Jump to content

Rover 4.6 V lumpy idle then revs by itself


PeteMck

Recommended Posts

Still struggling to find the vacuum leak. It actually idles pretty well until it gets up to temp then it wants to be around 1000rpm to run well. Have checked the butterfly valve in the plenum and that seems fine. Could it be the seals where the butterfly valves connects to the throttle linkage and tps sensor? 

Link to comment
Share on other sites

I can't remember if it is or not. It enters in front of the butterfly valve though I think. I've changed the valley gasket today as now working my way up and the rocker covers seals as well. One thing I did notice this morning is that when starting from cold it idles well until it starts to warm up and only really starts hunting when it's up to temp. Don't no if that helps narrow down the causes.

Link to comment
Share on other sites

Sorry, getting my left and rights mixed up! The right hand breather, but guess you have answered that one...

I went to a 3.9 setup, which links the two breathers into one port. Is the top end all 4.0 stuff, or a mixture?

Link to comment
Share on other sites

  • 1 month later...

Right, slight update. Ive got another plenum and tried that incase I had an air leak where I'd put all the pwm pipe work on or incase I had a leak around the throttle housing and still got the same problem. Starting to run out ideas as to where to look for an air leak. 😖

Link to comment
Share on other sites

Yer well I was wondering if I had a leak with the plenum (blanking plugs, throttle housing, stepper motor wasnt shut fully, where I had mounted niges pwm pipe outlet etc) so put another plenum on and still got the same problem. I can find any air leaks anywhere incl rocker cover pipes, changed valley gasket, rocker cover gasket, I've blocked off the brake servo pipe incase that was leaking and it's still wanting to idle around 1000rpm

Link to comment
Share on other sites

I seem to remember that the stepper allows air from a port coming in from the main throat of the plenum (concentric to the stepper hole) to take a 90 degree turn through a small port on the inboard side. You'll need to jam something in to block both holes- I think I wrapped a drill bit in insulation tape until it was a snug fit when I set my base idle.
 

This was all quite a while ago though so I may be talking total piffle.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy