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Date:         Sun, 24 Jan 2016 18:31:26 -0500
Reply-To:     Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject:      Re: no start?
Comments: To: Michael McSwain <michaelmcswain@GMAIL.COM>
In-Reply-To:  <CAE_mVa2DZA4pi8_o07ry9ZzZECuqVQ7aOKj4Ywa3W+JT3=kdBA@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"

When you say no start, should we assume that the starter is no turning the engine over? Based on you slow cranking past I'll begin there.

If we are going to do our own work we need to learn how things are designed to work and follow some plan for diagnosing things that go wrong. For things electrical you have to start either at the beginning or the end and work your way over. Often things are not as simple as the power is on or not. Especially for battery circuits there is an important relations ship between the load, voltage and current. Most of you can't measure current on high amp circuits so some assumptions may have to be made.

Let's begin at the starter. The starter consists of two main components, the motor and the solenoid. The solenoid has two functions. When triggered by the ignition switch the coil pulls in a plunger which extends the starter pinion gear and closes a contactor to connect the starter motor to the battery. So to test get your handy multi-meter set to DC (Usually 20V range) and connect it to the starter solenoid coil terminal and a ground close by. With the key turned to the start position you should see at least 9.5 volts here. If yes, the solenoid should click, pull, try to do something. Release key. Using a wrench on the alternator pulley gently turn the engine clockwise. If you feel-hear the starter gear snap back you know it tried and got stuck part way. This is where that hammer trick sometimes gets a starter to go. If the gear does not fully extend the contacts for the motor will not close so no crank.

Now there are a number or reasons this may happen. Insufficient current to the coil, worn gear, no tapered edge, bad coil, mechanical problem including starter bushing, etc. If the gear is not moving at all, (didn’t jam) these conditions may also apply. In addition if the solenoid end gap (plunger positon at rest) is not right extra voltage-current is needed to get the plunger to begin moving at all. This is a common problem on very old-worn out units and also plagues a lot of rebuilds. Even when the solenoids are replaced somehow this is not corrected. This is probably what really get compensated for with a starter relay add on. Yea lets install a relay to get the relay to work! Of course weak wiring and bad connections can call for this but that will show up in the voltage you should have checked earlier.

So after ruling out the solenoid action we then need to check the if the contacts on it are closing. So get that same meter and connect it to the terminal that connects directly to the starter motor. Turning the key to the strt position the solenoid should pull in and we should see battery voltage on that connection. If we do and it doesn’t turn then we need to look at a few more details. If no voltage at all probably a bad solenoid contact. If some voltage, how much? This is also important for addressing slow cranking. If the voltage drops much below 10 we need to determine the cause. Excessive starter motor current, battery not capable of delivering the current, bad battery, ground cables-connections. So now to work our way along the circuit to figure out where the losses are occurring. So go to the battery and check the voltage there while trying to crank the engine. Should be within 1-1.5 volts of what was at the starter. Next step is where the current meter comes in real handy. If the starter is drawing 400 amps and still not turning it is the problem. If <150 amps then you do not have a good current supply, either battery or cables.

Ultimately consider getting one of the GoWesty starters. These use a different (modern) permanent magnet and gear reduction instead of field coil design that simply needs much less current to get the job done. The solenoids are also much improved. I have been using these for about three years now. Even on the automatics they make all that intermittent crap go away. They so far just work.

Dennis

-----Original Message----- From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Michael McSwain Sent: Sunday, January 24, 2016 4:04 PM To: vanagon@GERRY.VANAGON.COM Subject: no start?

So where would you start? The past couple of times I got in my van and cranked it up, the engine would barely turn over, but after two or so revolutions it started. Until it didn't. I have one of those cigarette lighter volt meters and after sitting overnight it reads 12.6 volts. When I turn the key to crank it, it doesn't drop below 11.5 volts or so. I put a trickle charger on it just to be sure, but it still won't start. Currently I hear no noise whatsoever when I turn the key except for the fuel pump priming. Before this started I regularly watched the plugin volt meter and while running it stays at or over 13v. So I'm pretty sure it's not the 1.5 year old battery or the age unknown alternator. I assume that's a safe assumption. If you disagree I'm all ears. So if it's not the battery, would a bad connection be the next most likely place to look and if so where? The only place I've checked out so far is the actual battery which shows no signs of corrosion at all.

Thoughts?


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