I've had my '84 B250 6 cyl parked for about a month and now it is not happy.

When it started the engine yesterday it had a very severe stutter where it felt as if the engine was cutting out for a fraction of a second every second or two. Pressing down on the accelerator just made the engine rev up more between cut outs. It did this once before last year, but it was on an incredibly cold day (-10f or so) and went away once it warmed up so I assumed it was a temperature issue at the time.

This time, after it warmed up it still had the same problem. But after reving it a few times it backfired and a nice puff of black smoke and charred bits flew out of the exhaust pipe. The engine stalled at that point, but after starting again everything was working fine. In fact it seemed to have more power than it did the last time I drove it.

When I went to move it into the garage today to work on it, it's having the same issue right after starting.


So far guesses are that the catalytic converter is having issues or that an animal had taken up residence in the exhaust system. Most of that stuff is welded together so I am looking for more opinions before I pull stuff apart. Repair manual isn't a big help as it says to take it to a shop for issues with the converter.

first of all you have to sit there and talk to your car. tell it the your sorry but the new charger is your new baby. lol just playing...

all i can say is to check catalytic convertor or check if its getting enough fuel.

Forgot to mention...

I did pull the engine cover and air filter off and I can hear the fuel spraying in even when the engine is cutting out, so I didn't think that it would be a fuel issue.

Forgot to mention...

I did pull the engine cover and air filter off and I can hear the fuel spraying in even when the engine is cutting out, so I didn't think that it would be a fuel issue.

now that i remember my friend had the same problem too. even though you can hear the fuel spraying, it doesn't mean is good. it can be that its over filling and making it backfire or/and that the TPS is bad. ether way just check it just to make sure.

What is TPS? I'm not familiar with that acronym.

So far guesses are that the catalytic converter is having issues

Just so you don't have to start cutting the exhaust apart, disconnect the Y-pipe from both exhaust manifolds and move the pipe away a bit. Then take a larger shop-vac setup on blow, or use a leaf blower, and push as much air into the tailpipe at the back of the van as you can. If the cat is clogged at all you will get a whole lotta' black stuff blowing out the y-pipe ends. If you do bolt the exhaust back up, then test drive it and see if you're all set.

What is TPS?

Throttle
Position
Sensor

It's on the throttle body, opposite the side with the throttle cable and has a 3-wire connector.

Discovered that the Shop-vac is next on the repair list.

Instead I just pulled the converter away from the engine to just let it vent straight out to avoid the exhaust system entirely. Still having the same issue. Testing that sensor is next, just need to figure out who borrowed my multi-meter.

After an adventure in getting my meter back and then getting a new battery since that ran away too, I went to check the TPS.

I don't seem to have one. The only wires go to the throttle stop solenoid. Is there another system that would take the place of it on an 84'?



As far as checking if there is enough fuel flow, how is that determined? I can see/hear the fuel spraying in, but I'm not sure how to know if it's "enough" or too much.

Also, here's an awful video I made to give a better idea of the cycle it's doing. Unfortunately the mic on that camera is awful.

http://www.youtube.com/watch?v=YYHMsw65zAE

I went to check the TPS.

I don't seem to have one.

You have a carburetor???

You have a carburetor???

A Holley 1945 if that helps anything.

Ah okay then, I though 82 on up had injection. Then based on the symptoms you've posted, it sounds like either your carb float is set incorrectly or you have a clogged catalytic converter.

A magic day so far...

Poked around at it some this morning and it was still being weird. Did some searches online to find a gasket to replace the old one after pulling it apart as well as looking up float prices in case the float sprung a leak.

Went outside later to move the van to the garage and it started right up with no problems. Drove around just fine for 15 minutes or so. If it is the float, maybe it's just getting stuck?

Also thinking about just sinking the $10-13 in to get a new float if I'm opening it up anyway. The old one was a black plastic thing that was pretty discolored compared to the images I'm seeing for new ones.

have you looked at the distributor cap/rotor? it sounds electricial to me,maybe the
cap got moisture in it,loose wire. did you check each cylinder for firing?(pull plug wire)

The float itself isn't really what gets stuck, it's the float needle that does. Sometimes the seal also gets worn and fuel will bypass it and overfill the bowl even though the float is trying to stop the flow of fuel. If you do get a new float, I would also get a carb kit then clean and rebuild the carb while you're in there.

Running fine again today :/

I did a rebuild on the carb about 10 months ago, so the seals should be ok unless I screwed something up.

I really wish the carb had a little window in it like my brother's old Toyota to know for sure if it was too much fuel in there. It had a problem with the needle, but all it needed to fix it was a couple sharp blows with a mallet to the right spot. Symptoms were a bit different though, it just wouldn't run at all.


have you looked at the distributor cap/rotor? it sounds electricial to me,maybe the
cap got moisture in it,loose wire. did you check each cylinder for firing?(pull plug wire)

I did pop that open, didn't see anything weird or discolored.

Also pulled the plug wires one by one, but the engine was running so roughly it was hard to tell on a couple of them, but it seemed like it was different each time..