1985 Econoline hesitation

I have a conversion van that I use for parts chasing and towing. It is a 302 carb. Last year for carb as far as I know. It has developed a stumble or hesitation when it is warmed up.

I can't figure out how to fix it. It has new plugs wires and cap. I can't find any vacuum leaks. The engine has high miles but is tight. The info that I have read says to adjust the mixture screws or check the vacuum advance. This truck has neither thing on it. The engine is covered in little black boxes with wiring and vacuum hoses that go all over the place. The carb has all kinds of gadgets on it.

I have never messed with it because it has always ran good up to now. Anybody here ever deal with this setup?

i can't remember what those carbs were called, but i do remember people having a lot of problems with them. if all the vacuum hoses are hooked up and in good shape, then maybe pull the carb and put a rebuild kit and float in it.

302 should not have the variable venturi carb, so you are just stuck with fighting a computer controlled carburetor. 2bbl Motorcraft carbs are the kindergarden toy of overhauls, and they are prone to leaking power valves. That will give you a rich mixture at light throttle. Modern semi burnable gas-like swill has less fire in it than back in the olden days. I have fixed a number of older vehicles with bigger main jets, if its lean.

Check all the vacuum hoses and repair all the split ones. Make sure the EGR valve is not opening too much- it probably has a pressure feedback built into it, and may be opening too much at part throttle. If you unplug it and the problem goes away, buy a new egr valve. While you are there, make sure it hasn't burnt out the aluminum egr plate under tha carb.

If all that fails, set it on fire, take the insurance money and buy an injected van.

Not intended to endorse arson or insurance fraud.

In reply to Streetwiseguy:

It is definitely not a variable venturi carb.I had an LTD with one of those. Can I just leave the EGR unplugged if it makes the problem go away?

variable venturi- that's the name of the carb i couldn't remember. i swear one of my friends' family had a 302 powered LTD that had one of those carbs on it when i was a kid..

I had an '88 cop car with a 351 and VV carb.

It might be possible.

Shawn

KevinC wrote: In reply to Streetwiseguy: It is definitely not a variable venturi carb.I had an LTD with one of those. Can I just leave the EGR unplugged if it makes the problem go away?

Not a great idea on an old Ford, since they rely heavily on egr for detonation prevention. Thats not to say there isn't a whole lot of them missing.

In reply to Streetwiseguy:

I unplugged the electrical connector on the EGR but it didn't change anything. The bog is still there when pressing the throttle off idle. I can turn the idle higher and the bog decreases. Runs real good other than that.

In reply to KevinC:

If the problem started without you touching it . . . (sounds like) then I bet an adjustment won't help. IMO, the stumble is a "lean off idle" condition - possilbly dirt in the accel pump circuit - or the accel pump developed a hole.

That's my guess, and I'm locking it in!

Good luck!

In reply to DavidinDurango:

I like your suggestion. I have ordered an accelerator pump diaphragm for it. It's worth $15 bucks to see what that does before I tear into the carb.

In reply to KevinC:

atta boy. it doesn't take much "dirt" in a Holley to ruin the day.

In reply to KevinC:

Also: check the FAQ at holley.com. My latest carb has a "2" hole that moves the accelerator pump cam to give a little more juice. You might take the squirters out and run something (gas or wd-40) through - maybe you can get some dirt out. (don't expect to see anything)

Hope you get some happiness for your time.

Doesn't take much of anything to do in a Holley. Blown power valves from a backfire can cause a lot of grief that can be hard to find. I really haven't missed carbs much since EFI became so common.

In reply to DavidinDurango:

I got my happiness. Changing out the accelerator pump diaphragm solved the hesitation problem. I contorted myself enough to change it out under the van's cowl without removing the carb. Thanks for all suggestions. I always find the answer to my problems on this site.