Hello everybody, looking for some advice on my 89 wagon. It has the B230F 2.4L engine, automatic transmission.

For the past few months it has been stalling. It cold starts great, will idle indefinitely (I had it idling for 30 min), I was also opening the throttle and holding a steady rev for a little and it immediately snaps back to idle when I let go. Once I get in to the car and start driving, it will stall once I come to a stop. Usually when the engine is warmed up, I can usually drive for a bit if cold.

I first noticed it when driving to work one morning, started up and drove maybe 8 min to get on the freeway. Was able to drive about an hour with no issues, all on the freeway at a constant speed. The moment I came to a stop, the engine stalled out. It has been having the same problem for the past few months.

I have recently been trying to diagnose the problem. I started with checking for vacuum leaks, found one in the vacuum line from throttle body to charcoal canister, fixed that. Problem persisted.

Next I checked internal diagnosis, came back with a 3-2-2 code (Hotwire malfunction in MAF), replaced the no name brand with a Bosch OEM (last four: 2016). Car was idling better but problem still happened.

While I was checking the MAF sensor, I noticed there was a decent little amount of oil in the intake accordion hose and around the old MAF sensor. I cleaned the tube and checked for cracks, it was all good. Also did some research and it seemed like a faulty Pcv system. Ordered a new one off FCP Euro, installed the kit with the new hoses and flame trap. The car was having the same stall problem.

Checked and cleaned the IAC valve, it’s fully functional. Also checked the Engine Coolant Temp Sensor, had a spare used OEM one as well (last 3 digits: 032 or 069), checked two separate ones and was still having the stalling issue after driving with warmed up engine.

Also checked the TPS sensor, and have a spare, both are functioning and set to proper angle that clicks as soon as throttle opens.

Cleaned throttle body and replaced gasket, also new intake manifold gasket.

That I believe is where I’m currently sitting. My next effort will be checking out the Crank Position Sensor, have been reading about it online and it seems like a possible culprit. Visually mine appears to be in good condition, also sounds difficult to get an accurate reading of it with a MM because it’s an intermittent fault and it may read okay upon testing?

If anybody has any advice, I’m all ears. Very new to all of this, have only had this car for a little over a year. It was at an awesome mechanic, who specializes in Volvos. I have all new fuel pumps and new fuel filter, so I haven’t looked in to any of those. It’s been fun learning so much, interested in how people here with more knowledge would’ve gone about diagnosing this issue. Thanks !

 

You cleaned the throttle, and adjusted the throttle switch. Did you set the base idle? Base idle is the speed the engine idles at with the Air slide, idle motor, IAC - whatever you want to call it is blocked off. If your idle motor is old, it may not respond quickly enough to keep the idle speed from going too low when decelerating. Years ago I would simply clamp one of the idle motor hoses off, and after cleaning the throttle, adjust the throttle opening so the engine idles at 750 rpms. Then adjust the throttle switch to click when it's supposed to.

Years later I'm certain those idle motor hoses are not pliable anymore - so a different method will be needed to prevent any air going thru the idle motor when adjusting the base idle. (yes on some models there is a test point that when grounded will put a good idle motor in a static position - to be able to adjust the base idle speed)

 

I have not adjusted the base idle myself, my mechanic had when I first brought it to him, so I haven’t wanted to mess with it, but I’m sure it’s possible micro adjustments have happened since driving it around for the past year? Thanks for your input, I will have to look into that after work this evening.