Re: [MV] More test results ... re M151 mystery miss

From: Fred Martin (mung@in-touch.net)
Date: Tue Feb 08 2005 - 07:55:41 PST


Yesterday a friend and I stopped in at a (younger) family members
house.....he was having trouble with his four banger Ranger truck. He
had installed new spark plug wiring and upon restarting...it ran real
rough. Well, anyhow the 1342 firing order was the culprit. He mistakenly
thought the distributor ran in a certain direction but it ran the
opposite. He was trying to run it 1432.......switched two wires for him
and solved his problem and probably embarassed him at the same time.
Common mistake...I've done it too on an old Ferguson tractor. Fred Martin

Mil-Veh Co. wrote:

>RE: No fire on #2 cylinder. Stock M151.
>
>Summary: Looking for a miss on #2 cyl., but despite
>best efforts that miss continues.
>
>Lastest effort: Made a new set of intake gaskets in
>case it was a manifold air leak. (short version - it
>didn't help!!!)
>
>(long version) I applied a sensible amount of permatex
>blue gasket maker to the gaskets and let them skin up
>while I inspected the manifold and the intake ports on
>the head.
>
>They were all fine, #2 had black carbon on the top of
>the intake valve built up, but seemed consistent with
>an older engine.
>
>No obstruction and no leaks. Least none that I could
>determine by visual inspection or by applying ether to
>number 2 intake area during a prior test run.
>
>Checked all vacuum lines again (like 10-12 times now),
>all intact and no visible signs of any leakage.
>
>Removed the spark plugs again (at least 10 times now)
>they all seemed to be burning fine, except for number
>2..black sooty looking, but electrode clear of carbon
>buildup.
>
>Replaced intake manifold and tightened everything and
>used gasket sealer on all brass fittings.
>Re-inspected everything...looked darn good. A careful
> r/r was done to everything.
>
>Attempted to start engine, but engine bucked as if
>timing too advanced. Got a little backfire through
>the carburettor, this has been typical since problem
>started. Hard starting since miss on #2. So I used
>some ether and it started up, but ran rough. To me, it
>starts like its out of time, I say this because it
>resists or drags on the starter, which to me indicates
>overly advanced timing...but it will run and seem to
>have about 60% power on test drives, won't get any
>better by moving dist. around, only gets worse.
>
>Vacuum gauge said it was within time.
>
>Removed plug wire from #2 engine continued to run as
>before...rough. Visible spark to #2, but still not
>igniting fuel in cyl. Note: I had swoped plugs again
>with number 1 to see if the plug was somehow fouled.
>Didn't matter, problem stayed on #2.
>
>Swoped #3 lead with #2... no difference at all. #2
>still not firing!
>
>This is a NOS electronic dist. and its 3rd one I've
>had in there since this problem arose. The miss
>problem has stayed despite changing distributors,
>changing to NOS set of HT wires, and all plugs checked
>at least 10 times!
>
>Re-re-re-checked clearance on distributor magnet to
>cam lobe, right on. This all brand new stuff now,
>everything looks right!
>
>I swear the engine acts like it is out of time, will
>barely start, but then #1 reaches TDC and the timing
>mark lines up on crank pully???
>
>What the *%#%$#@&* is going on here!
>
>Next opportunity I'm going to replace the ground cable
>on the battery just to be safe, but it looks ok.
>Maybe somehow, someway there is corrosion somewhere on
>the negative cable, but I sure didn't see it. Maybe
>there is a short on the negative pole of the battery?
>But, it looks good.
>
>I'm basing my plug wiring order with number 1 HT lead
>being the at top/front left if you were facing towards
>the radiator from the rear of the Mutt.
>
>I replaced HT wires based on TM firing order.
>
>I tried to remember back to when it all started and it
>seemed I was having a low battery problem due to a bad
>alternator. Mutt was running great till then. When
>batteries were charged back up it ran fine for a day
>or so, but as batteries discharged it definately had
>an effect on the running.
>
>Since then I R/R'd the alternator, running the 8 ga.
>pos. lead direct to the pos. on the battery, charged
>both batteries back to full and it continued to run
>rough.
>
>Just FYI as a reminder: Compression test was done
>earlier after pulling all the plugs, each cyl. was
>about 101-105 lbs dry.
>
>Thanks for indulging me on this, despite not having
>found the cause, your suggestions have helped keep up
>my moral. I know I will find the miss eventually, but
>I have to admit this is an odd one and its been real
>frustrating. This should be an easy, no brainer,
>right? Uh-un, no way... stay tuned for more.
>
>
>
>
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>



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