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Re: Cold start coughing....1984 8-valve... Posted by Saana88 [Email]  (#207)  [Profile/Gallery]
(more from Saana88) on Mon, 15 Sep 2003 10:48:51
In Reply to: Cold start coughing....1984 8-valve..., AzureBlue, Mon, 15 Sep 2003 09:22:50 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I had the same problem this spring. First, take the rubber boot off the throttle body and clean the inside of the throttle butterfly valve housing. If you're picky you'll get a cotton swab or toothpick to clean all the little orifices and vacuum line vents to make sure they're not plugged. While the boot is disconnected, look at the top of the fuel injection metering body (the other end of what the boot's connected to.) Being very careful not to twist or push on the flap in there, clean any and all oil deposits off of that general area. If any of these things give you trouble, some carbureretor cleaner on a rag will be a good solvent. Put all that back together and make sure all your vacuum lines are connected.
Next, start your motor, let her warm up, and set the idle speed to whatever is specified on the sticker on the wheelwell- something like 875 RPM plus or minus a tad. The Tachometer on the instrument panel is not accurate enough for this job. The idle speed is adjusted by what looks like an 11 mm head bolt with a locking nut sticking out of the side of the throttle body. Hopefully there will be some oscillation in your idle speed, and that's exactly why there is the +/- spec on the sticker. That oscillation is your oxygen sensor doing its job. If the idle reading does not move up and down at all when the engine is warm, that's a sign of a dying or dead oxygen sensor.
I had the same problem in the spring- I'd fiddled with my idle speed, accidentally adjusted it too low, and driving with three feet gets interesting in a hurry!
Okay, but what's going on? First, those oil deposits in the throttle body are okay, it's normal for them to be there, just clean them up every once in a while. They are constricting the airflow into the engine at idle, literally choking the car. Second, any deposits on the venturi flap are adding weight to the lever which is set to move upward with the airflow coming in, weighing it down. This has the effect of fiddling with the mixture, I believe. Whatever it is, it's not good.
If you need any help with this, drop me an e-mail message and I'll supply some pictures of what exactly I'm talking about.
I hope this helps. Long live the 8 valvers!
posted by 128.205.1...
, Mon, 15 Sep 2003 10:48:51 <-- Viewing This Message
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