1996 Ford F250 460 E4OD Problems

[erratic50]

We recently bought a 1996 F250 with a 460 and E4OD.

The truck came from an older gentleman in western Iowa in the Council Bluffs area. It was bought new to pull a gooseneck camper but it hasn’t seen one behind it in a very long time. It hasnt been driven much in a while either.

the PO said it has fresh new plugs, a new distributor cap, and rotor. Looking them over it appears to be true

We noticed when we switched from the front to the rear tank on the test drive that it stunk of old gas being burned but the truck ran good on the test drive on both tanks, etc. No stumbles or lack of power, etc.

Brought the truck home and added Seafoam to the engine oil and front tank to start cleaning stuff up with it. within 150 miles it has started acting up. Once the front tank was mostly gone and we switched to the rear, almost immediately, no power, etc. when you get to more than about 1/3 throttle the truck would pop out the intake tract and sputters and doesn’t make any power.

My son was driving it and said it really honestly just wouldn’t get out of its own damn way. It wouldn’t go up hills, etc. He filled the front tank with fresh fuel and it didn’t make much difference at all.

When I drove it again the truck acted like there’s no advance on the base timing and no advance on the spark map.

After fiddling we found a loose timing advance stub over by the ignition module.

After checking things with a timing light it appeares sonewhwre along the way some idiot timed it without pulling the advance first. It was 10 with the stub and ran like crap.

The moment I pulled the advance it was at about 4 degrees BTDC on the timing light. I set the advance properly with the spout removed but dialed it up to 12 degrees BTDC and put the stub back it. Timing jumped up with the spout in like it should and it goes up as you rev it.

By comparing to how the mustangs add timing with the spout out and also looking at the 460 I discovered timing wasn’t climbing any faster on advance with the spout vs without on the 460. We were just seeing more base advance but then nothing more than mechanical. Stick electronic advance? Maybe

I hooked up a volt meter and the TPS was all over the place. Flat spots, etc.

I added a new TPS which it obviously needed and it helped but it didn’t cure the run problems. Timing was still mia.

This is when I figured out things look corroded in the distributor and the dizzy was getting stuck as advance was being called for so it wasn’t moving.

it ran better but NOTHING like a truck with a 460 should. An inline 6 would pass this truckblike it’s tied to a stump.

I bought a new distributor for it and installed it earlier today. Still It doesn’t run how a 7.5L should at all on either tank.

I know we need to solve the problem with bad fuel in the rear tank but that doesn’t explain the crappy performance with the fresh fuel in the front tank

Where I’m at with it is finish doing routine maintenance things for starters.

Treat and burn the bad gas in the rear tank or get it out of the tank
change the fuel filters
Service the transmission fluid and filter
Service the cooling system
change oil

I’m grasping at straws and don’t know where to go next for sure.

It doesn’t show any codes and the check engine is not on

the truck is an EEC-IV with Speed Density EFI.

it runs about like the map has had a diaphragm fail but that should show codes

i plan to inspect looking for broken vacuum lines, or a MIA line by the map sensor, etc.

also measure fuel pressure too

If this comes up with nothing I’ll drop the tanks and check the fuel pumps and socks and pump to hanger rubber hose, etc.

not opposed to throwing an ECU at the problem if there aren’t ways to rule it out

I am looking for additional ideas

The truck did get nearly 18 MPG being ran on the interstate at 80 for 80 miles. This points to lack of fuel delivery or fuel map troubles as most 460’s in the mid 90’s are known to get about 8-10 city and 12-14 highway.

it is running hot which also points to being lean.