Wont Slow Down!??!
07-12-2016, 02:56 PM
#1
Advanced
Thread Starter
Wont Slow Down!??!
Hi. I recently had a motor and transmission rebuilt. As part of the motor rebuild I went with a custom cam which required a custom tune. The shop that is doing this work has been struggling to get it right. I guess every persons version of "right" is different...
Anyway... right now the issue we have is that the car idles high when moving or otherwise not in park. If It's in park it will idle about 850-950rpm. You put it in gear and it drops to about 800-850ish. As you drive it the in gear "idle" starts going up to where it's hard to hold the car back at a stop. If you put it in park it revs up then calms down to the original idle rpm, however if you put it in neutral it revs up to about 2K.
Any thoughts?
When the engine is cold it only revs up to about 1100 then slowly goes up as you drive it longer. I've never seen it go over 2100 so far but it's downright frustrating!!
Going back to the shop around 5 today to see if they can fix it. I'm not holding my breath because they've attempted 5 times already. The last time he told me the high idle in neutral going down the highway is because it's based on tire speed.
I know better... although I know most cars will idle a bit higher if you are doing 60 and throw it in neutral than the do when you are at a stop, it's usually a couple hundred rpm at most.
I'm looking for anything I can suggest to them to help get this resolved and quit spending all my time at their shop.
Anyway... right now the issue we have is that the car idles high when moving or otherwise not in park. If It's in park it will idle about 850-950rpm. You put it in gear and it drops to about 800-850ish. As you drive it the in gear "idle" starts going up to where it's hard to hold the car back at a stop. If you put it in park it revs up then calms down to the original idle rpm, however if you put it in neutral it revs up to about 2K.
Any thoughts?
When the engine is cold it only revs up to about 1100 then slowly goes up as you drive it longer. I've never seen it go over 2100 so far but it's downright frustrating!!
Going back to the shop around 5 today to see if they can fix it. I'm not holding my breath because they've attempted 5 times already. The last time he told me the high idle in neutral going down the highway is because it's based on tire speed.
I know better... although I know most cars will idle a bit higher if you are doing 60 and throw it in neutral than the do when you are at a stop, it's usually a couple hundred rpm at most.
I'm looking for anything I can suggest to them to help get this resolved and quit spending all my time at their shop.
07-13-2016, 09:47 PM
#2
Melting Slicks
To throw you a bone I'm going to guess your tuner is not familiar or comfortable with DBW, drive by wire throttle body. Maybe more of F body tuner that uses a DBC, drive by cable throttle body.
They should be logging all the throttle follower & cracker parameters that are available to them both in gear & out. For no other reason than to eliminate a vacuum leak that could easily cause your issue.
Based on your comments my confidence with your shop isn't good.
The good news is you know it's not right, good on you to get it resolved.
They should be logging all the throttle follower & cracker parameters that are available to them both in gear & out. For no other reason than to eliminate a vacuum leak that could easily cause your issue.
Based on your comments my confidence with your shop isn't good.
The good news is you know it's not right, good on you to get it resolved.
The following users liked this post:
rriddle (07-14-2016)
07-14-2016, 06:40 AM
#3
Advanced
Thread Starter
To throw you a bone I'm going to guess your tuner is not familiar or comfortable with DBW, drive by wire throttle body. Maybe more of F body tuner that uses a DBC, drive by cable throttle body.
They should be logging all the throttle follower & cracker parameters that are available to them both in gear & out. For no other reason than to eliminate a vacuum leak that could easily cause your issue.
Based on your comments my confidence with your shop isn't good.
The good news is you know it's not right, good on you to get it resolved.
They should be logging all the throttle follower & cracker parameters that are available to them both in gear & out. For no other reason than to eliminate a vacuum leak that could easily cause your issue.
Based on your comments my confidence with your shop isn't good.
The good news is you know it's not right, good on you to get it resolved.
Thank you! I will pass this on to them. Yes my confidence is low in their knowledge of the DBW throttle body as well. They have actually commented on the complexities of that as opposed to the DBC systems.
On a good note they have been willing to look at it every time I've asked so until they stop working with me like that I'll keep working with them. We are closer... at least I have it at home now and they are only about 6 miles from me so I can get to their shop fairly easily.
Thanks again for the update! I'll post back any responses or progress.
07-18-2016, 08:42 PM
#4
Le Mans Master
Member Since: Aug 2005
Location: CA.
Posts: 5,255
Likes: 0
Received 281 Likes
on
258 Posts
St. Jude Donor '13-'14-'15
Many issues can cause a hanging idle
Most often it is caused by
1 Too much "desired airflow" in the idle tables---adjustments are avail for both In gear and P/N Try subtracting like 15% to all as a start
2 Too much "throttle follower" was removed for the cam Again adjustable for both in gear and P/N Try ADDING like 10% to all
3. Too much timing was set into the "base timing tables" avail again for in gear and P/N
adding timing is always done wit a bigger cam
4 Final timing was set too HIGH in the idle RPM areas --not allowing the timing to adjust itself on it's own as needed to retain a constant idle speed
5 Finally The ETC pedal TQ reduction table was set to high in the lower TQ ranges which includes idle and coast down ---Set this table back to STOCK and only input 100% beyond the 40 TPS range--- This table is strictly for DBW throttles many tuners set this entire table to 100% which can cause a dangerous throttle hang at coast down and the engine won't throttle back
Most often it is caused by
1 Too much "desired airflow" in the idle tables---adjustments are avail for both In gear and P/N Try subtracting like 15% to all as a start
2 Too much "throttle follower" was removed for the cam Again adjustable for both in gear and P/N Try ADDING like 10% to all
3. Too much timing was set into the "base timing tables" avail again for in gear and P/N
adding timing is always done wit a bigger cam
4 Final timing was set too HIGH in the idle RPM areas --not allowing the timing to adjust itself on it's own as needed to retain a constant idle speed
5 Finally The ETC pedal TQ reduction table was set to high in the lower TQ ranges which includes idle and coast down ---Set this table back to STOCK and only input 100% beyond the 40 TPS range--- This table is strictly for DBW throttles many tuners set this entire table to 100% which can cause a dangerous throttle hang at coast down and the engine won't throttle back
The following users liked this post:
rriddle (07-19-2016)
07-20-2016, 06:15 AM
#5
Advanced
Thread Starter
Many issues can cause a hanging idle
Most often it is caused by
1 Too much "desired airflow" in the idle tables---adjustments are avail for both In gear and P/N Try subtracting like 15% to all as a start
2 Too much "throttle follower" was removed for the cam Again adjustable for both in gear and P/N Try ADDING like 10% to all
3. Too much timing was set into the "base timing tables" avail again for in gear and P/N
adding timing is always done wit a bigger cam
4 Final timing was set too HIGH in the idle RPM areas --not allowing the timing to adjust itself on it's own as needed to retain a constant idle speed
5 Finally The ETC pedal TQ reduction table was set to high in the lower TQ ranges which includes idle and coast down ---Set this table back to STOCK and only input 100% beyond the 40 TPS range--- This table is strictly for DBW throttles many tuners set this entire table to 100% which can cause a dangerous throttle hang at coast down and the engine won't throttle back
Most often it is caused by
1 Too much "desired airflow" in the idle tables---adjustments are avail for both In gear and P/N Try subtracting like 15% to all as a start
2 Too much "throttle follower" was removed for the cam Again adjustable for both in gear and P/N Try ADDING like 10% to all
3. Too much timing was set into the "base timing tables" avail again for in gear and P/N
adding timing is always done wit a bigger cam
4 Final timing was set too HIGH in the idle RPM areas --not allowing the timing to adjust itself on it's own as needed to retain a constant idle speed
5 Finally The ETC pedal TQ reduction table was set to high in the lower TQ ranges which includes idle and coast down ---Set this table back to STOCK and only input 100% beyond the 40 TPS range--- This table is strictly for DBW throttles many tuners set this entire table to 100% which can cause a dangerous throttle hang at coast down and the engine won't throttle back
Thank you for the response. Unfortunately the shop I used does not take suggestions very well. Looks like I'm looking for another shop west of Atlanta...
08-24-2016, 02:18 PM
#6
Advanced
Thread Starter
New Tuner or Tuning Help
Does anyone know of a good C5 tuner west of Atlanta or a good way for me to give my cam specs to someone and get a tune, while retaining the existing tune for backup?
My tuner is an idiot that will not accept help and cannot get it right. I'm not sure why but sometimes the idle will hang around 14-1500rpm while rolling and I have to ride the brakes in parking lots or on the highway at lower speeds to keep from running up on people.
Thanks for any assistance you can offer.
I'm not in a position to buy the HP Tuner software package right now. So I'd prefer to give the specs and receive a tune that I can run with until I get the where I can tune myself.
My tuner is an idiot that will not accept help and cannot get it right. I'm not sure why but sometimes the idle will hang around 14-1500rpm while rolling and I have to ride the brakes in parking lots or on the highway at lower speeds to keep from running up on people.
Thanks for any assistance you can offer.
I'm not in a position to buy the HP Tuner software package right now. So I'd prefer to give the specs and receive a tune that I can run with until I get the where I can tune myself.