Revs rise when drive selected
Thread Starter
Staging Lane
Joined: Jan 2008
Posts: 59
Likes: 3
From: Broughty Ferry Scotland
Revs rise when drive selected I'm in the final stages of my 1950 Morris Minor build with 98 LS1 and 4l60E box. When I stick it in drive the revs rise and it's hard to hold it on the brakes. I bought the engine box combo a while ago and the harness was complete and connected to engine/box. I had the ecu flashed to remove vats etc and engine started first time and seems ok. Box has fresh oil and new filter. It was a bit sluggish to engage reverse, but this has improved a bit with gear linkeage adjustment. I've tried to search for this symptom, but as usual when looking I can't find anything similar - any ideas? I've not had it out on the open road yet to see if it changes up and works correctly.
Here's some pics and a couple of vids showing the problem:
PLUS - some action shots:
Cheers
Pete
Here's some pics and a couple of vids showing the problem:
PLUS - some action shots:
Cheers
Pete
Thread Starter
Staging Lane
Joined: Jan 2008
Posts: 59
Likes: 3
From: Broughty Ferry Scotland
I sent the ecu away to get flashed (350 miles) - no one near me does this - they used an efi live programme to remove vats etc (I had to buy a license). I did give them the tyre size and final drive ratio to programme that in too, but who knows if it was done correctly.
LS motors aren't too thick on the ground here unfortunately.
Cheers
Pete
LS motors aren't too thick on the ground here unfortunately.
Cheers
Pete
I agree most likely tune, maybe throttle cracker portion. I know nothing, but suggest you try the tuning section. In your situation I think you should consider learning to tune and getting the gear...or pkan to spend a lot of time shipping back and forth.
You have certainly chosen a unique build. Ive never seen such a thing, I bet its a hoot. I cant see the videos...I hope it has a nasty cam. Would be cool to hear a little thing like that snorting and spitting.
You have certainly chosen a unique build. Ive never seen such a thing, I bet its a hoot. I cant see the videos...I hope it has a nasty cam. Would be cool to hear a little thing like that snorting and spitting.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
A tune for a hot cam will raise the idle speed to about 1000 rpm. If you still have a stock converter, that would give you a very strong "creep". Also a hot cam may not produce enough vacuum for power brakes. (I run Hydraboost which doesn't need vacuum. Also much more compact.)
Getting a tune right for a special setup like yours really might require driving and logging with the car.
Getting a tune right for a special setup like yours really might require driving and logging with the car.
Hey I thought of something:
Start the car and let it idle. Then get out and unplug the IAC. Get back in and put it in drive. If the idle doesnt jump it is definitely the throttle cracker section of the tune...it wont drive well without the IAC working, so this is just for testing.
Start the car and let it idle. Then get out and unplug the IAC. Get back in and put it in drive. If the idle doesnt jump it is definitely the throttle cracker section of the tune...it wont drive well without the IAC working, so this is just for testing.
Last edited by therabidweasel; Jul 26, 2013 at 10:16 PM.
Tune commands more base idle airflow when in gear,
at least the stock tune. There's no reason you'd want
less.
If actual trans load is less than that's based on, then
RPM will rise.
at least the stock tune. There's no reason you'd want
less.
If actual trans load is less than that's based on, then
RPM will rise.
