First I want to thank all of the contributors to The Brickboard. I purchased two high mileage 700s last year, '87 740GLE sedan & '88 740GLE wagon, both automatics, B230F. I have been able to solve innumerable problems with both vehicles with the help of the 700 FAQ and Archives. There is one I have not been to solve. The '87 sedan starts fine but often stalls as soon as it is put in gear. I have swapped between the cars, the IAC valve, the AMM and the knock sensor. The ECT thermistor reads 2.8k ohms at 70 deg.F(a little high). Throttle body is clean, plate and TPS properly adjusted. Valve timing is correct(now). The ignition timing is 12deg BTDC. My question is about the throttle position switch. In two different postings as well as the FAQ I have read that the timing should advance 10-12 deg. as soon as the switch opens, off idle. Neither of the cars change timing when the switch is open. Could something else be overriding this signal? I have traced the signal back to the Ignition Control Unit and it is getting that far. The '87 still stalls and the '88 is fine. Any insight would be greatly appreciated.

Hi Bruce,

Under the throttle body is a black screw like thing....this is what is most likely causing your problems...i had a similar one, except mines a manual, so it would make it to the end of the street then stall.....Given that the throttle body is clean and all, go to the left hand side (exhaust side) of the inner fender. There will be 2 connectors there, one is white with a red stripe, the other is white with a green stripe. What you have to do is ground the RED stripe wire....(Just use some alligator clips or something), oh, don't ground the green one, it comes directly out of the ECU for fuel mixture checking....god knows what would happen if that was done!! Now, with the red stripe wire grounded and the car WARMED UP (!) the idle should be VERY low, i.e. if you put it into gear the car will probably stall. Now, get a meter of some form to measure RPM (or just make an approximation using the dash guage) and adjust the idle RPM to approx. 700-725 (for manual, not sure about auto, sorry) but even that should get the car running MUCH nicer. Have you ever noticed that the car idles low when pulling up to a stop quickly? Should have noticed something like that...Once you disconnect the grounded red wire the engine will race to about 1200-1500rpm for a little while, then slow down....this is the IAC setting itself right. After this you should notice a HUGE improvement over cold idle.....My idle was about 200-300 RPM when i grounded my cable...the car was BARELY turning over.....(emphasis BARELY)...

That should be all you need to do!

Azza

Hello Azza,

Thanks for the information. I have been setting the base idle speed by clamping off the hose to the Idle Air Control valve. I had read about a way to set the base idle by disabling the IAC valve, but I didn't know how to identify the test point. I will try your method this week, but I suspect the base idle speed is correct.

Regards,

Bruce