High engine Load on Trailblazer

[mrhoden0324]

I have a 2005 Trailblazer LT with 130k on it. The problem with it is it has no low end power just high end. If I'm at a stop sign and floor it, it takes off like a turtle. Bad mpg. Also with AC on and idling I get ALOT of lifter Chatter, like it's under a load. Hook my scanner up to it, has no stores or pending codes. I checked the load on the engine and it's like 60 to 70% load at idle with ac on and in gear. Only around 25% load at idle in park no ac. I done a tune up back in March, new plugs, clean throttle body, Sea-foamed. Did back pressure test, cat is fine and checked and tested the front O2 sensor.
I'm at a lost to what it might be, any help would be great! Thanks in advance!

 

[Wooluf1952]

Welcome

In case you haven't heard:
http://gmtnation.com/forums/topic/218-welcome-to-gmtnationcom-heres-the-story/

Do you know about the torque management? I don't know how much this is affecting your off the line acceleration, but it doesn't help.

 

[gmcman]

When did you purchase the TB? What plugs did you use? These motors like the AC 41-103 iridium. Do you have any brakes dragging? You can wave your hand around the wheel and if so one would feel real warm. When you start off, put the shifter in 2nd and see if the response is the same. The trans will start in 2nd from a stop if in 2nd. Is your air filter clogged or intake tube restricted?

Check for vacuum leaks, the big hose under the resonator, and the molded hose between the 3rd and 4th intake runner. Intake manifold bolts tend to get loose on some motors. What oil are you using and did you go to a quickie lube to get the oil changed? If you didn't change it yourself, drain it and put some synthetic 5W30 in there, mainly synthetic to clean things up.

Check your CPAS, it's the "D" size battery looking component behind the power steering pump, pull the electrical connector and if there's oil in it replace it. You can also remove it and check the screens and clean them off.

This should get you started. Please let us know what you check and the results, it helps alot.

Welcome to the club!

 

[mrhoden0324]

That was a quicker response than a thought thanks! I bought the trailblazer back in October. Had no problems but crappy mpg but figured it just needed a tune up. Did not get around to tune up till March. I did use AC41-103 plugs. No brakes dragging, I did get a code around 2 months ago. P0014 I replaced the CPAS and changed the oil using 5w30 synthetic. Cleared code and has not come back. But it did not fix the issue that I've been having. Will look at the trans and try the 2nd gear thing and let you know. Thanks again!

 

[Trios]

I don't know why, but I'm getting a 'plugged catalytic converter' vibe from your symptoms...

 

[mrhoden0324]

Ok I look for vacuum leaks, all good there and tried 2nd gear response. It's the same in 2nd as in drive.

 

[Mounce]

That means your first gear is MIA. Has your transmission fluid ever been changed? Should've been done at 100k.

If you put the shifter in first gear what does it do? Nothing?

 

[mrhoden0324]

I put it in 1st and it is there. It response is just like 2nd,3rd and drive. Had the transmission fluid changed at the dealer back in March.

 

[mrhoden0324]

Just a thought talking it over with a few friends, some said it maybe the torque converter. That's its stays lock and that's what's causing the high engine load at idle. I found a video of the same thing going wrong with mine,
Here's the link

Take a listen and let me know what yall think! Thanks again!

 

[gmcman]

Calculated load and throttle position are much different. A light pedal when accelerating will give you 100% calculated load.

I would remove the upstream o2 sensor and see if it gets better. A locked converter at idle would stall the engine.

 

[Mooseman]

It almost sounds the same as my problem with the timing chain tensioner. Goes away when above idle.

 

[gmcman]

I found this O2 socket to work the best.

 

[mrhoden0324]

I removed the upstream O2 sensor this afternoon and drove it with it out and still having same problem, I will say that it got a little better but not enough to burn $250 on a new cat. I could still hear that chatter a little and it still started out like a turtle. Wish this thing would give me code to point me the right direction. Any body else got any more tricks that I can try? I don't believe it is the timing chain because of the sluggish acceleration on start up.

 

[gmcman]

I just now watched the video....that sounds crazy. Almost sounds like it's dieseling but doesn't make a lot of sense that it goes away above idle.

Does any exhaust come out of the tailpipe, or at least a steady flow?

Without being there, I cant tell where the noise is coming from, but you could try pulling one coil lead at a time and see if it goes away. You may get a check engine light but if you only keep the lead off for a few seconds or so you may not.

If its in the torque converter you should hear it pretty good if you get under the vehicle.

 

[Trios]

I removed the upstream O2 sensor this afternoon and drove it with it out and still having same problem, I will say that it got a little better but not enough to burn $250 on a new cat. I could still hear that chatter a little and it still started out like a turtle. Wish this thing would give me code to point me the right direction. Any body else got any more tricks that I can try? I don't believe it is the timing chain because of the sluggish acceleration on start up.

If it's a plugged cat, it will only get a little better when you pull the O2 sensor. That port is like, 3/4 of an inch or less; it'll flow about a quarter as much as a free flowing exhaust.

It seems to me you found your culprit.

 

[Mounce]

Am I the only one that saw where he said he done a back pressure test and it was within spec? If that checked out fine like he says, I would have to assume his cat isn't plugged..

 

[littleblazer]

Hey that sounds like my volvo diesel... defiently sounds like lifters. If the timing chain hopped a tooth, it would be fine up higher I suppose and chatter at idle? Could you check oil pressure at idle with a mechanical gauge? I'm wondering if the top end isn't getting enough at idle and the pressure coming up can force it past. I don't really know.

 

[mrhoden0324]

I finally track down the people who posted the video that I reposted, he said: It might had been transmission related, I don't remember. I think this was the A/C condenser. I believe I bypassed it with a smaller belt and it stopped the problem, but we lost A/C.

What yall thinking????

 

[Mooseman]

The compressor clutch bearing I would suspect if it was doing it with the A/C off. Pretty much confirms it if the compressor is bypassed and the noise is gone. I do believe the parts are available but difficult to find.

 

[Trios]

Am I the only one that saw where he said he done a back pressure test and it was within spec? If that checked out fine like he says, I would have to assume his cat isn't plugged..

Evidently, yes. I totally missed that'n.

 

[mrhoden0324]

Alright I took the ac belt off and it's still doing it so I know that it's not that. I believe it is some thing todo with the transmission, I guess I'm going to break down and take it to the stealership! And see if they can figure this one out.

 

[mrhoden0324]

Solved! I think! Took it to the dealer and they said it is my Torque Converter. Will fix in a week or so I will let yall know

 

[yonkster4g4]

Did you figure out your problem? I am having a similar issue with mine and figure it out. How did the dealership figure out the torque converter was bad?

 

[Mike w]

So that's what a TB would sound like with a D-MAX I do believe that is a torque converter rattle..