Akila

Having problems with the rough running ast Idle & popping when holding acceleration. Thought I had a vacuum leak but cannot create a steady idle with carb cleaner troubleshooting. Took apart the intercooler & intake, checked all for leaks. Now, I adjust the Idle speed & it does nothing noticeable with raising or lowering Idle. What could be causing this?

Mark Houghton

A few thoughts:
(1) you have a bad plug, or plug wire. Check this at idle by individually disconnecting one plug wire at a time and see if it causes the engine rpm to drop. If no difference is noted, then that particular plug or wire is shot.
(2) your mixture A/F ratio is way too lean. This you'll need access to a CO meter. Very easily adjusted, however.
(3) your WUR is acting up. You would have to check all the fuel pressures and need the gauge setup to do that. Search this forum for how-to.

Akila

Mark,
Thanks for the steps. I believe it is my AFR, since I had sealed some leaks in the system. If I can find someone over here with a Gas analyzer. I would know for sure. The WUR is fresh from Leask. The engine freshened last year, thought my wires would have been changed. May have to check that too.

Mark Houghton

Let us know when you get it all sorted out...so we can collectively add the findings to our diagnostic memory banks!

Akila

Another piece to the puzzle. Had a bad plug wire, I think. The wires were OEM & I am running an MSD, dont know if this matters. But, one of the wires appears to be bad, had some blue corrosion type color on cylinder #2, color was at he distributor connection. Changed out wires to Clewett engineering wires. Broke a small piece of plastic from the distributor cap so had to send out for that as well. Living way out here, its a pain to get parts, always have to wait for the order!! Hopefully this was the problem.

Mark Houghton

Keep at it, you'll figure it out. Hopefully it's as simple as a bad plug wire.
I can relate to the "waiting factor" when it comes to repairs and parts. I'm out in the middle of small-town-USA myself, so consequently I do 100% of the work myself....which means ordering parts and waiting for them to show up. The nearest Porsche dealer and/or service location is 120 miles away, so I don't even bother with them. And so far, I haven't been stumped yet to where I would cave in to letting someone else work on my car.

Akila

One wire was bad as was the plug. Runs smooth though acceleration, but it has that popping at Idle & on decel. One of the symptoms is the idle adjustment does little. I was told I may still have a vacuum leak. I have checked all over for that leak & just cant find one. Still seaching any suggestions?

Akila

The latest. It was popping all over the place. Adjusted the AFR, eliminated the popping almost completely, still heard one down around idle. Idle is moving around slowly about 1-200rpm, set at about 1000rpm. Runs fairly smooth till I hit the gas & around 3300-4000 kinda bogs. Idea's?

Mark Houghton

What's your AFR or carbon monoxide % at idle? It sounds like your engine is "hunting" with the rpm's not holding steady. At steady throttle, say around 25 mph in 2nd gear, do you notice any surging? Need to confirm what your mixture is. I run mine at 3% CO, which is high, but most 930 owners do the same or close to it. This is without an O2 sensor connected at idle.

Akila

No analyzer, or dont know of anyone out here as of yet. Adjusting by using others tips on Pelican. I think I may be fairly close, because of the symptoms being lessened.

Mark Houghton

Hmmm....you really need to know what the CO is. Although I haven't read Pelicans tips on this, tuning by "ear" is probably fine up to a point, but you're trying to diagnose a problem so you need to know more accurately.
Because of local non-availability for testing here, I eventaully ended up purchasing a tester made by Gunson. For my purposes, it did the trick just fine. There happens to be a new one listed on eBay, or you could wait for a used one to show up. Not overly expensive, but then again sometimes it's the only option we have when local service is not available....or if we just choose to do our own work regardless. See the link to eBay http://cgi.ebay.com/ebaymotors/Gunso...WDVWQQtcZphoto

Akila

I saw that as I was doing my research. I may know of a shop that might have one, but I am hesitant, because I didnt like their service on our Beemer. I will just ask around & see if there are any in the area. There was a new one I was too slow to bid on, I could have shipped it to Brother, who is currently having trouble passing smog in Ca. with his 77' 930, so he tells me he's thinking about parting with it. It would be ashamed to see it leave the family seeing it has 4x,xxx miles & is very clean! Thanks for the response. You wouldnt happened to have any trusted associates in Maryland, would you? Got a line on some Porsche items I would like to purchase & send.

WPOZZZ

Stuart - Here's a Gunson for sale. http://forums.pelicanparts.com/showt...ghlight=gunson

Akila

Thanks Bryan. Got a good one. Lets just say my rebuilder left something where it shouldnt have been. It was small & almost insignificant, until I had to use it. Kind of a "whaaaat?" reaction.

notthd

huh????????