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-   -   '95 YJ 4 Cyl 2.5L Rough Idle (http://www.wranglerforum.com/f218/95-yj-4-cyl-2-5l-rough-idle-70424.html)

josi1089 11-28-2010 09:41 PM

'95 YJ 4 Cyl 2.5L Rough Idle
 
Spent about $850 on new exhaust manifold, R/R vacuum hoses, and sealing up a hole on my exhaust pipe. Also spent about $50 on a new IAC valve which I replaced myself. Cleaned out the throttle body and my Jeep still idles rough. Any suggestions would be appreciated.

My Haynes manual tells me to also check the PCValve but suggestions on other threads state that this is nonexistent on my model.

jgwalt 11-28-2010 09:51 PM

you have a CCV rather than a PCV. there is a line that connects to the front of the head. It's pretty small if I recall. It is part of your ccv and can get plugged up. unscrew it and make sure it's all clear. Also, there is a small section of rubber hose that connects it- make sure it's not cracked and leaking. This did the trick for me one time. Report back.

MCE Mike 11-29-2010 01:39 AM

I'd check the plugs, cap and rotor, and plug wires if you haven't already.

rogertc1 11-29-2010 06:32 AM

Try a new gas cap. If it doesn't seal you can have issues too.

josi1089 11-29-2010 11:44 PM

gentlemen (going off the usernames here, apologize if i offend), i appreciate the suggestions. i'll check my ccv valve this weekend. as for the plugs, wires, rotor, and cap, it's already been done. will try a new gas cap if the ccv doesn't work, but what did you mean by a seal problem too? seal on the gas cap?

josi1089 12-05-2010 07:04 PM

status update... (@jgwalt) cleaned out my ccv and still idling rough. thanks for the reply though. will update once i get it resolved. thinking about taking it back to a shop to get another diagnosis.

pReDiTuR 12-22-2010 04:09 PM

Not to deter from your original question Josi1089, but how do you clean/replace your CCV?

josi1089 12-23-2010 02:25 AM

if you can wait till this weekend i can put up pics. i may be wrong but maybe the community can decide.

Garyk 12-23-2010 02:59 PM

You could have a bad or clogged injector, have you tried running some injector cleaner thru it.

60mg 12-23-2010 03:24 PM

Is the engine light on by any chance?

JenkinsJeep95 12-24-2010 10:34 AM

It could be a number of things really. Just go throught the list and elininate them 1 by 1 starting witht the cheapest or easiest fixes first I would suggest. But here they are in no particular order:

1. Check vacuum hoses for leaks.

2. Check intake manifold gasket surfaces for leaks.

3. Check EGR or CCV valve for leaks or plugs.

4. Check fuel pump pressure, and fuel filter.

5. Check for leaking head gasket (requires a cylinder compression check)

6. Worn timing chain.

7. Timing out of adjustment.

8. Burned or leaking valves.

9. Dirty or clogged injectors or carb.

10. Idle speed out of adjustment.

11. Camshaft lobes worn.

Check that and let us know if and what fixed it.

josi1089 12-30-2010 02:01 AM

yo preditur... sorry it took long to post this, but below is pic of my engine. like i said the community can judge on whether i got this right. according to jgwalt i do not have a ccv. but to answer your question i pulled off the hose from the brass valve (i think this is my pcv) and unscrewed it to clean it. hope this helps. for the community, if i am wrong please feel free to correct my ignorance.
http://www.wranglerforum.com/attachm..._engine_01.jpg

josi1089 12-30-2010 02:12 AM

@ garyk, i haven't ran a legit cleaner through the injectors... just poured in the stp fuel injector solution during regular trips to the gas station.
@ 60 mg, no light.
@ jenkins, your suggestions are money. do you have a shop in socal (orange county) by chance??? and on which fixes would you allow a novice to diy? and which ones should i take to a shop?

falatude 12-30-2010 08:01 AM

Quote:

Originally Posted by josi1089 (Post 953803)
yo preditur... sorry it took long to post this, but below is pic of my engine. like i said the community can judge on whether i got this right. according to jgwalt i do not have a ccv. but to answer your question i pulled off the hose from the brass valve (i think this is my pcv) and unscrewed it to clean it. hope this helps. for the community, if i am wrong please feel free to correct my ignorance.
http://www.wranglerforum.com/attachm..._engine_01.jpg

I pulled my valve cover and discovered both pickup tubes were plugged solid. Took them both apart, cleaned and reassembled.
Made a slight difference. Don't forget to install a new gasket.
When you remove your oil fill cap on top of your valve cover (engine running) do you get oil spitting out or excessive air pushing from the opening?

MikeMTJ 12-30-2010 09:54 AM

My YJ was running rough, so I added some Lucas injector cleaner. I would drop to almost 500 RPMs. Once I ran that stuff through, I was back to normal.

falatude 12-30-2010 10:06 AM

Quote:

Originally Posted by MikeMYJ (Post 954064)
My YJ was running rough, so I added some Lucas injector cleaner. I would drop to almost 500 RPMs. Once I ran that stuff through, I was back to normal.

+1
Lucas is good stuff.

Garyk 12-30-2010 01:11 PM

Quote:

Originally Posted by josi1089 (Post 953803)
yo preditur... sorry it took long to post this, but below is pic of my engine. like i said the community can judge on whether i got this right. according to jgwalt i do not have a ccv. but to answer your question i pulled off the hose from the brass valve (i think this is my pcv) and unscrewed it to clean it. hope this helps. for the community, if i am wrong please feel free to correct my ignorance.
http://www.wranglerforum.com/attachm..._engine_01.jpg

That is a picture of a CCV. The rear line goes to air cleaner and front line goes to special orifice at manifold. Make sure the orifice at the manifold is clean.

JenkinsJeep95 12-31-2010 03:16 PM

Quote:

Originally Posted by josi1089 (Post 953814)
@ garyk, i haven't ran a legit cleaner through the injectors... just poured in the stp fuel injector solution during regular trips to the gas station.
@ 60 mg, no light.
@ jenkins, your suggestions are money. do you have a shop in socal (orange county) by chance??? and on which fixes would you allow a novice to diy? and which ones should i take to a shop?

No I'm afraid I'm on the other side of the country in SC.

However half the fun of owning a Jeep is doing the work yourself, learning and sharing your experiences. That being said I recommend anyone willing to get their hands dirty and DIY. You should be able to go to your parts store and buy a manual such as Chilton or Haynes and it can help walk you through everything I listed.

But if its a daily driver and time is an issue then I suggest trying these first: 1,3, and 10. They are all quick and cheap to check and fix. Also you might want to replace the oxygen sensor. If its old and not giving good readings to your computer then your air/fuel mixture could be off.

If that doesn't work move on to: 2,4,7,and 9. These either take a little more cash, or time to do, but you shouldn't have much trouble with it.

If none of that works and your still worried about how your Jeep is running then you can dive deeper in the rabbit hole, or take it to a shop.

sevenservices 12-31-2010 03:35 PM

did it start doing this "all of a sudden?"

a lot of times its moisture or a little bit of water in the fuel system. Did you run a full tank through it since the fuel injector cleaner? To rule this out, with a full tank of gas it should not idle rough. If it still does after a fill up, then its not water in the gas.

Three things an engine needs to run smooth. Gas, air and spark. One of them is either getting to much or not enough. Check for air restrictions, nests in the intake system, clogged air filter, wet air filter, oily air filter, gas leaks, etc... you already confirmed good spark so its got to be air or fuel related.

Garyk 12-31-2010 05:43 PM

In re-reading your original post you mentioned a new manifold. Maybe the gasket is leaking. With engine warmed up and idling, spray carb cleaner along intake manifold gasket mating surfaces, base of throttle body etc,vacuum connections... listen for change in engine idle....could be a slight vacuum leak..
also check the power brake assist for leaks.

sevenservices 12-31-2010 06:01 PM

Did you or do you have any blackness coming out of the front connection where your exhaust goes into the catalitic convertor? Just a thought... On mine, my cat was plugged up bad. Major loss of HP plus when I would accelerate I could hear a "ffffft" sound under there. If your not getting enough air flow throught it, it could cause an issue like yours. Again, just speculation as most of our thoughts at this point!

chensley 01-01-2011 12:23 AM

Most of all that timing jargon is controlled by the computer. However, do not forget the basics....fuel, air, and spark. If all those check out then your left with just a few "minor" things..such as grounds,shorts,wife,and the depths of your pocket (hoover flag anyone!?)

josi1089 01-01-2011 11:15 PM

awesome feedback gentlemen (and ladies, if any)... will update with outcome. thanks and happy new year!!! may it bring your jeeps a trouble free ride.

pReDiTuR 01-02-2011 04:30 PM

Josi1089 I definitely appreciate the picture and help, hope you get your Jeep up and running soon.

omniscientgregg 01-03-2011 02:30 PM

Quote:

Originally Posted by falatude (Post 954080)
+1
Lucas is good stuff.

+2
I put in a bottle every 2000 miles.

jibber 01-28-2012 10:51 PM

Any Update?

jibber 03-01-2012 04:12 PM

Bump. Any Update????

josi1089 12-19-2012 12:19 AM

this post is for jibber. sorry it's 9 months (too late), but the culprit was the vacuum hose. mechanics also found out my intake had a hole so replaced that too.

jibber 12-20-2012 08:31 AM

Quote:

Originally Posted by josi1089 (Post 3120272)
this post is for jibber. sorry it's 9 months (too late), but the culprit was the vacuum hose. mechanics also found out my intake had a hole so replaced that too.


Thank You!! I actually sold my YJ. :( I miss it, but don't miss trying to fix all of the annoying little things.

Jibber

matrix311 05-02-2013 01:19 PM

Quote:

Originally Posted by josi1089 (Post 3120272)
this post is for jibber. sorry it's 9 months (too late), but the culprit was the vacuum hose. mechanics also found out my intake had a hole so replaced that too.

Did they say which vac line it was by chance?


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