(ALH) Hard to start when cold (after rebuild)

So; the saga continues on this 2003 Jetta.

(from here: http://forums.tdiclub.com/showthread.php?t=484921 )
(and here: http://forums.tdiclub.com/showthread.php?t=481319 )

Since I got the engine back together, I have started it, and taken it for a couple of quick test-drives. The smoking has stopped, and it was definitely burn-off of engine degreaser. There's no more leaking going on, as far as I can tell.

The engine does not overheat anymore. It seems to have a little more pep than it did before all this, or that may be my imagination. The exhaust seems clear, no smoke.

No coolant leaks.

The problem is, when I let the car sit, and cold-start it (and when I say "cold" we're talking, California-cold, like 50-60 degrees F, don't be a hater - I have to move out of state anyway) - when I first start it up, it will run for a second or two, then stumble and die. Then I will go through a couple more rounds of startup and die, and each time, it gets a bit worse and worse, until it won't run at all and it's 100% crank.

Then, after about 10-12 tries, it miraculously chugs it's way to life, and it runs fine.

When the car's warm - it starts just fine.
(Brand new battery, by the way.)

So that's the symptom.

I've gone through this rigamarole about 4 or 5 times now. I'm guessing that the problem might be fuel-related. Maybe there's fuel between the pump and the injectors, but air in the line between the filter and the pump?

Fuel lines are all new - the original lines were dry rotting, so a few months back, we replaced them with new diesel-safe fuel lines. Not the OEM parts. They fit snug, and are clamped good and tight, but I don't have the clear one, so I can't see if there's a bubble in there.

Does this symptom seem familiar to anyone?

Yes, sounds like a seal in your IP is letting air in. To definitively rule it out I would let the car sit for a period of time where you know how it would start. Before starting prime the IP and see if it starts any better. If yes, then you need to reseal your pump which can be done in the car. HTH.

air in line. Did you replace the check valves at the tank? I highly suggest you upgrade to a walboro pump if you want a pump. As for air at the fuel filter, its common but this much is not. Nictane.com and get this uber filter kit or go with a ditzel mod and a cat filter. Either way your in an area that you dont need the thermo tee so i would delete it.

one way or another your losing prime on the fuel system and i suspect your fuel filter is draining. If you have a cracked air line post filter it just runs like junk. if its draining the filter or letting enough air into the filter than it will have your symptoms. Next time this happens, take the filter off the moment it stops sputtering and only cranks. I bet you $10.00 that the filter is bone dry.

Of course on my car it was valve leakage on the head. Warm starts fine. Cold starts slow but start. Then around 20 degrees F it was a challenge to start. Nick did a leak down test and found the problem.

Curious Chris said:

Of course on my car it was valve leakage on the head. Warm starts fine. Cold starts slow but start. Then around 20 degrees F it was a challenge to start. Nick did a leak down test and found the problem.

Click to expand...

Yeah, that was a fun one.

Not sure about valve leakage. I supposed that's a possibility. The machine shop shaved off .003" from the head, but didn't do any valve work. On the other hand, he said he pressure-tested the head and said it didn't leak.

¯\_(ツ)_/¯

Anyway, my other problem is that my mytvac itself is leaking. So it's hard for me to verify, now, if the fuel lines are leaking air; I can use it to draw fuel though. What I did find was that the T-30 bolts on top of my IP were not tight. I had loosened them in preparation to do try a hammer mod, back when I was first trying to get the car started. I thought I had locked them back down, but I guess I forgot. So I snugged them back down. I couldn't find a torque spec anywhere for them, so I called 10 ft lbs good. They're pretty small bolts, I'd be afraid to go any tighter.

Result: 4 cold start tests. 3 successes. 1 fail (success on 1 retry). So the situation is much improved, and we'll see if it gets better over more trials, but I think that this was the problem.

If this persists, I guess I'll have to do a leakdown test.

My problem is: (personal drama) ... the car was put on NON-OP status, because it needed to be smog-tested (California), back when I originally had the overheat problem. Since that time, I have come to grips with the fact that I'm going to relocate to Arizona now. So rather than getting this car re-registered and smogged in California, then moved to Arizona, and re-registered and smogged there, I'm going to try to get the 1-day moving permit in California - the day I drive it to Arizona. And hope it makes it all the way and doesn't strand me. And hope that it's not overfuelling so much that I end up with like 10 miles per gallon on a 600 mile trip.

Oh yeah, and I'm going to pull a trailer too.

And to think I was ready to have it hauled to the scrap yard. . .

Might want to search for it, there's a discussion (or several?) in which people merely parking nose up (or down?) shows up having an effect.

Got it.

Yes, I'm parking uphill on a fairly steep driveway.
Also; on the last 1/8 tank.

It's also a pretty new fuel-filter. (this is one reason why I was so enthused to rescue this car: new fuel filter, new timing belt, new tires, THEN it overheats and blows a head gasket!). I'm suspecting the Thermo-T doesn't fit the new filter very well. All my previous filters were black, and this one is shiny silver, so it's a different brand. I don't remember what brand, I think my son probably did the replacement.

FWIW....Whenever I do any major repairs on a vehicle I try to put some local miles on it before setting off on a long haul, especially when towing a trailer.
From my experience the chance of something going wrong increases after a lot of things have been taken apart and put back together.