But it idles right at where it should...
With a warmed up engine, I'd use a
Rubber Cork, and plug the IAC hose at opposite end of IAC's hose. Then startup engine, and see what RPM is.
Or, consider another person's observations (LH 2.4 manual explains this, mine is on another computer):
To adjust the closed throttle plate rest position, the 1/4 turn method is the correct Volvo adjustment procedure. With the lock nut loose and the TPS switch loose (not everyone remembers to do that), while holding the plate closed, advance the stop screw until it's touching the stop and to the point where the plate is just about to start opening. Advance the screw 1/4 turn more and secure in position with the lock nut. If you're a purist, Volvo calls for adding a drop of paint or thread locker to serve as a tampering indicator. This is all best done on the bench when cleaning, holding the plate closed from behind with your fingers on the lower edge of the plate to best sense plate movement.
You then adjust the Throttle Position Sensor switch with the throttle plate closed, rotating it clockwise until it clicks as it opens. Most of us just set the TPS switch so that it clicks just as the throttle plate begins to open, but of course it shouldn't be set on the hairy edge of clicking, there should be some freeplay. Volvo TSB 25-202 on LH 2.4 throttle body adjustment is much more specific and calls for different procedures depending on the TPS used. For the Bosch switch, keeping the plate held closed, you open it until you get the click, then continue turning it open until you reach end of travel then secure the screws. For the VDO switch, you insert a 0.25 mm feeler at the stop screw, rotate it open until you just get the click, then secure the screws. I'm unsure of the exact LH 3.1 TPS adjustment spec, but I imagine the same specs would be close enough.
With the throttle body installed, you re-connect and adjust the linkage rod between the throttle body and the throttle cable spindle. Again, most of us just adjust for a little bit of freeplay before getting the click. The Volvo TSB of course calls for feeler gauges to be used and it's different for the various engines. You insert the feeler gauge at the cable spindle stop tab (not at the throttle shaft stop screw) and tighten the linkage rod turnbuckle until you get the click. For all 240 B230F you're supposed to use a 2.0 mm feeler, for 700/900 B230F and all B230FT it's a 2.5 mm feeler, for all B234F manual trans and early production B234F automatics it's 3.3 mm, for later production B234F (w/auto TB tensioner and auto trans) it's 1.6 mm. Why there should be different spindle freeplay specs, I have no idea.
For adjusting the throttle cable, most of us will simply want to adjust the slack out of the throttle cable, leaving a minimal amount of freeplay to achieve an immediate throttle response at the pedal. I've heard of others wanting to adjust the throttle cable to achieve full WOT when the pedal is at the floor, which would only be correct if our cables were so short as to be taught when at WOT, but that is generally not the case and could inadvertently cause TPS malfunctioning if adjusted that way. Volvo of course has a factory adjustment spec, measuring freeplay at the pedal.
And finally, for automatics you get to adjust the kickdown cable. The Volvo TSB spec I have calls for adjusting the distance between the brass ferrule on the cable and the end of the adjuster sleeve. If the kickdown cable has ever been replaced then that ferrule is arbitrarily clamped on by the installer and no longer a reliable point of reference. The way most Volvo Vista Techs do it is as described in the FAQ. While plucking and releasing the kickdown cable, starting with the cable slackened, you adjust out the sound of the clunk where the metal pawl on the end of the cable can be heard striking the bottom wall of the kickdown chamber in the trans. You need to do that in a quiet area. It's best to keep track of the number of nut faces turned from the original adjustment position in case you have difficulty and need to get things back to where they were.
Phil yes thats the problem for many of us shadetree types using Bentley Haynes and other manuals These manuals were mostly written in the heyday of the early 240s with KJet and LH 22 In most
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