SOMETIMES IT WILL IDLE BUT IDLES VERY ROUGH

2002 Jeep Liberty

Tiny

JimsAuto

May, 9, 2012 AT 10:04 PM

Working on a 2002 Jeep Liberty. Doesn't have any codes coming up. I have already replaced the CPS, CKS, 2 coils, all 6 plugs and cleaned the TB and IAC. Issue has improved but not by much. It is smoking and smells of gas when running.

FOUND 2422 RELATED QUESTIONS

10 Answers

Tiny

hmac300

May, 9, 2012 AT 10:36 PM

First scan for codes and check fuel pressure including fuel pressure after shut down. Then check for a vacuum leak or hoses disconnected or holes in them

Tiny

JimsAuto

May, 10, 2012 AT 12:30 AM

I have already scanned and don't have any codes, also checked fuel pressure and vacuum hoses. One weird thing was while trying to figure this out had fuel injector on #2 disconnected from harness and coil and plug out on #1 and the engine smoothed out a lot.

Tiny

ASEMaster6371

May, 10, 2012 AT 1:11 AM

You cancelled the companion cylinder by doing that and it will run smoother.

Did you do a compression test?

Roy

Tiny

JimsAuto

May, 10, 2012 AT 2:01 AM

Haven't yet, does this one recommend operating temp for compression check or not(I don't have a book that covers the 3.7 V6)

Tiny

JimsAuto

May, 10, 2012 AT 2:06 AM

Also just talked to the customer and was told a compression check was done about 4 or 5 months ago and was fine then.

Tiny

hmac300

May, 10, 2012 AT 1:37 PM

Because of the miles also check cam or followeres for wear, maybe a lobe is rounded off and you get compression but valves aren't workin g right. That wold not show up on a compression check or fuel pressure regulator may be screwed up as well

Tiny

JimsAuto

May, 10, 2012 AT 7:24 PM

Did compression check today and #1 cyl was 0, all others were between 155 and 175 psi after 6 strokes(first stroke was above 130 on all but #1). Looks like either a valve is stuck open or a valve spring broke. Customer deciding what he wants to do now

Tiny

hmac300

May, 10, 2012 AT 7:26 PM

It may be more thatn that. That may not be a free spin motor so look for engine damage inside cylinder. Or pump oil in cylinder and seeif compression comes up at all.

Tiny

JimsAuto

May, 10, 2012 AT 9:39 PM

I used a small LED snake light to look in through the plug opening and all I could see was the piston, of course don't get to see much that way. Plus with the research I have been doing this model Jeep with the 3.7 has a sludge problem and valves like to stick open. Also some cases of broken valve springs.

Tiny

hmac300

May, 10, 2012 AT 11:04 PM

You'll see when or if you get teh valve cover off

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