Tuning saga.. tuner said possible bad PCM?
02-08-2016, 09:29 AM
#1
Tuning saga.. tuner said possible bad PCM? Mild combination - 1998 firebird, 241 stock unported heads, fast 92mm intake and NW 92mm tbody, cam (.588/.595, 228/232, 114 LSA), 1 7/8 headers, alum flywheel.
So first tuner had car running like crap for anything but WOT. It would always go to PE table and cruising around 10:1. Gave him 2 chances to correct it but he didn’t give a crap.
Second tuner (after weeks with the car) said he had car running great. But on the next night says he says its getting 4 degrees KR and found knock sensor error code and figured he changed the knock sensors. While doing that, he saw the knock sensor wiring harness crimped in between the transmission and the engine and said that was causing a short and triggered the error code. So he put in new harness and continued tuning. Said he said that now it’s running great again and come pick it up. I come after work the next day and his O2 wideband is still attached to my car … I asked “whats up because I thought it was done?” He said he wants to finalize the tune with me in the car. OK whatever… We go for a cruise on highway and now he is seeing KR at WOT. After an hour driving around and him lowering timing and adjust MAF table, he can’t get rid of it and tells me to :
-take it home and
-swap out the plugs because maybe running on the old tune for so long fouled them
-maybe the pinched knock sensors wiring harness broke the PCM
-log more files at home
So yesterday I log more files and get KR anytime I got WOT. Logs attached. Note: The a/f in the logs in skewed because I think I didn’t set it up right in HP Tuners but my in car wideband shows pretty solid 12.5 at WOT. The logs show about 13.4 at WOT but I’m pretty sure the logs are off and my wideband is right on.
I will swap plugs soon and re-log but I think new plugs will only make it burn better and leaner which could exasperate the issue if its caused by leanness (which I don’t think it is).
I have a call in to tuner today and I know he’s gonna push replacing the PCM but I think that is bogus. Car runs great around town, very close to 14.7 while cruising.
My thoughts:
I’m fairly certain he started my tune with a base 98 calibration and tweaked it from there..
-My car has 5 wire 85mm c5 z06 MAF and his MAF table looks very close to stock 98 table where as for reference, my old c5 cars had lower numbers in that table. Should the 85mm c5 maf require lower numbers in the MAF table (I think 98 fbody and mine are about 36 to 38 but the c5’s I’ve seen are more like 32).
-I don’t think PCM is damaged at all. No codes and no drivability issues. Only issue is KR at WOT. Can pinched knock sensor harness fry a portion of the PCM?
This is really frustrating. Thanks for any suggestions…
So first tuner had car running like crap for anything but WOT. It would always go to PE table and cruising around 10:1. Gave him 2 chances to correct it but he didn’t give a crap.
Second tuner (after weeks with the car) said he had car running great. But on the next night says he says its getting 4 degrees KR and found knock sensor error code and figured he changed the knock sensors. While doing that, he saw the knock sensor wiring harness crimped in between the transmission and the engine and said that was causing a short and triggered the error code. So he put in new harness and continued tuning. Said he said that now it’s running great again and come pick it up. I come after work the next day and his O2 wideband is still attached to my car … I asked “whats up because I thought it was done?” He said he wants to finalize the tune with me in the car. OK whatever… We go for a cruise on highway and now he is seeing KR at WOT. After an hour driving around and him lowering timing and adjust MAF table, he can’t get rid of it and tells me to :
-take it home and
-swap out the plugs because maybe running on the old tune for so long fouled them
-maybe the pinched knock sensors wiring harness broke the PCM
-log more files at home
So yesterday I log more files and get KR anytime I got WOT. Logs attached. Note: The a/f in the logs in skewed because I think I didn’t set it up right in HP Tuners but my in car wideband shows pretty solid 12.5 at WOT. The logs show about 13.4 at WOT but I’m pretty sure the logs are off and my wideband is right on.
I will swap plugs soon and re-log but I think new plugs will only make it burn better and leaner which could exasperate the issue if its caused by leanness (which I don’t think it is).
I have a call in to tuner today and I know he’s gonna push replacing the PCM but I think that is bogus. Car runs great around town, very close to 14.7 while cruising.
My thoughts:
I’m fairly certain he started my tune with a base 98 calibration and tweaked it from there..
-My car has 5 wire 85mm c5 z06 MAF and his MAF table looks very close to stock 98 table where as for reference, my old c5 cars had lower numbers in that table. Should the 85mm c5 maf require lower numbers in the MAF table (I think 98 fbody and mine are about 36 to 38 but the c5’s I’ve seen are more like 32).
-I don’t think PCM is damaged at all. No codes and no drivability issues. Only issue is KR at WOT. Can pinched knock sensor harness fry a portion of the PCM?
This is really frustrating. Thanks for any suggestions…
02-08-2016, 10:40 AM
#2
If you doubt the MAF calibration, find a C5 Z06 file in the repository and compare.
I can't see your tune on my phone, but check 2 things. Stoich set to 14.68 and the PE table set to 1.17 above 3500 rpm. This would tell the car to run at 12.5:1.
If that's all cool, set those PE numbers to 1.22 (12:1) and see what the KR does. Maybe 12.5:1 is just too lean.
I can't see your tune on my phone, but check 2 things. Stoich set to 14.68 and the PE table set to 1.17 above 3500 rpm. This would tell the car to run at 12.5:1.
If that's all cool, set those PE numbers to 1.22 (12:1) and see what the KR does. Maybe 12.5:1 is just too lean.
02-08-2016, 01:53 PM
#3
I checked your datalogs and the AFR is in the mid 13's with some spots at 13.7. That is very lean for WOT, it may be the cause.
Also, the timing tables are a little aggressive at low RPM/high load.
Something's not right, it's reaching 97 KPa at less than 2000 RPM and closed throttle. You have either a bad MAP or something is wrong. You can't see WOT pressures with closed throttle or low RPM unless it's blown.
WOT timing is pretty conservative. You have several issues to fix, I suggest you find a good tuner who can actually tune and troubleshoot.
Also, the timing tables are a little aggressive at low RPM/high load.
Something's not right, it's reaching 97 KPa at less than 2000 RPM and closed throttle. You have either a bad MAP or something is wrong. You can't see WOT pressures with closed throttle or low RPM unless it's blown.
WOT timing is pretty conservative. You have several issues to fix, I suggest you find a good tuner who can actually tune and troubleshoot.
02-08-2016, 02:45 PM
#4
If you doubt the MAF calibration, find a C5 Z06 file in the repository and compare.
I can't see your tune on my phone, but check 2 things. Stoich set to 14.68 and the PE table set to 1.17 above 3500 rpm. This would tell the car to run at 12.5:1.
If that's all cool, set those PE numbers to 1.22 (12:1) and see what the KR does. Maybe 12.5:1 is just too lean.
I can't see your tune on my phone, but check 2 things. Stoich set to 14.68 and the PE table set to 1.17 above 3500 rpm. This would tell the car to run at 12.5:1.
If that's all cool, set those PE numbers to 1.22 (12:1) and see what the KR does. Maybe 12.5:1 is just too lean.
Stoich is set to 14.42254 because tuner said his "GM contact" said to run this number due to winter additives to the fuel. The PE table has all fields set to 1.137. I think that corresponds to 12.72 AFR
The VE table is exactly the same as the fbody. So that is untouched. Is that a bad thing? I thought that it should be tweaked but as per attached, all cells have the same value.
Last edited by 2MCHPWR; 02-08-2016 at 03:06 PM.
02-08-2016, 03:04 PM
#5
i have to figure out to get hp tuners to read my Innovate MTX-L Wideband accurately.
Also, the timing tables are a little aggressive at low RPM/high load.
Something's not right, it's reaching 97 KPa at less than 2000 RPM and closed throttle. You have either a bad MAP or something is wrong. You can't see WOT pressures with closed throttle or low RPM unless it's blown.
WOT timing is pretty conservative. You have several issues to fix, I suggest you find a good tuner who can actually tune and troubleshoot.
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02-08-2016, 09:58 PM
#9
Engine>Airflow>Dynamic>High RPM Disable is set to 100 rpm. It is not using the VE table at all. It is 100% MAF tune. What injectors are in it? The IFR table is the only injector table changed and is set up for around a 35.6 lb @ 4 Bar injector. If that is not correct the MAF will not look correct as it was changed to compensate for bad injector data.
02-09-2016, 01:38 AM
#10
It's also set to go into PE at 10% throttle 2800 and above. This isn't necessary. Stock numbers in that table are prob ok.
A little more data logging at cruise would tell just how far off the WB is in the log. One would expect right around 14.7 or so AF at cruise.
AEM WB always seem to have an offset in the log, at least all the ones I've used do. It gets hard to know which reading to trust.
Timing table at WOT area looks ok to me. Essentially between 20-24 degrees at WOT. Guys seem to think that's pretty low. But that's not necessarily true.
2xLS1 is exactly correct on the tune being set up for MAF only. It's not a bad thing.
But as he stated, it appears the injector numbers have been changed to something around 36lb/hr. If it does have 36lbers, then the tune is essentially correct. If the injectors are stock, then the injector table may have been changed to get the fueling right. Not so cool.
Clearly the MAF has been tuned, you can tell because the slope isn't text book perfect like a stock tune would be. It has wiggles.
As far as the 85mm MAF numbers are concerned, I know there are two diff vette MAF's. Screened and unscreened. There is also an 85mm truck MAF.
On my C5, I swapped an 85mm screened for an unscreened and had to make significant changes to the MAF curve to get the fueling back to correct. I was surprised. Perhaps the unscreened unit I had was from a truck. Dunno.
BTW it's also MAF only and runs excellent.
As far as the vE not being tuned, well it doesn't need to be when in MAF only. And my experience with tuning the dual VE setup on these older cars is a pain in the butt!
What I would do first is make it richer. set the PE to 1.20 and see if the knock goes away. That's 12:1.....I know, sounds a bit rich.
If that works, change it back and remove 2 degrees from the timing table (both as they are set to be the same) bottom three rows from 2800 up.
Just see what it does.
Lastly, I forgot how lumpy data logs from the 98 pcm is. Might try logging a lot less stuff. Like O2v, STFT and LTFT as well as Fuel Trim cell. That might clean up the data a bit.
Ron
A little more data logging at cruise would tell just how far off the WB is in the log. One would expect right around 14.7 or so AF at cruise.
AEM WB always seem to have an offset in the log, at least all the ones I've used do. It gets hard to know which reading to trust.
Timing table at WOT area looks ok to me. Essentially between 20-24 degrees at WOT. Guys seem to think that's pretty low. But that's not necessarily true.
2xLS1 is exactly correct on the tune being set up for MAF only. It's not a bad thing.
But as he stated, it appears the injector numbers have been changed to something around 36lb/hr. If it does have 36lbers, then the tune is essentially correct. If the injectors are stock, then the injector table may have been changed to get the fueling right. Not so cool.
Clearly the MAF has been tuned, you can tell because the slope isn't text book perfect like a stock tune would be. It has wiggles.
As far as the 85mm MAF numbers are concerned, I know there are two diff vette MAF's. Screened and unscreened. There is also an 85mm truck MAF.
On my C5, I swapped an 85mm screened for an unscreened and had to make significant changes to the MAF curve to get the fueling back to correct. I was surprised. Perhaps the unscreened unit I had was from a truck. Dunno.
BTW it's also MAF only and runs excellent.
As far as the vE not being tuned, well it doesn't need to be when in MAF only. And my experience with tuning the dual VE setup on these older cars is a pain in the butt!
What I would do first is make it richer. set the PE to 1.20 and see if the knock goes away. That's 12:1.....I know, sounds a bit rich.
If that works, change it back and remove 2 degrees from the timing table (both as they are set to be the same) bottom three rows from 2800 up.
Just see what it does.
Lastly, I forgot how lumpy data logs from the 98 pcm is. Might try logging a lot less stuff. Like O2v, STFT and LTFT as well as Fuel Trim cell. That might clean up the data a bit.
Ron
02-09-2016, 06:12 AM
#11
Engine>Airflow>Dynamic>High RPM Disable is set to 100 rpm. It is not using the VE table at all. It is 100% MAF tune. What injectors are in it? The IFR table is the only injector table changed and is set up for around a 35.6 lb @ 4 Bar injector. If that is not correct the MAF will not look correct as it was changed to compensate for bad injector data.
Last edited by 2MCHPWR; 02-09-2016 at 07:31 AM.
02-09-2016, 09:22 AM
#12
Originally Posted by RonSSNova
A little more data logging at cruise would tell just how far off the WB is in the log. One would expect right around 14.7 or so AF at cruise.
AEM WB always seem to have an offset in the log, at least all the ones I've used do. It gets hard to know which reading to trust.
Timing table at WOT area looks ok to me. Essentially between 20-24 degrees at WOT. Guys seem to think that's pretty low. But that's not necessarily true.
2xLS1 is exactly correct on the tune being set up for MAF only. It's not a bad thing.
But as he stated, it appears the injector numbers have been changed to something around 36lb/hr. If it does have 36lbers, then the tune is essentially correct. If the injectors are stock, then the injector table may have been changed to get the fueling right. Not so cool.
Clearly the MAF has been tuned, you can tell because the slope isn't text book perfect like a stock tune would be. It has wiggles.
As far as the 85mm MAF numbers are concerned, I know there are two diff vette MAF's. Screened and unscreened. There is also an 85mm truck MAF.
On my C5, I swapped an 85mm screened for an unscreened and had to make significant changes to the MAF curve to get the fueling back to correct. I was surprised. Perhaps the unscreened unit I had was from a truck. Dunno.
BTW it's also MAF only and runs excellent.
As far as the vE not being tuned, well it doesn't need to be when in MAF only. And my experience with tuning the dual VE setup on these older cars is a pain in the butt!
What I would do first is make it richer. set the PE to 1.20 and see if the knock goes away. That's 12:1.....I know, sounds a bit rich.
If that works, change it back and remove 2 degrees from the timing table (both as they are set to be the same) bottom three rows from 2800 up.
Just see what it does.
Lastly, I forgot how lumpy data logs from the 98 pcm is. Might try logging a lot less stuff. Like O2v, STFT and LTFT as well as Fuel Trim cell. That might clean up the data a bit.
Ron
AEM WB always seem to have an offset in the log, at least all the ones I've used do. It gets hard to know which reading to trust.
Timing table at WOT area looks ok to me. Essentially between 20-24 degrees at WOT. Guys seem to think that's pretty low. But that's not necessarily true.
2xLS1 is exactly correct on the tune being set up for MAF only. It's not a bad thing.
But as he stated, it appears the injector numbers have been changed to something around 36lb/hr. If it does have 36lbers, then the tune is essentially correct. If the injectors are stock, then the injector table may have been changed to get the fueling right. Not so cool.
Clearly the MAF has been tuned, you can tell because the slope isn't text book perfect like a stock tune would be. It has wiggles.
As far as the 85mm MAF numbers are concerned, I know there are two diff vette MAF's. Screened and unscreened. There is also an 85mm truck MAF.
On my C5, I swapped an 85mm screened for an unscreened and had to make significant changes to the MAF curve to get the fueling back to correct. I was surprised. Perhaps the unscreened unit I had was from a truck. Dunno.
BTW it's also MAF only and runs excellent.
As far as the vE not being tuned, well it doesn't need to be when in MAF only. And my experience with tuning the dual VE setup on these older cars is a pain in the butt!
What I would do first is make it richer. set the PE to 1.20 and see if the knock goes away. That's 12:1.....I know, sounds a bit rich.
If that works, change it back and remove 2 degrees from the timing table (both as they are set to be the same) bottom three rows from 2800 up.
Just see what it does.
Lastly, I forgot how lumpy data logs from the 98 pcm is. Might try logging a lot less stuff. Like O2v, STFT and LTFT as well as Fuel Trim cell. That might clean up the data a bit.
Ron
The meter is from a ls6 c5 z06 with no screen.
I have the innovative MTX-L wideband; i have to fix how it logs in the scanner so its more accurately displayed in the log.
thanks again!
02-09-2016, 02:27 PM
#13
upgraded to version 3 and did some logs.
Used a better adjustment (preset in the new version) for af so you guys can see its running mid 12's.
Still getting up to 4 KR.
roads covered in salt so only took it up to 70.
didn't adjust the tune at all. seems like sold mid 12's should not be the reason for the KR.
Since MAP was mentioned before, what are normal MAP pressure readings at idle and before giving it throttle? I saw some readings in the 40's at while coasting at low 1200 RPM after the WOT runs. How would bad MAP induce KR? at WOT, the MAP readings look normal to me (~100) and that is where the KR is. still confused
Used a better adjustment (preset in the new version) for af so you guys can see its running mid 12's.
Still getting up to 4 KR.
roads covered in salt so only took it up to 70.
didn't adjust the tune at all. seems like sold mid 12's should not be the reason for the KR.
Since MAP was mentioned before, what are normal MAP pressure readings at idle and before giving it throttle? I saw some readings in the 40's at while coasting at low 1200 RPM after the WOT runs. How would bad MAP induce KR? at WOT, the MAP readings look normal to me (~100) and that is where the KR is. still confused
02-09-2016, 02:56 PM
#14
Depending on whether you're using the analog or digital input to the tuning software HPT/EFI Live can be more or less accurate than the gauge. The gauge is setup by the manufacturing to display an accurate AFR ratio. When logging AFR, we're making 2 systems (the wideband controller and the tuning software work together) and there is always measurement error.
02-09-2016, 06:07 PM
#16
so for a test i did 2 changes, one at a time.
first i lowered the timing across the board 75%. hpt file and associated log attached.
second i kept the lowered timing but also richened the PE table to be high 11's. hpt fle and associated log attached.
still getting KR.
the 2nd log file is short and easy to see the WOT hits and KR.
thoughts?
first i lowered the timing across the board 75%. hpt file and associated log attached.
second i kept the lowered timing but also richened the PE table to be high 11's. hpt fle and associated log attached.
still getting KR.
the 2nd log file is short and easy to see the WOT hits and KR.
thoughts?
02-09-2016, 06:31 PM
#17
You may find it odd, but have you tried going the other way with the AFR? Leave the timing to something reasonable and lean it out and see if it still has knock. There is such as thing as under timed/too rich causing knock. I've seen it more than once on boosted cars.
02-09-2016, 08:32 PM
#20
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Your knock sensors look like they are set up to be more sensitive vs a stock tune. Here is your knock sensor level vs RPM vs cyl:
6 5 6 6 6 5 7 6 7 6 8 8 7 8 8 8 8 8 8 8 8
9 4 5 9 9 9 8 9 8 8 8 9 8 8 8 8 8 8 8 8 8
8 4 5 8 7 8 7 7 6 7 7 8 7 7 8 8 8 8 8 8 8
7 4 5 7 7 6 7 8 7 7 6 6 7 7 8 8 8 8 8 8 8
6 4 5 6 6 8 7 6 6 6 8 8 7 8 8 8 8 8 8 8 8
9 4 5 9 8 6 7 7 8 6 7 7 7 7 8 8 8 8 8 8 8
8 5 5 8 7 7 7 6 7 6 6 7 7 8 8 8 8 8 8 8 8
9 4 5 9 7 6 7 8 8 6 7 7 7 7 8 8 8 8 8 8 8
Here is the stock table:
9 9 10 10 10 10 10 9 11 10 10 9 9 9 9 9 9 9 9 9 9
10 10 11 11 10 10 10 11 10 10 10 11 11 11 11 11 11 11 11 11 11
8 8 9 9 10 9 9 10 9 10 9 9 9 9 9 9 9 9 9 9 9
8 8 9 9 10 9 9 9 8 9 8 9 9 9 9 9 9 9 9 9 9
9 9 10 10 10 9 10 9 9 10 9 10 10 10 10 10 10 10 10 10 10
10 10 11 9 10 10 9 9 11 10 10 8 8 8 8 8 8 8 8 8 8
9 9 10 10 10 10 10 11 10 10 10 9 9 9 9 9 9 9 9 9 9
9 9 10 11 10 10 9 10 11 9 11 9 9 9 9 9 9 9 9 9 9
lower numbers mean the sensors react sooner to vibration .
I suggest putting the stock knock sensor values back in and see if it improves any.
6 5 6 6 6 5 7 6 7 6 8 8 7 8 8 8 8 8 8 8 8
9 4 5 9 9 9 8 9 8 8 8 9 8 8 8 8 8 8 8 8 8
8 4 5 8 7 8 7 7 6 7 7 8 7 7 8 8 8 8 8 8 8
7 4 5 7 7 6 7 8 7 7 6 6 7 7 8 8 8 8 8 8 8
6 4 5 6 6 8 7 6 6 6 8 8 7 8 8 8 8 8 8 8 8
9 4 5 9 8 6 7 7 8 6 7 7 7 7 8 8 8 8 8 8 8
8 5 5 8 7 7 7 6 7 6 6 7 7 8 8 8 8 8 8 8 8
9 4 5 9 7 6 7 8 8 6 7 7 7 7 8 8 8 8 8 8 8
Here is the stock table:
9 9 10 10 10 10 10 9 11 10 10 9 9 9 9 9 9 9 9 9 9
10 10 11 11 10 10 10 11 10 10 10 11 11 11 11 11 11 11 11 11 11
8 8 9 9 10 9 9 10 9 10 9 9 9 9 9 9 9 9 9 9 9
8 8 9 9 10 9 9 9 8 9 8 9 9 9 9 9 9 9 9 9 9
9 9 10 10 10 9 10 9 9 10 9 10 10 10 10 10 10 10 10 10 10
10 10 11 9 10 10 9 9 11 10 10 8 8 8 8 8 8 8 8 8 8
9 9 10 10 10 10 10 11 10 10 10 9 9 9 9 9 9 9 9 9 9
9 9 10 11 10 10 9 10 11 9 11 9 9 9 9 9 9 9 9 9 9
lower numbers mean the sensors react sooner to vibration .
I suggest putting the stock knock sensor values back in and see if it improves any.