First gen blues. 87 2.9

[rebel ranger]

Alright first gen guys, I think I've toasted the ecm in my '87 2.9 4x4. I was jump starting my '03 Ranger with the '87 just like I've jumped any vehicle before. Truck acted funny when I hit the starter on the '03, it almost died, but caught back up and was running fine. I didn't like what happened so I disconnected the jumper cables. As soon as I disconnected the cables the '87 died, and would not fire back up. No fuel pump buzz when I cycle the ignition switch and turn the engine over. Checked fuses in the fuse block, all is good. Does this sound like the ECM, or is there a fuse I am missing in my search? Thanks for any suggestions.

 

[Shran]

Jumper cables were hooked up right?

Check your negative battery terminal and the pigtail that is connected to it, it often gets bumped or unplugged... that is your ECM and fuel pump ground. #1 point of failure I've found. Secondly, check your ECM and fuel pump relays on the passenger fender, there may be two or three of them, they all need to be functional.

Pretty unlikely that you killed the ECM.

 

[rusty ol ranger]

Do you still have electric power?

Kinda sounds like you had a weak/dead alternator and the burden of running the 87 and trying to start the 03 ate what little bit the battery had left.

 

[franklin2]

Jumper cables were hooked up right?

Check your negative battery terminal and the pigtail that is connected to it, it often gets bumped or unplugged... that is your ECM and fuel pump ground. #1 point of failure I've found. Secondly, check your ECM and fuel pump relays on the passenger fender, there may be two or three of them, they all need to be functional.

Pretty unlikely that you killed the ECM.

He is right, there is a little ground wire over at the battery, it's pretty small, and comes right off the large negative cable clamp. I have pulled this wire off before and my truck would quit and not hit a lick till that wire was put back on the negative terminal.

 

[rebel ranger]

Ok, I'll check the ground. Yes, cables were hooked up right. I have power, the engine spins over. It actually started the first time after it went dead, like it was using what fuel was in the rail then died. Thanks for the replies. I'll be back.

 

[rebel ranger]

Nope, grounds are all good. No relay click, so no fuel pump buzz up. Battery is strong in '87. Battery in '03 is pretty strong. The whole reason for the jump start is because the dern door ajar dealio in the '03 was keeping the dome light on and drained the battery. I usually would have just put the battery charger on it for a few minutes, but the power was off for 5 hours here that day. Now I have a dead Danger Ranger. :/

 

[franklin2]

Do your headlights work? If not, you have a main power problem. You can see in the 1987 diagrams below, after the alternator, the headlights are the next thing to be tapped off the battery power.

 

[rebel ranger]

Like I said before, everything works, I have power to everything. Lights work, horn works, starter is turning the engine over like it should. I'm not getting a fuel pump relay click, and that is controlled by the ECU if I am not mistaken. Is there anyone here that knows who repairs these? Or do you know what goes out in them that can be replaced. I am decent with electronics repair. The way I look at it, if it's not working now, what have I got to lose if I can get some information on what is usually replaced in them. I can find a used, or rebuilt ECU if I can't fix this one.

 

[alwaysFlOoReD]

I think the caps go in them.
@RonD
@adsm08

 

[rebel ranger]

I think the caps go in them.
@RonD
@adsm08

These are the guys that know ECUs?

 

[alwaysFlOoReD]

A couple of the more knowledgeable guys off the top of my head. I'm sure there are others that have the knowledge too.

 

[rusty ol ranger]

These are the guys that know ECUs?

Yes the capacitors leak over time. But i doubt thats the issue here as it happend when you jumped the other truck.

Stupid question....but do you have spark?

 

[rebel ranger]

Yes the capacitors leak over time. But i doubt thats the issue here as it happend when you jumped the other truck.

Stupid question....but do you have spark?

Yes, there is spark. If you read post #5 where I say it actually started the first time I turned it over after it initially went dead, like it burned the last bit of fuel out of the fuel rails. Then no firing up, but it spins over great, and there is fire at the plugs. No fuel pump relay click, so no fuel pump buzz up. No start. Since everyone that has posted here says they don't see how it could be the ECU, is there another fuse I am missing somewhere?

 

[rebel ranger]

Inertia switch is bypassed.

 

[alwaysFlOoReD]

50/50 test;
Will it fire up if you spray fuel into the throttle body? If so then its fuel related. If not then electrical.
There is a green relay on the passenger side fender. It sends power to the fuel pumps. Check that. Also the brown one is the ecm relay and if its pooched no power gets to the green one.