Weird electrical (igntion?) issue

[jdmckay]

Hello Everybody,

Been driving my '89 MM w/rblt motor & weber for about 18 months now.. been running perfectly, very happy.

My AirTex electric fuel pump died yesterday. AAA towed me home, did some circuit tests to make sure fuel pump was getting electricity (it was), went to nearest AutoZone and got a replacement this morning. It is installed and seems to be working fine (wondering why the AirTex had such a short life, under 10k miles).

Whether coincidental or not, the following occurred after getting new pump installed: motor starts and runs fine as long as I hold ignition in START position. However, as soon as I release key to RUN position it dies. I didn't change anything in circuitry I installed for original electric fuel pump setup, only unplugged a couple of my connections to check circuit to ensure it was the AirTex that went bad.

Only thing that bugs me (long shot) is: there is a ceramic connector on the drivers side firewall above the wheel well, a couple terminals on each end. I'm running hot wire off this for my fuel pump circuit. This thing broke when I did rebuilt a few years ago, and just a few days ago was doing some maintenance and hit it accidentally. I fixed original break w/epoxy, and did so again. This time I noticed there was a spring inside, not sure what it is there for if it could possiby be causing problem I describe above.

Also wondering i this could be a coincidental ignition switch failure... but right now I'm just guessing. Hoping one of the geniuses here can give me a more precise suggestion before I start replacing parts with my fingers crossed. Even suggestions on what circuit to test appreciated, just not sure where to begin with this not knowing what wires should be hot in RUN position.

Any help greatly appreciateed, hope you all are well.

[geezer101]

The ceramic resistor is the ballast resistor for the ignition coil. These things can't be fixed with epoxy resin and need to be replaced when they crack (it will kill your ignition when it gets hot). You shouldn't connect anything to the coil side of the ballast resistor as a power source. Replace your resistor and (fingers crossed) your issue will be gone.

[royster]

Hey jdmckay...I'm no expert on such issues, but might be entertaining until someone shows up to give you good answers.

Electrical problems are NOT my forte, which is why I try to wire things like pre-amps and auxilary circuits on their own, new circuit line, rather than tap into "mystery poles". As your truck is some 27 years old, an ignition switch might be suspect.

Woops, posting this and I see Geezer showed up. Thank gawd!~

[jdmckay]

Thanks Geezer. I'm going to take your advice: none stocked in ABQ, several local parts stores say they can get it by Tues or Wed. NAPA already closed... try them 1st before I order it.

>> These things can't be fixed with epoxy resin and need to be replaced when they crack (it will kill your ignition when it gets hot). <<

It broke when I finally got it running X-MAS 2014. I epoxied it then, had no problems until now.

My starter died earlier this week, and I broke this resistor again when pulling that starter out... bumped it. :( Did not glue nearly as cleanly this time... ran ok for a few days. I can't imagine but... any chance that could have had anything to do with killing my fuel pump?

> You shouldn't connect anything to the coil side of the ballast resistor as a power source. <

I had Weber Electric Choke hooked up on this side (engine side). Guess I should move it to other end then.

> Replace your resistor and (fingers crossed) your issue will be gone. <

Thx again, I'll let you know.

I'm wondering, are these prone to breaking? If local U-PULL yard has one (save time having it shipped) any chance it would be problematic if not cracked (no visual damage)?

[geezer101]

They normally don't just 'break' and they do get warm when the engine is running (apparently it is more noticeable when the engine is at low rpm/idle). Being ceramic they don't like taking a hit. Hooking the fuel pump up to the distributor side of the ballast resistor will drop the current flow to the fuel pump which is not good for it. An indicator that the ballast resistor is fragged will be the engine dying for no obvious reason and then being able to start it again in 5 or 10 minutes - if it dies and the resistor is red hot to touch it has failed. One from a u-pull-it yard is a small gamble as, unless the crack is obvious, a fine hairline crack will be hard to spot but you'd have to be unlucky to get a dud.

[jdmckay]

Hi again... finding this balast resistor has proven challenging. Autozone's part is no longer available, NAPA does not list it and local Mitsubishi Dealer can't even find it in their catalog.

Summit Racing has 2 that are close, both Beck/Arnley parts:

- part # 178-8139 (https://www.summitracing.com/parts/bck-178-8139/applications/make/mitsubishi/model/mighty-max)
- part # 178-8000 (https://www.summitracing.com/parts/bck-178-8000/overview/)

The first one, on Summit's site, says it's good for an '87 2.0L (my engine)... mine's an '89. I'm not familiar enough with this parts' function to buy this one w/out someone in the know telling me it will work. The tech I spoke with at Summit said if I had an ohm requirement for this part on my truck he could call Beck/Arnley and dbl check with them.

Advanced Auto Parts here says the 178-8139 cross references to a Borg Warner # ru500. Their website says this Wells resistor (http://shop.advanceautoparts.com/p/wells-vehicle-electronics-resistor-ja703/10305022-P?searchTerm=ignition+coil+resistor) will work, but I spoke with tech support at Wells, they have no listing or my MM. Interestingly, he told me Mitsubishi is pulling out of US market next year. :(

Appreciate if anyone can tell me if either of these will be ok, give me an ohm requirement or suggest another manufacturer/part # that is tried and true.

UPDATE: I searched this forum, found this thread (http://www.mightyram50.net/vbulletin/showthread.php/4190-Igniter-ballast?highlight=ballast+resistor) ... maxdsm says he put the Beck/Arnley 178-8139 on his '88. Looks like this is my best shot, but will wait to hear from gurus here before I pull the trigger.

Thanks again.

[geezer101]

Seeming the trucks all use the same type of spark trigger in the distributors I'll say you'll be safe with the Summit unit. Nothing on eBay?

[pennyman1]

the resistor should be 0.8 to 1.2 ohms resistance for the ballast resistor.

[jdmckay]

Seeming the trucks all use the same type of spark trigger in the distributors I'll say you'll be safe with the Summit unit. Nothing on eBay?

I checked all the local parts stores (hoping to get my MM on the road ASAP) for the Beck/Arnley, nobody had it in Albuquerque.. Advanced Auto did have a cross-referenced mathching Borg-Warner, part # ru500 @ their local warehouse. I'll pick it up at 10am, hopefully it will do the trick.


the resistor should be 0.8 to 1.2 ohms resistance for the ballast resistor.
Thanks, good information. None of the ones I listed above had their ohm rating in item's specs on any of the sites I checked. Only manufacturer that had a tech 800 ph # was wells. Had I known this this morning, probably would have gone for a Wells part because I've had good luck with some of their other parts.

Anyway, thing I'll be ok with this Borg-Warner. I'll post in a few days with some results after a little driving.

And Geezer, just wanted to say I found several good articles describing #1 symptom of a failed resistor is symptom I described in my first post. I've wrenched a fair amount over the years, but was completely unfamiliar with this part and it's function. So I think you nailed it... Thank you very much. :)

[geezer101]

http://www.ebay.com/itm/Ballast-Resistor-Ignition-Coil-Resistor-BWD-RU500-/121647345860?fits=Make%3AMitsubishi&hash=item1c52bf30c4:g:8DgAAOSwHnFV3ycp&vxp=mtr

Take note in the ebay link that it has a list of compatible part numbers as well.

[jdmckay]

http://www.ebay.com/itm/Ballast-Resistor-Ignition-Coil-Resistor-BWD-RU500-/121647345860?fits=Make%3AMitsubishi&hash=item1c52bf30c4:g:8DgAAOSwHnFV3ycp&vxp=mtr

Take note in the ebay link that it has a list of compatible part numbers as well.

Thx. Interestingly, compatability for this part not the same as the Beck/Arnley it was referenced from... does not list MM models. I confirmed it was same ohm rating however, so I bought it. Also price at Advanced was $8 out the door so no point in mail ordering.

[geezer101]

Yeah, I'd guess the best you could do is save a buck or 2 but have to wait for it...

[jdmckay]

17433

Borg Warner ru500 installed... works fine. Came with it's own mounting bracket, a little easier to install I think then reusing old bracket. Drove about 100 miles, heating well within acceptable limits.

Thanks or the help, especially geezer!

[geezer101]

:thumbup:

[sforan01]

17433

Borg Warner ru500 installed... works fine. Came with it's own mounting bracket, a little easier to install I think then reusing old bracket. Drove about 100 miles, heating well within acceptable limits.

Thanks or the help, especially geezer!

Is this fix still working for you? I'm having the same issue and I'm also in Albuquerque!

[jdmckay]

It's worked just fine. :)