No-Start After Plugging Into Shore Power

[KurtFranz]

Hello Folks-

2002 190 Chevy Versatile - Here is the scoop.

Van was starting fine prior to all of this.........

Was getting ready for a weekend trip and plugged into shore power to pre-cool the refrigerator. Was plugged in about 4 hours or so. Was all loaded and ready to go and turned the key to start the van and click click click the starter went.

So - I got the jumper cables out and tried that - no change in the situation. Checked the cables and terminals for any corrosion - none at all. Checked the battery with the meter 12.8 a few mins later it was 12.7 and it stayed there.

Figured I would try starting it one more time for the heck of it - and it fired right up.

So, I plugged it into shore power again for a while and the same thing happened. After I disconnected both battery cables again and then reconnected it fired right up. I let it sit over night and it fired right up.

My initial thought is that one of the relays is getting tripped which corrects/resets after the power is disabled. My thinking is that it has something to do with the isolator malfunctioning which is disabling / reducing power to the starter , lights etc.

The house battery is charging when the engine is running and there are no issues with the DC side of things. It is definitely related to the AC side.

Possibly something with the converter?

No need to reply to this with a lecture on how the isolator does noes not charge the engine battery etc....

Just want to know if anyone has had this happen and what was done to correct it as I do not want to start throwing parts at it.

Thanks much
KF

 

[KurtFranz]

Our AI friends all say it is the isolator and I have read all of that stuff so no need to repost anything derived from that. Just want to hear from someone who had the exact issue and what they did to fix it.

AI is quite often wrong and I do not usually trust the initial answer.

Thanks

 

[booster]

Personally, I don't off hand see how that could happen as all wiring diagrams for isolators could find showed the van starting and running connections not going through the isolator, just the charging. It would have to be doing something like taking the alternator output to ground or something similar to get the voltage drop to cause the no start.

You have an adequate battery at 12.8v and a jump didn't help. It would probably would be good to check the battery voltage at the battery and starter while trying to turn the engine over as the clicking is normally a cable, starter or relay issue. You mostly know the ignition switch is working as it does try to start with the initial relay or the starter relay making noise.

Most of the time that symptom would be a bad connection at the battery, starter, or in the engine ground strap or a failed starter solenoid. It could, however, be a failed relay that is not giving full voltage to the starter solenoid, but that should happen more of the times you try to start.

None of this explains why the van starts when unplugged in the two tests however. To test that I think you could disconnect the charge line from the isolator to the alternator and the excitation wire to the ignition at the isolator.

But first, I would do some more tests. Have it on shore power and try to start the van. If it doesn't start turn off shore power and see if it starts. If it does start then just turn it off and plug back in to confirm it is the shore power causing the no start.

I did a similar AI search and got random answers that conflated isolators with relay type charge relays/separators so nothing that really made any sense. Most of the time it thought the voltage was dropping because the relay closed and the coach took all the power, but that shouldn't happen if you are on shore power and the coach battery charger is on and working (have you checked that it is charging on shore power?)

 

[TX-Trek]

This may worth a check....

I've encountered failing relays in the underhood GM fuseboxes, particularly the Powertrain and the Starter relays. Over time, heat and thousands of cycles they can fail suddenly or weaken.
Powertrain relay failure will kill the engine.
Starter relay failure will kill the starter.
Depending on the wiring logic, failure of either or both will kill the fuel pump.
Weak relays- intermittent strange things happen. Sometimes all normal, sometimes things don't work.
I carry spares of these relays, easily obtainable. Usually both will interchange with each other and one or two other relays in the fusebox. Easy to swap out to check or replace.