Hello! Having some difficulties and thought I would ask here. I am not a mechanic, though I know how to tinker, but I am at a lost. Family inherited an 1990 B250 from a friend, and I have recently gained possession of it. To my understanding it worked great and the previous owner took great care of it, tuning and taking care as needed. However, when it came into our care, it has sat. For about 2 years. When I picked it up, it started great, and it sounded good, if not like a boat. The issue comes into play when entering gear, it appears to lose idle but it will not stall then. There is no RPM meter on the dash so I am unable to determine its true idling numbers. Now, after giving it gas, when coming to a stop, it will stall on me. When driving it home, I went about 90 miles and it stalled 3 times, though I didn't give it much thought assuming it was due to lack of driving, and it started back up again both the 1st and 2nd time. The 3rd time however it needed a couple minutes, and since then, it has become an issue where if it stalls on me, it may not start up, including even attempting to turn over, needing up to several hours plus. It will then turn on as if nothing had ever happened and idle just fine. Lights turn on, and I am able to perform all other electrical actions after it has stalled. I have a couple ideas, but thought I could ask here whilst I perform them and maybe the community has idea's I do not.


Things I have Done:

Before posting this I have changed the Air Filter, which I didn't think was the issue but it did need it.

I changed the ignition coil, as well, since I had read that on older models when overheated would not turn over. The problem persisted on the immediate test drive and I never exceeded 30mph. It decided to turn on again after about 5 minutes post stall.


Things I want to Do:

I was looking into changing the Idle Speed Control Valve. I can not however seem to locate it. When watching videos, the oldest model I can locate with one is a 1993, and the valve is right underneath the carburetor. This video is what I referenced. Instead, I have what looks like an air vacuum tube. Which looks just like this video. . I hope that helps to an extent with what I am looking at. If this particular engine has an Idle Valve, where would I locate it or is it the vacuum?

Speaking of Vacuums, I intend to look for an air leak as well. I have never done that before so am still watching videos on how to properly look for air leaks. A gentleman I know says he didnt hear any whistles of a leak when we replaced the Ignition Coil, nor do the cables look bad, but it's always best to do the simple things first.

I was also thinking of replacing the TBI Fuel Injectors as in the second video I referenced.

Lastly, giving the EGR valve a cleaning. Some forums have mentioned that it could get stuck also causing issues which would cause stalling as I stop. I need more videos on this as well.


Other Information:

I do not know the proper miles on it as the entire speedometer does not work, but it ended at 90,349 miles. Now we know we can add about 90 to that for my drive home. I'm willing to bet it has a fair few more as the prior owner used it pretty consistently for 30 years.

When it stalls, the oil level indicator drops like a rock, with both it and the check engine light turning on. There is oil, as when I checked it was about half full. I added a touch more just to be safe. There also does not appear to be a leak, as no oil is below the truck currently as it sits on the street.

Engine Coolant is also nice and full.

The gas is relatively new as well. She was below a 1/4th of a tank, and I filled it halfway and the 90 mile drive took it back to about a quarter tank left. This is as of a week ago.

Finally, when the gas is pressed, it sounds good and it trucks along wonderfully when in park. No idling issues and RPMS sound good. But when I switch to drive, it sounds like I have a loss of rpms, but will continue to idle. Only after giving it gas, and coming to a stop, will it attempt to stall. I managed to get it home on my test drive by switching to neutral and giving it gas while I stopped. I do not know if it happens in neutral. I will test that soon and update.


There is very little electrical components to the van as well. Bare minimum everything and with it stalling, and my own financial situation, currently do not dare to attempt to drive to a mechanic to get any potential codes, if this van even has the computer to give them.

I hope this long explanation has helped, and if anyone has other ideas, I would love to hear them so I can get this "old warhorse" back up and running. I can also take pictures and upload in a day if requested and needed to give people a better idea of what is under the carb.

 

An auto parts store should check for codes free of charge. You can check for vacuum leaks with a spray can of carb cleaner or such that is combustible. Spray it around on the manifold and throttle body with the engine running and if you hear a change in the idle speed you have found your leak. Check all your vacuum lines for cracks and leaks. Might also be a good idea to run some good fuel injector cleaner through it. Chevron Techron is the one I tend to go with. Make it a stronger concentration than what they put on the bottle.

Your engine speed should drop when you put the vehicle in gear. It sounds like yours might be dropping more than it should.

 

I'm not sure if they will scan a pre-OBD-II vehicle.

But he can read codes on his own by doing the key dance: insert the key and turn it on, off, on, off, on, now watch for the CEL to flash the codes. The code will be a series of flashes for the first digit followed by a slight pause then a series of flashes for the second digit. This sequence will repeat for all codes, then the sequence will repeat for a total of 3 times, then stop.

Example: flash, flash, flash, pause, flash, flash, flash, flash, flash=code 35

 

Sorry about that. Wasn't thinking.

 

You have an idle motor not a IAC(idle air control) It is on the drivers side of the throttle body(you don't have a carb). If you take off the air cleaner you can see it adjust the idle speed. Here is a diagram for reference. They call it a ISC(idle speed control) and you have to adjust it after you replace it for the correct idle speed.

 

Thanks for the headsup on the codes, I figured them out.
Codes 23, 33, and 55, with 23 being the only relevant one, as the AC belt is gone and 55 just means end of codes. According to this site https://www.allpar.com/threads/the-1...-codes.229009/ Code 23 is Air temp sensor. Which in the second video I sent, in regards to the fuel injector, that man mentions he actually thought that was the problem and had switched it as well. I have not switched them out yet, but I did run a leak test and nothing sputtered and bubbled up. Hoses still look great, if not a little better since I did do some cleaning on the engine best I could to remove some of that grime. Dish Soap and Water.

I did end up attempting to adjust this a little. Not much seemed to happen, and so I'll need to do more tinkering on this. I've adjusted the Idle on some scooters before and it would always be an immediate change in difference, but obviously this is drastically different. Do you, or anyone else, happen to know where I can find a manual for this engine? It's been a bit of a pain attempting to find the proper information since it seems shortly after this they switched the engine just enough to make it a nuisance. Been looking around, I intend to clean out the EGR out tomorrow if I can find a video to give me a hand on that, along with a change in the fuel filter. I have read that if the fuel filter is clogged it can also cause issues with stalling and then not starting back up.
Thanks
While doing all this, I am also doing a basic tune up with a change in the spark plugs and wires, and hitting the dist cap and rotor on the inside. I don't expect those to actually help with the stalling, but is relatively easy for me to learn and relatively cheap. Thanks for all the advice so far guys and that picture. That was super useful, and again. If someone can link me to a pdf of the booklet so I dont have to rely on what Autozone and O'Reilly think I need. Otherwise I would have bought a valve.

I have 2 days off in a row so hopefully I can get those done tomorrow and give y'all an update.

 

Ight y'all, it has passed the basic test so far. After doing that tune up, and changing out the fuel filter, It ran around the block without stalling when coming to a stop. I can also hardly hear the damn thing until I am actually at a stop. Lord help me if I had the windows up, It would be relatively smooth sailing. I will attempt to make it to work tomorrow and if that works I'll call it a minor success. I'll probably change out the Fuel Injectors and Temp sensor at my own pace now depending on how it feels. Does anyone outside of the Auto shops actually recommend sea foam or not? Help clean out a little more nonsense in the engine or just let it be.

 

Seafoam sure doesn't hurt anything.... don't know if it helps though either....