Starting issue when engine is at operating temp.

[Krisverde]

On my 1981 Jetta when engine is cold enough for glow plugs to come on, starts right up within a crank or 2.   Now when I am driving around and go in somewhere for about 45 min and come out to start...I have to crank for maybe 10-15 sec before the car starts. I just replaced the battery so that is good. What can it be? I was thinking about hooking up a switch to the glow plugs so I can manually glow them.  Thoughts?

[pointynoggin]

Sounds like air in your pump.  Do you have bubbles in the lines?

[Krisverde]

Yup now that I looked at the line I see small bubbles running through it (unless that is cavitation??). I don't see any diesel leaks anywhere. I mean the little return lines between the injectors used to leak before I replaced them. Would that of caused air into the system?

I should of mentioned too that when I crank for a while and let off and crank again it will usually crank right up.   So will I need to prime the pump?


ALso maybe she cranks too slow ill get a vid.

[theman53]

I was going to say cranking speed and glow plugs. I had an 84 that did similar and I thought it couldn't be glow plugs as I just put a set in 3 months prior. But 2 had burned up. I replaced them and it started normally. It was weird as it would do this even at 60F, as I replaced the glowplugs in the middle of winter and by April it was having problems. I checked all things that were more possible like timing, starter, battery and finally I did the glow plugs and all was fine.

I would test them if they are unknown. Then look for fuel leaks, usually at the fuel filter on an MK1 the seals can go bad. Then check out the starter. If the glows and temp sensor are good and the engine is warm enough not to glow, your starter might not have the stuff to get it to light quickly.

[Krisverde]

Glow plugs are good from when I tested them. I can double check. Also I didn't see any fuel leaks around the filter. I also did just replace that.

I made a quick video this morning of me starting up the jetta. Doesn't really crank long enough to really judge cranking. But yall may catch something.

http://youtu.be/uc5rq4jM4Rc

not sure how to embed at the moment.

[8v-of-fury]

On my 1981 Jetta when engine is cold enough for glow plugs to come on

With these engines that is pretty much every day below 30c lol.

Now when I am driving around and go in somewhere for about 45 min and come out to start...I have to crank for maybe 10-15 sec before the car starts. I just replaced the battery so that is good. What can it be? I was thinking about hooking up a switch to the glow plugs so I can manually glow them.  Thoughts?

It could be the glow plug controller, it may still see the engine as "warm" after sitting for a while and not fire the plugs..  When in fact it is not warm enough.

I am pretty sure just doing a manual switch for the glows will easily solve your problems .

[8v-of-fury]

That did have kind of a slow beginning crank.. but if it were too slow it wouldn't have fired on half a crank.. so id say that were ok.

[Krisverde]

I've been wanting to do a switch. Ill look around the site and see what I can find. Would I just be wiring up a 50 amp switch to the relay?

Also here is a warm start video.

http://youtu.be/WzmEw61L40c

[8v-of-fury]

The voltage drop you are seeing to 10.5V is pretty normal. So I'd say your battery is good. However you may be experiencing voltage drop at the battery and starter connections.. search on here for how to do a voltage drop test.

Looks like you  still have the 81 starter or at least the mk1 style. BIG HUGE starter, no gear reduction. An upgrade would be the starters found on 85-92 diesels, bolt in affair.

I am fairly confident that a manual GP setup will solve this issue.

Google Vince Waldon HOW TO pimp your glow plugs.

[Krisverde]

Awesome ill start checking on this stuff. I appreciate the help.

[damac]

That video shows your crank speed is terrible.  Worse than I ever had to deal with.

I saw some slight issues with warm starting with my car when warm that just made me wonder if something was up because it took longer to start than when cold.

So I got my battery checked and got a new one under warranty which was only like 15 months old.  It seemed to surface charge but wouldn't hold once a load was applied.  This might have been caused by some people borrowing my car and leaving the lights on all day more than once

And I have dealt with old bad grounds before so I got a wheel grinder and grinded all the ground areas and ran some new marine larger grounds with an extra going to starter mount bolt and directly to alternator just for the heck of it.  Also replaced the main power wire a size bigger.

And thanks to a forum member on here, I changed the starter to some specific model tdi starter that bolts right up.  I believe its a gear reduction starter.

Now my car spins over way faster than before and I could do a bunch of glowplug start cycles on a regular sized battery with a good charge. 

[srgtlord]

Just a question, but which tdi starter did you use?

[damac]

Just a question, but which tdi starter did you use?

pm this member below.  he was nice enough to answer my questions and he sold me one for a good deal

http://www.vwdiesel.net/forum/index.php?action=profile;u=2064

[Krisverde]

I wonder if that starter is going to give up the ghost. Sometimes while cranking it'll pick up a little more speed.
Also I unplugged the wire that is used for the engine temp for the glow plugs and that helped out this issue. although leaving this unplugged I don't know if it's good or bad. I still want to do the vince waldon mod.

[ORCoaster]

Listening to that warm crank vid I think your starter is the problem,  swap it out or service it both internally and externally.  I have done the direct wires to each glow plug from a distribution block and I like that setup.  Not sure that it really makes much difference where I am it is pretty warm by comparison to some of these guys freezing arse up north.  I like the ability to source out individual glow plug troubles without dismantling the bus bar.

By the sound of the starter and you voltage drop measurement I think the battery is still good.  But it never hurts to clean and maintain those connections as well. 

If you have fixed the air in the line problem, not sure if you said that went away or not, then I think your last fix will be the starter. 

I read where you replaced the fuel filter.  What a pain that thing can be.  If you took the lines off and the bracket out in order to twist the filter off then you may have sealing troubles with the banjo bolts now.  Those copper washers need to be looked at for grooves.  Most of the time you can heat them up till they are blue and let them cool and put the back on.  I had to actually use some diesel and 400 grit wet sand sandpaper to get the deepest grooves out then heat em up. 

That should get the air leak fixed.  Oh and the leak isn't always going to show you where it is by fuel coming out.  It is an air leak when the system is under vacuum, just the reverse.  Once you get past the inlet to the IP the leaks turn into pressure related ones and that is when you will see the weeping of fuel on the outside of connections or at the hoses.

My part to the party.  DAS