Rough idle when drive is engaged? Log Out | Topics | Search
Moderators | Register | Edit Profile

Australian RR Forums » Silver Shadow Series » Rough idle when drive is engaged? « Previous Next »

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

Geoff Wootton
Grand Master
Username: dounraey

Post Number: 644
Registered: 5-2012
Posted on Saturday, 14 February, 2015 - 03:11 pm:   Edit PostDelete PostView Post/Check IP

My car has developed a rough idle when Drive is engaged. The idle is fine in P or N and drives perfectly well. The problem shows itself when waiting at traffic lights. The idle can seem quite lumpy and a little disconcerting. If I put the car into N the rough idle goes away. I suspect it may be the engine mounts. Could anyone confirm this or give any other ideas as to what may be causing the problem.

Regards

Geoff
Top of pagePrevious messageNext messageBottom of page Link to this message

Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1367
Registered: 6-2006
Posted on Saturday, 14 February, 2015 - 10:54 pm:   Edit PostDelete PostView Post/Check IP

What happens if you're in gear and just rev the engine slightly 50rpm extra?
Top of pagePrevious messageNext messageBottom of page Link to this message

Geoff Wootton
Grand Master
Username: dounraey

Post Number: 645
Registered: 5-2012
Posted on Sunday, 15 February, 2015 - 06:42 am:   Edit PostDelete PostView Post/Check IP

Hi Paul

Increasing the revs by 50 - 100 on a hot engine does help a lot. Here is some more info. The car runs as it should when cold. Ambient temperature was 63F (17C). At the first corner at the end of the road I live in there is no lumpiness to the tickover at all. RPM on a cold engine at idle is 656-660 rpm with D engaged, brakes applied. It is only when the engine comes up to operating temperature the engine starts to run badly. This is particularly noticeable on tickover with D engaged. The engine revs are also much more variable (629 - 645). The solution to this problem is obvious - remove the thermostat (JOKE). I'm moving away from my original thought of engine mounts and wondering if I am running far too rich a mixture. I'd appreciate any advice.

Regards

Geoff

Add Your Message Here
Post:
Bold text Italics Underline Create a hyperlink Insert a clipart image

Username: Posting Information:
This is a public posting area. Enter your username and password if you have an account. Otherwise, enter your full name as your username and leave the password blank. Your e-mail address is optional.
Please quote Chassis Numbers for all vehicles mentioned.
Password:
E-mail:
Options: Enable HTML code in message
Automatically activate URLs in message
Action: