Ye 'Ol cold start thread

[DieselBalz]

So this morning it was marginally better on the starts. Temperature was just below freezing.

It still ran like a bag of hammers after it started though.. Puffing blueish smoke like no other and missing. While I had the pump off i took each GP out and visually tested it on a spare battery. All perfect working order.

Its such a weird issue.. once the car is even remotely warm, you can start it up without gp's like a diesel with perfect compression.

Mine does that too. When the car is warm, say I run into the Circle K to grab something, I can come back out and with no gp pause, it will fire on the first the first or second turn of the starter.

In general, what does bluish smoke mean out of these diesels?

[EcoTX]

New member here, but long time reader since registrations were closed.

You said you haven't checked compression yet, please do!   

Your cold start symptoms sound exactly like my 1.6 NA with 300-350 psi in the cylinders from a (supposedly) blown headgasket.

I put new glowplugs in mine and some rebuilt injectors as well, but it will still require a few starts and some throttle to stay running when cold.

It's very rough, stumbly and sounds like hammers beating on the cylinders for a few minutes and smokes like crazy till it's warmed up.
Then once warm it starts so easily, like instant-on-start the second I turn the key.
My "cold" starts are only in the mid 30's - 40's too, I could only imagine that Canadian cold.    I have a video of a cold start on my phone too of it doing all this I could upload.

I have a rebuild planned with lots of pics in the coming months before summer, looking forward to it.  It's my project car right now, it isn't road legal yet.

[burn_your_money]

In general, what does bluish smoke mean out of these diesels?

It can mean retarded timing

[ORCoaster]

Or valve stem guide leaks?  I thought that oil would also run down the valve stem and sit on top the cylinder and get burned with the first few strokes upon firing up.  Or is that not possible without loss of compression and that would show in the numbers when doing a comp check? 

[8v-of-fury]

I did a HG in June of last year. So I do believe that is al good.

Once hot I can leave the car for a half hour or more and still fire off on the first crank.. So I don't think compression is my issue either. I would check it, but the injectore bore adapters I bought have the pressure nozzle way up inside what is supposed to be the "injector" this will give me one hell of a falsely low reading for sure. So I can't trust that.

I have tried the timing at 1.00mm, 0.90mm and now 0.95mm smokes just the same at all settings. Yes Tyler I do have the fast idel pump, and pulling the advance so it advances and bumps throttle helps, but it still smokes and misses. If you rev it up to what sounds like anything above 1350rpm it does not miss any longer.

Weirdest thing!

[dieselweasel]

Once hot I can leave the car for a half hour or more and still fire off on the first crank.. So I don't think compression is my issue either.

The fact that it starts fine when hot only further points to low compression as being the possible cause of your trouble.  It is obvious that a diesel engine's ignition source is heat.  That heat is generated primarily through compression.  An engine with low enough compression on one or all cylinders will be hard to start cold and when started, will run rough (not enough heat to vapourize and burn the fuel).  When hot, the engine will often start and run much better since the absorbed heat in the cylinder walls, pistons and head serve to mask the compression issue.

When you start the engine again cold, I suggest loosening the injector lines one at a time to see if you can pinpoint a weak cylinder. 

[R.O.R-2.0]

my old audi wouldnt start when cold unless you gave it a shot of ether..

once warm, it fired up just like a healthy diesel..

[8v-of-fury]

poor compression nooes. Well thats weird it is definitely all of a sudden.. this past summer I could easily start the car WITHOUT glow-plugs when it was above 20c ambient temp.. even after sitting for over 12+ hours.

I am not too worried about it, as I have the TDI motor I am working on getting in there within the next month.. so its not TOO much of a worry.

I still want to lean away from compression.. i think its still fuel related..

[R.O.R-2.0]

poor compression nooes. Well thats weird it is definitely all of a sudden.. this past summer I could easily start the car WITHOUT glow-plugs when it was above 20c ambient temp.. even after sitting for over 12+ hours.

I am not too worried about it, as I have the TDI motor I am working on getting in there within the next month.. so its not TOO much of a worry.

I still want to lean away from compression.. i think its still fuel related..

well then take a compression check and rule out compression.. or else keep pondering.

[8v-of-fury]

I may have too. However the adapter i got for my compression gauge has the pintle WAY up in what would be the "injector".. giving me a queer false reading..

[R.O.R-2.0]

I may have too. However the adapter i got for my compression gauge has the pintle WAY up in what would be the "injector".. giving me a queer false reading..

if you got good compression, it will still prolly register with an acceptable number, but a tad low..

if your compression is low, it will make it seem even lower..

is it the kind of adapter that threads in where an injector goes? or where the glow plug goes? i like the glow plug type personally, unless the injector type has the check valve in the BOTTOM..

[theman53]

When my starter bushing and starter acted up and all the glow plugs were bad I had the same symtoms. This was in my 84 rabbit.

[R.O.R-2.0]

When my starter bushing and starter acted up and all the glow plugs were bad I had the same symtoms. This was in my 84 rabbit.

his plugs are fine tho, he just checked..

and i imagine he would notice the starter slow down also..

and i dont think a starter bushing can just go out, i think its more of a slowly occuring thing, that happens over time..

[Mark(The Miser)UK]

At some point do a compression check. If you have one of those rather roomy adaptors, fill the void with little coils of lead sheet.
Meanwhile, your desciption of engine sound makes me reiterate "too advanced". The figure off your  gauge confirms this.
You should try down nearer 30 thou.
 [Working in metric is better for reference to VW figures; just divide your readings in thou by 39.]
 Additionally, you said you were operating nearer 125bar than 135bar. Diesel compresses less at these lower figures [1% @100bar-ish] thus diesel appears more like a solid, and the timing accelerates  towards a timing figure of  0mm, or there abouts
I have operated at 0.7 for 125bar, and as low as 0.5mm/20thou.

OK You have starting issues which will probably get worse when 'retarding'
However, a common starting issue can be because the max power screw is out a little too far. Screw it in half turn.

Blue smoke is oil. Oil can be from rings but it sounds like it could indeed be the inlet valve seals...

[8v-of-fury]

Alright here is whats up. Its -18c here right now. I started it up earlier to move it in the driveway, just a whore to start. I went with my brother down to his shop he works at to spend the day doing stuff to his car, came back and went to dinner in my car. so the car sat in -18c all day pretty much. From noon, until I started it again at 7:30pm. It started fine, ran like ass, but started fine. It also missed for quite a bit while driving it.. always does.

Kevo its the injector type. Got it from Prothe lol. I guess i'll be checking compression in the next few days.

Glow-plugs all check out, and the starter is definitely cranking REAL quick. so i rule cranking speed out too.

Mark, you are a rambling man. lol lemme see if i can follow you. It may be too advanced, but I tried it at 0.040-0.035inch (1.00mm-0.90mm) and it did the same things.. if not it was worse to start when retarded.

You want me to try timing to 0.030? 0.030 inch = 0.762 millimeters I think that will be a tad TOO low, wont it? what do you mean by I am operating nearer 125bar as opposed to 135bar?

I have messed with the max fuel screw quite a bit, but i do believe I have it in as far as I can possibly have it.. I have the other two "idle" adjustments practically bottomed out so I can have the fuel screw in as far as possible without a hanging idle! lol

Also the motor is using zero oil. This happened prior to my last oil change and I am now running a 5w40 full synthetic.. and it is still not using any. I wouldnt say it is blue like your text there mark lol.. definitely smells like un-burnt diesel as opposed to oil.