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Contributor
Location: Cupertino, CA | Okay, 968 is running again, and using new spark plugs and heat resistant spark plug wires. But, with it running so much better a miss has shown up. Mechanic says it is the fault of the original electronic ignition and the way it misses, I tend to believe him.
So the question is/are, being an old points and condenser guy, I don't know the parts I need to inspect, troubleshoot or replace. Then comes sourcing the parts.
Like most of you, there is budgeting involved for me too, so give me an order to troubleshoot and replace.
The miss is more of a no load miss than at load. It is like one misfire that is rotating through the cylinders. The miss shows up in the timing light as well as being able to hear it driving down the road. It does not cause the engine to buck or backfire. Easy start and smooth idle with an occasional miss
/non-fire.
There you have it! | |
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Veteran
Location: Olympia, Washington | The stock FMC ignition is standard Chrysler products electronic ignition composed of a distributor mounted pick-up, an ignition module and a ballast resistor both mounted on the firewall. Any parts store should be able to give you a price and supply them. | |
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Contributor
Location: Cupertino, CA | Thanks. I checked with Jim Black and he advised starting with the point and rotor cap. The people working on it suggested upgrading to an aftermarket system, but FMCs seem to run well enough on the stock system, so will probably follow your suggestion. Jim also suggested carrying a wire long enough to reach from the distributor to the battery to bypass the ignition module in emergencies. When thinking about it, it is probably a good idea to have wire in the coach anyhow and it currently isn't in my parts bin.
Interesting side: My coach is the former J Welsh coach 968 which I picked up from your area. Though I have had to spend some money to keep it running, I think I am nearly done with the major expenses and looking forward to some road trips once the new engine is broken in.
Again, thanks for the suggestion on finding the needed parts, I will follow it. | |
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Extreme Veteran
Location: Scottsdale, Aridzona | I am fascinated by your report that Jim Black said to run a wire between the battery and the distributor. Sure you got that right ? There is no 12V power in the internals of a Mopar distributor. There is a wire into and back out of the magnetic pickup that gets the very small electric pulse timing signal from the 8 "bladed" reluctor. That "to/from" wire set goes to the Ignition Module. Nothing "works" without that module. That module gets 12V power from the ignition switch as Start and Run. Just what is a 12V battery wire supposed to "hook to" at the distributor ?
Perhaps JB was refering to a jumper around the Ballast Resistor which can burn out. When "cranking" a full 12V goes to the coil. In the "run" position the 12V goes thru the ballast resistor that lowers the voltage to the coil which extends coil life. I carry a spare ballast resistor. You can see if the are "burned out" if you remove it and look at the wire behind the ceramic, or just use a continuity tester end to end. Careful ! The ballast resistor get very HOT ! Many Mopar guys run a really high voltage coil and don't use a ballast resistor at all.
All the ignition stuff gets heated by the high exhaust manifold. The Control module MUST have a GOOD GROUND. A poor ground might cause a occasional "miss". About the only "improvement" that was ever made to the excellant Mopar Electronic Ignition System is the use of a MSD (Multiple Spark Discharge) 6A control that fires multiple times below 3000 RPM, and does away with the ballast resistor. There was a "Mopar" MSD unit but they are not "stocked" anymore. There are lots of good wiring diagrams on the Nets if you use "Mopar Electronic Ignition" in Google and then select "Images". There are also good diagrams of the MSD contoller used with the Mopar distributor.
Please remember that the rotor turns CCW on the B/RB big block Mopar engine used in our favorite FMC. Spark ON, Lou #120 | |
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Contributor
Location: Cupertino, CA | Thanks, Lou! As always a veritable font of information - useful information! I MAY have misunderstood JB and what you are describing makes a lot more sense. I would have sworn that he described a failure of the electronic Ignition and bypassing it. Could the bypass of the Ballast Resistor be done for an extended time? He indicated he did it to enable him to continue a trip until he could get home.
Also, he suggested replacing the points and condenser. I haven't been doing the work on the engine, so didn't notice if the distributor has them. Gawd, I'm so stupid at times.
Now where do I find the ballast resistor, so I make sure I am working on the correct part?
I will check the grounding of the Module. Jim also recommended to check that the connectors were tight in fully inserted.
I am having fun learning about my machine (and FMCs in general). Nice thing is the shop where I have it stored (indoors) has no complaints about my working on it there.
Shorting - out | |
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Extreme Veteran
Location: Scottsdale, Aridzona | "Also, he suggested replacing the points and condenser."
???? WTF ???
Chrysler Electronic Ignition Systems DO NOT HAVE POINTS AND CONDENSER.
That is why they are so good and last soooooooooooooooo looooooooooooooooooong.
Could you have made a mistake dialing JB and somehow got the Prince of Darkness - Lucas Electric - on the connection ?
That could be an explanation. Remember Lucas invented the Elecric Short and has the worlds first Patent for a Flickering Bulb.
ZAAAAAAAAAAAAAP !!!! Lou #120 | |
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Veteran
Location: Olympia, Washington | First intermittent wipers also. | |
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Contributor
Location: Cupertino, CA | I have raised my right hand, and am swearing.
I had an Austin Healy Sprite when in college. Between the spark (arrested) and the carburetors, it was a fun little car. Used to work on it regularly, and regularly, and . . .
Also had a FIAT X-1/9, a Studebaker, an OLD Dodge sedan that wouldn't run up a hill (I lived in the mountains), a 1966 Volvo p-144, and probably some other "interesting" cars that taught me about wrenching.
Now the FMC has taken over, but the wrenches are either heavier, or my body weaker!
Today I got all the lights working as they are supposed to except the Emergency flashers. Hmmm, I guess I shouldn't have said all the lights, Hemi354 will take me to task for the imprecise language! All the lights light. Most of them light when called upon to do so. Better?
May even get around to replacing the radio/CB this week so the only noise it makes is not - - SKREE!
Oh, When I was asking about the Ballast Resistor (above) location, I didn't mean on the internet, and I didn't mean the Chrysler EIS. I am not certain I know what the BR looks like or where it might be in the engine compartment.
SSSKKKRRRRREEEE! Larry #968 | |
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Contributor
Location: Cupertino, CA | Okay, George, I know the FMC is a vastly superior being to anything Lucas, but. . .
I drove it in the rain the other day, first mistake. Second on was to turn on the driver's side Windshield Wiper (a first time thing for me in THIS coach) and it wouldn't touch the glass. What? says I.
Seems someone installed a wiper blade that has one of those 'wings' on it to hold it to the glass. Unfortunately it was installed so the wing was scooping the air to lift, not land the blade. As soon as I slowed to 24MPH it worked, but it had stopped raining by then.
You may think this type of experience is unusual for me - or you may think I am Blonde! Neither is actually true. My wife has suggested I write a book about Larry's Great Adventures. . . | |
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Veteran
Location: Olympia, Washington | The ballast resistor is white ceramic 1.5"x3" with 4 wires, should be on the firewall near the ignition module. Twenty years ago as a mechanic we would always carry a spare when going on service calls. Great adventure indeed! Welcome to the wonderful world of FMC ownership. | |
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Veteran
Location: Oslo Norway | Larry, from one scandinavian to another this is just a kind advice.
One way to get to know your coach little by little and part by part or one system at a time is to study the manuals. Manuals will not tell you the answer to any question and that goes for the FMC 2900R manuals to. But are they not the best place to start? The manuals are easy reading because they are written for people like me that dropped out of school to let their hands make their paycheck. For example the ignition system, manuals could learn you how things work, what parts are called, how they look and where they are to be found. How about printing the pages on ignition from both the service and parts manuals, make yourselves a good cup of coffe, take with you some pen, paper and a test bulb then spend an hour studying the system real life back in the engine compartement and up front to learn the system. That is quality time and after that hour you will be the one helping out others in here or elsewhere on the net.
Internet is great, not only is it full of people that will share and answer anything, but it's also a place to find manuals like on www.fmcmotorcoach.com Forums are great to, keep asking questions.
Stay cool and keep us updated
Kjetil
#477 | |
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Elite Veteran
Location: Medford, OR | Out of all the rv's i've owned, big, short,tall and fat....I never could have dreamed of having the availability and access of having an RV specific large MANUAL!!!! A great wealth of information for our coaches. Try getting a Fleetwood/Winnebago built manual??..........WTF......oh..and to have original parts and pieces avail...sweet machines for tinkerer's like ourselves.... | |
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Contributor
Location: Cupertino, CA | Maybe I complain, but when asked if, after I get everything working right, will I sell #968, the answer is: No!. You are right,though heavy machinery, the systems CAN be worked on by us for the most part. If I don't feel I can work on one safely, then I farm it out.
I LOVE MY FMC!
As Lou would say - - Roll on | |
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Extreme Veteran
Location: Scottsdale, Aridzona | As I have learned . . . Owning an FMC is a THERAPUTIC life changing experience. It keeps you around the house, out of the local Bars and whore houses, and extends your overall intelligence backward as you try to figure out what the thinking and State of the Art was in 1973-76.
You learn where the Man Malls are in your area, establish a First Name relationship with Auto Parts Store Counter Persons (instead of Bar Tenders), and learn the true value of Part Number Cross References. Occasionally, a short trip, not too far from your Main Repair Facility, is worthwhile, where you might gather with other similarily mentally affected FMC Owners, some from across the Great Oceans of the World, where you share tales, myths, and parts sources, while symbolically sacrificing a FMC to the Fire God in Stephan's FMC Campfire Fire Box. Bolder FMC Owners have actually ventured forth to seek out and discover just how few Repair Facilities there are in this most Industrialized Mechanical Nation on the face of the Earth that have ever even seen a FMC much less know how to get one running again.
Oh my, Life Is Good ! Dream ON, Lou #120 | |
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Regular
Location: Opelika, Alabama | So true Lou!! But We love it! | |
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Electronic Ignition