Engine stubbles at idle speed

[Gjac]

The MH in my signature has become Ihard to start and falls flat when I give it the gas. The problem seams to be progressing. Changed fuel filter before trip, ran can of seaform. Still does it when it's hot. Runs normal once im driving.

[wildmanbaker]

You should not see more than 300 ohms on any wires. Lightly pull and twist the wires as testing them, as their may be bad areas on the inside. Bad wires usually do not show up at idle, as it only takes about 5,000 volts to fire the plugs. As loads increase, it will take more voltage to jump the gap, and that is when bad wires show up. Has anyone put a timing light on it? IS the timing jumping back and forth more than 5 degrees? Check slop in the timing chain by turning the engine forward until you see the rotor start to move, then turn the engine backwards until you see the rotor move the other direction. If it takes more than 10 Degrees of movement at the crank pulley, it may be the timing chain has jumped a tooth. Keep plugging, and let us know what turns up.

[azrving]

Gjac wrote:

rjxj wrote:

enblethen wrote:
Without hearing it, the plug wires depending on composition could have burnt open or nearly open and not have insulation failure.

That too. Get out an ohm meter and possibly not waste parts.

what should wires ohm out to?

No idea. If in a walmart parking lot I'd mainly look for big differences in valves between wires.

[Gjac]

rjxj wrote:

enblethen wrote:
Without hearing it, the plug wires depending on composition could have burnt open or nearly open and not have insulation failure.

That too. Get out an ohm meter and possibly not waste parts.

what should wires ohm out to?

[Gjac]

jwoods61us wrote:
OP, did you try the old method of a can of carb/TB cleaner, spraying everything? The reason I say this is your issue is if I read your original post correctly, with the idle circuit; there is a pin hole in the TB that sometimes starts to gum up and restricts airflow causing the idle air solenoid to work harder and the idle to degrade. Spray liberally while engine is off, then restart (sometimes a hard start) and see if it goes away. Possibly a $5 fix.

. I ran a can of seafoam through TBI before the trip. Is that pin hole about 1/16 of an in just above the throttle plate? If so I stuck a small wire in there to insure that it was not clogged.

[jwoods61us]

OP, did you try the old method of a can of carb/TB cleaner, spraying everything? The reason I say this is your issue is if I read your original post correctly, with the idle circuit; there is a pin hole in the TB that sometimes starts to gum up and restricts airflow causing the idle air solenoid to work harder and the idle to degrade. Spray liberally while engine is off, then restart (sometimes a hard start) and see if it goes away. Possibly a $5 fix.

[azrving]

enblethen wrote:
Without hearing it, the plug wires depending on composition could have burnt open or nearly open and not have insulation failure.

That too. Get out an ohm meter and possibly not waste parts.

[enblethen]

Without hearing it, the plug wires depending on composition could have burnt open or nearly open and not have insulation failure.

[azrving]

Spray the wires down with a water spray bottle. Look at them for arcing in the dark. Don't get knocked on yer fanny.......

[Gjac]

Walt,Bud at this point after checking sensors and replacing things it could be distributor or wires I could not feel any play in distributer shaft itself but about .020 play in the bronze rulucter. I don't no how else the check the distributor.

[enblethen]

Had a brain fart middle of the night after more discussion on phone and text!Slowly getting worse does sound now like plug wires.
Testing does not show codes or problem with sensors.

[wrgrs50s]

Please post the results from the shop. I'm guessing distributor related.

[Gjac]

Called Rays RV in Spokane he could not take me in until a week. I want to thank Bud emblethn he found a shop in Moses Lake where he lives that can take me in tomorrow If I can make it there the engine is now running rough at high rpms. I am very great full to be able to to take it somewhere. Thanks to all who have responded will possible solutions . It is very stressful trying to diagnose problems on the road much easier in your driveway at home.

[Gjac]

Went to oriellys and they tested the pickup coil inside the distributer and it showed bad I replaced it and the coil and the problems still there. I give up and need to take it somewhere.

[Gjac]

wildmanbaker wrote:
I may be miss remembering, but isn't there some small screens in the TB before the injectors, or on the inlet to the spraybars? One of these may have something in them causing the problems. All of the replies are plausible. This really a problem when out on the road. Remember, think electrical first, then fuel.

. Where are the spay bars? I don't see any screens on top of injectors.

[Gjac]

DryCreek wrote:
Just a wild guess on my part, but the OP did mention a *full tank*. Did the problems start shortly after topping off the tank?

Bad gas?

. The problem did not start all at once after getting gas it has progressively gotten worse. It started as 2 cranks to get it started then 3 then giving it some gas to start. I changed fuel filter again this morning but still same problem. Old filter that was changed last mo had some black stuff but not enough to stop gas flow. It seems like a electrical issue like a failing coil or or something in the distributor like a reluctor or pickup coil. Any way to check these?