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VW Starter problems

professor229

New member
Good morning... I got an education two days ago after a long long day...... I worked in my garage on a new shed project, and needed a sheet of fiberboard in the rafters directly above my Sterling. Obviously it was a good idea to move the Sterling out to the driveway so I didn't make a major screw up and drop a 4x8 sheet of fiberboard on the car. I unplugged the trickle charger that is on the battery, turned on the ignition toggle switch, and pressed the momentary button to start the car. As always, it started like a champ and I parked it in the driveway. So... what's the problem? When I was beat, ready to call it a day, it was time to start the Sterling to move it back to its home..... I hopped in, turned on the ignition toggle switch (coil) and pressed the momentary button to turn the starter.... and got.... nothing....This has happened before and was one of those electrical gremlins that required research, but that was a few years ago. I remember finding a possible/probable answer to this, but forgot all about it until I was sitting in the Sterling in the driveway, thinking that perhaps the momentary switch was faulty..... and that was my first intervention... Testing that switch is not the easiest of tasks because I fabricated an overhead console for the car for that "cool look" and built in some LED lights to indicate the accessories toggle switch and ignition toggle switch were "on"...... along with a NASCAR type push button momentary switch to engage the solenoid on the starter..... and yes, it did look cool but getting the momentary push button switch out to see if there was a bad connection, broken wire, or just plain old faulty switch (it is over 20 years old) meant that the console had to come down off the ceiling of the car.... I bit the bullet and had a built in hanger so now I have a rather large (relative) console hanging down next to me. I examined the wiring and it still looked as good as the day I installed it. So I removed the two wires to momentary switch, and had the switch in my hand. The next thing to try was like you see "in the movies" where the hero touches the two wires together to complete the ignition sequence and the starter should work.... in other words, I simply eliminated the momentary switch which. if bad, meant that touching these two wires together SHOULD HAVE sent some juice to the starter solenoid..... and the starter should have worked. It didn't.

But, I took the momentary switch and my electrical tool box to my boat.... Why? Because that is where I have my 12 volt trolling motor batteries. I hooked up the test light in line with the momentary switch and pressed the momentary switch button... The test light lit up perfectly meaning the momentary switch was just fine and working properly. Remember, I had just been through a long day, have an overhead console hanging down and at that point I was ready to just push the car into a garage stall until the next day but decided to do one more intervention.

A long time ago, trouble shooting micro computers, I was told to "check the obvious" instead of over-analyzing problems, looking for some kind of common fault. Then it hit me. Whenever I started the car in its home with the trickle charger indicating a full battery charge (and yes, this happened both with a decent Delco battery and now the new Interstate battery so you can eliminate a bad battery from this equation too) with a green light, I had NO PROBLEM getting the starter to turn. The problem was ALWAYS after that initial start and backing it out or taking it for a very short drive, shutting it down, and then a starter failure. But if I used a set of jumper cables, there was no problem starting it again. Hmmmmm

So in this case, I plugged in the trickle charger (it's a good one $$$$!!!!!) while the car sat in the driveway, and the trickle charger, as you might expect, showed red meaning it was charging and the battery was not fully charged, presumably because I ran the starter, and used the linear actuators a couple times, causing a slight voltage drop/battery drain. After reinstalling the now confirmed good momentary switch and waiting a few minutes, I pressed the momentary switch button and bingo, the starter turned fine and the car started fine.... With the console still hanging there, I drove it back into its home, shut the doors and called it a day.

Then it all came back to me.... something about a VW solenoid demanding a full 12 volt pulse.... and anything less or even a slight voltage drop would not let the solenoid "do its thing." This fiasco kind of confirmed that theory, and the solution is to drive the car for some time to let the car's charging system charge the battery. But that is not always the case these days. More often I just start the car and move it a short distance so the battery does not recover to a full 12 volts again..... in other words, not enough battery charging time on the road....

When I researched this problem years ago, there was a major discussion on The Samba site discussing older VW starting systems and the fact that they demand 12 volts.... and the solution was to by-pass the VW starter solenoid, and install a good old fashioned Ford solenoid to engage the starter motor. In other words (again) the VW starter solenoid is too demanding.... and a Ford solenoid is more forgiving and does not require a full 12 volts (even six volts will make it function). This morning I researched looking for the schematic/diagram of this Ford solenoid installation and found the You Tube video below that was decent and explained it, relative to a VW starting problem, extremely well. And in the commentary below the video, someone wrote the quote that more/less confirms what happens....

Now, my question.... Considering that the problem is probably the original VW starter solenoid, would a brand new VW solenoid/starter rectify this? Is it possible that the solenoid has deteriorated enough to where it requires an exact 12 volts to start? And would a new solenoid be a little forgiving on this and not as picky? OR.... Should I just do the obvious, and buy a cheap Ford solenoid, install it and smile a lot? Has anybody developed an aftermarket starter/solenoid that can be installed on a 1971 VW motor that is not as picky?

Has anybody else installed a Ford solenoid or had a reason to? And yes, I realize that if I drive the car a longer distance, the battery charges and this should not be an issue... and I have contemplated carrying a second fully charged battery and jumper cables with me on a short distance run to a store.... just in case.... It's really tough to look cool standing next to the car when it won't start.....

Two cents appreciated..... below is the quote from below the video and yes, there are several other VW owners who have had this same problem who commented also.

Have a good one!!! Dennis

"And the reason why the vw's do that is because the bosch or german solenoid's need a full 12V + to work and it loses about a 1/2 Volt along the system for some reason, resistance/connection ect. just use a ford solenoid the ford work's with only 6V to complete the connection. Great vid "

 

farfegnubbin

Site Owner
Staff member
That's a nice write-up on the diagnostic process for this problem. And it's great info for someone who might be having this same problem with their Sterling (Cimbria, etc.) I haven't had that particular problem with my cars but only one has a VW engine. I also didn't build that car so I don't know whether it's the VW solenoid or an aftermarket one.

From the position of a detached observer I'd say I can't really think of any reason to NOT just switch to an aftermarket solenoid that isn't so finicky. I think I read (from your cache of info) that the Ford solenoid will still pull in with much less than 12v. It's always nice to build a safety-factor into any system.

I've had a project car or two that required a robust 12v for the ECU to run, which always frustrated me. If the car sat for a while I'd often have enough juice to turn the engine over (which is obviously a high draw) but the car wouldn't start because the ECU apparently needed like .2 volts more than was availabe, which was annoying. I'd say if you can eliminate any annoyances like that, do so.
 

letterman7

Honorary Admin
Hi Dennis. Huh... well, I'm guessing you're talking about the solenoid that is piggybacked to the starter and not an independent solenoid in the circuit to draw the power from the starter (to/from the battery). To be honest, I've never had a separate solenoid in that circuit - I've always run a wire from the key switch to the starter. Not proper (I think I did fuse them though), but it worked. Every time. Now, if you're talking about the piggy-backed solenoid on the starter itself that operates the Bendix, you have to stick with the proper VW replacement. Personally, I'd go ahead and find/purchase an automatic gearbox starter as a) the Bendix is self-supported (no bushing needed in the transmission housing) and b) they're a little more robust. A new starter like that can be a little salty, but eliminates a few problems : http://vwparts.aircooled.net/Bosch-SR-17-Starter-Rebuilt-12-Volt-SR17-p/sr-17x.htm
 

professor229

New member
Hi Dennis. Huh... well, I'm guessing you're talking about the solenoid that is piggybacked to the starter and not an independent solenoid in the circuit to draw the power from the starter (to/from the battery). To be honest, I've never had a separate solenoid in that circuit - I've always run a wire from the key switch to the starter. Not proper (I think I did fuse them though), but it worked. Every time. Now, if you're talking about the piggy-backed solenoid on the starter itself that operates the Bendix, you have to stick with the proper VW replacement. Personally, I'd go ahead and find/purchase an automatic gearbox starter as a) the Bendix is self-supported (no bushing needed in the transmission housing) and b) they're a little more robust. A new starter like that can be a little salty, but eliminates a few problems : http://vwparts.aircooled.net/Bosch-SR-17-Starter-Rebuilt-12-Volt-SR17-p/sr-17x.htm

Wow... sticker shock!!!! I might research this a little further but there has to be an aftermarket starter out there that I could try... but for now, I will just go with what I have... My theory on this has proven to be true several times as I do use an expensive trickle charger and every time I go to start the car there is no problem.. What I need to do is to drive it around for a good half hour and park it back in its home and then try to start it after the car's own charging system has had time to fully charge the battery.... I suspect there will be no problem.... In a different car I restored, a 1971 240Z, there were also "starting problems" and I spent a lot of time researching that until I found out exactly what the problem was... There was a voltage change through a special coil for this car... I don't quite recall, but I think when the ignition key was turned, the car started and it ran on nine volts, not twelve..... So if you bought a standard old 12 volt coil, it would burn out in short order.. I think I have that right... it's been awhile... but at the time, that problem was a nightmare....

Today I took pictures of the enclosed snowmobile trailer I used to store the car... The Menard's shed that I added four feet to as a covid project, now houses the car.... The snowmobile trailer became expendable....

Thanks for all the advice.... Does anybody know if there is a more reasonably priced starter for a 1971 engine? Am I right in assuming that the starter/solenoid might just be old enough to be finicky?

Have a good weekend!!!
 

letterman7

Honorary Admin
Yeah, they can be salty. There are aftermarket mini-starters that seem to have become popular elsewhere on that site (and I just pulled that site from saved VW pages - there are many out there, so you can kinda pick and choose). The other option is to simply take the starter to someone to have rebuilt. Around here, it runs about $65.00
 
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