1991 240 b23 with 230K. Runs fine driving, stopped at lights, etc. Problem starts when I shift into park after driving the engine really bogs down and then finally stalls after 45-60 seconds. It shakes the whole car as it is bogging down. Don't have an RPM gauge. Restarting requires revving the engine right after starting for about 10 seconds until you can shift into a gear and then it is hit or miss.

When it is cold and starts up no problem and idles well for the first few minutes. But if it sits idling for a few minutes too long (don't know exactly the time frame) and warms up it starts with the bogging down problem.

Any thoughts?

 

If your car has the original engine, you have a B230F, not a B23. Similar...yet not. If the car has indeed been re-motored w/ a B23, all bets are off. If you haven't had the car too long, there is a litany of things to check/fix/replace. I say this because quite often with Volvo rwd's, it is not a single failed item but rather several items working at the low side of normal. You really need a manual and a digital mult-meter to start sorting things out.
That having been said, if the car starts and idles fine when cold but idles poorly after a couple of minutes you could have a bad O2 sensor. It takes about 2 minutes for the O2 sensor to warm up and start sending input to the Engine Control Unit. The ecu takes this input and adjusts fueling, idle air and timing...the O2 input is critical. For the first couple of minutes before the O2 warms up, the car runs in what is called closed loop, a pre-programmed one size fits all operation. It sounds like as soon as the O2 warms up, things get wonky.
Hows the gas mileage? You could have a bad cat....it idles fine warm until you put it into park? Does it smoke at all?
So many things to check....air filter, air mass meter (in line w/air tube to Throttle Body), fuel pressure regulator (small silver or gold colored cylinder middle front top of motor, has a vac hose on the front), vacuum hoses throughout engine bay.
Still...my money is on the O2 sensor!

 

thanks for the feedback.

first off, it is not the original motor and the only documentation I have on the current motor is a volvo dealership invoice listing "B23" motor. Are there pictures out there of the two that can help me identify the issue?

second, how many o2 sensors are there on these engines? My suburban has 4 and my nissan has 2, yet looking at parts online I can only seem to find one for the 240.

third, where is the o2 sensor and is it a DIY job on this car. on my suburban I did them myself, no problem. on the nissan I physically could not get to the front one and had to pay someone to change that one out.

fourth, has new air filter, and I cleaned the MAF sensor. The car smokes a little at startup, but not after warming up


thanks so much for getting me started.

 

just confirmed the car has a b230F, but not the original. there is a sticker with a bar code on the engine with the info. the dealer who replaced it must not have thought the "0F" part of the equation was relevant....

I'll start with the low-cost solutions. I am going to disassemble the throttle body and give it a good cleaning tomorrow.

 

The O2 sensor (there's only one!) is on the header pipe below the car, just aft of the engine bay. It is a 3 wire sensor, 2 white, one black. The white is the heater element wiring for faster warm up and the black wire is the actual sensor wire that goes to the ecu. fcpgroton.com has the universal sensors for cheap. the diff between universal and o.e. is you have to cut, solder and heat shrink the universal, o.e. is plug in connector. The connectors are on the passenger side firewall. The 2 heater wires have a duplex connector, the signal wire is separate but nearby. Keep us posted. TB is a good place to start, examine the gasket behind it; it doesn't need to be replaced every time, but on some cars it NEVER gets changed.

 

okay, just disassembled the air intake and all the connecting hoses and WOW was it ever sludged/gunked up. There was oil in the air intake accordian looking pipe, probably not a good thing. The hoses connected near the throttle body were nasty as well. I ended up taking apart several pieces including what the volvo dealer called a nipple and flame trap. It is a plastic piece that comes out the top of the engine and has two hoses, connected to it: one skinny that comes out the side and runs to the back of the throttle body and one fat that runs to the air intake just before the throttle body. Once again, WOW for all the gunk and sludge.

After two hours and $11 for the nipple and flame trap I drove it for a few minutes and then parked in the driving, leaving it running and sure enough, after a minute or two it started bogging down again so next step will be o2 sensor I guess.

Also, also figured out something disturbing - the tranny won't shift into 4th gear. I don't drive the car much and when I do it's never at highway speeds. The 16 year old drives it. Well, today on my test drive I managed to get up to 60 and still in third gear. What now?

 

First things first: Cleaning the throttle body and flame trap (pcv) was a great thing. Crankcase pressure can get so high it will blow the cam seal at the rear of the cylinder head out completely. At highway speeds, it will cover your windshield! So, kudos for that.
As for the shifting/ not shifting into overdrive it is most likely not a major expense to repair. The first thing to do is (I do this first thing in the morning when it's relatively quiet) get in the car, leave door open, foot on door jamb switch to turn dinger off, turn key to run...don't start it, just have all the red warning lights lit. Hit the OD switch on side of shifter repeatedly and listen for a click as you engage/disengage. Lean out ofthe car door and listen under the car...no click? Getthe jackstands and get under the car. On the driverside of the transmission there is a vertical, cylindrical unit about 3" tall with a wire coming out of the end and then to a clip on the side of the transmission. This wires catches hell from tranny fluid, oil, p/s fluid and heat. It often deteriates and frays...even breaks. Follow it to where it disappears into the drive tunnel. If you see bad spots, replace them with solder joints and heatshrink...anything less is a band-aid fix. While you're there, note the cylindracal object mentioned earlier. That is your overdrive solenoid...they fail but rarely. If you found wire breaks, you're probably done. If not, it's time for stage 2. Pull your glove box by removing the 7 screws. Pay attention to the glove box lamp so it doesn't get ripped out. Look for a rectangular relay, white in color like this...

Try putting your hand on the relay and press the OD switch off and on...does it click? From this point on, you really need a multimeter. If the relay clicks on and off it's getting power. If it doesn't click it may be bad or it may not be getting power from the od switch on the shifter. The OD relay is an altogether too often fail item. Technically, you can remove the case and find failed solder joints and re-solder...but I prefer new. The wiring under the car is another quite common issue. Lesser fail items are the solenoid under the car and the switch in the shifter itself. Good luck and let us know.

 

will do the overdrive check this weekend. in the meantime I ordered a throttle body gasket online for $2.74 plus $5.51 shipping as no one near here had one in stock. I didn't want to take it apart only to have the gasket crumble and then not be able to let the kid drive it for a few days, until the gasket came in. I am extremely curious to see just how much gunk is in there once it's apart.

thanks for all the help.

 

When you clean the throttle body, pull the idle air control and clean and test it as well. It may help your idle issue. It is a little easier to access it when the throttle body is off.

 

can hear a click when switching OD on and off, took out glove box and can feel it click too. Does this mean relay is okay and getting power? Checked the wiring underneath and it looked okay, no fraying or broken wires. #11 fuse is good too, put a new one in to double check. That leaves the solenoid, right? Or could the relay still be the culprit? So confused...and bummed...

How hard to remove the solenoid and reinstall? Any special tools required and can I do any damage where I end up being unable to drive it and have to tow it to a shop and pay big $$$ if I screw it up?

 

The solenoid is a no brainer. Held on w/ 2 -10mm or 13mm bolts, I forget. The issue is when doing it in the drive way you will be operating blind as the bolts go into the top. Since you now know the shifter handle switch is working...do you get the arrow on the dash to flash on and off? And, do you also here clicking coming from under the car? If so, your solenoid is fine. Many times the relay behind the glove box can be intermittent and fail w/ heat. If the relay clicks, the solenoid clicks and the arrow come on and off...that leaves the overdrive unit itself. If that's the case, an entire transmission is the way to go as even when new, Volvo seldom opened 'em up. If your light on the dash is not lighting with the switch movement, theres a chance there is a wire loose on the back of your cluster. If not, I'd buy a new relay as they are inexpensive. If you think you need a solenoid, drop me a pm as I have a couple of used ones I'd sell cheap.
The old idle air units could be disassembled; the new ones are pressed together. I've had good luck cleaning them with brake fluid but frankly, never had one truly fail. In my case, it always was the idle circuit in the ecu. Luckily they are cheap on eBay.

 

maybe I misread your post but please tell me it's not a whole new transmission.

Here's what I got:

1. OD arrow goes on and off on the cluster as I press the button - everything seems okay there.
2. relay clicks as button is pushed. After removing glovebox I found the relay to the left behind the center of the dash area. I could feel it clicking as I pushed the button with my hand on the relay.
3. wires underneath seem okay. does not mean they are but visual inspection looked good.
4. could not make out any click from underneath car. was by myself and the relay clicking was so much closer it made it hard to hear anything underneath the car. tomorrow I will have an assistant (5 year old) to push the button while I'm underneath car.

What if during #4 above I hear a click underneath? What if I don't hear a click?

You've been extremely helpful so far, thanks for the patience! This isn't my area of expertise. I one of those guys who can put almost anything together with directions, but couldn't write the directions or tell you why it works.

 

I just wanted to follow up about the original issue of my post - the warm engine idle problems - and how I have managed to fix it.

First, thanks to all for the help, this forum is absolutely fantastic and there is no way I would have tried to tackle this problem without this resource.

Okay, here is what the problem was - once the car was warm the engine would really lug, it would shimmy and shake and eventually sputter out. When restarted it would die almost immediately. But, if you gave it gas it would be fine.

This only happened in park. Once shifted into drive or reverse the idle was fine, perhaps a little high, but fine.

So here is what I did:

1. new air filter.
2. disassembled entire air intake. Cleaned thoroughly with about 4 cans of walmart supertech carb cleaner applied liberally. I did use specialty MAF cleaner for the MAF even though it was $7 for the can.
3. took off throttle body and cleaned thoroughly. Lots of gunk in there
4. took off idle air control and carefully cleaned as I was not sure if carb cleaner would damage the unit
5. - and this was what I thought was the biggest thing - I took off the oil separator and cleaned it. I sprayed the heck out of it with carb cleaner and let some kerosene soak in it for an hour or so. WOW! some of the chunks that came out of that thing could have been considered independent nations. Clogged doesn't even begin to describe it. Also, when researching the removal of the oil separator I read some folks talk about the need to remove the intake manifold. Well, if the air intake, throttle body and idle air control are out it makes removing the oil separator pretty simple, and the throttle body gasket is only a few bucks (although you could probably reuse the old one as mine was in great shape but since I had a new one on hand I went ahead and replaced it)
6. replaced the flame trap and cleaned the big hose that goes back to the intake. To say it had sludge in it would be too kind. Also, the small hose that leads to the brass fitting on the backside of the intake manifold was clogged and was difficult to unclog. The fitting at this point was completely clogged and cleaned
7. All hoses, tubing, connectors, etc were thoroughly cleaned and scrubbed using an old toothbrush, bent wire coat hangers, pipe cleaners, and anything else I felt would help. the carb cleaner was used liberally to say the least
8. everything was put back together, the car started but the idle was much higher now. After 10 minutes of adjusting the idle (9.5 of which were spent looking for the nut I dropped into the engine bay) it runs so smooth and so much quieter.
9. Car no longer wants to die when idling in park when warm


Maybe one day this will help someone with a similar problem.

 

I’ve had the EXACT problem with my 91, so yes, you’re helping me. Thanks!