What is your best timing for winter starting and operation? :)

[iamdieselnutmechanic]

The way my 1.6td is set right now, it starts well.. but its only been down to 20F . It will fire off ok, but then indefinitely need the cold start handle pulled. Which is fine, because that is what it is there for..

However, if you leave it in and raise the idle a touch manually the engine smokes a little blue (obviously retarded) but it still sounds marbley (advanced). How does that make sense? I can't recall what I have it timed too..

Pulling the cold start (with idle bump) makes the engine run perfectly until it warms up or I drive off and push it in. I am just wondering though, what is the best you have found on your application that works best for extreme cold operation??

[vanbcguy]

What you are describing sounds exactly like an IDI diesel that is properly timed to me...

[ORCoaster]

I seem to remember that smoke can occur at both ends of the timing spectrum.  Too late and too early.  The cold start adds a few degrees to the advanced side of the timing and if you raise the idle you would also increase the pump pressure and hence the smoke would be puffing out and the marbles will roll around under the valve cover.  I don't think there is anything wrong with your setup.  Sounds like it is running as designed. 

Pull the cold start, let is get a little heat and push it back in and drive.  If it needs the lever pulled to start and yet sounds advanced it seems time to check it out.  What is keeping you from doing that?  Equipment?  Time probably, we never have the time we need. 

[iamdieselnutmechanic]

Time and space.. I have recently moved to a basement apartment (for work) and i dont have the big driveway and double wide garage i left back home.. lol I also work nearly 70 hours a week, so i work and sleep. Weekends are useless too haa.

I have the equipment and know-how, just no time or space lol. I wanted to do as much key board mechanizing as possible before getting the knuckles busted eh?

I think i have it timed low, from what i recall.. possibly .95mm or lower? I honestly do not remember.

[TylerDurden]

AIUI,

Cold engines clatter more because of combustion lag... more fuel is in the cylinder by the time the air reaches the temperature of diesel's self ignition point. When it lights-off, the additional fuel causes a shock (knock).

The period when combustion is sustained is narrower until the engine is warm... on both sides of TDC. A warm engine can ignite earlier and burn longer.

The cures?
Higher compression: Air in the cylinder will be hotter when fuel is injected and the burn will start earlier with less fuel, less shock. Stays hotter longer.
Controlled delivery: a pilot charge will start combustion with less fuel, reducing the shock and raising temperature and pressure for the main delivery.


TL;DR
Agree with vanbcguy.

[Renax]

Mine is the same, start in 0°C, no problems, but sounds "funny". If i push the coldstart lever back in before its heated up a bit it will start to smoke an run bad, and sometimes stall...
I've been thinking about advancing timing a bit more before real winter kicks in...

[theman53]

I have found with many different diesel vw's that the timing really didn't matter if it was in the Bentley range. I found it actually started worse advanced more to 1.05mm or over that, than it did at .95mm. My theory is that the quicker the injection event is started it fights the piston up the bore, slowing the cranking speed and not wanting it to start. The biggest deal for me was battery cables and starter *new starter bushing every time*. If you put a new bushing and starter in and have new and heavier battery cables it usually will fire and run.  What you are describing sounds like it starts fine and then runs rough, which is what I find normal for any diesel. Even my E TDI runs rougher and louder when started at 0F compared to 78F. It will also do the white smoke until the engine warms. The only other thing I have done that makes a different result is to plug the block heater in and the engine is warmer. When I do that there is not much rough running or smoke.

[Renax]

Thanks for the info:-)  i have just timed it off the sound of idle, no clue where its at, but it sounds good, runs good, and uses little fuel..., so it cant be far off, however, when i timed it the Lda thing on my JX IP was in the way so i could'nt advance more.. that issue is gone so i will try and see.

All my cars (petrol also) i time with my ears rather than instruments, hillbilly method maybe, but everytime ive doublechecked with instruments its perfect:-)

[RabbitJockey]

same here, its just the nature of the diesel, as long as it's running you're good.  fastest way to warm it up is to just drive it, its even in the owners manual, drive it but take it easy, it warms up quicker that way.

[iamdieselnutmechanic]

The cures?
Higher compression: Air in the cylinder will be hotter when fuel is injected and the burn will start earlier with less fuel, less shock. Stays hotter longer.
Controlled delivery: a pilot charge will start combustion with less fuel, reducing the shock and raising temperature and pressure for the main delivery.

So I need to replace it with a brand new DI engine basically lol.

I have found with many different diesel vw's that the timing really didn't matter if it was in the Bentley range. I found it actually started worse advanced more to 1.05mm or over that, than it did at .95mm. My theory is that the quicker the injection event is started it fights the piston up the bore, slowing the cranking speed and not wanting it to start. The biggest deal for me was battery cables and starter *new starter bushing every time*. If you put a new bushing and starter in and have new and heavier battery cables it usually will fire and run.  What you are describing sounds like it starts fine and then runs rough, which is what I find normal for any diesel. Even my E TDI runs rougher and louder when started at 0F compared to 78F. It will also do the white smoke until the engine warms. The only other thing I have done that makes a different result is to plug the block heater in and the engine is warmer. When I do that there is not much rough running or smoke.

Yup I have a manual glowplug setup and 1/0 guage power and ground wires. The next step may be a new mk4 auto tdi starter, and a large deep cycle battery.

[TylerDurden]

I suppose you could turn back the fuel so far that you don't get clatter or smoke, but I don't think that would be a very useful option.

So I need to replace it with a brand new DI engine basically lol.

Well, that's what Volkswagen did...

[theman53]

if it starts the issue is not your starter or battery. you could add those things and it will still smoke at a freezing could start up.

[iamdieselnutmechanic]

Yes it starts no problem down to about -15F.. much colder than that and it needs to crank too much to fire and i lose battery power. So I will be getting deep cycle in there in the next little bit to battle that. A battery that has no issue cranking for more than 5-6 seconds before the starter slows lol.

[ToddA1]

After you get the battery issue sorted, report back.

It's been a while since I dd a IDI in the winter.  When I did, ithe Rabbit would start fine, but buck badly if I tried to drive it right away.  My timing was set to .95.  I advanced to 1.05 or 1.1 and the issue disappeared.

I had a Rabbit truck that never had issues starting in the cold.... always fired up as if it were warm.  Prior to changing the TB, I read the timing. It was at 1.4 and ran fine. I reset it to 1.0 and noticed no change.

Basically, set the timing where the engine runs the best.  I use 1.0 as a baseline.

-Todd

[Renax]

I figure: IDI is a bit worse to cold start in the cold, but for a winter car i wouldn't change to TDi anyways, the IDI gain heat faster and generally runs hotter, which means i freeze less while driving it... TDi's just use too long time to heat up...