No Crank when Hot Problem

[RWebb]

1986 VW Vanagon - will not crank or click if the engine is Hot AND it sits for 20 minutes or more

If cold, starts fine.

If hot and sits for 5 minutes (gas stop) starts fine.

I can hear the fuel pump run when I turn the key to Start and all the proper dash LEDs light up.

Entier fuel system gone thru and brought up to snuff; new distr. cap, wires, plugs, etc. Hall Effect sensor wires seem fine and other common ignition problems seem ok (even tho these would affect cold starts too).

Any ideas??

[rusnak]

solenoid. I'd change out the starter.

[sammyg2]

914s have a common hot start problem but not sure if it applies to vanagons or not.

The teener problem is a design deficiency where the entire voltage for the starter solenoid goes directly through the key ignition switch. Putting a seperate solenoid in line takes the amp load off the ignition switch and allows more power to get to the starter solenoid.

I kinda doubt they'd repeat that mistake with the vanagon so it's probably a starter solenoid as previously stated, or less likely just corroded electrical connections at the starter that are making marginal contact.

[aigel]

^^^

Heat soak of the starter. The resistance goes up with temperature, and now, with the same voltage applied, you don't flow enough current to move the solenoid switch.

It may be connections as well, which would limit current as well and combined with a heated solenoid, it may push it over the edge.

That said, I never had this turn out to come from poor connections. It was always the starter / solenoid.

G

[Zeke]

The test is too cool the starter with water at that 20 min mark when it won't start. After a half a minute of cool water flowing over the starter case, it should start. But, you will need what Sam and Geo are recommending if so.

[cstreit]

What these guys said. I fixed mine on the racecar by wrapping it in reflective heat insulator...

Like this: Starter Heat Shield - 7x 22 Wrap [THT-14150] - $30.49 : The ProRaceStore, Racing Parts for the Professional

[john70t]

Originally Posted by RWebb

1986 VW Vanagon - will not crank or click if the engine is Hot

Classic starter. Heat soak.
Check timing and cooling to be safe.

But if just no start, I'd suspect the head temperature or crank/cam sender sensor. First.

Had an 87 Golf which liked to die randomly.
%#$@*&***
Would not start after driving until sitting for a while.
Turned out to be the Bosche fuel pump relay.
Random.

[RWebb]

Thanks all.

Sammy - you overestimated the geniuses at VW - the Vanagon has that exact design deficiency.

What I don't understand is why it will restart fine when hot if it sits for 5 minutes or so (note the problem description in the OP, not just above).

It only doesn't restart if it sits for 20 minutes or more.

I am going to install a relay kit to address the design deficiency, and get a shop to look at the starter & solenoid.


oh yeh - I had a shop inspect the electrical connections at the starter/solenoid - then a year later I did as much as I could myself (i.e. w/o pulling everything apart) - VW has cleverly designed it so the connections are hard to get at...

[Nostril Cheese]

Check your ground straps for before you do anything. After that, starter solenoid.

[rusnak]

Here in Central Kalifornia, when it gets over 100F like it is now, we see a lot of starters needing replacement. My 7.4L truck will eat a starter every few years. It's definitely heat related, as everyone else is saying. I've found that for the nominal cost of changing out the starter for a rebuilt one, it's less cost and less hassle than trying heat shielding blankets, magic dust, polar bear farts, etc etc.....

You might simply go to a high torque starter and be done with it.

[aigel]

Originally Posted by RWebb

What I don't understand is why it will restart fine when hot if it sits for 5 minutes or so (note the problem description in the OP, not just above).

It only doesn't restart if it sits for 20 minutes or more.

It takes time to "soak". The starter / solenoid have a pretty large heat capacity and it takes time for them to heat up after the cooling is off and the heat is coming out of the engine.

G

[Joe Bob]

Sticky solenoid.....whack it with a BFH, replace the solenoid, hot start relay.

[sammyg2]

Here's a pretty good article I've used a couple times, not sure how much applies but it might help.

Pelican Technical Article: Starter System Troubleshooting

[RWebb]

Thanks again - I guess the thermal mass is high and it does not reach as high a temperature when moving b/c of the air flow.

BTW - a PO had the starter replaced in 2003; that was 31,000 miles ago

oh yeh - while stranded on said back road, I spent a while hitting the solenoid with a specially constructed stick (VW Tool # 1234-666)

also, Cu has a temperature coefficient of resistance of ~ 0.4% per oC

[aigel]

Originally Posted by RWebb

Thanks again - I guess the thermal mass is high and it does not reach as high a temperature when moving b/c of the air flow.

Exactly. Same thing can be seen on the temp gauge of a water cooled car. After you shut the engine off, the coolant temp actually goes up!

G

[john70t]

Originally Posted by RWebb

oh yeh - while stranded on said back road, I spent a while hitting the solenoid with a specially constructed stick (VW Tool # 1234-666

Universal tool rock-on-side-of-road (#whatever) also works in a jiffy.
It either spins the motor/engine, or it dont.


Just one of the situations where folk wisdom proves true.

[RWebb]

nope - you cannot get a rock in there, unless you find a fossilized dildo...

[sammyg2]

Years ago, went to the pomona swap meet in the 914 turbo just after I got it running.

It started raining right after I paid the $12 gozillion for parking.

I found a parknig spot and sat there waiting to see ift he rain was gonna blow over. It only got worse.
After a while i decided to heck with this, I'm outa here. Onlist problem was the started didn't wanna work.
So there i am, laying under the car in a 1" deep puddle of water in fricking January, using a screw driver to short across the poles to engage the starter.

It worked but I couldn't have gotten much wetter if I had jumped in as swimming pool.
Kinda scarred me and now I'm allergic to starter problems.

The next day I replaced the starter and solenoid, added a second ground strap, replaced the connectors, fixed the ignition switch, and added a hot start solenoid.
I hate fricking starter problems and made darn sure I never had another with that car.

If my 3 year old truck developed starter problems that happened more than twice I'd trade the POS in.

[GH85Carrera]

Originally Posted by RWebb

nope - you cannot get a rock in there, unless you find a fossilized dildo...

That is funny right there.

My 911 had the same problem. It would work fine in town even on very hot days. Only on long trips after several hours it would just lock up when completely heat soaked. I had the great fortune to be parked right in front of the Hershey Hotel with a huge crowd trying to check in and my starter locked up. The good news is there were several people there to push start me.

I bought a replacement Bosch starter and that solved the problem. However the Bosch reman starters are a POS. It started haveing problems engaging the flywheel. I had the old one rebuilt. The guy said it was dry inside and it would be fine. My first long trip proved that was not true. I had the reman starter back to the shop for a new solenoid. Swap it back on and no hot start problem. It started haveing the same solenoid problem.

Since my engine is out right now I put the high torque starter from Pelican on it. I will scream if I have any more problems. I havee two Bosch starters I can sell!

[Turbo_pro]

Originally Posted by RWebb

nope - you cannot get a rock in there, unless you find a fossilized dildo...

Just a couple more birthdays and it could be your new user name...........