Need Help

Over the last month the truck has started to stall when stopping at a light.  As the month has gone on, it has started running a bit rougher and stalling more often.  Starts right back up and is not a problem when sitting in neutral or park, just seems to be when under a load.  There has not been anything changed under the hood as for timing, and I have tested the distributor to see if it might of been loose, which it is not, maybe changing timing?  Any ideas of where to start looking first.   In my mind this is the plan of attach that I had.

1)  Pull engine cover off and check plugs and wires
2) check distributor and rotor
3) ?  not sure after

Don't see it as being a fuel issues since it is only happening when it is under load.  Not sure why it would be getting worse as time has been going on.  Truck is not driven often, say once or twice a month.  Did go out and blow carbon out of it last time it was driven.

Any ideas?  Thanks for any help.  Am thinking this will also be a good time to redo all the engine covers with paint and insulation.

Check the points and dwell.Also look at the fuel filter.

I can see the points but not understanding how the fuel filter would play into it. Figured if started for fuel it would happen when launching or all the time. Just seems to happen when stopped and in gear.

heres my thoughts from experience!= try a new float & needle & seat (carb kit!) why??- floats can become soaked with fuel or small hole in it!- allowing float to weigh more & allowing fuel level to rise also = ya its only slight yet will make a problem! you must realize -under a load- air is less= flowing thru carb=velocity! than when in neutral or park. Thats my educated guess -if all other specs have been checked & verified?

Well have covers off and checked the plugs and cap and all looked good. A few plugs over gapped but nothing major. Checked vacuum hoses and all are good and tight. Seemed to run pretty normal when I had it started but truck was not warm, which seems to be when it starts to act up. Oh and points are good also. Any ideas?

I assume its an automatic. If it starts to die can you shift to neutral or park and it stays running?

ok you are saying ="Checked"? get specific! whats dwell set at & crank timing ?? used a vaccumn gauge at all?? Looked into carb throat when this is actually happening?? with a flashlight?? Let us know. 

i'll bet your carb is the problem, may need to rebuild it, like twinpilot said the float could be bad,

Twinpilot001 wrote:ok you are saying ="Checked"? get specific! whats dwell set at & crank timing ?? used a vaccumn gauge at all??  Looked into carb throat when this is actually happening?? with a flashlight?? Let us know. 

well to be specific, I do not have a vacuum gauge, but did look at all the vacuum lines and they are all new and in good shape.  I did look down the carb throat,  not sure what I would be looking for, and this was when it was idling good.  

As for the carb, it was rebuilt in March of 09.  That was when the drivetrain was totally gone through with all new hoses, freeze plugs, fuel lines, new gas tank and sending unit, filters and many other things fixed or replaced. .  That is why I was not figuring a float would be bad, but not real familiar with how often you can get a bad one in a rebuild.  I will put some feeler gauges on the points to see what they are set at as I did not get time to do that.  Did look at the contact areas and they looked like new and figured that since it had been running good till now that they would not of changed unless major wear was showing.  I will check on that one.  How do you check the crank timing?  Timing light??

Ive had brand new rebuilt carbs right out of the box need me to rebuild them again, if all else fails spray it out with carb cleaner, and/or get a rebuild kit. Doesn't take long to do and kits are pretty cheap.

a bit of trash in one of the ports or in the bowl can cause it to run really badly.

Just had a similar problem...ended up being the negative wire at the coil was loose (very loose). I was having hard starting and stalling issues. At higher RPM's it would drive fine, but start to stall at lights when taking off. Runs great now.

Generally if the needle/seat or float were the problem you would gas running or drizzling down the carb throat.
A heat related issue I've had was a bad coil.

A silly thing I ran into once was the screw holding the condenser down was loose,, stumbled like a bad carb. Was on a /6.

Heres just some good advice =as we all just want to see a fellow Vanner get along the roads without any problems. Again -not knocking anyones mechanical abilitys! Many here dont seemingly have an extreme mechanical ability- ie: new Vanners-us old guys have been thru so many problems it isnt funny & really just want to help all!! That being said!= if anyone doesnt have the experience . tools & esp. test equipment for checking specs , dwell of points, Crank timing?? Trust me - its futile! You need a friend, fellow vanner or a experienced mechanic! Yes=we all have to learn too! Yet -what im seeing is most all are guessing at the really odd things that have happened to everyone of us & could be leading another vanner to get very flustrated ! Please get that experienced help - & =learn!! We all have been there one time or another! We are all here to help-just cant teach with a hands on approach over the net.Wish we could!! 

Twinpilot, you and I gotta have a sit down and have a couple beers someday!

Blackace, he's right. I'd also guess an electrical issue is most likely, but if you don't know how to check dwell and timing, it will be hard to explain how to diagnose an intermittent stall issue.

it's a bunch of stuff you can learn, heck WE did and we were doin' stuff back then that was not great for learning and memory! You list your age as 50, so at least you were around back then and know these things didn't die all the time.

Start with the basics; How to do a full tuneup. You have great reference material with manuals and videos. The meters are a lot better too. Then increase that with some electical and fuel diagnostics. Vintage stuff is a lot simplier than newer stuff, but it's old, worn and has been messed with for many years. It's almost always a simple fix, you just gotta know what to look for and how to find it.

I found this series of xideos showing how to test a circuit using the voltage drop method. I've reviewed the first 3 and they are great.
https://www.youtube.com/watch?v=6Sqk_Gai59I

I hope this helps. I'm going to write up a thread on this and put it over in the This Is How It's Done section.

Just a =COUPLE!! ROD????????????? Thanx heeh some day ill be over your way too -count on it!! 

Youtube is just =GREAT!! also the NET for all the google questions - us older types didnt have that when we learned!! had to go by the old garages & gas stations & hand around! wash parts for free & ask questions & learn what we could! Remember there wasnt any epa then & we all did everything with our hands in chemicals you wouldnt even think of today!! GEEZE!! I miss the old days !!    

you got that right TP no computers to see how its done, i spent long hours at a gas station and asked lots of questions, hands on training is the only way,,

Wheelie wrote:I assume its an automatic. If it starts to die can you shift to neutral or park and it stays running?

Yes the truck will stay running if in neutral or park. It is how we keep it running when coming to a stop light or stop sign.

Twinpilot001 wrote:Heres just some good advice =as we all just want to see a fellow Vanner get along the roads without any problems. Again -not knocking anyones mechanical abilitys! Many here dont seemingly have  an extreme mechanical ability- ie: new Vanners-us old guys have been thru  so many problems it isnt funny & really just want to help all!! That being said!=  if anyone doesnt have the experience . tools & esp. test equipment for  checking specs , dwell of points, Crank timing?? Trust me - its futile! You need a friend, fellow vanner or a experienced mechanic! Yes=we all have to learn too! Yet -what im seeing is  most all are guessing at the really odd things that have happened to everyone of us & could be leading another vanner to get very flustrated ! Please get that experienced help - & =learn!! We all have been there  one time or another! We are all here to help-just cant teach with a hands on approach  over the net.Wish we could!! 

Twinpilot, I agree what you said about not being able to teach with a hands on approach over the net, but there is also the ensuring the one persons description or terminology is understood on the readers end. When I asked the questions, I was in my mind trying to figure out how these readings would cause the stalling issues when under a load, stopped and with the engine hot. With the entire driveline gone through, and most new items added at that time, I was trying to question how these items would of changed over the last month to start causing this condition. I have done a good bit of work on these older engines and know how something can be easy and others a real pain in the butt, but figured I would get some key things to look at upfront before going from front to back of the entire thing. I will be taking it out to a mechanic I use to have the dwell checked as I don't have a meter to check that. I hope to get the timing degree checked this next week. I am also in the works of repainting and insulating the engine covers, similar to how Rod did his. I liked how he taped all the edges and kept it all clean. I hope to also paint all the covers to spruce things up a bit.

Thanks for all the different areas to look. I will check to see what a new carb rebuild kit is.

One thing that I just read on the internet is that with an automatic, low transmission fluid might cause the stalling due to a difference in pressure caused by stopping. Not something I would of thought of but will be something that I am going to check as I know it has dripped some when parked. Just not sure if any of you had heard of this and one to keep in the back of the mind when looking for solutions. Will give an update on this next week.

sometimes the solution is so simple, we over look it expecting it to be something hard or involved. Usually when a vehicle dies at a stop sign, it is from low idle speed. The idle screw has a spring on it. Sometimes the spring gets weak and the idle screw backs off a little with vibration. If you can keep he van running by holding the brake peddle and also giving it a little gas, the the problem is just low idle speed. You can also check it with a tach. With auto trans, running in gear it should be about 750 rpm.

I been having this same exact same issue off and on! Sometimes it does it, sometimes it doesnt.
Sign me up.

Thought I would post some pics of the engine since I had the covers off and had not gotten any after the cleanup and recondition.