Reduced Engine Power...
Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
Update: Replaced the pigtail and that didnt fix it. Its getting a new ECU next week. Car has been sitting this week and I noticed by clock is off by 8 mins. I have an aftermarket radio but isnt the clock being off a potentially sign of a bad battery cell?
I wonder if Autozone would let me just plug in a brand new one so I could rev the engine and see what happens....
I wonder if Autozone would let me just plug in a brand new one so I could rev the engine and see what happens....
Melting Slicks
Joined: Dec 2013
Posts: 2,232
Likes: 315
From: Bridgewater New Jersey
Update: Replaced the pigtail and that didnt fix it. Its getting a new ECU next week. Car has been sitting this week and I noticed by clock is off by 8 mins. I have an aftermarket radio but isnt the clock being off a potentially sign of a bad battery cell?
I wonder if Autozone would let me just plug in a brand new one so I could rev the engine and see what happens....
I wonder if Autozone would let me just plug in a brand new one so I could rev the engine and see what happens....
Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
Melting Slicks
Joined: Dec 2013
Posts: 2,232
Likes: 315
From: Bridgewater New Jersey
Got to have the load test done, as it will simulated a high drain on the battery like when you start the car, which the starter will be the highest drain that it will see.
While the load is applied, the battery voltage will be displayed, indicating the true strength.
If only one cell is bad, the voltage will drop like a lead balloon.
While the load is applied, the battery voltage will be displayed, indicating the true strength.
If only one cell is bad, the voltage will drop like a lead balloon.
Last edited by extrapilot; Jan 28, 2016 at 09:17 PM.
Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
Battery tested out to be fine. What is interesting though is that since switching the PCM, I have noticed that the vehicle starts easier and has a better idle.
I also only throw one code now, 1516.
The 2101 code appears to have resolved...
I also only throw one code now, 1516.
The 2101 code appears to have resolved...
Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
After having the new PCM for a day the problem now occurs all the time. Car will start fine and then approx 30-60 seconds into idling it goes into reduced power. Have an excellent shop working on the car now and they plan on looking at the harmonic balancer work and checking the grounds near there since it was the last thing that was changed before this problem.
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Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
That is incredibly weird.. I really just want to know what it is at this point. I think they're going in the right direction by looking over the balancer install first
Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
The first shop that did the install is very well known and has done great work in the past. I have been giving them the benefit of the doubt with the original work but if it turns out to be a poor install im going to have a conversation...
Racer
Joined: Jan 2010
Posts: 293
Likes: 2
From: Atlanta Georgia
I have not read through this entire post but I wanted to share a little info with you. I had the exact same problem and codes. Replaced throttle position sensor, throttle body, pedal, etc. I was pulling my hair out. On the advice of Zip Corvettes, I flashed the ECM back to stock and re-tuned the car and the problem never happened again. Its been several years ago but we did figure out what in the tune was the likely issue but I can't recall exactly what it was.
Just a thought. Wish I would have known that earlier. Best of luck.
Josh
Just a thought. Wish I would have known that earlier. Best of luck.
Josh
Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
I replaced the PCM and had it re-flashed. Loaded the previous tune and same problem at first but now its manifested into it happening all the time. With a brand new PCM it seems like this is something related to a ground.
Platinum Supporting Vendor
Joined: Sep 2001
Posts: 3,665
Likes: 341
Take your fuel maps, air maps and timing tables and reload those onto a new tune. Flash that into the car and see how it does.
Also do you have any stereo cables or amp cables running close to the throttle pedal.
Racer
Joined: Jan 2010
Posts: 293
Likes: 2
From: Atlanta Georgia
You can't just re-load your tune. If the problem is in the tune you just reinstalled it into the new PCM. Here is a thought, Reflash your new PCM.
Take your fuel maps, air maps and timing tables and reload those onto a new tune. Flash that into the car and see how it does.
Also do you have any stereo cables or amp cables running close to the throttle pedal.
Take your fuel maps, air maps and timing tables and reload those onto a new tune. Flash that into the car and see how it does.
Also do you have any stereo cables or amp cables running close to the throttle pedal.
Justin is who recommended my flash that fixed my problem. If you reload the same tune, you defeat the purpose.
Josh
Last edited by jatolbert; Feb 15, 2016 at 03:06 PM.
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Reflashed as in by GM to get it setup for your car OR by another company with HPTuners/EFI Live/etc.?
Thread Starter
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
They had a GM guy come in, install a new PCM, and reflash to make sure it matched my VIN, etc. They looked over the speed density tune (everything looked normal) and put it back on there with the same result which obviously could point to the tune being the problem. However, the following day it started occurring all the time so we are getting a different result.
I can pay them to just can the current tune and do their own, but before dropping another $800 I figured I would spend a little less to have them look for some bad grounds near the pulley. Ultimately the car ran fine on its current tune up until the point of the pulley swap. I know tunes can sometimes cause this but how is it possible that it works flawlessly for a few months and suddenly becomes a problem?
I do have an aftermarket stereo, sub, etc. Dont believe I have any of those wires near the pedal though. Im not against ripping it out though
I can pay them to just can the current tune and do their own, but before dropping another $800 I figured I would spend a little less to have them look for some bad grounds near the pulley. Ultimately the car ran fine on its current tune up until the point of the pulley swap. I know tunes can sometimes cause this but how is it possible that it works flawlessly for a few months and suddenly becomes a problem?
I do have an aftermarket stereo, sub, etc. Dont believe I have any of those wires near the pedal though. Im not against ripping it out though
Last edited by Spoolin8; Feb 15, 2016 at 07:02 PM.