Reduced Engine Power...
Platinum Supporting Vendor
Joined: Sep 2001
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There could be an issue in the tune that you don't see. Not all tables are shown in HP Tuners or EFI Live but depending on the EFIlive you can modify tables that not everyone can see. Also some tuners will use copies of copies of cals, and you can get a corruption on this. The BEST scenario to solve this is to start with a fresh GM cal and then modify that calibration with data from the old tune, not copy it in, but actually modify the tables. It should not cost you $800 for this, if you want to send me the PCM out of your car I will do it for $400 including the new GM calibration. This would also include the license I would need for your car.
Justin
Justin
Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
Understand. I spent $800 the first time because I also got a brand new PCM itself. I can probably get a hold of the old one to send you. If this was a tuning problem why would it not rear its ugly head until swapping out the pulley?
Does this also mean that wiping the current tune and putting a new one on wont work without first doing a GM re-flash?
Does this also mean that wiping the current tune and putting a new one on wont work without first doing a GM re-flash?
Race Director
Joined: May 2004
Posts: 16,667
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From: Raleigh, NC
St. Jude Donor '15
I looked over tune and don't see anything that would cause this issue (at least with what you can see in hp tuners). I was thinking somebody might have messed with the throttle maps but they are totally stock so that wasn't it
Your boost VE table looks a little weird but I'm not going to criticize the tune
Your boost VE table looks a little weird but I'm not going to criticize the tune
Tech Contributor
Joined: Jul 2002
Posts: 14,950
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From: St. Louis, MO
St. Jude Donor '08
I wish I had a home run solution here but I don't - just the question I ask every time something stops working - "if it worked yesterday and doesn't work today, what changed between yesterday and today?"
Thinking about it, installing a balancer requires removing the rack and perhaps disturbing the ABS wiring when doing so. If I read correctly the car's TPMS system wasn't working either.
I would suggest looking very closely at the wiring for the rack and the ABS... I'm wondering if there is something amiss here.
Did you have the dealer check for BCM error messages with their Tech 2? A wiring fault might show up there.
Thinking about it, installing a balancer requires removing the rack and perhaps disturbing the ABS wiring when doing so. If I read correctly the car's TPMS system wasn't working either.
I would suggest looking very closely at the wiring for the rack and the ABS... I'm wondering if there is something amiss here.
Did you have the dealer check for BCM error messages with their Tech 2? A wiring fault might show up there.
Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
Thats where we are at right now. Going to basically to a pulley un-install to try and find the problem. Dealer wont touch the car unless im open to paying for them to replace all the parts I already did...
The TPMS is also the one clue that makes me think a ground is amiss. I have since gone to TireRack and they relearned the front ones but they could not get the rear ones. Said it was like the rear wheels didnt even have the sensors in them???
The TPMS is also the one clue that makes me think a ground is amiss. I have since gone to TireRack and they relearned the front ones but they could not get the rear ones. Said it was like the rear wheels didnt even have the sensors in them???
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Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
I'd be looking at the shop that replaced the balancer for some help...
It worked fine when you brought it in and now it doesn't.
It worked fine when you brought it in and now it doesn't.
Last edited by Joe_G; Feb 16, 2016 at 06:10 PM.
Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
I find it ironic that I had a perfectly working 750hp vehicle and decided to spend $1300 for precautionary maintenance which has now cost me much more lol
For the individuals interested in looking at the tune/maps or want to follow along to learn, I will post what I have in just minute.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
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From: St. Louis, MO
St. Jude Donor '08
Wait a second.
What triggers the meth? It must be tied into the throttle body wiring. Try unhooking the meth wire that taps into the TB wiring and see what happens.
Ran into this once on a nitrous install. The car did not like the voltage drop on the TB wire when the solenoid kicked in.
What triggers the meth? It must be tied into the throttle body wiring. Try unhooking the meth wire that taps into the TB wiring and see what happens.
Ran into this once on a nitrous install. The car did not like the voltage drop on the TB wire when the solenoid kicked in.
Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
It happens at idle now though.
The meth is dependent on the boost.
Example. Car is in neutral and I rev it - No meth but can cause reduced power
Ive disconnect the 12v supplied by the engine fuse as well to try and get a different result but nothing. Appreciate the idea though.
The meth is dependent on the boost.
Example. Car is in neutral and I rev it - No meth but can cause reduced power
Ive disconnect the 12v supplied by the engine fuse as well to try and get a different result but nothing. Appreciate the idea though.
Last edited by Spoolin8; Feb 16, 2016 at 08:30 PM.
Platinum Supporting Vendor
Joined: Sep 2001
Posts: 3,665
Likes: 341
It happens at idle now though.
The meth is dependent on the boost.
Example. Car is in neutral and I rev it - No meth but can cause reduced power
Ive disconnect the 12v supplied by the engine fuse as well to try and get a different result but nothing. Appreciate the idea though.
The meth is dependent on the boost.
Example. Car is in neutral and I rev it - No meth but can cause reduced power
Ive disconnect the 12v supplied by the engine fuse as well to try and get a different result but nothing. Appreciate the idea though.
As far the PCM is concerned the old one is fine for the reflash. I would update it with the latest OS.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
Do you have anything hooked into the TB wiring harness? These are very sensitive to voltage variations. Depending on year they run two or three sensors on them. If you ran a Meth wire to it you could have some low voltage back feeding that can throw one of the sensors off and cause your issue. May have nothing to do with pulley so don't be too stuck on that. Maybe they damaged a crank sensor voltage wire but I don't think they are tied in on the same 5v ref. You really need a Tech2 to start scanning. You can get freeze frame data from it from what triggered the occurrence and try and find it from there.
As far the PCM is concerned the old one is fine for the reflash. I would update it with the latest OS.
As far the PCM is concerned the old one is fine for the reflash. I would update it with the latest OS.
Unhook any wires from your TB wiring and test the wire for broken strands and see what happens.
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Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
It is an alky control kit and I dont believe anything was touched with the TB wiring harness until I did when troubleshooting. I cut the pigtail/6 inches of wiring and replaced it with an updated one. However, there was no change after doing this. Unless the meth kit is hooked up to the TB harness near where it connects to the PCM I dont believe that it is.
Last edited by Spoolin8; Feb 17, 2016 at 11:44 AM.
Platinum Supporting Vendor
Joined: Sep 2001
Posts: 3,665
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It is an alky control kit and I dont believe anything was touched with the TB wiring harness until I did when troubleshooting. I cut the pigtail/6 inches of wiring and replaced it with an updated one. However, there was no change after doing this. Unless the meth kit is hooked up to the TB harness near where it connects to the PCM I dont believe that it is.
Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
I had the problem before I ever cut the wires though. I soldered the new pigtail on and everything operated as before cutting them. Ran the car like that for a few weeks before having the pcm swapped. No change after swapping the PCM until the following day when I got on it a little more than usual to the point when it would happen all the time instead of just full throttle. The problem has been getting worse over time which is telling me that its something that is deteriorating or rattling loose. At least Im hoping its something that simple.