2001 ALH Stumbly Smokey Cold Starts

Hi,

I'm having stumbly smokey cold starts on my 2001 ALH. Mods are 11mm IP, PP520 nozzles, STOCK turbo and a Malone Stage 3. I have a Stant 195*F thermostat installed in it also. I previously had the IQ set at 6.8 (was told to by tuner). I woke up this morning and checked the group 7 temperatures with VCDS before start up:

Fuel temp: 10.8*C
Intake air temp: 9.0*C
Coolant temp: 10.8*C

I also checked group 12 glow plugs, those readings before start up are:

Glow period preheat: 2.02
Supply voltage ECM: 12.16V
Coolant temp: 10.8*C

NOTE: Glowplug time was extended with VCDS before last winter.

Then I took her out for a drive to get her up to temp to check timing. Timing graph is below:


I also reset the IQ back to stock value of 32768 to put IQ at 4.0 when fully warmed up.

Today's startup wasn't smokey but it did stumble for about 2-3 seconds before it smoothed out.

Group 7 readings after fully warmed up were:

Fuel temp: 29.7*C
Intake air temp: 30.6*C
Coolant temp: 100.8*C

Any input??

At 9*C that engine should fire right up. IQ will definitely change cold starting characteristics (at least it has for me going from 6 to 4), but it matters more in very cold temperatures.

I would start by putting my timing at the green line when warmed up. This will make sure your mechanical injection timing is the most advanced when starting in the cold. Advanced mechanical injection timing does help with cold starts.

Beyond that, I would be thinking about the condition of my fuel filter and injector nozzles. If you really want to go crazy you could check compression, but that never helped me on my quest to track down my cold start issue.

Once the temp starts dropping below 30*F, slight stumbling after the engine fires is normal. These engines don't like the first few seconds after firing up, but should smooth out once things get moving.

A slow starter makes things harder to start when cold. Should have 250+ rpm.

I was having very similar issues with my 2002 ALH golf. What it was on my car was the egr valve. Try unplugging the vacuum line goin to it and put a bolt in the open vac line. My would smoke so much and run verrryyyy rough until I unpligged it.

UhOh said:

A slow starter makes things harder to start when cold. Should have 250+ rpm.

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The starter is still strong. The car starts very quickly, only on the starter for 1/2 a second before it starts. It's just the smokey starts when cold and stumbles for 2-3 seconds. After that it smooths out. I will replace the fuel filter and thermotee o-rings and see if that solves the issue. FYI, no glow plug faults found...

JDSwan87 said:

The starter is still strong. The car starts very quickly, only on the starter for 1/2 a second before it starts. It's just the smokey starts when cold and stumbles for 2-3 seconds. After that it smooths out. I will replace the fuel filter and thermotee o-rings and see if that solves the issue. FYI, no glow plug faults found...

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This is pretty much how ALHs react to starting when cold. I wouldn't worry about it too much.

LNXGUY said:

This is pretty much how ALHs react to starting when cold. I wouldn't worry about it too much.

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If temps were colder.. like -10 - -30 then I would agree here, but not at 9*C ambient with a healthy engine, glow plug system, starter and battery.

Even with no faults, I would inspect the glow plug harness and measure all glow plugs with a meter. Even pull them all out and see what they look like. If the tips are clean with a white residue - they are working properly. If the tips are black and full of soot then that plug is not glowing.

Advanced timing likely will not help considering where your at right now.

I think all the data you posted looks good.

Check out the IP pressure relief valve? Sounds like your symptoms could be similar, and if you've never looked at it with your mods, might be worth checking out. Seems like a pretty easy quick job, and if it has backed out, consider getting a "keystone" in there to keep it in place:

http://forums.tdiclub.com/showthread.php?t=351228