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For those with high idles and can't find anything wrong

M

mattbred

NAXJA Forum User
Location
Canada
Try replacing your injector o-rings!

I replaced my intake manifold gasket recently (for another issue - exhaust was cracked) and when I took the old injectors out I found that there was a bunch of carbon and grease where they seat into the intake manifold. Once I cleaned that out, they didn't seal worth shit anymore. My idle was around 1000-1100.

I just replaced them with yellow Ford 19 pounders with new seal kits, and my idle is perfect now.

So if you've chased everything down and still can't find your vacuum leak, check your injector o-rings!

This tip brought to you by beer. mmm beer.
 
wierd... mine idles at 1k rpm, and my gf's civic's weedeater engine idles at about 750-800rpm... are our Jeeps really suppoed to idle at 1k? maybe in 'extended idle' for the few who have an ex-cop Jeep... but I dunno...
 
I think spec idle RPM is 750, but I'm not sure.
 
XJ manual idle 700-750 rpm.

XJ auto, fully warmed and in DRIVE, 700-750 rpm.
 
JJacobs said:
Nah, diagnose it first, don't just start throwing parts. A vacuum leak like that is easily found with brake cleaner or propane.
Click to expand...


They aren't always easy to find, especially if you don't have a good ear.

So this hasn't completley fixed my high idle, although it's helped. My cold idle is a consistent 750 RPMs, yet when it warms up it either wants to idle at 1000, or if I put a load on it (like holding the brake on while letting the clutch out) it'll drop down to 750 and stay there.

I'm thinking it may now be a sensor issue. :)
 
Who said anything about listening to it? A propane torch or can of brake cleaner is often used to find a vacuum leak. When the flammable gasses are sucked into the engine it revs up for a second, making it very easy to pinpoint the leak.
 
JJacobs said:
Who said anything about listening to it? A propane torch or can of brake cleaner is often used to find a vacuum leak. When the flammable gasses are sucked into the engine it revs up for a second, making it very easy to pinpoint the leak.
Click to expand...

I havn't had any success using brake cleaner or a propane torch to locate my vacuum leaks. Maybe I just suck with them. On the same note, I also don't agree on spending oodles of money on parts trying to chase it down. In my case, what I did had to be done for other reasons and I enjoyed the benefits. :)
 
My 89 at cold start, idles low at700 rpms. This would make me think IAS, but when leaving the liquor store for instance,if it cranks and doesn't start right up, the next start will rev up and idle back down with IAS working as it should. So I figure my CTS or MAT sensors or grounds arn't up to par for proper cold start idle. Like most of the guys say it's mostly ground or sensor connections that cause our problems.
 
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