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Nothing happens when I turn the key

TM
Tom McManus
Sat, Jul 31, 2021 3:33 PM

In the last month or so I have seen people having starting problems have the starter battery cable connected to the boost side (Left) of the boost
solenoid. This will have the house battery as the starting battery. The engine will start but only if the battery has a good charge.  The alternator
will only be charging it through the isolator. Hitting the boost will engage the engine battery to start and everything will seem normal until you try
and start the engine again.

--
Tom McManus
1977 Royale

Chesapeake VA

In the last month or so I have seen people having starting problems have the starter battery cable connected to the boost side (Left) of the boost solenoid. This will have the house battery as the starting battery. The engine will start but only if the battery has a good charge. The alternator will only be charging it through the isolator. Hitting the boost will engage the engine battery to start and everything will seem normal until you try and start the engine again. -- Tom McManus 1977 Royale Chesapeake VA
ES
Emery Stora
Sat, Jul 31, 2021 3:58 PM

Why would they have it wired so it starts from the house battery? That doesn’t make sense to me.  There are a lot of reasons it should start from the engine battery.

Emery Stora

On Jul 31, 2021, at 9:33 AM, Tom McManus 94nubble@cox.net wrote:

In the last month or so I have seen people having starting problems have the starter battery cable connected to the boost side (Left) of the boost
solenoid. This will have the house battery as the starting battery. The engine will start but only if the battery has a good charge.  The alternator
will only be charging it through the isolator. Hitting the boost will engage the engine battery to start and everything will seem normal until you try
and start the engine again.

--
Tom McManus
1977 Royale

Chesapeake VA


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Why would they have it wired so it starts from the house battery? That doesn’t make sense to me. There are a lot of reasons it should start from the engine battery. Emery Stora > On Jul 31, 2021, at 9:33 AM, Tom McManus <94nubble@cox.net> wrote: > > In the last month or so I have seen people having starting problems have the starter battery cable connected to the boost side (Left) of the boost > solenoid. This will have the house battery as the starting battery. The engine will start but only if the battery has a good charge. The alternator > will only be charging it through the isolator. Hitting the boost will engage the engine battery to start and everything will seem normal until you try > and start the engine again. > > -- > Tom McManus > 1977 Royale > > Chesapeake VA > _______________________________________________ > GMCnet mailing list > Unsubscribe or Change List Options:
KB
Ken Burton
Sat, Jul 31, 2021 5:42 PM

As has been stated by several posters and me here, the circuits are the same when starting on the house or the engine battery.  The ONLY difference
between in the two scenarios is the engine battery and it's cables.  So forget looking for fuses, switches, boost solenoid, etc.

You need to take voltage readings when the key is turned to the start which puts the engine battery under load.  Use the same ground reference for
your meter that the starter is using (the engine block).

I strongly suggest that this is a battery to engine connection problem or the battery itself.  I have experienced in the past where the connections
are visually clean, even wire brushed clean, but not electrically clean and still did not work.  You can prove all of this by using your meter and
referencing all of your readings to engine block ground.  Then only take readings while the key is turned and held in the start position.

All of the above assumes that the coach is wired in the OEM configuration with no modifications to engine and house battery electrical systems.

Do not throw any parts at this until you have proven with your meter what the problem is.

Ken B.

ktcnyc wrote on Sat, 31 July 2021 06:48

I have good voltage from the engine batt to the solenoid - cables are good and clean.

Where is this fusible link between the key and the starter?

What "fuse would be blown"?

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

As has been stated by several posters and me here, the circuits are the same when starting on the house or the engine battery. The ONLY difference between in the two scenarios is the engine battery and it's cables. So forget looking for fuses, switches, boost solenoid, etc. You need to take voltage readings when the key is turned to the start which puts the engine battery under load. Use the same ground reference for your meter that the starter is using (the engine block). I strongly suggest that this is a battery to engine connection problem or the battery itself. I have experienced in the past where the connections are visually clean, even wire brushed clean, but not electrically clean and still did not work. You can prove all of this by using your meter and referencing all of your readings to engine block ground. Then only take readings while the key is turned and held in the start position. All of the above assumes that the coach is wired in the OEM configuration with no modifications to engine and house battery electrical systems. Do not throw any parts at this until you have proven with your meter what the problem is. Ken B. ktcnyc wrote on Sat, 31 July 2021 06:48 > I have good voltage from the engine batt to the solenoid - cables are good and clean. > > Where is this fusible link between the key and the starter? > > What "fuse would be blown"? -- Ken Burton - N9KB 76 Palm Beach Hebron, Indiana
K
kcloutier@nyc.rr.com
Sat, Jul 31, 2021 5:55 PM

John- You were so right in the basic logic -
"Since BOOST works, logic says the problem is on the hot side before the boost junction. Positive battery cable to boost junction or battery itself.
Could also be the Neg cable or connections on engine battery side. You don’t need to look elsewhere as Boost starts it. "

It was a very funky, dirty connection to the ground battery terminal connector.
Moby (my coach) fired right up!

Many many thanks and to all that chimed in

KC

--
Kevin Cloutier -'77 Eleganza II-455, 6 disk brakes, Edelbrock carb, headers, , resident of NYC and Dingmans Ferry, Pa.
'72 MGB-GT & '73 MGB convertible
Member GMCMI since 8/20

John- You were so right in the basic logic - "Since BOOST works, logic says the problem is on the hot side before the boost junction. Positive battery cable to boost junction or battery itself. Could also be the Neg cable or connections on engine battery side. You don’t need to look elsewhere as Boost starts it. " It was a very funky, dirty connection to the ground battery terminal connector. Moby (my coach) fired right up! Many many thanks and to all that chimed in KC -- Kevin Cloutier -'77 Eleganza II-455, 6 disk brakes, Edelbrock carb, headers, , resident of NYC and Dingmans Ferry, Pa. '72 MGB-GT & '73 MGB convertible Member GMCMI since 8/20
KB
Ken Burton
Sat, Jul 31, 2021 8:10 PM

Great.  You got it and hopefully are on your way.

Ken B.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

Great. You got it and hopefully are on your way. Ken B. -- Ken Burton - N9KB 76 Palm Beach Hebron, Indiana
TM
Tom McManus
Sat, Jul 31, 2021 11:14 PM

[quote title=mailto:stu@97381.com, Emery  wrote on Sat, 31 July 2021 11:58]Why would they have it wired so it starts from the house battery? That
doesn’t make sense to me.  There are a lot of reasons it should start from the engine battery.

Emery Stora

Because it works and when something works, life go on until it doesn't. I had a guy that thought that the boost solenoid was the starter solenoid. He
had owned too many FORDS. I have told more than one owner to back away from the vehicle and call a professional.

Tom McManus
1977 Royale

Chesapeake VA

[quote title=mailto:stu@97381.com, Emery wrote on Sat, 31 July 2021 11:58]Why would they have it wired so it starts from the house battery? That doesn’t make sense to me. There are a lot of reasons it should start from the engine battery. Emery Stora Because it works and when something works, life go on until it doesn't. I had a guy that thought that the boost solenoid was the starter solenoid. He had owned too many FORDS. I have told more than one owner to back away from the vehicle and call a professional. -- Tom McManus 1977 Royale Chesapeake VA