EFI bus won't run after it gets hot

[ClimbingNV]

I've been having an issue with my bus for moths now where I can run the bus, but after I drive it around a lot after I turn the car off it won't start again. I think there must be a censor or something that's bad because I've cleaned as many grounds as I can find, replaced the battery cables and everything. Maybe the starter? I'm really not sure what do. When the bus won't start I turn the key and it won't turn over or anything just a low humming. Seriously at a loss now, and I NEED my bus this weekend. Thanks for any help in advance

[busdaddy]

Starter or ignition switch troubles but since you hear the whirring of the fuel pump the starter is more suspect. Removing both battery cables and cleaning both ends of each as well as where they attach is a good place to start, the ground strap at the front of the transmission should also get the same treatment.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!

[SGKent]

common failure for a bay or bug - it is the starter solenoid. It needs to be removed from the starter and cleaned or replaced. The grease inside hardens, and gets dirt in it, then the solenoid sticks, Can happen hot or cold. A temporary fix is a hot start relay. There is no permanent fix because they all do it in time - just a matter of when. Clean wires and grounds as BusDaddy said helps prolong the intervals it happens at to the maximum. More voltage overcomes the friction for many more miles between failures. My 1971 would do it faithfully every 80,000 miles or so - sometimes more sometimes less.
_________________
"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[ClimbingNV]

I'm actually really glad to hear that, I was suspecting the starter but my dad didn't think so. Is there anything strange that I should know about replacing it? Also for the starter seloniod, what is that? I am assuming it's the large round thing next to the starter. But what's it for and how should I clean/replace it ?

[TomWesty]

As I recall, it does double duty. When energized, it pulls on one end of a fork, the other end of which has a gear that engages with your engine flywheel. It also has contacts that close the circuit to the starter motor and cause it to be energized and turn the gear that is engage with the flywheel, thus turning the engine. You clean it by first disconnecting the ground strap from your battery and making sure it won't accidentally touch the post it was disconnected from. Then you remove the starter as per the Bentley manual that you own or just bought. Then you remove the solenoid from the starter and clean the gunk off the mechanisms and then reassemble. You may lube it or not, your preference. SGkent may repost and give you some tips on how to lubricate it.
_________________
If you haven't bled on them, you haven't worked on them.
Visit: www.tomcoryell.com and check out my music!

[ClimbingNV]

I think it's funny that you mentioned your 71 Bus always having the starter issues every 80,000 miles because my bus has 81,000 miles on it 😂

[Wildthings]

The solenoid consists of a plunger that moves axially through a fairly tight bore. The plunger is originally lubed so that it slides easily, but the stock grease dries out with time and causes the plunger to stick in the bore. Relubing is possible as is buying a new soleniod, though a new solenoid may well cost more than a rebuilt starter does.

When buying a rebuilt starter you are also buying someone else's used solenoid that likely also has old grease in it and thus may soon experience problems with sticking.

[sjbartnik]

[Tcash]

Get it to do it and Jump the starter. If the engine turns over the problem is not in the starter.
Please read and understand the instructions and be careful.
Jumping the starter

If the starter works clean the push on connector.
Still don't work.
Test ignition switch.
Ignition switch testing , voltage drop test

Some starter info.
http://www.thesamba.com/vw/forum/viewtopic.php?p=5526134#5526134

Good Luck
Tcash

[SGKent]

all of the above posts that address the solenoid are excellent and say it better than I can. Most long time VW owners who service their own cars have gone thru this drill. Telford even pointed out that the extra electricity these use when they hang are switch killers - which sounds right and I had not thought of that so it is good to get this fixed sooner than later.

I use a little WD40 or more preferably electric contact contact cleaner to wash the old grease and dirt out and spray white grease as new lube. That way I don't have to do more than pull the solenoid off. If one wants to take it apart further there is soldering involved.

You can see the plunger on the left in the photo below from the Internet. Just spray WD-40 / contact cleaner into it while it is upside down so it runs out rather than puddles inside, move the plunger a few times to help clean it, spray it again and wash it out. Then use a moly little grease on it or spray white grease and work it a few times. That usually gets if for another 60,000 -> 80,000 miles. Some folks here have suggested other high temp synthetic greases that may work better. Maybe they will post their suggestions. Other folks will suggest what is called a hot start relay. It allows more voltage to this solenoid so it overcomes the friction (for awhile). I like just cleaning the solenoid and it works almost as well as a new one. Some sit in a platicized / paper tube inside you don't want to use anything that is water based or MEK/acetone/lacquer based to clean it. contact cleaner works well.

_________________
"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[ClimbingNV]

So how do I actually take the solenoid apart? I have it in my garage but now what? The two screws twards the back of the solenoid closest to the plunger are still in and I've removed the two in the front. Help!!

[SGKent]

mark it so you can put the pieces back together. Leave the black cap on

Two screws on the end attached to the starter hold it on. There is also a wire strap and nut. When it comes off it will look like the photo.

Hold the plunger end facing down over a oil drain bucket and spray all around the plunger to wash old grease out. Work it a few times and spray again. That way the dirt comes out and does not drain back into the end with the cap on it. Put a little moly grease and work the plunger, or some spray white lithium grease on it and work it. I use the spray grease only because it can be sprayed into the small area between the body and plunger. Then work it a few times. Stick it back onto the starter and put the two screws back. Then bolt the started back up. You might put a little grease on the nose of it too. DO NOT hook it to a battery while it is out of the car because it does not have a support on the nose side. That side is supported by the bell housing. Bolt it back up. Hook up the wires and prepare to do it again in 5 to 8 years. Don't forget the wire and nut when putting it back together.
_________________
"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[Wasted youth]

I would only like to embellish one thing SGKent mentioned.

If you have the complete, ready to install starter on your work bench, and you are tempted to hit it with a battery to see if it works, you will likely ruin your starter. As Steve mentioned, the nose is unsupported while removed from bus. When it is installed correctly, the free end of the armature shaft is centered and supported by a bronze bushing press fitted into the bell housing of the transmission. Without that forward support, the armature will thrash around when electricity is fed to it, and that thrashing will damage field winding insulation, perhaps so bad as to heavily nick the wiring. You can also screw up the brush and armature relationship if you run it long enough.

This is why you can't take your starter to AutoZone to have it tested. They don't have a setup to be able to mount and support the starter. A halfway decent VW shop will have an old bellhousing setup exclusively for this test.