to get going. does that make sense? i am going to have the dealer take a look at it on monday. just curious as to if anyone has had the same issue. thank you for your time.

66nova · May 1, 2009

It might have to do with the headers, maybe they caused a cat problem

Great...that's exactly what I DID NOT need. I guess I'll just have to take it to the dealer and see what they blame me for doing...

Thanks for the info Tex-Mex...

Anyone else have any ideas?

Does it only do it after 1st gear...when it changes to 2nd gear?

Is it ok after you speed up a little and it changes to 3rd and 4th?

Or does it do it ALL THE TIME after it changes OUT of 1st?

Need more info.

jim,

after driving it this morning this is what i noticed.

when i start up in the mornings i hear what i guess people call piston slap? after about a min or so the sound softens but does not go away. in first gear taking off you can hear the clatter but not as much. its when you get to higher gears that you can really hear it. the sound reminds me of manual trannsmission car when you have it on a high gear and the engine calls for a lower gear to get going. does that make sense? i am going to have the dealer take a look at it on monday. just curious as to if anyone has had the same issue. thank you for your time.

Are you sure you haven't got into some bad gas. Sounds like a octane issue or water in your fuel.

udeleon · May 2, 2009

Are you sure you haven't got into some bad gas. Sounds like a octane issue or water in your fuel.

I have thrown in cleaner, and I even used 93 octane this past fillup...same o' ....

I'll keep everyone posted...

superjim · May 2, 2009

Are you sure you haven't got into some bad gas. Sounds like a octane issue or water in your fuel.

I have thrown in cleaner, and I even used 93 octane this past fillup...same o' ....

I'll keep everyone posted...

My guess at this point...without being able to actually HEAR IT...is a bad knock sensor.

From your description earlier, it sounds like what we used to call, LABOR KNOCK.

Now I think they call it detonation.

The ECM will advance the timing until it gets a signal from the knock sensor that detonation is occurring.

At that time it backs off the timing just a hair.

Periodically it will try to advance the timing AGAIN...until it gets the signal from the knock sensor.

Without the signal from the knock sensor...it just keeps advancing the timing until detonation (labor knock) is happening.

Let us know what you find out.

txab · May 2, 2009

Warranty, Dealership. Use them if you think you've got a problem.

udeleon · May 5, 2009

The verdict:

Out of tune truck + headers = lots of header noise...

Black Bear Tune process will be in session soon…I am hoping this will correct the timing of the truck with my current mods…

Thanks guys for your help…I’m thinking I may wrap my headers to see if the sound dampens a little, but will need see if there are any drawbacks to it.