wanted: eberspacher advice

[beetlemandan]

I'm trying to troubleshoot my 69 beetles eberspacher. I've got it to light once, but it will not light again. the tag on the heater claims it is a B2 model.

can somebody tell me why the light on the heater vent in the cab doesn't light up when the heater is turned on? or is it a warning light only? I also pulled the glow plug out and it only heats up to about 250f, and the weird voltage drop coil thing under the heater gets just as hot. I tried jumping some extra 12v power to the plug when its running to get it to ignite, but it just pops and farts, but its like the fuel just burns to fast.

I got fuel going to it, I know I have air, just no sparky. 

[WESTY69]

I was told  almost 20 years ago , bench test first , those heaters are known to to up quick , for gawd sakes be careful !!
I hope you can get it going safely , good threads on samba as well

[pittwagen]

Well good on you for doing this now and not when it gets cold!!

I would do the following:

- download the appropriate manual from the Samba and follow the trouble shooting procedures.

- I have found in rebuilding many of these over the years that the contacts are problematic.  Clean each one and make sure they are tight.  Many will look ok but are loose and when you go to tighten them they break off.

- does the fuel pump actually pump gas? Check the fuel pump points and the pump output.  The diaphragm in the pump is usually hard and won't pump fuel.  You may need a new one and you will have to speak very nicely to one of us that has replacements or the appropriate material to make a new diaphragm.

Bruce Tweddle is the expert on B2's.  He runs one in his 75.  He likes the simplicity of the early heaters.  I'm sure he will chime in when he is available.

PS.  I gave Steveo_32 two tested and running B2's a while back but I think they got tossed in their move.  I pretty much concentrate on the later stuff now.

[beetlemandan]

I know what you mean about the loose contacts, I've found a few already, and have been scraping off the 45 years of corrosion as well.

I'm getting about a tablespoon of fuel per minute out of the pump, which jives with the .7 liters/hour fuel consumption that the heaters claim to use.

it would be really nice to have a factory fresh 1969 beetle right beside mine so I could break out the multimeter and start comparing. there really isn't a whole lot to these furnaces, but this a virginal experience for me. I've never gotten the chance to learn what and whys to them.

my hunch is that the resistor thing before the glow plug just isn't delivering the amps needed. it produces 12v without a load, but near nothing when the plug is hooked up, the test light just barely glows.

[BUSDADDY]

All the glow only heaters won't light unless they are getting a full 12V or more, a weak battery or even just not having the car running is enough to keep it from lighting up. As already mentioned good wiring is very important but don't forget the grounds in there as well, all those electrons need to go somewhere.

[pittwagen]

Read this.
http://www.thesamba.com/vw/archives/manuals/heat_ac_shop_manual/f5.pdf

First one in heater section. Scroll down. Download the B2 pdf.

Further to what  Busdaddy said, you will need 12.7 volts+.  I always use a battery just off the charger when starting an old heater.

[beetlemandan]

after cleaning every wire connection, a new ground, then borrowing a multi meter, I have the culprit(s)!

the wiring to the heater is only delivering about 10 volts while operating, even with the engine at about 1800 rpm. so I grabbed a spare battery and some heavy duty jumper leads and brought it up to 12 volts when operating.

but...

the weird resistor-coiled wire device seems to be limiting the voltage to around 2.3 volts, yet shows only .5 ohms of resistance. if I run a jumper wire from the battery to the glow plug it fires instantly, but then the fire dies when the cable is disconnected. if I leave the jumper connected it stays running. it even goes into the cool down mode when shut off!

so I guess I need some parts,huh?

[pittwagen]

You should be seeing about 4 volts.  See if Steveo still has the heaters.  He is pretty busy moving.  If not Bruce T. may have the part.

Have a read of that manual noted above.  I didn't see a reference to the resistance across the coil but I looked at it very quickly.  Might have missed it.  Don't have one here any more to test.

[Bruce]

Sounds like your glow plug is no good.
Test:
Connect the series resistor to the glow plug and apply 12V through the two with the glow plug out of the heater.  Does it glow?
I think above you estimated 250F.  If that's the case you need a new glow plug.  They don't last forever.

[beetlemandan]

if I put 12v directly to the plug, it instantly glows bright orange. and I really do mean instantly!

I seem to recall an old vw factory mechanic saying that you can cheat the resistor by taking a few coils out of it. I'm just worried about breaking it. no matter what I did to it, I just couldn't get it to go above 2.3 volts to the plug. and no, it doesn't glow at 2.3 volts. my thermometer gun claims about 250f off the coils even after a minute

 I think I read that manual about 6 times! I don't know how I missed it on thesamba earlier before this thread. and I don't see anything about resistance or heat. it just proclaims how it lowers the voltage to 4 volts. I pretty much had everthing figured out after going over everything in that b2 today, the manual just confirmed my suspicions and gave me some proper numbers.

[pittwagen]

Geoff has your glow plug!

http://www.thesamba.com/vw/classifieds/detail.php?id=1639805

[dale-j]

Read this.
http://www.thesamba.com/vw/archives/manuals/heat_ac_shop_manual/f5.pdf

First one in heater section. Scroll down. Download the B2 pdf.

Further to what  Busdaddy said, you will need 12.7 volts+.  I always use a battery just off the charger when starting an old heater.

Thanks. That's what I need to help troubleshoot mine.

Steve