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Sun Apr 15, 2012 9:07 am

When I start my 1983 Air Cooled Vanagon on a cool morning, it starts right up within 2-3 seconds of cranking. If it stalls, or even if I just shut it off, before driving 5 minutes or so, it is difficult to start again. The starter turns the engine fine, but it just does not ignite. I finally get it going by holding the start engaged for at least 10 seconds, and then it starts and sputters like it is only running on a couple cylinders, then smoothes out and runs fine. Once warm, restarting is no problem at all.

I remember seeing a post here recently, where the poster had the same problem. They would have to unplug a wire, I believe the white wire, from the coil, replug that wire, and then it would again start fine. Someone suggested a sensor that cost under $20 as the fix. That poster also had an Air Cooled Vanagon. I have searched and searched, and can no longer find that topic.

Can anyone point me to that topic, or tell what the sensor is that causes this kind of problem?

Sun Apr 15, 2012 10:10 am

there's really a bunch of things it could be.

you are describing though the injector pulse wire on the coil & temp sensor 2 on the 3/4 head.

does it stall when cold often?
I bet the problems are related.

Sun Apr 15, 2012 10:19 am

It is an automatic, and stalls when the transmission is engaged, but at a stop, and only for the first few minutes. If I sit five minutes and let it warm up, it runs fine even when stopped and the transmission is engaged.

It starts wonderfully the first time, but even if I shut it down after only a few seconds, not allowing anything to warm up, I still have the hard start problem. The post I remember, but cannot find, seemed to have the same problem.

Is THIS the part you are refering to?

Sun Apr 15, 2012 2:48 pm

yes that is TS2.
never hurts to replace it, but your symptom is not sounding like it's TS2 related.
you can test it's resistance w/ a multi meter.
you'll find the specs in your manual & here too:
http://www.thesamba.com/vw/forum/viewtopic.php?t=482560

when you start cold, what RPM does the engine run?

I don't know all the ins & outs of auto trans even though I own one :oops:
but I'd be looking at doing a basic full tune up, test fuel pressure and look for vacuum leaks--focusing around the AAR and cold start system.

Sun Apr 15, 2012 2:58 pm

I would also have a look at the aux air regulator.

Sun Apr 15, 2012 3:45 pm

I don't know what RPM it idles at: no tach. I forgot to mention, that a change of the AFM did not change the symptoms. I think I will go for the full tune up before looking too far: have not done that since last summer, and there was a 4500 mile coast to coast trip in between.

I was at the recyclers, and picked up a FI harness, temp 2 sensor, thermo time switch, and auxillary air regulator. If the parts are good, I should have what I need: that just about covers the whole FI system, except for the injectors and ECU.

I wish I could find that post I mentioned above. As I recall, the poster had just had work done on the engine, and figured out the disconnect/reconnect the coil (or something like that ...) and took it back to the shop to show them.

Mon Apr 16, 2012 10:10 am

I think you were referring to my vans symptoms. It's related to the cold start valve, I had the van at the shop for two days, they switched the location of the cylinder head temp sensor to be at cylinder #2, and grounded the three white wires to the Egr. Then they disconnected the cold start valve and it starts up every time.

Mon Apr 16, 2012 1:00 pm

This is a typical and almost universal problem with these engines during cold weather particularly at altitude where the engines already run a bit rich. Since the TTS switch senses heat from the block and the block heats up very slowly, the switch will cause too much fuel to be dumped in while cranking if the engine has been allow to run for only a few minutes before being shut off and restarted. Unplugging the harness from either the TTS switch or cold start valve will do the trick.

I have seen this countless times at ski areas. People come down to their vehicles at the end of the day and immediately hop into the driver's seat and start their engines. After the engine has run for a minute or so they realize they need their keys to open up the back, so they shut their engines off and unlock the other doors. Then when they try to restart their engines and it is a no go as the TTS still thinks the engine is stone cold, but the heads are already hot enough not to warrant the addition of any extra fuel.

Replacing your TTS sensor will likely help with this, though may not fix it entirely.

Mon Apr 16, 2012 1:55 pm

@ShultzRoadHouse: Yes, that was your post I was talking about. Odd, I looked at the thread a few times, but just did not see the actual post I was looking for ...

@Wildthings: Sounds like it, but does it really warm up that fast? If I shut down after less than 5 seconds running, I have this problem. Really: 5 seconds, or less. That is what leads me to suspect a faulty electrical piece: I wouldn't think 5 seconds would warm the engine up. On the other hand, if I warm it up five minutes, it will start again fine. It almost seems like I am warming something up with the long cranks of the starter, and then when it finally catches it sputters, like running on less than 4 cylinders, for a minute, and then is fine. In any event, I will start with a fresh tune up before looking too much further. For now, I just make sure it does not stall for the first couple of minutes, and then I am fine.

Mon Apr 16, 2012 2:25 pm

The Temperature/Time switch (or is it the Time/Temperature switch???) is both time and temperature sensitive. It senses the engine block temperature and then indirectly the amount of time the starter has been cranking. Combining the two it tells the cold start valve whether to add extra fuel when cranking. If it is too slow to open it will tell the CSV to dump in fuel when it shouldn't. I think it operates up to around 90°F ambient, but for a very brief period at higher temperatures. If it tends to stay closed too long for the temperature, you could get an initial start, but still have the CSV adding extra but unneeded fuel on restart, even if the engine has only been run for a very short period.

I have found many L-jet systems run too rich immediately after starting as well. Sometimes putting something like a 3000 ohm resister in parallel with the TSII sensor can give a better leaner mixture in the first minute or two of running without affecting the mixture once the engine is hot.

Mon Apr 16, 2012 2:36 pm

Thanks, Wildthings, for the detailed description. I will do the tune up first, and then I have all the FI electronics from another CV/Jetronic engine in case the tune up alone is not enough. Glad to get a better understanding on how it works.

Mon Apr 16, 2012 5:18 pm

TTS = thermotime switch.

When the engine is below about 90º, it will give about 8 seconds of fuel to the cold start valve. If the engine temp is above that, it doesn't do anything.

Might want to have a look at the AAR. That little 90 º boot can split and will do what you are describing.

Mon Apr 16, 2012 8:50 pm

Is that the switch under the right side of the plenum? If so, then that would make sense, its an original part I haven't replaced yet. It's a rare and expensive part.

Mon Apr 16, 2012 9:19 pm

Yes, the Thermo-Time Switch is under the plenum. The Auxillary Air Regulator is just to the rear of it.

Tue Apr 17, 2012 11:32 am

Don't replace either of them until you test by means of the Bentley manual to see if they really are at fault.

I have never seen a TTS go bad, but I am sure it can happen. If yours is indeed NFG, send me a PM. I think I have one around someplace.

Sometimes the AAR has to be taken out, cleaned with Gum Out, impedence tested to see how close it is to 30 ohms, and the little round door is adjusted correctly.

This way....

http://www.itinerant-air-cooled.com/viewtopic.php?f=50&t=7834

Tue Apr 17, 2012 11:38 am

The thermal time switch works off of ambient temp, but also has a heating element in it. That means that when you test it on a cold engine, after a couple times with the key on, the time switch electically turns off and needs to cool off again.

Sun May 13, 2012 3:24 pm

Well, the weather has warmed up, and that may effect things. In any event, I put in new rotor, cap, and wires, and that did not help. Today, I put in new plugs, and a used Auxillary Air Regulator, and so far it seems to "second start" much better. Looking through the AAR, I did see that it was a little less open at rest than the replacement unit. Both units measured between 30-32 ohms on the bench test.