Im going to look at an 83 F250 Ext 4X4 with a 351 and an auto. tommorow afternoon that has electricatal problems. Im really good with automotive electrical things, but mostly on newer cars, its a kids truck who has moved away and his mom wants it gone, she says that its the computer that has gone bad, My first question is it at all possible to completly by pass the computer and get it to run?, like by pass the starter, fuel pump, what other things??? and where would i by pass them at? My next questions is i would like to convert this truck over to a really simple truck, with as little electrical as possible, i was reading about some people doing this but wasn't sure on exactly what all it in tails thanks agin ryan

 

there shouldn't be a computer on an '83 f-250. but if there is, you can disconnect it, plug in a duraspark II MOD, and you should be able to fire. (you need a duraspark II distributor as well to run correctly).

my guess is that there might be sometihng else wrong though.

 

Sorry for my ingnorance but whats a duraspark II MOD,? how much do you think one might run at a junk yard? When i go tommorow ill run the starter to make sure the motor is free, ill do a compression check on it, she had said that the computer was underthe drivers seat, which sence i know that there arn't any under the seat i assume that its in the drivers kick area, and i had read some where that there were fuseable links on it so im hopeing thats whats wrong, any other things to check on that you can think of? thanks again ryan

 

the duraspark II mod is a 6x6" module with about 3 plugs on it that sits on the driver's side inter-fender under the hood.

I think i bought one for like $20 at an auto parts store, but I've been told that the FORD OEM one at the junkyard are better.. i bet you could get one for like $5 at the yard.

if it's actually under the seat, I believe that is a duraspark III system, which i don't know much about.

if you are going to be working on this truck, go spend $20 on a haynes manual from advance auto or auto zone. it describes all of ford's ignition system in detail, and it's where i figured out a good bit.

 

bremen242 is right. If the computer (ECA) is under the seat it is most likely to be an EEC-III engine.

A few ways to confirm EEC-III:
1. It will be listed as such on the decal on the upper radiator support bracket.
2. The ignition module has a brown grommet.
3. The distributor rotor is disk shaped and has electrodes on both sides.
4. There is no vacuum or mechanical advance mechanism on the distributor.
5. There is a ring with 4 lobes behind the harmonic balancer.

The ECA control's the ignition timing and advance. It gets a signal from a Crankshaft Position Sensor mounted over the 4 lobed Pulse Ring. The CPS is a simple coil wound magnet. If it fails, the engine won't start. You can easily test it in place with an ohm meter. It should test 100-640 ohms. If it tests open circuit, it's failed and is easy to replace.

If someone unfamiliar with this type of ignition did something as simple as change the plug wires without knowing what they were doing, it could make the engine run rough or not at all.

The firing order is normal 351w:
CCW 1-3-7-2-6-5-4-8

The the order the wires are arranged on the cap is:
CCW 1-5-7-8-6-3-4-2

This is because the EEC-III distributor has electrodes on both sides of the rotor. So it fires alternately from both sides. So even though it's wired in a different order, if you go back and fourth from one side to the other, the firing order is the same.

EEC-III is often misunderstood because it is overshadowed by the greater number of the more simple Dura Spark II ignition. EEC-III (Dura Spark III) is more complex, but is capable of controlling the ignition advance up to a maximum of 50 degrees advance and control the engine more efficiently. It was used in both carbureted and fuel injected engines.

Oh, and yes, there is a relay on the ECA to protect it from reversed battery polarity.

Scott

 

is there a way to check to see if the box is still good,? im leaveing right now but will be back with a lot more information on the truck so that i hopefuly will be able to trouble shoot it thanks again for everyones help

 

I'd see if it has spark first. then check that coil horsepuller mentioned.