Spark

[Hobo]

I have 1986 Bronco II 2.9l 5 speed. was having issues off and on for about a month or so and it finally died. noticed the fuel pump was out/going out so i replaced it. it was all melted and crap.went to start it. it ran fine for about four min then died. replaced the TFI module some1 said might be out so i changed it. still nothing. so check spark coming outta coil. it sometimes sparks and sometimes don't. so i replaced the coil along with the wire. still same issue. checked all ground i could find don't have book. and they seemed fine . so replaced the ignition module just in case that was issue. still nothing so went and got a computer for it. still nothing. still an intermittent spark.. have no clue what issue is. pls help need car back. main car and we are baffled. have posted 3 forums diff sites no response.!

 

[ForOffRoadDriving]

have you inspected or replaced the pick up module in the distributor? i had problems with mine when i rebuilt my motor, the magnet on the module kept getting broken after about 5,000 miles so i had to replace it 3 times before i got a good one. i eventually traced it back to bad grounds with too much resistance. i had intermittent spark on random cylinders and it ran too poorly to drive.

 

[Hobo]

checked the distributor already took it apart looked cleaned it before i put the TFI module on it. looked fine. its the spark coming off the coil thats all wacky. so its before the distibutor. cant find what it is. but the ignertia switch sets off. when i push the button it will start up and run for lil while before dieing. can push it again and it will run. how does that affect the spark tho. thought that was a fuel emergency breaker kinda deal. or will that affect the spark when it goes off??

 

[ForOffRoadDriving]

did you reset the base timing when you removed the distributor to clean it? that wouldnt explain the random sparking unless it was really off though..... hmm. you can bypass the inertia switch if you suspect that to be the cause. heres a link to more info on the switch, http://www.therangerstation.com/tech_library/InertiaSwitch.html

 

[Hobo]

yeah that's the link that made me think of it... dunno if it would affect the spark tho. was no spark issue till we put fuel pump in. that's whats baffling me some. and the old fuel pump got so hot it melted. that could be from a faulty ground? were just lost atm. hope its the switch. but its being switched by something. and i dunno whats doing it. dont think theres a leak anywhere. will run fine once i figure this dam spark issue out im sure. seems like alot of ppl have had this issue from what i have found out. but yet no1 can answer why or whats the issue. if the timing is off will that affect the spark outta the coil. dont think it should but best ask some ppl that would kno.

 

[ForOffRoadDriving]

have you thoroughly checked the 4 grounds? you should have one from 1) the back of the drivers side head to the window motor stud, 2) from the neg terminal to the core support, 3) from the neg terminal to the drivers side frame rail - just behind where the brake line mounting bracket is attached behind the drivers side coil spring bucket, 4) from neg battery terminal to the engine block- usually attached to a transmission bellhousing bolt. if one of these is corroded or loose it can wreak havoc on the electrical, and from the sounds of it the pump already has suffered from too much resistance.

 

[fyre82]

I had similar issues, it was a weak inertia switch. I jumped it out and no more problem. Eventually replaced it with another one and haven't had an issue since. Between that and good grounds I haven't had an issue.

Good luck

Rich

 

[Hobo]

yeah checked three of those four spots. ill look for the other one. almost wanna re run the one to the engine to make sure it aint all oiled up. last owner didn't fix leaks. put another used inertia switch in it didnt help but that one could be bad too. dont wanna buy a new one from dealer till i find out for sure. ill try to bypass it but i really dont want something else to go out if i do. and the mechanic helping me is one that dont like to use the meter to test stuff. just replaces crap and tired of spending money i dont have lol.. but will temp bypass i guess, just dont sound too safe check grounds first tho i think. any1 kno the resistance suppose to be?

 

[kimcrwbr1]

The closer to zero the better Take them apart and sand them metal to metal and degrease them. A simple test for the pickup coil and coil take a plug and put it in the wire from the coil going to the dizzy and set it on a good groundand turn it over if you get a good spark steady and blue then look at the cap and rotor if not pull the TFI module and test the hall effect pickup for resistance http://www.therangerstation.com/tech_library/TFI_Diagnostic.html here is the link to the values you need. But first clean and replace the ground wires and look at all the wires and connectors for burnt or cracked wires and connections. Take all the connections apart and clean them with elect cleaner and give them a little dielectric grease when you put them back together. The first thing your mechanic should have done.

 

[Hobo]

its not a shop so not gonna be done how it should. hes a honda mechanic dont like working on fords its just at his house where tools/shop i can use is. he gave up so i said screw it ill figure it out. so i asked for other opinions from this helpful site. glad i came across it. just gotta make it back out there when i have time to sit and tweak. just wish the computer was closer or my dam printer had ink. the coil wire has a weird spark. dont spark like it should thats my whole problem just gotta find where it is thats the issue. melted the fuel pump so im aiming towards the ground atm

 

[Hobo]

took all grounds going to and from the block. while i was doing that had a buddy rebuild the internal of the distributor. was kinda worn down. but now it starts and runs. finally. after going through everything. now just need make sure timing is good. thanks for all in inputs tho!

 

[ForOffRoadDriving]

awesome, glad to hear it was a simple fix!

 

[techsvcs]

was the fix the grounds or the distributor or both?