Thanks guys, as I found out after following your advice the throttle body was really dirty, so a complete cleaning is in order. Fitz thanks for the kudos on the '88 I liked the sedan so much we added an '88 245 to the stable as well. Again, thanks hope I can repay the advice down the road.

John

'88 240
'88 245
'92 960

After grounding the the blue and white wire from the test terminal...The engine would die.

You'll want to make sure that your IAC Valve and the Throttle body are clean before you set your Idle. Since the car stalled when you grounded the test connnector, it seems that your IAC Valve is working, -but you may want to clean it for the sake of not having to do it again later (see thread on cleaning the IAC Valve). However, I would assume that your Throttle Body probably has some varnish, sludge, and accumulation in it which is causing a blocked bypass passegeway.

Remove your accordian tube and inspect the throttle body. Observe the black thumbwheel screw on the lower front edge that is used for idle adjustment. Turn this screw to the left and back it all the way out. When it doesn't want to come out any further, gently pull while turning and it will pop out (it's retained by a small o-ring). Clean the throttle body with Throttle Body Cleaner (Valvoline, Pyroil, and STP come well recomended, -avoid Gumout and the cheap stuff). Work the throttle back and forth and open and close the butterfly valve. Spray the cleaner through all the vacuum nipples and especially through the bypass passegeway that you removed the Black Thumbwheel from (you should also notice connecting passegeways that lead from it up to the throttle-plate/butteryfly-valve area). Once it's clean, reinstall the black thumbwheel and turn it in so that about 50% of the threads are showing. Restart the car, warm it up, and then follow the Bentley instructions for setting the idle.

Note: The Black Thumbwheel Screw is what's used for setting the "base" idle speed. If it's all the way in, your base RPMs will be at zero (thus stalling the engine). The IAC Valve is used to provide supplimentary air to increase the RPMs during warmup conditions and when you have the AC on, and to keep the engine from stalling when it's in gear and your foot is on the break.

By the way, congrats on owning an '88 240. They're great vehicles and you've got the best Fuel Injection ECU, Timing Controller, and wiring harness out of all of us fellow LH-Jetronic 2.2 owners ('85-'88). I've got friends who are waiting in line for '88 240 Volvos.

God bless,
Fitz Fitzgerald.
--
'87 Blue 245, NA 237K

Grounding the blue/white wire closes the air control valve as you say. At that time the only air getting to the engine is through the idle air bypass screw. If the idle air bypass screw is all the way in it would not allow air to pass and the engine would die. Another possibility is that the air passageway controlled by the bypass crew is clogged.

Another possibility is that the throttle switch is either bad or misadjusted. I was able to improve the idle in my 940 with the B230 engine by doing a complete readjustment and setting of the throttle plate , linkage, and throttle switch.

John,

I am not an expert on LH injection, but the problem might be your baseline idle is set to low. When you remove the constant idle feature by grounding the lead your engine stalls because the mechanical idle is set to low. Try adjusting the mechanical idle speed higher so the engine holds when the electronics are removed (see note on page 241-26 Bentley). Hope that helps.

Mario