This morning I decided to go after the problem of a too-fast idle on my new 89 244. First stop--idle stabilizer. It was dirty inside, so I cleaned it. Tested it by connecting to 12V---worked normally. Had a look inside the intake boot. Found an oily mess. the throttle body was really nasty, so I took it off and cleaned it thoroughly. The smaller of the two holes for the vapor recovery system was completely blocked with crud. While it was off, I set up the throttle position switch, which appeared to have been correctly adjusted in the first place. Also cleaned the intake boot. Took off and cleaned the breather box (oil separator) and flame trap hoses. they were as bad as the throttle body. Went to put it all back together, found the culprit---the short linkage piece between the throttle cable drum and the lever on the throttle shaft was adjusted way too short (by well over 1/8") which kept the throttle from returning all the way to the stop. This prevented the throttle position switch from making contact, so the idle stabilzer wasn't engaging. Reassembled everything, adjusted the linkage rod so there was no tension on it in either direction (it rotates freely from side to side) started it up and it worked perfectly.

What would cause this Ball and Socket linkage to ever change in length?

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'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.no.net/ebrox/Tony's%20cars.htm

I don't think you can ever rule out a SPOT (Stupid Previous Owner Trick) or a bad mechanic in these cases. I wonder if the amount of "weathering" on the threads could provide the tell-tale evidence?

There's also the set screw for the throttle plate "stop". Is/was that set right? Should be tweaked just enough that the throttle plate doesn't touch the housing and bind.

Though, I'm with Jorrell... great idea to check the throttle cable.

-Ryan
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Athens, Ohio
1987 245 DL 314k, Dog-mobile
1990 245 DL 134k M47, E-codes, GT Sway Bars
1991 745 GL 300k, Regina, 23/21mm Turbo Sway Bars
Buckeye Volvo Club

Someone who doesn't know what they're doing, attempting to adjust the idle speed.

Or maybe one of the ends had to be replaced, and whoever did it just screwed it on, without realizing that the length of the rod needs to be correct.

The cables will stretch over time. You just have to get a 13mm wrench and tighten it up just a bit to take up any slack. There is adjustments for both the kick down cable and the accelerator cable, one is on the front side and the other is on the back side of the throttle body. You do not want to get that too tight. It can keep the Throttle Position Switch from closing if it becomes too tight.

I agree that getting shorter is not normal, something else has to be going on most likely.

Regards,

Paul

Blue Horse:

Excellent info and a great job on fixing the problem. One thought though is that the throttle cable usually stretches a touch and doesn't get shorter. May I recommend that you check the pedal end of the cable to see if it is fraying at the firewall? If so, replace that sucker asap unless you want to drive home from work at idle!

jorrell
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92 245 250K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!

Your point is a good one, so I went out and inspected the cable carefully this morning. I found that while the outer plastic covering (in the engine compartment) is somewhat deteriorated, the inner braided cable looks just fine at both ends where it is visible.

I also noted that there is a stop on the drum, so that when the engine is at idle, there is only enough tension on the cable to keep it from falling off. In other words, a stretched cable would have no effect on the relative length needed for the linkage rod. Someone who didn't know what they were doing must have worked on the car previously, and for whatever reason, adjusted the rod length incorrectly.

Mr. Goodwrench works in only a few places. Mr. Badwrench works in a lot of places.

Bill