Rough idle continues

Post by **luketrash** » 14 Nov 2006, 22:37

The Bosch 'oem' spec plugs I got from FCP were all gapped to .032 and needed to be pinched down to .028.

dasapir · Post by **dasapir** » 15 Nov 2006, 18:55

Well, I received my OEM volvo platinum (turbo) plugs today from FCP Groton and they were all gapped at 0.28". Incidently the plugs arrived loose in a box. Something I would not expect fro FCP Groton. I did speak to them about it and they said they would check with their packers.

So they are in and the idle has not improved. However, a very interesting find. when I started to replace the plugs I noticed I had difficulty removing the old/new NGK plugs. when I looked inside the socket I noticed that the rubber internal washer was missing? So having a spare socket I used it to remove and replace the new Volvo plugs. Well, low-and-behold! When I went to remove the last plug (cylinder #5) there was the rubber washer quietly sitting around the last plug. How in the world the boot of the Bougicord ignition wire fit I have no idea, but somehow it did. For a short while I was overjoyed thinking i found the proble to the rough idle, but no that was not the problem.

Anyway as long as I was at it I again remove the idle control valve to stick my finger in there and rotate the valve. Luketrash, I am small, but you must be absolutely dainty. How in blazes can you get even your pinky in there to reach the valve? I couldn't. A screwdriver didi it. Resprayed and replaced. and the car drive nicely idling at 875 rpm.
Still feels a little like a pick-up truck ( even sounds a little like one when idling, but will live with it).

So new volvo plugs gapped at 0.28 not 0.03. Pretty plugs. fine point tips, like the iridium. I may still check out the mount.

Post by **luketrash** » 15 Nov 2006, 21:32

I haven't yet serviced the IAC on my 850. On the 240s and 960 I have, I can definitely stick my finger in there.. But I'm pretty much girlsized.. I think I wear a size 6 ring..

When servicing the plugs in my 850, I ditched the sparkplug socket in favor of my regular, deep well socket and used a piece of rubber fuel line to pull the plugs up and out and also to start them in their holes. I learned that a long time ago when working on my Kawasaki W650, where the plugs reside way down in the head like that.

tca217 · Post by **tca217** » 17 Nov 2006, 04:24

After reading all the replys here about the rough idle, I was wondering why nobody ever brought up the fact that there might be a vacumn leak? I have found that a vacumn leak can cause more hard to find problems than almost anything. Just an idea.

Post by **luketrash** » 17 Nov 2006, 07:11

I think I mentioned it, but there's nowhere to tell a person to start looking.

Speaking of which, do any of you have any vacuum spec sheets?

I have a vacuum tester, and would be interested in testing vaccuum at the intake and elsewhere to continue hunting for my blowby issue.

tca217 · Post by **tca217** » 17 Nov 2006, 11:16

The way I go about checking for a vacumn leak is just to spray some starting fluid around where the vacumn lines run. You will have a noticable change in engine RPM when are are in the correct area. One of the most troublesome spots I have noticed is the vacumn tree by the throttle lionkage and under the cover that goes over the injectors.

dasapir · Post by **dasapir** » 17 Nov 2006, 13:11

TCA17 thank you for your suggestion, however, I am not sure whether or not you noticed in the beginning of my first post in this thread, when listing all the things just done, one of them was replacing all of the vacuum lines with silione lines (from sylinmotors.com). If there is a vacuum leak I am not sure from where since all lines fit tightly and were cinched down with zip ties. I am willing to search for a vacuum leak in the lines just replaced, however, I do not think this is where the problem lies.

I had the manifold and TB off when replacing and cleaning the PCV system and at that time had "relatively" easy access to the vacuum lines. So based on a suggestion from MIJ to repalce the vacuum lines and upgrade to silicone, it was then I replaced them. So there are no rubber lines or elbows in the vacuum system. The lines going to the TB tree are all new and snug. However, just to be sure I will check again. I do thank you for your suggestion and input.

Luketrash, my Haynes does not seem to have vacuum specifications. Does Chilton?

Post by **MadeInJapan** » 17 Nov 2006, 21:13

If you had a vacuum/boost gauge like I have, you could test the vacuum quite easily. I have mine mounted on a pod on my A-pillar, but you could get a cheap gauge at any auto parts store. Take off any one of the caps on the vacuum tree and connect it up... pull it into your driver's area and with the car in park and at idle you should read 17 to 21Hg's. If you gun it, you should see the needle go to zero and then come quickly back down to the 17 to 21 level. If it doesn't there is a problem. If it does, but creeps back up slowly, there's also a problem, or if at idle it isn't in the range I mentioned there's a problem. There is a great site that tells what happens with the vacuum when there are bad rings vs. bad valves or a leak...been looking for it but can't find it. When I do, I'll edit this post and put the link here.

earthguy00 · Post by **earthguy00** » 19 Nov 2006, 10:30

Have you checked the pcv valve or the oxygen sensor? A simple change on a pcv valve for a car in the past help solve this problem.

Post by **MadeInJapan** » 19 Nov 2006, 10:54

Unfortunately there is no PCV valve on our cars...the PCV is a SYSTEM of small hoses as well as the oil trap (separator/breather) located under the intake manifold. A way to test it is to take the oil dip stick out while the car is running to see if smoke comes pouring out of it. It should not blow out, but have some suction (vacuum).