OK, I am starting my own thread on this one because I am about at my wit's end now. I have been tagging on other threads or talking about specifics but now I really need help troubleshooting my problem, which has been going on for a couple of months now.

Here is what I have:
1993 Volvo 240 wagon with B230F engine, LH-2.4, EGR, and Pulsair.

Here is what happens:
Once the car is warmed up it starts stalling any time I am just coasting along. It could be 1 MPH or 30 MPH. If I slow down and have to take my foot off the gas then it will start stalling. I can feel the idle start to get unsteady as the car gets warmer and warmer. When it is hot out, then it is particularly bad. I have to commute through a lot of traffic filled surface streets and the only way I can get home from work is to keep one foot on the gas and one foot on the brake almost the whole way.

Here is what I have done:
I determined that the in-tank fuel pump was not running at all and replaced that but it didn't fix my problem. I got a fuel pressure gauge and was getting low readings (except the dead-head pressure was fine) so I replaced the fuel pressure regulator. However I now have reasons to mistrust the readings from the gauge, one of which being that replacing the fuel pressure regulator didn't do a thing for my problem or the pressure readings. Another being that the fittings on the gauge were cheap crap and fell apart after one use. So, for the purposes of this thread, I am just going to pretend I never got a fuel pressure gauge.

Here is some additional history:
I bought the thing from a mechanic whom I now don't trust any further than I could throw him. I don't even want to have to deal with his BS and what I have determined to be constant lies. Not even to sue him. The car started acting up the day after I bought it and he has given me nothing but BS. I am only telling you this so you will understand when I say I have no idea how long it was messed up or what the hell he did to it, and that I can't expect him to do anything about it. I just want to fix it and get on with my life.

Help!
So, if anyone has any suggestions on what could actually be my problem and how to check for those things, I would really appreciate it. It seems there are so many things that could be causing this problem, especially with all the extra emissions stuff added on, that I am at a loss as to where to start.

 

Do you ever have hard starts? Could be mass air flow sensor. I'm not super familiar with the 93s, but I believe they have a hall sensor in the distributor that is known to cause stalling in warmer weather

 

'93 has MAFS, not Hal Sensor. And the MAFS is not your problem.

I'd do a tune up first: plugs, rotor, dist., etc. Don't have to change them necessarily, just make sure they are OK. Then clean the Idle Control Valve, Throttle body, etc. Not a difficult problem but you just have to check a bunch of things see what's what and neglected, etc.

 

check this link of a guy selling a distributor and the reasons why:

he had a stalling problem....frequently and fixed it by replacing the distributor so he got another one just in case....

look at your distributor wires going to the timing box by the window washer reservoir...kinks, cuts or something of that nature.......

1976 1984 Volvo 240 Distributor 0 237 003 009 | eBay

 

Rather than a hall sensor in the distributer for timing, these late model LH2.4 & LH3.1 fuel injection systems had a crank position sensor to provide timing to both the ignition and fuel systems. The sensor is located on the top of the bell housing and has a thick black wire about the size of coax cable running to a plug on the firewall. Check this wire. If the insulation is cracked or flaking off, its time for a new one. This is a common cause of stalling in these systems.

Good luck.

 

It sounds as if you are saying, "It's not a difficult problem if you are willing to shotgun troubleshoot by just fixing everything."

While I agree that is true, and I am working on doing just that, I would prefer to start with the things that are most likely to be causing my problem.

That said, some things require either more research or more tools or spare parts than I have at the moment. So I am starting with some things simply because they are easier to do.

For instance: Checking the idle air valve usually requires removing the throttle body, which you might as well clean at the same time. But I am concerned about breaking those plastic clips on the throttle linkage, so I have a separate thread where I am working on learning about and finding a good source for those. Once I get those plastic pieces, I will work on the throttle body and the idle air valve. I have already researched everything I need to do to test, clean, and adjust them.

I had been concerned about being prepared to work on the flame trap while I had the throttle body out, but I discovered that mine sticks up high enough to get to from the top. So, even though the flame trap couldn't cause this problem, you will be happy to know mine is checked and clean. This morning I will work on cleaning the port from the flame trap into the intake manifold, because I can get to it and I know what to do now.

So, I am working on what I can, when I can. I was just hoping for some insight as to priorities or ways to diagnose the problem other than "just fix everything."

Thanks

 

It starts just fine. The only time it has given me any trouble starting is just after it stalls. And, even then, only if I am in a rush and just immediately turn the key and mash on the gas. So now, when it stalls, I just turn the key all the way off, turn it on and let the fuel pumps run for their couple of seconds to repressurize the fuel system, then turn it over and it starts right up.

I have read of others who have to wait two minutes before it will start. I never have that problem. So, I guess I am a little better off than some.

 

Wouldn't those cause random stalls at almost any time? My problem definitely happens only in the situation I outlined above. It has never happened when going normal speeds, unimpeded by traffic or speed bumps.

On the other hand, it sounds as if it is easy to check. So I will take a look just for good measure.

Thanks

Update: I checked and there are no wires or cables coming off of my distributor other than the spark-in and four spark-out cables. No sensor wires of any kind.

 

"It sounds as if you are saying, "It's not a difficult problem if you are willing to shotgun troubleshoot by just fixing everything."

I say that because this is a car NEW to you, and looks like it has some issues, like any 20 year old car with uncertain history. I go through this all the time, and it's not as daunting as it may sound, a couple of hours work. To address just the stalling, do what I put in my previous post, go from there. BTW, the Crank Sensor should not be the problem...

 

Of course, it is only a couple of hours work for you because you do it all the time. I haven't checked plugs in 30 years. I don't even know if the spark-plug socket I have will fit my plugs. So, for me it is a bit of research and making sure I have all the tools and parts available before I get started. I can't pull something just to see if it is bad and then run to the auto-parts shop in my other car.

So, I will work through your list. I will focus on the throttle body and idle air valve first.

Thanks

 

I just cleaned the mass air flow sensor and the port on the intake manifold where the flame-trap connects to. I know these aren't the cause of my problem, but any little bit may help some and it was what I could do today. The MAF was definitely dirty. It looked like a copper wire when I started and now it looks like platinum. I'll let you know if it makes any difference.

 

LH2.4 cars have a 'DTM 3' on the diagnostic block you can activate that cycles through each of the engine actuators turning them on/off/on/off a few times before moving to the next actuator. this cycle includes the idle air control valve, which you should feel clicking during the test, and if you disconnect the hoses to it, and hook up a rubber hose you can blow in, you should feel the air gettting chopped on/off/on/off with this test.

see this FAQ page for the details on DTM#3...
Engine and OBD Diagnostic Codes
(this requires no tools or test gear, its just a pushbutton and LED thing built into the car).

 

Does the car have electronic fuel injection or is there a plate inside the air filter box? I had a 240 series that the accordion looking hose would squeeze close due to the vacuum created when accelerating and when I took my foot off the pedal it would stay squeezed shut depriving the engine of air. Since your car restarts the power stage chip seems okay (for now).Check that hose from the air cleaner to the manifold opening.

 

LH cars are electronic injection, pretty much everything from 1984+, and LH2.4 is the better/later version of that, complete with an onboard diagnostic box (button + LED + jumpers), used on 1989+ cars.

 

Yup. I had seen you mention that in another thread and I am certainly planning to do that. But thanks for mentioning it again.

 

My air duct is plenty sturdy. I have no worries that it is collapsing on me.

Thanks, though.

 

So, I finally did this test. The idle-air-control-valve clunks very solidly when it is activated by the ECU. I disconnected the end of the hose that goes to the air duct and jammed a short length of 1/2" I.D. hose up in that. I left everything else connected. I ran the test and blew through my hose. I could definitely feel the "tut tut tut," as you have described it in the past, as the valve clunked back and forth. However, it didn't seem as if I was able to blow a whole heck of a lot of air through the thing. It didn't seem as if it was enough for a car to idle on. (Doh! I just realized I was blowing into a stopped engine with the throttle-valve closed. I'll try it again while holding the throttle-valve open.)

I have figured out that I should be able to get that idle-air control-valve out from under the throttle-body without too terribly much trouble (because I have long, skinny arms and can reach all the way through from the front to disconnect the connector in the back) so I will try to get that thing out and have a real look at it in the next few days.

P.S. All the injectors vibrate too.

 

fuel filter?

 

The one that is under there looks brand-spanking new. Hardly even any dust on it. So, I am guessing it is OK. But then, one never knows.

I don't have a floor-jack or jack-stands so getting to the fuel-filter or main-fuel-pump is a no-go for now. Yes, I could buy all those, but right now I rent a bedroom in someone's house. I wouldn't really have much place to store them. And getting to where I could get a good deal is a bit of a haul for me right now, especially while the car is acting up.

Sooo... I am hoping that the problem is something up front. Not that I won't go down under there if I have to, but that is my last resort unless there are strong indicators that that is the problem.

Thanks, though.

 

OK, it has been cooler here for the last couple of days, so that may be causing my engine to not get as warm on the drive home, but in the two days since I cleaned the mass-air-flow-sensor (MAF) it seems to be behaving a lot better. It did start to sputter just once as I was rounding the last corner to the house today, but I had made it all the way through all that crawling traffic and all those speedbumps for over half an hour at 15-25 MPH with nary a hickup.

When I pulled the MAF the outer screens were black and the platinum wire looked like a copper wire. When I was done, everything was shiny and bright. So, I'm guessing that would have caused problems anyway.

It may very well be that Lev is right. It may be that there are just so many little things wrong that they add up to a big problem, but with no one silver-bullet fix.

So, I'll just keep plugging away at cleaning and checking and adjusting.