Hot wire Pierburg (UPDATE)

[wimwolf]

2nd post, here we go...(I try to get some grip on the Pierburg)


Pierburg 1.9DG 1989 (in 1985 VAN (syncro))
Managed to get the wiring as told in the Haynes
idea:The 2nd temp sensor :Thermoswitch F35 (lila-black wires) gives a signal (+) to the solenoid as long as the watertemp is <65°C.
The solenoid is now activated and there's current on the big red cable going towards following elements:

-N1 auto choke
-N52 heater element for throttle channel (what is this?)
-N51 heater element for inlet manifold

The red cable feeding these elements is getting very hot as soon as I turn the key (engine still off). I first thought this was normal and would cool down if the watertemp was +65°C, but even with hot engine and thermostate open (87°C) the thermoswitch keeps giving a signal towards the solenoid, the red wire stays very hot.

Thermoswitch broken? (keeps giving a signal even at 90°C)
Heater element manifold broken? (maybe asking to much current, all the time?)
Something with the choke?

The engine runs fine (high idle though) but starts difficult, so I need to check the choke.

The red wire shouldn't be hot at any time, right?
The thermoswitch must stop giving current when the water is hot, right?

anyone some advice please? I 'd love to get this beast on the road after many ours of work...

thx a lot!

[kevtherev]

OK
I presume you have removed the thermo switch and tested it... and if you found it is on constant, past 70 deg then the thermoswitch has failed.

If the Relay (solenoid?) is stuck (No.1, Junction box, engine compatement.) it will draw current, check it switches off.

The thick red wire should not get hot, if it does it would suggest a dead short. resistance should be 0.25 ohms to 0.50 ohms any higher would indicate a short

Does N1 and N52 get hot also?

N 52 is a de icer in the carb venturi

[wimwolf]

thx!

So I first check the temp switch (put it in boiling water and circuit should be open when hot?)
Relay N1 is fine, clicks on and off when adding/removing current. The relay should be ON untill temp switch2 open, no?

Couldn't measure the resistance for the wire yet. But it gets hot from the moment I switch on the ignition.
I suppose temp.switch is broken and to be replaced and a dead short somewhere...

How to test N1- N51 and N52? I ain't got no clue.
(choke and heater elements for inlet and throttle)

grts.

PS. We had the Rock Werchter festival for 4 days so no time to test anything yet, We do are still alive...

[kevtherev]

thx!

that's a digital sound Co. isn't it?

So I first check the temp switch (put it in boiling water and circuit should be open when hot?)
yes

Relay N1 is fine, clicks on and off when adding/removing current. The relay should be ON untill temp switch2 open
yes

Couldn't measure the resistance for the wire yet. But it gets hot from the moment I switch on the ignition.
I know, you said that already

I suppose temp.switch is broken and to be replaced and a dead short somewhere...
yes dead short in the manifold heater element the resistance test will prove that

How to test N1- N51 and N52? I ain't got no clue.
(choke and heater elements for inlet and throttle)

Do you have a multi meter that measures ohms?

[wimwolf]

Sorry for the late reply.

I measured the resistance (multimeter on (200) ohm) and the manifold heater had 2.1 ohm.
I tried a spare one and it was 3.1ohm.

So the're both broken or I can't measure. (one side on the wire and the other one on the mass?)
Can I easily find-replace a spare manifold heater element?

Thank you.