find your cold start thermostat

[albert]

i have find in my notes ,,the description for the cold start thermostat,for the cold start injector ( inj,5 ) , we have 4 différent cold thermostat ,,we have the pn. 311-906-161 ,,,-12 to -18 cel. ,,,,,311-906-161 A .... 0 deg. cel. to +10 ,,,,,311-906-161 C ,,,-6 to -14 d.cel. ,,,,311-906-161 B ,,,,-2 to -8 d. cel. we have no reading on the vtvm bellow the first no,,, example if we have the thermostat -2to-8 cel.. the vtvm geeve you ,,o,,reading ( or no continuity ) if we have ,,0 or -1,,,, outside temp. with this note we can buy the exact thermostat for were we live ,, ps,,the type3 therm. is good for the type 4 or 914 ,,albert

[raygreenwood]

Yes!....and they are color coded as well. I know that a great many people over the decades probably had starting issues because they did not have the proper thermostat. This country ...compared to Germany...has way to many climates. Ray

[albert]

yes RAY,, for me i live in the contry with a big randge in the weather ,of + 30 cel,to -30 cel. in the winther,, i use the termostat,,-2to-8 d,cel. or 20to30 de.fr. and my 412 start with no difficultys,,albert

[wildthings]

What do the different thermostats do? At 20°F you need the right amount of fuel for 20°F no matter what the coldest temperatures you see.

[albert]

yes and no,,wildthing,, that is for économy on gaz ,, and the running time for the injector no.5,, beefore the first no. and afther the secon,no. the termostat is of ,,that carbonise your spark plug for nothing and that geeve a bad signal for the cpu ,by the head thermostat ,,ray can geve more long information for that ,, my tech.english is limited,,albert

[albert]

oh ,,wildthings,, last winther i have make one expérience with a fridge cooler room thermostat ,, made by johnson,, the pn. 19abc24 , with capilary tube,of 60inch.long ,with a randge -40 to100 d.fr. witch 1 to 9 dr.différentiel,, and we can adjust this thermostat for many différent situation,, the running time for the swith on , and the adjustable dr.fr. example.. if i adjust the thermostat for 30 d.fr. the inner swith is on at 30 to-40 and if i want 2-3 minutes ,swith,on ,,i adjust the différential for 1 or2 dr.fr. and the injector no.5 stay on for the time i want ,,he geeve me an excellent présition compared with the non adjustable original cold start thermostat,, but it is a bit expensive ,,appx.60.$ with this thermostat i have see the importance for the exact temp. thermostat,, albert

[raygreenwood]

The thermotime switches we are speaking of do not allow the injector to run for more than 30-50 seconds...I can't remember exactly how long they run. It may be just during cranking. Its a ground wire.
Its not designed to be any part of baseline cold starting mixture. Its just that when weather gets cold enough your injection system cannot get enough ignitable fuel into the mix in some situations.
This gives and overly rich mixture for a very short amount of time.

I will look in my Henry Elfrink manual this evening. He gives a really detailed explaination of how teh cold start injector system on D-jet works. In most cars it came as part of the fuel injection system.
This is going off memory now so I may be incorrect.....but in the cars where the cold start is wired in from the factory....the thermotime switch allows it to be turned on...but something in the ECU or starter circuit tells it when to turn off.
In cars that had teh auxiliary cold start system installed....a dealer installed kit version...I can't remember how it worked. I think it only works during cranking when the key is in start position.

Oh...and if you really wanted to be safe and interesting...you could wire your cold start switch up to a toggle up front to operate teh cold start injector when you want and for as long as you feel you need to.

This is useful in places where during the fall months you could easily see 80 degree days, 35 degree mornings and near "0" degree nights during the same month. Places like Kansas , Oklahoma and Nebraska are this way for sure. In that case...sometimes cold start is needed....but the switch you have in it may either nit trigger or trigger too soon or late depending on your enegines state of tune.

Thats another issue. Cars I have seen with D-jet that are still just running with factory basic tuning.....can seem to be more dependent upon needing the input of the cold start injector....and its wide temp range can be a hindrance with some. Tighter tuned cars can sometimes do fine without it. Ray

[wildthings]

At least on the L-jet the cold start circuit feeds off the starter solenoid IIRC and therefore only works when the starter is engaged. Don't understand why one would want a thermotime switch set to your climate? Maybe they sell different switches not for your climate but for other tuning reasons, like manifold design or cam timing. Again if I remember correctly the T4 thermotime switch only runs for 15 seconds max probably to lessen flooding if you don't get a quick start. Maybe other thermotime switches have other time/temperature parameters.

I have at times wanted to have the cold start circuit controlled manually from up front, but then once I fix what is actually wrong with the FI I am again happy to let everything be done for me automatically.

The thermotime switches we are speaking of do not allow the injector to run for more than 30-50 seconds...I can't remember exactly how long they run. It may be just during cranking. Its a ground wire.
Its not designed to be any part of baseline cold starting mixture. Its just that when weather gets cold enough your injection system cannot get enough ignitable fuel into the mix in some situations.
This gives and overly rich mixture for a very short amount of time.

I will look in my Henry Elfrink manual this evening. He gives a really detailed explaination of how teh cold start injector system on D-jet works. In most cars it came as part of the fuel injection system.
This is going off memory now so I may be incorrect.....but in the cars where the cold start is wired in from the factory....the thermotime switch allows it to be turned on...but something in the ECU or starter circuit tells it when to turn off.
In cars that had teh auxiliary cold start system installed....a dealer installed kit version...I can't remember how it worked. I think it only works during cranking when the key is in start position.

Oh...and if you really wanted to be safe and interesting...you could wire your cold start switch up to a toggle up front to operate teh cold start injector when you want and for as long as you feel you need to.

This is useful in places where during the fall months you could easily see 80 degree days, 35 degree mornings and near "0" degree nights during the same month. Places like Kansas , Oklahoma and Nebraska are this way for sure. In that case...sometimes cold start is needed....but the switch you have in it may either nit trigger or trigger too soon or late depending on your enegines state of tune.

Thats another issue. Cars I have seen with D-jet that are still just running with factory basic tuning.....can seem to be more dependent upon needing the input of the cold start injector....and its wide temp range can be a hindrance with some. Tighter tuned cars can sometimes do fine without it. Ray

[albert]

yes wield things ,, i geeve that for the ,,d,,jet ,,injection ,,for the ,,L,, it is différent ,,on the ,,d,, the cold start thermostat stay on ,,for as long the motor is not hot,,more of 30 dr.fr. albert

[raygreenwood]

The thermotime switch does stay "open" as long as the engine is not hot....but...and I have not had time to look at the chart I needed to last night....I believe you are also correct for D-jet that the + connection is given from the starter circuit and you only get fuel while cranking. I think....and as I said this is going off of memory....if it does not catch on the first try, this is so it will still operate on subsequent cranks.

There really is a very detailed explaination in the Elfrink manual. I was just busy at work until late.

The reason why they have different ranges of cold start switch is primarily for those who will be operating their cars in very cold places. Like near or below zero.
The thermotime switch because of its indirect mounting does not really reflect engine temperature. It more reflects engine comparment temperature. In very cold conditions...you may very shortly need to restart if you stop somewhere. In conditions that are very cold....and this has happened to me in temepratures of like 5-10F...that the engine can cool off very very quickly. Add to that...intake air temps that are below freezing and you may need extra fuel to start again even when the oil is warm.
For the fuel injected engines...all of them...there was only one cam timing. The early 411 cam timing was only slightly different.
One thing a lot of people do not realize is that there were at least a dozen different vacuum advance cans available. Most 411/412's got one of two....but when cars were ordered and built to specifications to be delivered to a specific location...it was not uncommon to find that VW put location specific advance cans in.
Cars that I have had came from dealers in Cold places like Denver and Nebraska had differnt advance units than those in moderate climate states. The type 3's I have found to have the same changes. I do not know if this was done by dealers or factory. Its possible the cold start thermostats were done the same way.