Engine trouble

J

jim d.

New member
Dec 23, 2017
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Hello gentlemen,
Need a little trouble shooting. Camper broke down today on the way to our last trip of the season. Driving fine then all of sudden two backfires
and engine shut down. Coasted to a stop on the side of the road. Had minimal tools to diagnose anything. After pulling over tried to crank engine over
again and nothing. Did check for spark which we had. Didn’t get a chance to check if we were getting fuel. Pregnant wife and a nice sheriff had the
rig on truck and towing it back home before I had a chance to mess around with it anymore. Any chance it would be fuel? Working with remanded S&J
engine. No upgrades or anything.
--
Jim DeMellia and Jen Radefeld and our cat Ickis
NH natives
1975 GMC “Palm Beach” ,455, her names Linda
Full time RVers exploring the beautiful and unusual parts of the country.
 
Maybe clogged fuel filter

Randy Hecht
Roswell, GA

1974 Canyon Lands GMC Motor-coach

>
> Hello gentlemen,
> Need a little trouble shooting. Camper broke down today on the way to our last trip of the season. Driving fine then all of sudden two backfires
> and engine shut down. Coasted to a stop on the side of the road. Had minimal tools to diagnose anything. After pulling over tried to crank engine over
> again and nothing. Did check for spark which we had. Didn’t get a chance to check if we were getting fuel. Pregnant wife and a nice sheriff had the
> rig on truck and towing it back home before I had a chance to mess around with it anymore. Any chance it would be fuel? Working with remanded S&J
> engine. No upgrades or anything.
> --
> Jim DeMellia and Jen Radefeld and our cat Ickis
> NH natives
> 1975 GMC “Palm Beach” ,455, her names Linda
> Full time RVers exploring the beautiful and unusual parts of the country.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
 
> Hello gentlemen,
> Need a little trouble shooting. Camper broke down today on the way to our last trip of the season. Driving fine then all of sudden two
> backfires and engine shut down. Coasted to a stop on the side of the road. Had minimal tools to diagnose anything. After pulling over tried to crank
> engine over again and nothing. Did check for spark which we had. Didn’t get a chance to check if we were getting fuel. Pregnant wife and a nice
> sheriff had the rig on truck and towing it back home before I had a chance to mess around with it anymore. Any chance it would be fuel? Working
> with remanded S&J engine. No upgrades or anything.

Jimmy,

Many of us have been there.
As it is a 75 and hence HEI, that would be my first checks, but you say you had spark.
Unfortunately, with HEI, it can recover in the time it takes you to get to the engine room. (BTDT, but not my coach)
So, in the morning run the whole diagnostic and if you still have questions, we are here to help.

Sudden shutdowns are common on HEI failures. This is why I suggest that all carry the complete kit. It is not difficult to install, but I have seen
every single part fail (module, pick-up and coil) These are not big or expensive parts and do not require special tools.

Sudden shutdowns can happen with fuel system failures, but they are not common. They are usually proceeded by a succinct loss of power. You did not
mention that. So, in the morning go out and pop the air filter and stroke the throttle and see if the accelerator pump spits fuel.

With a recent rebuild, it doesn't sound bad.

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
 
Thanks for the responses. Small update. Noticed fuel leaking to the back of the coach when it was on the hook. Can’t find the leak yet while it’s sitting on level ground.

Sent from my iPhone

>

>> Hello gentlemen,
>> Need a little trouble shooting. Camper broke down today on the way to our last trip of the season. Driving fine then all of sudden two
>> backfires and engine shut down. Coasted to a stop on the side of the road. Had minimal tools to diagnose anything. After pulling over tried to crank
>> engine over again and nothing. Did check for spark which we had. Didn’t get a chance to check if we were getting fuel. Pregnant wife and a nice
>> sheriff had the rig on truck and towing it back home before I had a chance to mess around with it anymore. Any chance it would be fuel? Working
>> with remanded S&J engine. No upgrades or anything.
>
> Jimmy,
>
> Many of us have been there.
> As it is a 75 and hence HEI, that would be my first checks, but you say you had spark.
> Unfortunately, with HEI, it can recover in the time it takes you to get to the engine room. (BTDT, but not my coach)
> So, in the morning run the whole diagnostic and if you still have questions, we are here to help.
>
> Sudden shutdowns are common on HEI failures. This is why I suggest that all carry the complete kit. It is not difficult to install, but I have seen
> every single part fail (module, pick-up and coil) These are not big or expensive parts and do not require special tools.
>
> Sudden shutdowns can happen with fuel system failures, but they are not common. They are usually proceeded by a succinct loss of power. You did not
> mention that. So, in the morning go out and pop the air filter and stroke the throttle and see if the accelerator pump spits fuel.
>
> With a recent rebuild, it doesn't sound bad.
>
> Matt
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
 
Look at hose and clamps

Randy Hecht
Roswell, GA

1974 Canyon Lands GMC Motor-coach

>
> Thanks for the responses. Small update. Noticed fuel leaking to the back of the coach when it was on the hook. Can’t find the leak yet while it’s sitting on level ground.
>
> Sent from my iPhone
>

>>

>>> Hello gentlemen,
>>> Need a little trouble shooting. Camper broke down today on the way to our last trip of the season. Driving fine then all of sudden two
>>> backfires and engine shut down. Coasted to a stop on the side of the road. Had minimal tools to diagnose anything. After pulling over tried to crank
>>> engine over again and nothing. Did check for spark which we had. Didn’t get a chance to check if we were getting fuel. Pregnant wife and a nice
>>> sheriff had the rig on truck and towing it back home before I had a chance to mess around with it anymore. Any chance it would be fuel? Working
>>> with remanded S&J engine. No upgrades or anything.
>>
>> Jimmy,
>>
>> Many of us have been there.
>> As it is a 75 and hence HEI, that would be my first checks, but you say you had spark.
>> Unfortunately, with HEI, it can recover in the time it takes you to get to the engine room. (BTDT, but not my coach)
>> So, in the morning run the whole diagnostic and if you still have questions, we are here to help.
>>
>> Sudden shutdowns are common on HEI failures. This is why I suggest that all carry the complete kit. It is not difficult to install, but I have seen
>> every single part fail (module, pick-up and coil) These are not big or expensive parts and do not require special tools.
>>
>> Sudden shutdowns can happen with fuel system failures, but they are not common. They are usually proceeded by a succinct loss of power. You did not
>> mention that. So, in the morning go out and pop the air filter and stroke the throttle and see if the accelerator pump spits fuel.
>>
>> With a recent rebuild, it doesn't sound bad.
>>
>> Matt
>> --
>> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
>> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
>> SE Michigan - Near DTW - Twixt A2 and Detroit
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
 
l leak is possibly from the fuel level sensor on top of the tank .
That should have nothing to do with the engine issue.
If your going to replace the coil or module, replace both as One can ruin
the other .

> Look at hose and clamps
>
> Randy Hecht
> Roswell, GA
>
> 1974 Canyon Lands GMC Motor-coach
>
>
> > On Sep 10, 2021, at 19:38, Jim DeMellia

> >
> > Thanks for the responses. Small update. Noticed fuel leaking to the
> back of the coach when it was on the hook. Can’t find the leak yet while
> it’s sitting on level ground.
> >
> > Sent from my iPhone
> >

> >>

> >>> Hello gentlemen,
> >>> Need a little trouble shooting. Camper broke down today on the way
> to our last trip of the season. Driving fine then all of sudden two
> >>> backfires and engine shut down. Coasted to a stop on the side of the
> road. Had minimal tools to diagnose anything. After pulling over tried to
> crank
> >>> engine over again and nothing. Did check for spark which we had.
> Didn’t get a chance to check if we were getting fuel. Pregnant wife and a
> nice
> >>> sheriff had the rig on truck and towing it back home before I had a
> chance to mess around with it anymore. Any chance it would be fuel? Working
> >>> with remanded S&J engine. No upgrades or anything.
> >>
> >> Jimmy,
> >>
> >> Many of us have been there.
> >> As it is a 75 and hence HEI, that would be my first checks, but you say
> you had spark.
> >> Unfortunately, with HEI, it can recover in the time it takes you to get
> to the engine room. (BTDT, but not my coach)
> >> So, in the morning run the whole diagnostic and if you still have
> questions, we are here to help.
> >>
> >> Sudden shutdowns are common on HEI failures. This is why I suggest
> that all carry the complete kit. It is not difficult to install, but I
> have seen
> >> every single part fail (module, pick-up and coil) These are not big or
> expensive parts and do not require special tools.
> >>
> >> Sudden shutdowns can happen with fuel system failures, but they are not
> common. They are usually proceeded by a succinct loss of power. You did
> not
> >> mention that. So, in the morning go out and pop the air filter and
> stroke the throttle and see if the accelerator pump spits fuel.
> >>
> >> With a recent rebuild, it doesn't sound bad.
> >>
> >> Matt
> >> --
> >> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> >> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> >> SE Michigan - Near DTW - Twixt A2 and Detroit
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
There are probably 10 things we could guess at. So with an instant stop without any missing or reduced power before that, I am going to guess it is
electrical and probably ignition failure. Maybe the module. I can think if a lot of mechanical problems too. If you think it is fuel. Take off
the air cleaner lid and look down the throat of the carb while you step on the gas a couple of times.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Well gentlemen finally got a chance to work on the camper. Swapped out the ignition parts that Mr. Colie suggested. I swapped out the module, pick-up
and coil. Low and behold she fired right up. Now when I pulled the distributor to replace the pickup coil and reinstalled I was sure to mark
everything as to line it back up with the reinstall. Now when I start it up it feels like it grabs “hard” when I start it up. It fires up every
time I go to start it up but not sure what is going on with startup now. Could I have advanced the timing on the distributor when reinstalling it just
enough for it have that feeling of grabbing more aggressively at startup.
Thanks again for the help
--
Jim DeMellia and Jen Radefeld and our cat Ickis
NH natives
1975 GMC “Palm Beach” ,455, her names Linda
Full time RVers exploring the beautiful and unusual parts of the country.
 
> Well gentlemen finally got a chance to work on the camper. Swapped out the ignition parts that Mr. Colie suggested. I swapped out the module,
> pick-up and coil. Low and behold she fired right up. Now when I pulled the distributor to replace the pickup coil and reinstalled I was sure to mark
> everything as to line it back up with the reinstall. Now when I start it up it feels like it grabs “hard” when I start it up. It fires up every
> time I go to start it up but not sure what is going on with startup now. Could I have advanced the timing on the distributor when reinstalling it
> just enough for it have that feeling of grabbing more aggressively at startup.
> Thanks again for the help

Jimmy,

In simple terms, you sure could have.

Without meticulous and accurate markings, getting a removed or replaced distributor installed back at time is very difficult.

Get out the belly board and your timing light and be ready to reset it.

Glad you found the problem.

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
 
> Sudden shutdowns are common on HEI failures. This is why I suggest that all carry the complete kit. It is not difficult to install, but I have
> seen every single part fail (module, pick-up and coil) These are not big or expensive parts and do not require special tools.
>
> Matt

Matt, Sounds like I need a spares kit for my '77 coach with the 403 and HEI setup.

Just wondering - would I order the 77 Olds Toronado parts?

Was looking at Rock Auto just now and looking at the three parts you recommended (module, pick-up and coil), do I need any other parts or are these
enough?

TIA

Larry
--
Larry - Victoria BC -

1977 Palm Beach 40,000 miles, PO said everything working but forgot the word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system,
6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses
 
Larry
I am going to share something with you that I have learned over the years.
Genuine GM parts are different than "white box" or "tan box" parts. The
internal components are of a higher tolerance and are more voltage spike
resistant than the other aftermarket stuff is. Nowhere is it more
noticeable than it is in modules.and coils and alternator regulators. I am
a GM trained technician, and there is a reason why genuine GM stuff is
expensive. It is better. GMC motorhomes are all 40 plus years old and their
electrical stuff is loose and corroded from weather and time. Voltage
spikes are common.
But, it is your hard earned money that you are spending. Just spend it
once for the same stuff.
Jim Hupy
Salem, Oregon

> > Sudden shutdowns are common on HEI failures. This is why I suggest that
> all carry the complete kit. It is not difficult to install, but I have
> > seen every single part fail (module, pick-up and coil) These are not
> big or expensive parts and do not require special tools.
> >
> > Matt
>
> Matt, Sounds like I need a spares kit for my '77 coach with the 403 and
> HEI setup.
>
> Just wondering - would I order the 77 Olds Toronado parts?
>
> Was looking at Rock Auto just now and looking at the three parts you
> recommended (module, pick-up and coil), do I need any other parts or are
> these
> enough?
>
> TIA
>
> Larry
> --
> Larry - Victoria BC -
>
> 1977 Palm Beach 40,000 miles, PO said everything working but forgot the
> word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system,
> 6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
 
While replacing the timing chain (and a lot of other stuff) on mine earlier this year, I discovered the mechanical advance was frozen. After soaking
the top of the shaft with Kroil for a couple of days, it freed up.

There was a noticeable increase in power on our first trip since the maintenance this week, probably some from the replacement of the very loose
timing chain, and the rest from having a mechanical advance actually working. The pins and weights on my advance are very worn, and I am going to send
another distributor to Dick Paterson for a rebuild.

If you haven't already done so, you should replace the timing chain and check the advance for proper operation.
--
Greg Crawford
KM4ZCR
Knoxville, TN

"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags
 
Or spend the kid’s inheritance and install the Howell EFI with electronic distributor and EBL!

Larry Davick
1976 Palm Beach

>
> While replacing the timing chain (and a lot of other stuff) on mine earlier this year, I discovered the mechanical advance was frozen. After soaking
> the top of the shaft with Kroil for a couple of days, it freed up.
>
> There was a noticeable increase in power on our first trip since the maintenance this week, probably some from the replacement of the very loose
> timing chain, and the rest from having a mechanical advance actually working. The pins and weights on my advance are very worn, and I am going to send
> another distributor to Dick Paterson for a rebuild.
>
> If you haven't already done so, you should replace the timing chain and check the advance for proper operation.
> --
> Greg Crawford
> KM4ZCR
> Knoxville, TN
>
> "Ruby Sue"
> 1977 Royale
> Rear Bath
> 403 Engine
> American Eagle Wheels
> Early Version Alex Sirum Quad bags
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
 
You were fortunate. The rusted weights sometimes stick partially advanced. I have seen a few that wore the weight pivot point holes and the pins
badly. I have a Dick Paterson rebuilt distributor and he puts a very small spot of grease on those points during rebuild. I checked mine after 15
years and the points were still lubed beautifully.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
I suspect a bad coil or module.

> You were fortunate. The rusted weights sometimes stick partially
> advanced. I have seen a few that wore the weight pivot point holes and the
> pins
> badly. I have a Dick Paterson rebuilt distributor and he puts a very
> small spot of grease on those points during rebuild. I checked mine after
> 15
> years and the points were still lubed beautifully.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
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