Yes, another idle issue, but it's a bit different than what lots of people are saying about theirs. I recently suffered through an idle control module replacement, which was causing my car's inability to idle for all this time (suffered because I had to manually wire it as the connector bracket fell off!). Well, it only partially solved my problem. Before the ICM replacement, my idle wouldn't exist; I had to keep my revs up until the engine warmed up. My current configuration was a bypass of the idle control valve (used a plumbing valve instead set to 1k rpm idle [warm engine]). So, now my ICV and ICM are in place. Now, the car idles fine when first started, but if you tap the throttle and let go, the idle is so violent and bounces so much, it would take your head off had it an axe. I decided to be helpful by uploading a video onto YouTube of its behaviour. God it took a really long time, but all in the name of science: Click here, even though you don't really care but can't let an E30 idle bring about its downfall Once the engine is somewhat warmed up, everything is fine and there are no anomalies to report. Notice in the video that 2k is the cutoff point; when cold, rpms after 2k, everything is smooth sailing, but anything under sometimes feels like it's only running on a few cylinders.
Idles like it has a fouled plug or two, or maybe a vacuum leak. When was the last time you: Adjusted valves changed/cleaned/gapped plugs changed wires or ohmed them (and what type are they?) checked/changed cap and rotor Also, really dirty injectors can have such a crappy spray pattern that they dump rather than spray fuel. In cases like that, it can cause poor idle when cold. My M5 would do that until I cleaned the injectors. One way to check for a dead cylinder is to pull the plug wires and see which one does not change the poor idle (but this is dangerous to your health if it zaps you.)
I'm a little overdue for a valve adjustment, but a valve adjustment isn't as critical as, say, a timing belt. A valve adjustment can wait; I don't have time to take it to the shop this week, maybe on the weekend. My plugs and wires were changed in the summer of 07 and I did them myself. I don't quite remember what wires I got, but the plugs were replaced again in April after the shop it was at told me that I had the wrong kind in there. Turns out the auto store gave me the wrong kind! But, that was replaced in April of 08, so the plugs should still be OK... I had a major service in May 2008 which consisted of a timing belt and tensioner, distributor cap and rotor, a valve adjustment and valve cover gasket, and an oxygen sensor. That was when the odometer read 104772 (really just a touch above 302k). It is currently just past 117k on the odometer. I'm definitely due for that adjustment, but aren't plugs and wires supposed to be good for 60k? Or is that only on newer cars? I wanted to pull my plugs and check the health but it's soooooo damned cold that I don't know if I can muster up dingleberries to go out there and risk freezing over, but I will if you think it is necessary. I don't think I have a dead cylinder. All 6 fire beautifully over 2k RPM and is as smooth as silk above that, every time. I used to have a problem with this back when the weather was warm, where the engine would run rough under 2k, as though it was severely down on power, and then run fine above 2k. Then that problem disappeared for a long time and didn't see it rear its ugly head until now, and now it only does it occasionally still, not all the time. I have the admit, these past days, it has been running very rough down low more frequently than it ever did, but it still doesn't do it all the time.
Valve adjustment = critical service! wires, cap and rotor (if they used quality parts) will still be good. If they used a cap and rotor from NAPA, well, good luck. I did not mean you have a totally dead cylinder, B. A dead cylinder can occur at low RPMs and not at high RPMs. And guess what, it will cause a rough idle. I suspect you have an ignition system issue or fuelling system issue causing a one or two dead cylinders when cold. DId you say take it to a shop for a valve adjustment? A handful of bolts and nuts and a feeler gauge will get it done (engine must be cold.) Seriously, though, if you can't adjust M20 valves, you are not helping me drop in an S50
I've never adjusted them before because I never had someone around to help in case something wasn't right. If I have no backup, I will not touch anything. Besides, it's fricking cold, and valve adjustment takes a while, no? I have no useable garage. If it was warmer, I'd try my hand at it, but, well, it's not warmer, so there you have it. I personally hope it's the spark plugs, because they're easy to replace. I'll check the health soon to see if any of them are fouled. The distro cap and rotor were parts from CarQuest; I have no idea if they're NAPA related or not.
Bosch or Bremi only on cap and rotor, or you may not like what you get. My friend's 325e had weird ignition problems on a newish cap and rotor and it turned out that the rotor flew apart (which is a common failure mode for the crappy ones.) Also you should be using regular Bosch plugs, not platinums as the small 6 tends to foul those out pretty easily. I can adjust valves in about 30 minutes, but it is pretty cold up there.
I think what I have for a cap is Bremi. That name sounds awfully familiar and think I saw it stamped somewhere on the cap. I think the rotor came separate and don't know what brand that is.
A shop should charge you no more than 1-2 hours for a valve adjustment. But really should only charge one.
