PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

New tune, some issues I'm having

Thread Tools
 
Search this Thread
 
Old Jun 13, 2010 | 01:07 PM
  #1  
thunderstruck507's Avatar
Thread Starter
11 Second Club
iTrader: (18)
 
Joined: Mar 2008
Posts: 8,358
Likes: 27
From: Northwest AR
Default New tune, some issues I'm having

Got the car dyno tuned and on the way home I found some things I don't like and would like to adjust. I'm going to call my tuner but I'd like to know what issues might be so I can better describe to him...he is 4 hours from home and right now I am 3 hours from there.

In gear the car idles perfect until rolling then rpm climb with no throttle even high enough to shift to 2nd...very hard on brakes.

On the highway when I let off from a locked highway speed cruise the engine rpm hangs, then drops hard...during the drop timing goes from 40* to 2*, after a second rpms shoot back up (timing follows) then falls slow and the engine feels like its engine braking a ton harder than it does with the old tune.

These should be easy fixes I think...I have efi live and my tuner has hp tuners otherwise I'm sure it would be even smpler as we could just email tunes.
Reply
Old Jun 13, 2010 | 01:14 PM
  #2  
JonCR96Z's Avatar
TECH Junkie
20 Year Member
Photogenic
iTrader: (33)
 
Joined: Jan 2003
Posts: 3,006
Likes: 19
From: Asheboro, NC
Default

The idling problem is Throttle Cracker. It needs to be lowered or disabled somewhat.

The other problem sounds like maybe DFCO is too aggressive. Try disabling the DFCO and see if the problem goes away. If it doesn't or if your DFCO is already disable then it'll be one thing to check off of the list.
Reply
Old Jun 13, 2010 | 06:28 PM
  #3  
DrkPhx's Avatar
10 Second Club
iTrader: (15)
 
Joined: Nov 2001
Posts: 4,519
Likes: 0
From: St. Michael, MN.
Default

In gear the car idles perfect until rolling then rpm climb with no throttle even high enough to shift to 2nd...very hard on brakes
I agree with above; sounds like the Throttle Cracker. Try to disable it completely.

On the highway when I let off from a locked highway speed cruise the engine rpm hangs, then drops hard...during the drop timing goes from 40* to 2*, after a second rpms shoot back up (timing follows) then falls slow and the engine feels like its engine braking a ton harder than it does with the old tune.
Could be a few things; Throttle Follower, DFCO and possibly the spark tables. If you have the old tune; use the comparison feature in EFILive to view the differences between the old and new tune so you can pinpoint the changes.
Reply
Old Jun 15, 2010 | 11:55 AM
  #4  
thunderstruck507's Avatar
Thread Starter
11 Second Club
iTrader: (18)
 
Joined: Mar 2008
Posts: 8,358
Likes: 27
From: Northwest AR
Default

DFCO are the same in both tunes

The throttle follower values are not, what should I be looking for as far as values that would cause this change?

I haven't looked through all the timing tables yet but I haven't seen one that commands such a low advance like that.

These are 2 entirely different tunes, first was a mail order tune tweaked and the new one was a dyno tune that started from scratch (hence me losing all my transmission settings I had tailored to my own driving style)
Reply
Old Jun 15, 2010 | 01:37 PM
  #5  
JonCR96Z's Avatar
TECH Junkie
20 Year Member
Photogenic
iTrader: (33)
 
Joined: Jan 2003
Posts: 3,006
Likes: 19
From: Asheboro, NC
Default

The idle overspeed spark control can cause it to drop off quickly during closed throttle conditions. I always zero out the last cell in the table just to avoid that.

I doubt it's setup to see that kind of drop that you are experiencing though.

Have you tried posting the tune and a log on here or EFIlive forums?

Last edited by JonCR96Z; Jun 15, 2010 at 01:42 PM.
Reply
Old Jun 15, 2010 | 02:51 PM
  #6  
thunderstruck507's Avatar
Thread Starter
11 Second Club
iTrader: (18)
 
Joined: Mar 2008
Posts: 8,358
Likes: 27
From: Northwest AR
Default

Not yet, I got home late after the tune so I didn't have time to go run logs. I'm in the process of moving but hope to be picking the car up and taking it to the track this weekend.
Reply




All times are GMT -5. The time now is 02:40 AM.

story-0
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-1
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-2
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-3
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-4
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-5
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-6
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-7
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE
story-8
Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0

The world was a better place when it was still around.

By Brett Foote | 2026-01-23 09:20:37


VIEW MORE
story-9
10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever

Slideshow: The 7.0-liter LS7 was designed for absolute cutting-edge performance.

By Verdad Gallardo | 2026-01-07 18:36:00


VIEW MORE