bad COMPUTER???

[yellowoctupus]

Unfortunately my intermittent running issues have not gone away yet. They don't seem to be related to any type of driving (smooth roads, bumpy driving, cold/hot engine, run yesterday, run a week ago...running, then dying, not running then running......) Sometimes I'll go out to it after sitting, it will fire right up, then die like 200ft later.

Replaced normal stuff so far (to find the bad map sensor, and this contproblem)

Battery
TFI
Cap, rotor
Wires
Plugs
MAP sensor
Fuel Pump relay, ECM relay and associated connectors


All engine wires look good, I pulled them all down (elec. tape etc, coverings etc) today when I was stuck (not in mud, just not running) back in the woods. No spout wire grounding out from the tfi (at least as far back as the heater, I didn't unravel the wires down there yet. It will run GREAT! fire right up etc etc. then just DIE-no sputtering, nothing, sometimes when I'm accelerating, sometimes when I'm just on the gas a little or something, doesn't seem to matter.

Now, after the lengthy intro, do computers or ignitions (like at the key) ever go bad intermittenly? I also tried jumping the ecm relay manually to try getting around the key ignition, is that all you need to run (hotwired) these things? If anyone knows how to check the key ignition, that'd be great too.

 

[Flat Toy]

Does the ignition switch look like this?

If so check the tabs that hold the plastic to the bottom of switch. The tabs get weak and let the switch separate and cause problems. I used wire ties to tighten mine up

 

[yellowoctupus]

Hey, thanks for the great picture. I have the same style ignition (scary how easy it would be to start the truck sans key...) and it was a little loose. I was able to tighten it up by putting the switch in a vice and tapping the little aluminum 'fingers' in with a machinists hammer. What problems were you experiencing when you noticed this problem? Would it just randomly shut off on you?

 

[Flat Toy]

Drove it up to the gate and got out to open the gate. It quit, I got back in and it would not start.

 

[yellowoctupus]

Ok, cause I have been hunting this mysterious problem down since I bought the truck ...6 mo ago. It would die, sitting in the road idling, driving whatever. I REALLY hope this helps something! I will certainly keep you posted, thanks a lot for the tip. I just couldn't give up on it since it ran SO good when it ran.

 

[yellowoctupus]

Still random no-spark!!

Flat toy, thanks for the suggestion, I think that takes one more thing off my list of suspects.

Quick question (long explanation below): I have fuel, no spark. Computer problem or something else?

Long Explanation:

Does anyone know if I'm getting fuel, does that mean my computer is good? Can they go bad intermittenly? I've been driving fine for the last two weeks to work (5mi one way) and yesterday, it died once, I pulled over and it fired right back up, then a mile later, died again! This time, I fiddled with everything I could think of, and about two hours later, it randomly fired back up, then made it a mile, died and fired back up right away. 2 miles later, died and wouldn't start until this morning, when it fired right up (needless to say I drove my motorcycle to work!!).

I have been through all the wires in my engine bay (in fact just taped them back up from my 2 week's ago escapades).

It does not seem to be a TFI, as I have two now and they both act the same it seems. (one is remote mount, it gave me the same issues during the two hour pause.)

My coil tests good for resistance values, and from previous experience if it works good sometimes, there's no reason for it to not work well now.

 

[88broncoll]

I have seen the ignition module on the distributor act up a few times on me with different fords, Is it hard to start at all? meaning wind over for a bit, or wind it over and stop, and try again and it goes? Thats what happened to me till it just stopped firing all together

 

[yellowoctupus]

Yeah, that's the TFI I think you're referring to, I just replaced it and have exactly the same problems as before.

 

[yellowoctupus]

Crazy electrical problem!!! Constant 7/8 V at starter solenoid!

I'm hoping there's a breakthrough here! I noticed when the truck is idling, I can pull off the starter solenoid wire and the idle drops down (and runs a little rougher).

The wire from the ignition to the starter solenoid shows 0V with the ignition off, 7.5V ignition on, and 8.5V running. Shouldn't it show 0V except when starting???

My ignition switch looks like new inside (I popped it apart yesterday), any ideas?? How could I possibly be getting 7/8 V? I could see 12V if it was connecting to a hot lead, or 5 to a sensor, but 8??

If anyone knows which wires to jump at the ignition block to make it run I'd be grateful to give it a try (if you'd like to PM or email me so it's not on the open forum how to hotwire one of these, that's cool too. Of course if you've got it apart this far all it takes is a ballpoint pen or a screwdriver or something to get it started, but I digress.....

I'm working on month 5 of my Ranger being totally freakin unreliable, and that $500 toyota 4 runner is starting to look awfully tempting........PLEASE HELP!!

 

[Landers]

Any update on this problem...I have the exact same problem and i am going nuts...Same year truck.


About to give up.

 

[holyford86]

Pull codes. All you're doing now is guessing, see what you get and go from there.

 

[BRUTUS_T_HOG]

well... does it have spark when it won't start? or no fuel? you should know how to check for spark, take a non powered test light and backprobe it into a fuel injector on the ground side, should flash while cranking.

does the fuel pump prime at key on? if you have spark, and you have fuel being injected. jumper the fuel pump relay and check to see if it will start

 

[holyford86]

Flat toy, thanks for the suggestion, I think that takes one more thing off my list of suspects.

Quick question (long explanation below): I have fuel, no spark. Computer problem or something else?

Long Explanation:

Does anyone know if I'm getting fuel, does that mean my computer is good? Can they go bad intermittenly? I've been driving fine for the last two weeks to work (5mi one way) and yesterday, it died once, I pulled over and it fired right back up, then a mile later, died again! This time, I fiddled with everything I could think of, and about two hours later, it randomly fired back up, then made it a mile, died and fired back up right away. 2 miles later, died and wouldn't start until this morning, when it fired right up (needless to say I drove my motorcycle to work!!).

I have been through all the wires in my engine bay (in fact just taped them back up from my 2 week's ago escapades).

It does not seem to be a TFI, as I have two now and they both act the same it seems. (one is remote mount, it gave me the same issues during the two hour pause.)

My coil tests good for resistance values, and from previous experience if it works good sometimes, there's no reason for it to not work well now.

its been checked

 

[yellowoctupus]

Gave UP

Sorry guys, I'm not much help on this one. I moved my TFI up to the battery box, and hadn't any problems for a couple of weeks so I sold the Ranger. I really wanted a stick, without the stupid 2.9, manual transfer case etc, anyhow. So...I got a Comanche. Hopefully moving your TFI will do something for you. The only other thing you might want to check is your PIP, there's something in the Tech library showing you how to check, I actually pulled mine out of the dizzy to physically look at it for damage/corrosion, and saw nothing bad. ?? Good luck - and Happy trails