hard to start all of a sudden?

[Vohaul]

hey all,

on my 93  (aaz) , over night , its become really hard to start (like if you leave it in -20 for a while not plugged in)...before started on 1st turn of key....now it turns over once, then the 2nd time it stumbles a bit, then the 3rd time will roar to life.

has lots of power and runs smooth and nice when running....

im fairly new to vw and diesels...even the fuses are different:)

help

Thanks

Paul

[Doug]

Check your glow circuit for approximately 50 amps draw on the glow cycle with a clip on ammeter. Alternatively check for voltage at the plugs. If none then likely the glow fuse or fuseable link has open circuited. Replace it.

[rabbitman]

If the GP's aren't working it would be very, very hard to start at that temp, so I'd guess that they're working.

[Vohaul]

If the GP's aren't working it would be very, very hard to start at that temp, so I'd guess that they're working.

lol...its not -20 out right now (thats celsius) its actually + 15 (but the car STARTS like its -20)

sorry for sounding dumb, but the little relays instead of fuses confuse me.....do i just replace it??

Thanks

[Vincent Waldon]

If the GP's aren't working it would be very, very hard to start at that temp, so I'd guess that they're working.

Yup... expecially if the fuse blows and so they are all gone at once.

Sometimes what happens is that a single glow plug burns out without notice, but when the second one goes it suddenly becomes noticable on cold mornings.

Further info on troubleshooting the glowplug system and some pictures here:

http://vincewaldon.com/index.php?option=com_content&task=view&id=41&Itemid=28

The other thing that can happen with an AAZ engine to cause sudden hard starts is a sudden shift in timing due to the crank sprocket suddenly starting to wobble.  With the engine running have a close look at the harmonic dampener... there should be no visible run-out.  If there is, shut the engine down immediately and search for "AAZ AND crank" on this board to read all about next steps.

[Vohaul]

If the GP's aren't working it would be very, very hard to start at that temp, so I'd guess that they're working.

Yup... expecially if the fuse blows and so they are all gone at once.

Sometimes what happens is that a single glow plug burns out without notice, but when the second one goes it suddenly becomes noticable on cold mornings.

Further info on troubleshooting the glowplug system and some pictures here:

http://vincewaldon.com/index.php?option=com_content&task=view&id=41&Itemid=28

The other thing that can happen with an AAZ engine to cause sudden hard starts is a sudden shift in timing due to the crank sprocket suddenly starting to wobble.  With the engine running have a close look at the harmonic dampener... there should be no visible run-out.  If there is, shut the engine down immediately and search for "AAZ AND crank" on this board to read all about next steps.

ok, harmonic balancer doesnt seem to be moving, other than the shaking from the whole engine. and when driving, power is the same...wouldnt power be less if timing got adjusted..or run differently....

..
sooo..question is...if its a decent day outside, and the glow plugs arent working, would you notice when the car starts if its been sitting for a few hours?...would the car even start without glowplugs working?

[rabbitman]

Sometimes what happens is that a single glow plug burns out without notice, but when the second one goes it suddenly becomes noticable on cold mornings.

That's happened to me. The first one burnt out and it got a little hard to start (crank about 5 seconds max), I just thought it was unhappy about something but then the second one burnt out and it got so it would crank for half a minute before firing and then it would shake real bad and stuff.

Changing the burnt GP's worked wonders .

If you think about it, an engine with fried plugs is only starting on the cylinders with good plugs and the other cylinders are just slowing it down........

[Vincent Waldon]

sooo..question is...if its a decent day outside, and the glow plugs arent working, would you notice when the car starts if its been sitting for a few hours?...would the car even start without glowplugs working?

Yes... even in the nice mild spring we Albertans are enjoying... your IDI engine needs a minimum of  2-3 working glow plugs to start easily, even after only a couple of hours of sitting.   If they were all gone you'd have difficulty starting at all after an overnight in freezing temps... depending on how good your compression is, timing, etc.

[Vohaul]

lol, do i dare ask how hard they are to change...

i had a look this morning....looks like they are pretty buried...is there a writeup somewhere?

cheers

Paul

[Vincent Waldon]

If you follow the writeup previously mentioned to trouble-shoot 'em you're 90% of the way there...  10mm deep socket and some patience are all that's left.   

[Vohaul]

k, ill be going over it this weekend....

to replace glow plugs though, ?...remove that buss bar from all 4 first?..then replace glow plugs..?

also, wheres the coolant sensor on the mk3s...your write up only talks about early and late mk2s for that section?

Thanks again for all your help


Cheers

Paul

[vanbcguy]

Pretty sure the Mk III's just have a single coolant sensor used for both the temp gauge and the glowplugs.  So if your temp gauge is working, the sensor is fine!