84 E350 ignition question

Reply Subscribe

Thread Tools

Search this Thread

Feb 7, 2012 | 08:07 PM

cchrrice

Thread Starter

New User

Joined: Feb 2012

Posts: 19

Likes: 0

84 E350 ignition question

I posted about fuel pump problem the other day and I appreciate everyone's help. I was able to get the rv running by running a hot wire to the rear tank. Drove it 80 miles and it started acting up and ran another 10 at about 35 miles and hour. It has no power but it is getting fuel. It will rough idle but has no power. It will hardly pull and will not go up any grade. I started pulling spark plug wires and found the wires were sparking from a screw driver to the plugs, but when you pull the wires there is almost no difference on nearly all the plugs. Only a few seem to actually be firing so I changed the plugs with no results. What else could be wrong? By the way I took the control module to autozone and had them test it 20 times before I drove it the first time. I don't know if that matters or not. This thing is driving me crazy. I need to get it up a small mountain and 10 more miles and then I can do anything and all to it. I just need to get it home. Please help!

Feb 7, 2012 | 08:50 PM

ctubutis

Moderator

Joined: Nov 2007

Posts: 22,415

Likes: 92

From: Denver Metro Area, CO

It's getting fuel, but is it getting sufficient fuel? Have you tested pressure & output rate at the engine?

1984 E350, I'm guessing you have a Duraspark ignition and not computer-controlled, correct?

Feb 7, 2012 | 08:54 PM

cchrrice

Thread Starter

New User

Joined: Feb 2012

Posts: 19

Likes: 0

It is a duraspark and no I haven't tested anything because it is on the side of the road. I did hook up an aftermarket universal fuel pump from a 2.5 gallon gas can instead of the fuel tank and it still does the same thing.

Feb 7, 2012 | 09:03 PM

Gary Lewis

FTE Legend

Joined: Jul 2010

Posts: 32,875

Likes: 48

From: Northeast, OK

Kinda sounds like the choke is on. Is it belching black smoke? Have you checked the choke?

Another potential problem that could cause it to be rich is a blown power valve. I don't know what carb you have, but the Autolites and Holleys have power valves that can be blown fairly easily by a backfire. Has it backfired?

And, if it is running really rich then pulling vacuum lines to let more air in should make the idle smooth out and/or speed up. Have you tried that?

Feb 7, 2012 | 10:16 PM

cchrrice

Thread Starter

New User

Joined: Feb 2012

Posts: 19

Likes: 0

The choke is not stuck, but I did notice what I thought was an exhaust leak is a metal triangle or diamond shaped plate with a metal tube running through it up from the intake manifold to the carb behind the electric choke. The rivets in the plate have come loose. When the truck is running it does have some thick black smoke at least for a while coming out the exhaust. The battery is dead so I brought it home to charge so I could not check the vacuum lines but I will tomorrow. Just for thought this thing is a 460 cu. inch engine with a motorcraft holley 4 barrel carb. It has the duraspark ignition with the wide cap distributor. Before I drove it home I removed the front bowl on the carb and checked the internal filter, cleaned everything with carb cleaner, replaced the power valve and needle and seat. And like I said before it ran great for 80 miles.

Feb 7, 2012 | 10:27 PM

Gary Lewis

FTE Legend

Joined: Jul 2010

Posts: 32,875

Likes: 48

From: Northeast, OK

The plate sounds like the stove for a hot-air choke. I don't know that carb nor engine, but a lot of the Fords had a tube that came from the air horn of the carb, through a well in the intake manifold right above the exhaust crossover, and then up into the choke housing. That heated the choke's bi-metallic spring when the engine ran and caused the choke to go off. If that isn't working properly you may not be getting enough heat to pull the choke off - I had it happen last week in fact.

Some of the Autolite carbs use an elastomeric poppet valve in the accelerator pump, and I can assure you that material does not like carb cleaner. Again, I don't know about that carb, but if you sprayed carb cleaner on everything you may have done some damage. And, when I did it the little valve didn't immediately fall apart. In fact, it might have gone 80 miles. I'd pull the bowl again and check things out. That thick black smoke says it is running very rich for some reason.

Feb 8, 2012 | 08:53 PM

cchrrice

Thread Starter

New User

Joined: Feb 2012

Posts: 19

Likes: 0

Removed the front bowl and replaced power valve. Checked everything out and reset float. Everything there seems to be right. I ran a holley on my mustangs back in the day, so I am very familiar with them. I agree that the fuel is not being burned, but I am not convinced it is because there is too much fuel. I think it is still a possibility the ignition is not working correctly. I had it pulled up to a shop today. I will let you know what they say.