Engine Misfire

[Jim Hupy]

I was originally planning on attending the Dakota Rally, as well as the
shindig in Louisiana this year. But, crap happens outside our control. Who
could have predicted this pandemic? Our coach has been sitting since March,
and that really sucks. These pharmaceutical giants need to pull their head
out, and develop an effective vaccine.
Jim Hupy
Salem, Oregon

On Sun, Aug 2, 2020, 7:54 PM Larry via Gmclist
wrote:

> > Jim,
> > I am impressed with your patient and thorough answers on this forum.
> Some enterprising soul should compile and publish then as 'The Hupy Method
> > - "Just What I Did".
>
> Me too. Jim is on my bucket list to meet before I..........
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[sgltrac]

Jimmy,

Fill the tanks, fill the fridge, fill the propane, fill the tires and hit
it!!!

Sully
Bellevue wa

On Sun, Aug 2, 2020 at 8:02 PM James Hupy via Gmclist <

> I was originally planning on attending the Dakota Rally, as well as the
> shindig in Louisiana this year. But, crap happens outside our control. Who
> could have predicted this pandemic? Our coach has been sitting since March,
> and that really sucks. These pharmaceutical giants need to pull their head
> out, and develop an effective vaccine.
> Jim Hupy
> Salem, Oregon
>
> On Sun, Aug 2, 2020, 7:54 PM Larry via Gmclist

>

> > > Jim,
> > > I am impressed with your patient and thorough answers on this forum.
> > Some enterprising soul should compile and publish then as 'The Hupy
> Method
> > > - "Just What I Did".
> >
> > Me too. Jim is on my bucket list to meet before I..........
> > --
> > Larry
> > 78 Royale w/500 Caddy
> > Menomonie, WI.
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[george beckman]

> Assuming my understanding of how the Howell fuel injection works is correct, my assumption is if #2 is not firing, and dumping raw fuel into the
> exhaust, the Howell will try to lean out the engine. Since my afm is on the left bank, I would just see a lean reading, since the raw fuel was
> going to the right bank.

Sorry you are having trouble. I just replace my engine. I did squirt oil into my weak cylinders with little or no improvement.

The others commenting are right. You have a leaking intake on 6. With 80 lbs, that cylinder is firing, just not making proper power.

Just a point of understanding, but an O2 sensor could care less about raw fuel. It looks at oxygen. When a cylinder misses, the O2 that was supposed
to allow combustion passes through, making the computer think the engine is lean, that there wasn't enough fuel to use up the O2. So the EFI (Howell
in this case) goes rich. One cylinder not using any O2 makes the other 7 eat lots of fuel, trying to use up the O2 and reach 14.7. It is one of those
times that is the reverse of what we first think.

More than the O2 rich correction, your explosion is leaking back up into the intake, lighting the fuel on fire. Even if it doesn't ignite, the air
moving the wrong way in the intake can foul up the next cylinders. Given our firing order, 5 and even 7 may have a "disturbed" flow at idle.

Randy Van Winkle had a "tuliped" valve on 4 or 6. I can't remember but think 6. Matt Collie explained that a bit of carbon got under the valve (or in
Randy's case a piece of the spark plug), held the valve open for a millisecond. Intakes are cooled by contact with the head. With no contact, the
valve got hot and became a little more "cone" like. Matt said this could be way worse because sometimes the valve head snaps off and we know it never
lands in a good place. This can happen on a long pull. Matt said this happens really fast, like one or two cycles of the engine. The tuliped valve
then leaked, fired weaker, and probably cooled stopping further damage. That's my theory.

Another problem with valves is being lean on a pull. A cutting torch heats the metal and the Oxygen valve burns it away. The engine has heated the
valves in a hard pull. Too much O2 and metal burns away. This is why EFI and Carbs have "power enrichment or power valve. Dump in more fuel to use up
the O2 and stop the burn.

I hope this helps. Good luck with the engine/head.
--
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George

 

[mark sawyer]

> > Assuming my understanding of how the Howell fuel injection works is correct, my assumption is if #2 is not firing, and dumping raw fuel into
> > the exhaust, the Howell will try to lean out the engine. Since my afm is on the left bank, I would just see a lean reading, since the raw fuel
> > was going to the right bank.
>
> Sorry you are having trouble. I just replace my engine. I did squirt oil into my weak cylinders with little or no improvement.
>
> The others commenting are right. You have a leaking intake on 6. With 80 lbs, that cylinder is firing, just not making proper power.
>
> Just a point of understanding, but an O2 sensor could care less about raw fuel. It looks at oxygen. When a cylinder misses, the O2 that was
> supposed to allow combustion passes through, making the computer think the engine is lean, that there wasn't enough fuel to use up the O2. So the
> EFI (Howell in this case) goes rich. One cylinder not using any O2 makes the other 7 eat lots of fuel, trying to use up the O2 and reach 14.7. It is
> one of those times that is the reverse of what we first think.
>
> More than the O2 rich correction, your explosion is leaking back up into the intake, lighting the fuel on fire. Even if it doesn't ignite, the air
> moving the wrong way in the intake can foul up the next cylinders. Given our firing order, 5 and even 7 may have a "disturbed" flow at idle.
>
> Randy Van Winkle had a "tuliped" valve on 4 or 6. I can't remember but think 6. Matt Collie explained that a bit of carbon got under the valve (or
> in Randy's case a piece of the spark plug), held the valve open for a millisecond. Intakes are cooled by contact with the head. With no contact, the
> valve got hot and became a little more "cone" like. Matt said this could be way worse because sometimes the valve head snaps off and we know it
> never lands in a good place. This can happen on a long pull. Matt said this happens really fast, like one or two cycles of the engine. The tuliped
> valve then leaked, fired weaker, and probably cooled stopping further damage. That's my theory.
>
> Another problem with valves is being lean on a pull. A cutting torch heats the metal and the Oxygen valve burns it away. The engine has heated the
> valves in a hard pull. Too much O2 and metal burns away. This is why EFI and Carbs have "power enrichment or power valve. Dump in more fuel to use
> up the O2 and stop the burn.
>
> I hope this helps. Good luck with the engine/head.

Thanks George... That's a great explanation.

--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX