1993 Ranger engine won't start please help...

[actbubba]

I have a 93 Ranger 4.0 4X4 5 speed. Recently the check engine light started coming on and when the light would come the engine would start idling lower and runnning very rough. I was also gettng black smoke like it was flooding. I would lalso lose a lot of power when this happens. It would do this and then start running fine again. When all this started I noticed that the fuel pump was acting differently. Normally when I turn the key on it comes on a few seconds and stops. Now it stays on and sometimes want start at all. I took it to a local mechanic and he changed fuel regulator, plugs, and checked relays. He cannot figure this out. He brought it back home and it was running. Now it won't start. It all started after I was working on my cb radio. I kept turning the key on and off trying move my antenna away from fuel pump get rid of the fuel pump noise in my cb. Could I have messed up tthe fuel pump doing that? My local mechanic says no. Any help would be much apprecitated.

 

[MAKG]

Your mechanic went after a fuel pressure relay with a complaint of an INTERMITTENT?

That's incompetent. It's almost assuredly electrical. And it's not an open circuit. It's a SHORT TO GROUND energizing something that shouldn't be energized. I'd look at the injector circuit first. Checking for a stuck relay is the only thing on that list that is reasonable given the complaint.

You didn't screw up the fuel pump circuit from cycling the key; about all you could do there is wear out the lock cylinder (which would make it never run at all). But you MIGHT have from an incorrect installation of that CB. If you remove it, does the problem go away?

You need a different mechanic.

 

[actbubba]

When I turn the key on the fuel pump stays on and the engine won't start. How do I troubleshoot the injector circuit? Since the fuel pump stays on where is the gas it is pumping going. What tells the fuel pump to turn off after it comes on for 2 or 3 secs.

I moved the coax and antennae to the back of bed and cb noise is much less now.

 

[MAKG]

The PCM does that. As I said, you have a short to ground that is emasculating your PCM.

It's not easy to find those. You need the help of someone hands on who can help you out, especially if you're not an ace with a voltmeter.

 

[289-tiger-]

When I turn the key on the fuel pump stays on and the engine won't start. How do I troubleshoot the injector circuit? Since the fuel pump stays on where is the gas it is pumping going. What tells the fuel pump to turn off after it comes on for 2 or 3 secs.

I moved the coax and antennae to the back of bed and cb noise is much less now.

I would probably eliminate the CB as the root cause of the problem. The Ranger is a 1993 (14 years old) Ever wonder why the heater goes bad when its cold? A/C goes bad when its hot? Old parts break when you are using them. Sometimes after you have repaired one area another will give, sometimes it has nothing to do with the next problem. Don't let it get you down. A dead short should burn a fuse if installed correctly. Is the fuel pump original? The fuel should be returning to the tank. Try pressure testing at the manifold rail. Let us know how this goes.

Good luck

 

[MAKG]

A dead short from power to ground should blow a fuse.

A dead short from a ground-side switched circuit to ground will energize the circuit as though the switch were on. MOST circuits in the vehicle are ground side switched. Including the injectors (would it be better to make it limp off the road coughing up black smoke, or just die in the middle of the highway because you blew a fuse?).

It's very hard to find these faults when you know what you're doing. When you're getting unknown-quality advice from the Net and you don't know what you're doing, it's not going to go well.

 

[289-tiger-]

A dead short from power to ground should blow a fuse.

A dead short from a ground-side switched circuit to ground will energize the circuit as though the switch were on. MOST circuits in the vehicle are ground side switched. Including the injectors (would it be better to make it limp off the road coughing up black smoke, or just die in the middle of the highway because you blew a fuse?).

It's very hard to find these faults when you know what you're doing. When you're getting unknown-quality advice from the Net and you don't know what you're doing, it's not going to go well.

As Makg says above, make sure you know what you are doing when troubleshooting a problem, always use safety. If you are unsure, consult a professional.

Good luck

 

[actbubba]

Thanks I am going to take it to another mechanic on Tuesday. He can hook it up to his machine and check the codes. Hopefully they will get r fixed. I will post later to let you all know how it goes. This problem is over my head for sure. By PCM do you mean the computer?

thanks,

 

[actbubba]

The mechanic says the computer is shot. I have purchased a used one to try. Still waiting for it....

 

[actbubba]

I got the used computer installed and that seems to have fixed it. It runs good now...

thanks!

 

[289-tiger-]

Good job getting it working!!!!

Good luck