1986 Ford Ranger Pickup Won't Start

On my 90 there is a 'collision' switch under the floor mat on the passenger side of the tranny hump. Push the button on it.[p] If jumpering the fuel pumps won't run the motor, you may have a problem like mine had a few weeks ago. I lost spark, everything else ran(fuel). I finally found a bad connection in a really nice o-ringed wire connector, suprising. I found it by studying the schematic and starting at what didn't run and going back through the wiring, unwrapping the harness and testing for power. Found this connector with juice in but not out. There you go.[p] What I've found about these computers is, they control the ground instead of the hot wire for some circuits. For sure check the ground wires from the computer to the chassis.

Thanks Mike,

It surely sounds like a connector -somewhere- has come loose. I worked at a Ford dealership back when these systems were being introduced and connections were emphasized as primary cause for electronic failures. That was so long ago I had forgotten about it until you brought it up again.

Again thanks,

Bruce

Check the ground on the cars it was close to the computer in the pass side kick panel. Some pickups the relays are on the side of the fender look for the ground.

Thanks, I have tried to check all the grounds, but I'm not finding something. I think that there is a sensor or relay somewhere that is stuck in a position that cause at least one circuit in the computer to "believe" the engine is running when it is not. This causes the computer to "not ground' the relays, and is also causing voltage to run through the computers grounding circuit.

I have, since my first post, gotten the engine to run -although poorly- by grounding the relay (ECU pin22). This allows the fuel pumps to work but the ECU does not properly regulate anything.

Your EEC power relay has two fusible links to it. One on a red wire, one on a yellow wire. Your fuel relay has a fusible link on the yellow wire. Your oxygen sensor has a fusible link on the grey/yellow wire. Good luck.

You should have a grey colored EEC IV relay and a green relay the EEC relay supplies power for the fuel pump relay.

http://www.alldata.com/ buy a years subscription. They have good wiring diagrams.

two things i would check, if you have 55,000 miles or in that area, check the timing belt make sure it did not jump a few teeth! 2, there might be a bad ground to the ecu or eec. you said when you put a different one in the pumps worked,that led me to believe problem #1 because you said it ran poorly.#3 it can also be a bad tps sensor! good-luck! P.S. this happened to me with one of my customers,& it was a bad timing-belt.

Thanks 58flh.

I had wondered about the timing chain. If it were not computerized that is exactly what I would have thought. However I can not see how that would cause the computer not not trigger to ground to start the fuel pumps. I'm not saying it wouldn't but I don't see how it would.

Can anyone tell me why the fuel pumps would not trigger on if the timing chain slipped?

Igniton module and TPS are things that failed on all of these trucks. Has yours been replaced yet? If not you must have very very low mileage. These failures are not amenable to tree shade diagnostics. Take it to a dealership or service facility. Even just learning about it is not worth the time and expense...to gain knowledge that will never do you any good. Your truck is so fault tolerant and reliable over the long run, that a few hundred invested now will be well spent and not raise your overall cost of ownership more than a scant amount.

I had given up working on this truck because I just had too many things to do. When I finally got back to it I decided that I would pull the front cover and check the timing chain... it was fine, even after 230,000 miles.

I got new gaskets and seals, even new valve cover gaskets because I new I WAS going to find the problem. I had nearly every electrical connection disconnected and reconnected while I was under the hood.

I found nothing.

Then, while putting the fan shroud back in it hung up on things and after jerking it around to get it in place a wire appeared. hmm Did I miss something? The wire came out of a harness under the alternator, but there were no missing wires there.

I thought I might have found the problem but where did that wire come from? I just slowed myself down and took the end of the loose wire and started moving it around to see where it would reach. It reached the ground post on the battery... and what do you know? It had pulled loose right at the battery cable clamp.

I knew I had looked at it before when I started this mess! It HAD been attached. Obviously though the wire inside the plastic insulator had NOT been attached and only the insulation was holding it in place. Catching it on the shroud pulled it off and revealed the problem.

I have worked on vehicles for over 45 years and can always learn new things but being thorough is one I seem to have to learn over and over and over.

Thanks to all who responded and tried to help.

Bruce

Ignition module and TPS are things that failed on all of these trucks

Still think you should pay someone to replace these parts?

So much for taking advice from someone that won't even put some made up name on their posts. Foe what it's worth now. Ford products during these years used a black 12 gauge wire connected directly to ground the fuel pump. There was a plastic connector within 8 inches of battery post. Good luck.