Allrighty,
Thought Id pick your guys brains a bit...so my 73 had been giving me problems recently and it seems as if they are still there. I just replaced the points...the carb....and even re timed it and it still feels like it wants to die when I step on the gas....it will idle fine and drive fine at under 20 mph but if I try to put my foot in it...she feels like shes only firing on a couple cylinders.

Any ideas as to why this is still an issue? Ive pulled the plugs and they look fine...no build up or corosion..look like the day I put them in there and my PCV is still functioning normally.

At this point the only thing I can think of is if the kick down switch has somehow gotten stuck...but the actuator seems to be moving regularly. Or possibly some kind of charging issue?

Any ideas or help bouncing them around would be greatly appreciated as Im about fresh out of ideas and patience.
-Chris

 

360/390 with a 2v carb? Replace the accelerator pump diaphram and check valve. Is there a fuel filter in the pump? Look at the pump, is there a tomato juice sized can on it? If so, there's a fuel filter inside, and prolly hasn't been changed in years. Could be carbon buildup in the EGR valve if you have one.


D5AZ-9B559-A .. Acc Pump Diaphram (Motorcraft CM-2092)

C4AZ-9576-A .. Check Valve (Motorcraft CM-825)

C4AZ-9365-A .. Fuel Filter (Motorcraft FG-1-A)


Kickdown switch? Nope, and it's not a charging problem either. Prolly fuel related...starving for gas is what I suspect. Other possibilities are besides fuel filter, is the in-tank plastic mesh filter screen, it slides over the end of the pickup tube.

 

A few other thoughts.

Check for vacuum leaks. They can rob you of all kinds of power.

Distributor cap in good shape?

Since you replaced the carb, did you replace the fuel filter as NumberDummy mentioned?

Is the timing chain in good shape/position?

 

I agree with Bill, it sounds like a fuel pressure problem. I would check to make sure that you have at least 6-7 pounds at the carb. Good luck.

 

73F350sc got the carb from me. I bought it remanned and ran it on my 360, and it had like 800 or less miles under it's belt. I even slapped it on my 400 for a minute when I was seeing if the old carb was shot, and it ran that motor really well too (360 had a PCV spacer, and the 400 carb had a PCV port in the back of it, so I couldn't keep it on). It'd been sitting in a box wrapped in bubble wrap until he came and picked it up.
Just trying to give you all some info on the carb.

 

Ya,
Ive been thinkin that its the fuel filter too as of late...I replaced and the fuel pump last time things were goin sour on it about 2yrs ago....the truck isnt run everyday so Im wondering if something hasnt clogged it up a bit. Thats also when I ditched the EGR in favor of just a spacer.

Taylor...believe me...the carb is awesome on it...I noticed an immediate imporvement over the old and was in the process of dialin everything in when it started actin up again.

Thank you all for your help and Ill let ya know if I manage to track it down...in the mean time if theres any other ideas...keep em comin...I can use all of em I can get.
-Chris

 

Hey Chris,
I ran the same gauntlet of troubleshooting recently on my 302 which was having the same problems, fine up to around 20MPH but put your foot in it and it started skipping and other assorted ruff running. Same problem if you ease it up to 60 then go for a little more.

Went thru the carb, fuel pump, fuel filters, finaly a pressure test at speed. fuel was fine. Checked compression, fine. Went thru air and EGR, good as gold. Vacuum, fine. Timing, then new timing chain, then new distributor, then new spark plugs. Plenty of spark at idle. New Duraspark (mine was a 1979 but you paralleled me in your 1973 with the new points).

I mean some of those things did need attention and would improve it a little but still the same old dropping off when you hit the gas to accelerate or roll up over 65.

Finally after spending all the dog's food money for the month on all that stuff, I replaced the "fairly new" spark plug wires with some "brand new" wires. Problem solved for under $25!

I wasn't mad but the dog sure was! Maybe check those plug wires on your FE for similar results?

 

also, check to see if the vaccuum advance is working on the distributor.

 

So heres an update,
As of earlier today I now have replaced the distibutor ( Ill relate why in a second)...the spark plug wires... after coming to about the same conslusion as Mikestrucks... rotor and cap and fuel filter and am happy to report that I seem to have it almost nailed down.

I didnt want to shotgun it with parts but after careful examination of the old dizzy and removal of some sludge on the gear at the bottom of the shaft...I noticed that one of the set screws that held said gear in place was suddenly MIA. Heaven only knows if it was the original dizzy...could very well have been.

So that being said I believe that the reason I would get it going one day...shut it off then be back at sqaure one the next was due to the fact that the gear was most likely allowing for a ton of wandering to happen....essentially throwing my afternoon of re timing off each time...by one tooth in either direction.

Once I get things fine tuned in the idle department...Ill most likely end up dropping the oil pan for one of two reasons...firstly...to find whats left of the set screw...and secondly because while working on turning the crank by hand I noticed that I could use a new one.

So it seems as if I gotten it squared away for now....the real test will come in the AM when I go to fire her up again.

One more question for you guys.... my old carb was equipped with the PCV fitting and the carb that I purchased from Taylor used the spacer...is it possible to run sans PCV and use just a breather in place? Smog police arent an issue seeing as it is exempt from testing where I am....I realize that there can be issues with not having one...but shouldnt it be ok as long as the pressure can vent?
-Chris
PS sorry for the oober long reply but I thought you guys could use the whole story to help get an idea of whats goin on. Oh and also on the replacement list are the power steering and alternator belts as those had begun to fall apart after a few months of only intermittant starting

 

Sorry I never replied to this thread.

One thing I mention on old worn engines is to check the distributor shaft for being worn out and and having an eliptical orbit causing spark related problems.

It happens a lot with old dizzy's.

No set screws on a dist shaft.

They is a shear roll pin though.

 

I wouldn't recommend the breather route, the vapors will still build up and find their way out through the valve cover gaskets, then your motor usually starts pissing oil out all over itself.

I'm doing a junkyard run this week, I'll keep my eyes open for a replacement spacer. If mine hadn't left with the old truck carcass, I'd still be using that carb myself.

 

for the pcv to work all you need is the right sized vacume port. it does not have to be under or in the carb. some of them were screwed into the manifold simmilar to the brakes. I would defenatly not go with the breather instead of the pcv

 

Now I find this out!

 

Yup Dennis...that little bugger was MIA.... my gear would turn nearly a 1/4 turn round the dizzy shaft by hand haha. Right now Im still tryin to work out the fine tuning as she seems to have a bit of "indigestion" after I shut her off with a couple burps and a not so lady like but shotgun like toot from her exhaust.

Its an issue that I think will only be resolved with the timing light...but so far Ive gotten her up and about again just by ear alone....fairly easy seeing as shes has a distinctive exhaust note. If I dont get it dialed in the rest of the way by ear or by light I think I'll double check the point gap on the new dizzy that was supposedly set already...never hurts to be sure right?

On another note...I piped the PCV into a handy little vaccum port on the backside of the carb that I would have otherwise capped off...so far it seems to be doing ok...but I may change that seeing as its a bit smaller opening and I dont want to restrict flow.
-Chris