The 223 inline 6 on my 55 F-100 is giving me fits! Hooked-up a vacuum gauge and at best, only getting 11-12 on the gauge which points to valve timing. Checked for vacuum leaks but could not locate any. Can improper valve timing cause the following idle problem: Despite setting the idle and air/fuel mixture after the engine is warmed-up (which will idle great with no sustained load) when I am cruising for more than 15 minutes and come to a stop, the engine either dies or the idle drops really low to where it's barely running. Sometimes I have to pull the choke out real quick to keep it from dying and sometimes that doesn’t work. When it quits, I have a tough time re-starting. I have the stock distributor vac advance. The carb was just rebuilt, new plastic fuel tank, and new fuel lines. Other than possible valve timing, it may be fuel delivery or float set too high or low however the low idle vacuum reading may be the primary reason. Appreciate any help.
Is your static ignition timing correct? Could the valves be bad? Is it a New carb? Is it a New engine? Sent from my iPhone using Tapatalk
Could be several things, or a combination. Sounds a lot like a vacuum leak. Is the carb throttle shaft worn and have a bunch of slop? Is it the stock carb? Also could be the distributor. Check the vacuum can to see if it works. The dist is totally vacuum controlled and must match the carb. Timing set to spec?
Thanks for the feedback. To answer the questions above: The carb a rebuilt Holley 1904. Best of my knowledge, the timing is correct and the engine is not new. Have not checked the distributor vacuum or run a compression test. I was hoping to find a vacuum leak but spraying carb cleaner in all the suspect areas didn't raise the idle.
Have you checked valve lash unleaded fuel and valve recession will tighten valve lash. Valve lash will decrease as the engine warms up.
No I have not. Honestly, I have never worked with overhead valve engines but fortunately have some local hot rod buddies that have. I will be making a few phone calls. My gut feeling tells me it has something to do with the valves. At least that's what my vacuum gauge is saying . Wish it had a Flathead like my 46 Coupe.
The tank and fuel lines were the first things I replaced 7 years ago. It ran decent with only a few idle situations. Over time, it has gotten progressively worse. I wish I would have taken vacuum readings back then so I would have something to compare to. The thing that's puzzling me the most is that when I start cold and into warm-up, I get a decent idle with no indication of dying-out or stalling after revving the engine several times to simulate a load. It's only after taking it out and driving that I experience the lousy performance. I forgot to mention but also experience backfiring or pop noise coming from the exhaust. I am beginning to wonder if the mechanical pump looses its prime has everything heats-up.
Check the valve lash. When it's set right move on to the timing and carb adjustments. Make sure the vacuum can on the distributor is functioning, or you will have very little to no spark advance. -Dave
Cylinder compression test is first tune up check to see what you're dealing with. Does a '55 have solid lifters? Tight valve lash will mean leaky valves (low vacuum, low compression).
Several ways. With it not running, pull off the vacuum hose going out of it and see if you hear vacuum escape. You can put a hose on the intake side and see if you can suck on it until it stops or just keeps sucking air. You can use a hand vacuum pump if you have one to do the same thing. It should hold a vacuum at the can Sent from my iPhone using Tapatalk
With the engine off I'd apply vacuum to the distributor with a handheld Mityvac or something similar. Then watch the linkage on the other side of the can to see if it moves. All 215, 223 & 262 had solid lifters and none had mechanical advance in the distributor from the factory. -Dave
Going out on a limb, with a story. Clogged muffler. I had the same symptoms with a 64 Ambassador. The straight 6 would idle great, rev up great and lose it all under a load in about 5 miles. I tried everything. Finally, real pissed, I held the pedal to the floor. "I'm gonna blow this sucker and get another car". The car lifted when the muffler exploded. A big black cloud covered the yard and the wife came out expecting the worst. After a glasspack repair, it ran great for another 15 years. Sounded better too. Maybe its pushing too hard. .02
Appreciate all the feedback. Since I just got the carb back from a rebuild, I went ahead and opened the steel bowl and sure enough, the float was really set high which made me start thinking that maybe some of the fuel may be spilling over into the manifold when I come to a stop. So, I lowered the float to where the fuel line is just above the square on my glass bowl. Since my original glass bowl has a tiny chip on the top right corner, I went ahead and installed it. So far, no leaks. I will take it out tomorrow and see what happens. I know this is a real long shot but you never know till you try.
I tried the hose test and after 3 seconds the plate started to slip back slowly. I think the can is not holding vacuum. I ordered a replacement from Rock Auto.
is the vacuum decent when you first start it and slowly drops? If so plugged exhaust would do this,and not just the muffler, some Ford head pipes were double wall and the inner pipe collapses.
I'm pretty certain it is occurring was the engine is good and warm. On initial start-up and as it gradually warms-up, I get a decent idle however....after 20 minutes of driving and then coming to a stop, the motor either stalls or the idle rpms drop really low which could be related to this problem. I could be wrong but it was clear from my test suggested above that the advance canister is not holding vacuum.
I had similar fits with my 223 last fall. I rebuilt the carb, did plugs, wires, coil etc. I had a cheap electric fuel pump and the stock Load-O-Matic distributor which are VERY sensitive to minor vacuum changes according to my reseach at the time. After countless hours of work, a bunch of money spent, and months of staring at a barely functioning vehicle I re-replaced the condenser. Just like that she ran like a dream. Your issues sound different than mine for sure, but my lesson was to not forget the basics. I also learned that ignition and carb problems really like to hide behind very similar symptoms.
Idiot condenser. I had one that was just hanging on at the can by a strand or two. Brushed it by chance and replaced it. Problem solved. Those glass bowl Holleys are cool. I picked one up as a package with a 223 for $15.00 additional.
Ok you get a compression guage. with all spark plugs removed and the throttle wide open. you check to see if every cyl has the same reading. Check again with a few squirts of oil in the cyls to determine if the piston and rings are bad. And since you already have the spark plugs removed grab a hold of the front crankshaft pulley and turn it back and forth. you will be able to determine when the valve train starts to move. and thus determine if the timing chain is worn out.
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