bronco ii tach and ignition help?

[lost86broncoii]

Hey all i need some help, my bronco ii has had a tach problem for a few months now and started stalling yesterday so i figured its time to get her straightened out... First off her idle has been off but i can't really tell how off, cause of tach not working some times it tries to work but reads lower than possible in the negative rpms lol, smells like its running a little rich or something. Pulling into my place last night the truck died just shut right off as smoothly as i had turned the key, then wouldn't start back up for a dozen cranks till i held my foot on the gas while cranking, didn't try driving it though. What could cause the tach to be so messed up like still reading engine rpm change to some degree but really low? I was leaning towards replacing the ignition control module... any ideas or thoughts? thanks in advance.

 

[RyanL]

As far as the vehicle dying and not starting unless you held the accelerator to the floor sounds like a possible bad fuel pressure regulator (I believe that holding the pedal to the floor cuts the fuel). If you can get it running, try pulling the vacuum hose off of the rear of the FPR and see if gas is dripping from it. If you can't get it running, you might have some some gas leaking from it with the ignition on since the fuel pump turns on for a minute. As far as your tack goes, I hope that it's just a bad one and not a wiring issue (it would probably be a mess to track down). You can probably get an instrument cluster fairly cheap. I wish I had a service manual with some wiring diagrams so I could tell you where to start. I don't even know if the tack wire comes straight from the coil or goes to the ECU and then to the tack or whatever.

 

[lost86broncoii]

yeah checked the regulator already plus i replace it and just about all of the fuel system last year due to excessive rust in the gas tank, clogged up my pumps and filters... well its running again fine today... not really sure what her deal is. so the tach problem is just the tach or could it be with the signal going to the tach, i guess i'm asking where the tach is getting its rpms from? ignition control module? ecu? thanks for the info so far.

 

[Vanner1993]

Coil maybe?

 

[Earl43P]

http://www.therangerstation.com/tech_library/EDiagrams/files/Diagrams_StartIgnition83to882_9.JPG


See them two wires in the middle of the diagram that go to Instrument Cluster?

DK/Y and BK/Y

My WAG is these wires feed the tach and yes, the TFI is involved.

 

[lost86broncoii]

Its got an old looking coil on it, and i'm pretty sure the tfi hasn't been changed. I googled the tfi and saw an accel one for 52 bucks i'm thinking about just going for that and see what happens, next week a coil to, maybe one for the explorer too and thanks again for the help guys.

 

[lost86broncoii]

so today the bronco started fine drove down the road fine till i parked it at kmart and tried to start it again, about 6 tries to get it to stay running, would turn and fire just like normal but as soon as i turned the key back the engine would just shut right off... well played around with the key, turns out the shutting off is caused by my ignition switch, some where between "start" and "on"/running postition there is a problem cause when i use the key like i would every day it won't stay running, but if i start it the just barely take the key far enough back to stop the starter turning the engine stays running just fine, but bumping the key cause it to shut right off again... any one ran into this before? maybe lose wiring, but i am thinking its time to replace some ignition components.

 

[RyanL]

Probably just the ignition switch that is bad. I only had one go bad on me ages ago. From what I was told, a lot of times they wear out from too much weight dangling from them. I've used those disconnect things on all of my key chains ever since then.

 

[Earl43P]

Could be the switch or the linkage.



http://www.therangerstation.com/forums/showthread.php?t=64081

 

[lost86broncoii]

it was the switch, the 4 little metal tabs that hold the metal part to the plastic part of the ignition switch had came lose i guess is the best way to put it and the switch was actually coming apart, like splitting in half and that's what was causing it to die. I just bent the tabs back with a big pair of channel locks while squeezing the switch back together and so far its worked great.