From: Dick (rertman@ix.netcom.com)
Date: Sat Feb 05 2005 - 20:31:47 PST
Can you latch onto a borescope? You might have a carbon bridge in the
cylinder that's effectively shorting out the high voltage.
The plug smells of fuel, so it's getting fuel, getting spark, but not
igniting the fuel/air mix.
Good luck,
Dick
----- Original Message -----
From: "Mil-Veh Co." <milveh@sbcglobal.net>
To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
Sent: 04 February, 2005 22:19
Subject: Re: [MV] Out of ideas... M151 still misses
> First, thanks for the fouling info., Joe, Cliff and
> anyone else who may still provide info.
>
>
>
> OK, just one more question and this is giving me fits,
> I'm still having a problem with a dead miss. Here is
> what I've done to correct a "no fire" in number 2
> cylinder on the M151:
>
> 1. R/R spark plug with new plug, could see decent
> spark, but still no combustion. Plug smelled of gas,
> but not wet with gas. (also checked plug wires for
> firing order, Firing Order: 1-3-4-2 )
> 2. Did compression check, 105 lbs...passable, all
> about 105 lbs while cranking. (new is about 135 lbs.)
>
> 3. R/R plug wire with new wire.
> 4. R/R dist. cap with new cap.
> 5. Replace entire Prestolite electronic distributer
> with new unit and replaced all wires with
> new...getting desperate!!!
>
> Still missing on #2!!
>
> 6. Replaced spark plug again, just to double check.
> 7. Removed valve cover, observed engine running,
> rocker arms moved up and down smoothly and checked for
> .....
> a. Broken valve spring
> b. Loose or broken push rod
> c. Proper lift on valves looking possible cam
> lobe damage. (all fine)
>
> 8. Checked to see if cam had somehow skipped time,
> engine was TDC on #1 when at the timing mark on crank
> pully..can't be cam timing.
>
> 9. Made sure batteries were fully charged and proper
> ground. No problems, they're new and wiring new, all
> tight and no corrosion anywhere.
>
> Everything seems fine, just noticed that the
> compression was a little low, but within range for an
> older engine.
>
> 10. I can't think of anything reasonable that it
> could be...now thinking its something unreasonable...
>
>
>
> Considered a foreign object (mouse, bird, rag, etc.,)
> may have somehow entered the intake manifold during
> the carb rebuild and is not allowing combustable air
> into number 2 hole..but then I did get good
> compression, so is that likely???? I'm running out of
> ideas, good ones, bad ones, I've been over this engine
> a dozen times and can't find a thing wrong.
>
> If I can't figure out anything else, then I will pull
> the intake manifold and look into the head for some
> sort of obstruction. I mean, what's left to check,
> right? Arrrrrgggggh!
>
>
> Summary... can't be fire, has good fire and good
> plugs. Can't be a valve, ok compression. Timing is
> on. Firing order is right. 3 cyls run great, so can't
> be carb.
>
>
>
>
>
>
>
>
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