The Stovebolt Site Forums The Shop Area General Truck Talk 235 missing at high rpm dying at idle

1954 235 Engine problem with engine, It starts right up no problem starting. missing at higher rpm and when idling after 30 to seconds it just dies. It feels like something is just shut off. Changed spark plugs and fuel filter no change. Looked at distributor cap and rotor all look ok.
points ? condensor ? coil ? carburetor ?
I have had this truck for 40 + years, first time a problem like this.
Any suggestions what I might do ?????
Richard (3800rao)

Dying at idle sounds like a fuel pump problem. Could it also be starving for fuel at higher RPM? I'd get a new fuel pump.

Trash in the tank.🛠

A fuel pressure gauge teed into the carb inlet would help sort it out.

With symptoms like those, you can throw parts at it until you run out of parts to throw.
When it "dies", does it shut right off like someone turned off the key, or sputters like you ran the tank dry?
Pull the park plugs and describe what they look like. They often tell you the story.
As soon as it dies, check to see if you have a decent spark by having an acquaintance hold the removed spark plug against a good ground while you engage the starter. This will let you know if the problem is electrical.

It shuts right off, spark plugs were a little dark. Tomorrow I will check fuel pressure and carb for dirt.

I just read the thread and I like where 52Carl is asking about spark.
Coils are very notoriously unreliable and can puke without notice or visible signs. If you are without spark, I'd swap coil for one that you know works. If coil is deemed good, then I would replace the points. Had a new set of points puke recently and chased my tail for a bit trying to figure that one out! New plugs have been known to be crap too... brand can make a difference. Don't rule out plug wires either.... Condensor failure burns the points....are they burnt?

In short, I would not bother with fuel, supply or carb at this point... I'd chase spark. If you determine your spark is good beyond all doubt, then chase fuel.

These old girls are pretty simple.. compression, (timed) spark and fuel is all you need as I know you know... good luck with it, keep us posted on your solution when you find it.

Just a thought , check for vacuum leaks if applicable.

Has the engine repeated the behavior of, "It starts right up no problem starting. missing at higher rpm and when idling after 30 to seconds it just dies," on several attempts?

If so, If it "shuts right off", then you need to check for spark at a spark plug as soon as it dies as I suggested earlier.
You can skip this step and dig into the fuel system if you fancy chasing your own tail. Personally I prefer to check the easiest probable causes before I proceed to the more difficult ones (like the fuel system).
With as many years I have been troubleshooting internal combustion engines, I have come up with my personal mantra which is, "Always save the carburetor for last. It is never the carburetor."
Now having said that, sometimes it has been the carburetor, but if you follow this advice, you won't waste time troubleshooting a perfectly good, more difficult to diagnose fuel system.
Good luck,
Carl

Seen lots of coils acting like that, They start breaking down and become intermittent. Doesn't sound like fuel to me. I agree with Carl.

How old is your fuel in the truck? Old fuel can do just what you are talking about, especially if you have to keep it choked to keep it running.

Could also be a bad ignition wire going from the battery to the ignition switch or from the ignition switch to the coil. A quick check is to use a jumper wire from the positive side of the battery to the positive side of the coil, start the engine up. You'll have to disconnect the jumper to shut the engine off.

Rick

Thank you all for the suggestions. Yesterday (at the suggestion of local auto mechanic) I pulled all spark plug wires and coil wires, checked all for good crimps and condition of the wires and tested coil, all checked out OK. Them on the distributor checked points cleaned up contacts and checked gap. Reassembled all and started up motor an so far it is running great. No cutting out at idle. I wish I knew what the problem was. ?????????????? This next weekend I will be taking trucks on a job. I will report back if the problem starts again.

I have a 235 and found the ideas here a good reminder, I just started it up after full rebuild by yours truly (licensed engine mechanic) and so far so good. One lesson I learned as an apprentice in an engine shop was from the foreman who reminded me not to believe that brand new out of the box was correct. So it was burned into my head never to assume, he had a favourite saying he would share with people. 'if you found a French safe in an apple box would you eat it?' and if he found you later assuming something his remark was 'so you like the taste of rubber', thought I would share that. We had an engine on the dyno that overheated within the first couple of minutes, after a few checks the foreman asked for the water pump to be taken off, brand new out of the box and it came with no impeller, so who wants to develop a taste for rubber

Very likely you just had dirty points. Your symptoms fit the bill for dirty points. I have had your very same problem on more than one occasion and it was due to dirty points. This happens a lot with an engine that has sat for extended periods.

Thanks for the update! Happy to see you got it fixed!
I agree with 52Carl that cleaning the points was likely your cure.

I just went back to read this entire thread and it made me go through the process which I always do when I have an engine issue.
Check the things which are easiest to check first. In this case, the first thing I would have done would have been to remove the distributor cap, spin the engine until the points close, turn the ignition on, and manually open and close the points and look at the quality of the spark. The reason why I would have gone straight to this is because I have had this be the problem a number of times in the past.
Other easy checks which I try to do initially are:
Spark plugs. Easy to do, and they will tell you a story.
Voltage at coil with ignition on. (Only if no spark after cleaning points.)
You can check ohms through the coil. It might not tell you much definitively, but a burned up one should show itself. One which only pukes when hot may not show up as bad with an ohms test.
Next I would check to see if you have gas making its way to the fuel pump by loosening up the fuel line there.
Then I would do a fuel pump test by removing the line from the carburetor and turn the engine over with the starter (ignition off) with the spark plugs still out from your spark plug examination. Let it squirt into a container.
Then I would move on to a compression test. Spark plugs are still out, right?
Last thing to do is the carburetor. Why? because it is the most difficult of the tests so far, and it is seldom ever the carburetor. The other reason is because you may be having more than one issue going on at the same time and you do not want to mess with the carburetor until you have tested all of the easier items.
Carl