First Problem on the Unimog 404

Well true to form ive already broken my new perfectly running rust free and cherry Unimog 404 Swiss.

Im not really too unhappy i made it two days before it happened..... (new record i think)

Well im not getting fire at the spark plugs and am thinking that the points have most likely given up the ghost. Everything was going fine and then *poof* nothing no fire at all at the plugs. Is this a common problem and if so do i have to replace them or is some other check/reset/ resize/ ect needed. Ive ordered the manual that probably has the answer but it hasnt gotten here yet.

Im still happy though....... its a great truck

side note: you know it really takes someone special to screw up a vehicle intended for the roughest use in the worst conditions designed by the world's best engineers in a mere two days.......As soon as someone tells me how to fix this one i just broke my anvil with my two pound marshmellow hammer.....

Semper Fi.......

Just POOF and no spark ,huh. Sounds to me more like a bad coil rather than the points. Usually the points either work or they don't after any sitting and since you had it running i'm gonna guess they are still OK. Then again i have zip for info on mogs.

Mine had fuses for EVERYTHING-- have you checked yours? If you know you're getting power to the hot side of the coil when the switch is on then a bad coil or condenser comes to mind as well as a tendency for the screw retaining the points to loosen and allow the points to "close up". See if the rotor hasn't lost it's tip or that the carbon contact in the center of the distributer cap is stll intact.
My Unimog had a preferance for factory parts and wouldn't run well with anything else.

To do a quick check of the coil; with the ignition switch on, remove the coil wire and set it close (within a 1/4" or so) to a ground then disconnect the small wire from coil to the distributer and with a jumper wire momentarily touch to ground. If the coil's good you'll get a spark between high tension lead and ground.
Distributer caps and rotors occasionally crack or develop a "carbon trace" Which in effect shorts them out. Wiping out the inside of the cap with a dry rag cleans out carbon and electrode dust build-up.
If the coil checks good then reconnect everything and remove the distributer cap. Turn the engine over to see if the points are opening; if not then re-gap. If the points are opening and closing you should have a spark at them when they break open. If not then check to make sure that the insulated (moveable) point has power.
Condensers can be checked with a VOM if you know the value they should be. If not then throw a new one in and see it that cures your problem.

well i checked a few things ( cant find my 24V test light) and am looking to just replace the entire thing with a civilian conversion unit. The sealed coil is around 300.00 which is the same price for the entire conversion unit.

Im going back to Iraq on Monday so this will give me something to do when i get back again in the fall. At least the truck made it to the house safe. This hobby wouldnt be near as much fun if the trucks ran well all the time would it.
I was planning on a new paint job, rubberized coating on the interior, and painting/ watersealing the cargo area anyway.Might as well do it all at the same time......

Dave,

Many of us with 404's do the 'civilian' conversion to unshielded plugs and spark cables, and also put in a Petronix ignition. I had continuing point problems before the Petronix upgrade. My guess would be bad points, and that's so easy to check. Just take off the dissy cap, set the dissy cam on a lobe (in 6th gear, manually bump/rock the truck to move the dissy shaft..) and check out the point gap...but you know all that. The engine will run with huge variation in point gap but it'll only run well with the right gap and dwell. You can set dwell and timing with 12 volt testers if you run them off a separate 12 v battery. Just make a common ground connection.

You should get on the Unimog forums. These mods are well covered.

http://tx4x4.com/mailman/listinfo/mog_tx4x4.com

http://www.benzworld.org/forums/unimog/

Bob

On my Mog, one day I had spark, the next day I did'nt. So I bought the entire Pertronix ignition and installed it, still no spark. After much trouble shooting I found that the ignition key had a 3rd position for the ignition to turn on and I had'nt been turning it all the way on . It was right after getting the mog and I still was unsure on how everything worked. Worth a try in case you are doing the same thing.

August 1st, 2008.

Dear David:

Likely I would check the coil first, then the points.... Unimogs are notorious for eating their points when run at road speeds, and I would also consider when doing the civillian conversion that the distributor cap (NEW) spacer is indexed right on the distributer body..... some of them are not on register and the engine won't run well (I know- I've been there), ALSO check the breaker panel under the hood- the Swiss used breakers instead of fuses, canny fellows!!! Also I forgot to mention yesterday that the small white lever over by the passenger seat, with the blackknob on top is your Forward/Reverse shifter, the the handle with the dog latch release is the parking brake. You cab roof looks good, but if not, let me know, I might have a maker for a new OD top and modified side window panels (with zippers-like jeep soft tops). The Unimog is a substantial performer, but do remember that is a FAST tractor.... or a very slow truck. The Unimogs will just about eat anything else for lunch for off road performance, but they like staying in the 30's or very low 40's when run on the road for any legth of time. And yes, you are special, anyone who can upset a Unimogs digestion in two days is a very unique individual.... Good luck with the Mog and keep the rest of us posted...

Sincerely,

Kyle F. McGrogan

1971 Kaiser Jeep M35A2 Wo/W "Saddam's Nightmare" Desert Storm and Vietnam Veteran Deuce
1968 Johnson Corp M105A2 Cargo Trailer 1-1/2 Ton
1967 Hercules MEP023A gas Gen Set APU
1963 Swiss Army Cargo Unimog S.404.114 MB, Where it all started last April!!!!

im going to be trying it but im leaving in the morning so am flat out of time. Who knows what i did to upset the thing...... Ive even tried aplogizing but it isnt listening i guess....lol

The electronic ignition was something i had in the works anyway so no big deal.....

Thanks for all the help ill talk to ya'll again after about 48 hours of straight airtravel and layovers......AHHHHH