Electrical Problem on GMPD4106 (Success!!!)

Fred Mc · September 27, 2016, 03:38:23 PM

First, a little background.

I have had a starting problem on my 4106(12V).Bus would start fine when cold but not after warming up.
So I took starter out and had it rebuilt. Rebuilder found some problems and fixed it.
So I put the starter back in and when I turn on the ignition I get nothing. Normally there is a sound of a solenoid in the engine compartment engaging. Also no power anywhere else on the bus.
BUT, if I manually engage the starter by pressing the contacts in the starter relay the starter will engage.
Other than removing and replacing the starter I haven't changed anything.

ALSO, when I put a test light on the negative terminal on the starter and touch the engine block with the test light there is a dim light which indicates to me there is power there .

Any ideas?

Thanks Fred

Utahclaimjumper · September 27, 2016, 03:57:25 PM

You should have no amprage between the two, the neg. terminal should be bonded to the block.>>>Dan

luvrbus · September 27, 2016, 04:12:54 PM

Nothing wrong with the starter if it engages just be sure you have the ground wire ( one of small terminals) the one close to the block from the solenoid connected to ground terminal on the end of starter not to + side

Fred Mc · September 27, 2016, 04:24:24 PM

"ou should have no amprage between the two, the neg. terminal should be bonded to the block.>>>Dan"
Is it not bonded through the starter frame?

Utahclaimjumper · September 27, 2016, 04:49:06 PM

It should be connected to the block and from that same point back to the battery bank negative. This isnt your fathers buick >>>Dan

Fred Mc · September 27, 2016, 05:59:37 PM

Clifford, I just want to confirm what you said about the ground wire (the one closest to the block) is connected to the negative (terminal on starter) cable. In fact it appears that wire is reversed with the other one. So the wire that comes from the realy(I presume) is closest to the block. I don't want to start willy nilly swapping wires and damage the starter. It is such a bi*ch to remove/replace.

Thanks

Freed.

bobofthenorth · September 27, 2016, 07:01:13 PM

Pictures would be very helpful.

Fred Mc · September 27, 2016, 07:14:17 PM

The 3 connections on the positive lug are the cable to the alternator, the positive cable to the batteries, and the connection to the bus electrical system.

Utahclaimjumper · September 27, 2016, 07:29:58 PM

The small terminals on the starter solinoid are marked..( "S" is for switch(the relay) The "connections to the bus electrical system" should get power from the alternator stud...(at the alternator)The ground wire from the solinoid sould go to the large ground stud coming out of the end of the starter, and from that same stud to the ground point on the block & back to the bank..>>>Dan

luvrbus · September 27, 2016, 07:38:39 PM

Hard to tell from the photo, do you have a cable going from the back terminal on the starter to the engine block ?

Fred Mc · September 27, 2016, 08:01:02 PM

Just went out and checked and the wires on the solenoid were on correct.
And no, I do not have a cable going from the back of the starter to the block.There never has been one there in the 25 years I have owned the bus. Could that be the problem? It does seem odd though that it was never a problem before. Is it possible the rebuilder changed something when he rebuilt it? Its easy enough to try though.

Fred.

eagle19952 · September 28, 2016, 08:23:35 AM

Quote from: Fred Mc on September 27, 2016, 08:01:02 PM
Just went out and checked and the wires on the solenoid were on correct.
And no, I do not have a cable going from the back of the starter to the block.There never has been one there in the 25 years I have owned the bus. Could that be the problem? It does seem odd though that it was never a problem before. Is it possible the re-builder changed something when he rebuilt it? Its easy enough to try though.

Fred.

there isn't much to change..and still reassemble it.

Fred Mc · September 28, 2016, 11:15:17 AM

Turns out that the problem was no negative cable between the starter and the block which a couple of you pointed out..This is REALLY puzzling.
A few years ago I moved the batteries to the old a/c compartment and ran the battery cables directly to the starter and everything worked fine EXCEPT it didn't want to turn over when the engine was warm. And THERE WAS NO CABLE BETWEEN THE NEGATIVE POST ON THE STARTER AND THE ENGINE BLOCK. I know I'm getting old and stupid (according to my wife) but NOT that stupid.

At any rate finally took the starter off and had it rebuilt. Last night I was on the Delco Remy website reading about these starters and noticed there is a model that the case is grounded and one where it is isolated. I'm going to talk to the rebuilder to see if MAYBE he changed the case. That is the ONLY thing I can think of.
Anyway it starts and runs and I will test it now to see if it will restart when warmed up.

Thanks for everyones help.

Fred,

luvrbus · September 28, 2016, 11:21:22 AM

Good for you,I usually hook the negative from the battery to the starter end and then use a cable to the chassis for a ground on GMs, grounds are always a problem on 1 it seems.They usually don't use a case ground with a aluminum bellhousing fwiw

Fred Mc · September 28, 2016, 01:47:31 PM

Well, looks like I spoke too soon. After having the starter rebuilt I'm still faced with the same problem-that is when the motor warms up it won't start. Starter engages but can't turn engine over. Only one thing left to try before selling it I guess. Im going to replace both cables from batteries to starter. I have 3 brand new 850cca batteries and even with the 2 from my truck hooked up(total of 5 x850cca) still the same problem.