Hard Cold Start ALH

Hey everyone,

So I am new to the TDI scene, having just bought a 02 4 Door Golf with the 5 speed just 2 months ago. I have been working on bringing it up to a reliable DD. It has 155,000 miles on it and has spent all of its life in Alaska (Fairbanks). Since buying I have: replaced E-brake cables and put erosion protection on the housing where the brackets are (reason for previous failures), replaced engine oil twice with Mobil 1, replaced the transmission fluid, removed battery heater pad, cleaned oil from intercooler, inspected intake manifold (desperate need of cleaning, looking for spare to clean and make install faster), new battery (old one would drop to less than 10 v when starting cold), replaced dog bone mount, increased glow plug timer a little bit, checked injection timing (right at the middle line), new air filter, cleaned snow screen, checked glow plug resistance on all plugs and all are within factory spec and not off by more than 10% from each other, and that may be it.

So the issue. When the engine is cold it doesn't like to start or won't. With the new battery the engine spins over awesome and will cough (sometimes fire but most not enough to get it to run). If I plug in the frostheater and factory oil pan heater for at least 5 hrs it will start right up, 3-4 hrs it will start after cranking for 10 sec or more and really have a rough time running. I have to hold the throttle to keep the rpm around 1000 rpm and around 20-40 sec later it will idle smoothly and without the throttle.

So being big into trying to figure stuff out, I plugged in the car and kept checking on it while it's warming up and the only noticeable difference between 3.5 to 5 hrs is the IP will be warm after sitting for 5 hrs. Even at -10 F temps the engine will be at 135 degrees being plugged in for 3 hrs but the IP pump will still be cold to touch. But after waiting another 1.5 hrs the IP pump will be warmer to touch.

Is this a sign of a failing pump? If not a pump maybe an issue with the fuel filter? I ran diesel purge through it, using a procedure found on this site and that helped a bit, but anything below 30 F still causes issues with starting.

If this post is too long please let me know, but I wanted to provide as much info upfront to help speed up the fix process and maybe help others to determine if their issue is the same or different.

Yes, today is my first post but I have read no less then 50 posts on this site for multiple maintenance and problem shooting. My scenario doesn't match the other posts I have found talking about cold start issues.

Thanks!

Are your vacuum hoses original? The ASV could be sticky when cold. If you have the VCDS device you might check the various temperature sensors.

Hey BobnOH, I did check the ASV and it moves freely. I haven't checked it while starting, but I will have a buddy look at it while I start the car sometime this week. The vacuum hoses look like the OEM type but haven't noticed any fraying or cracking from what I could see. I do have access to the VCDS and all the temp sensors match when I leave the car overnight or for days without it being plugged in.

I have also replaced the thermostat because the car used to only get to 165 while highway driving and that is now fixed. When the car is cold the GP light stays on longer and does go off, once off is when I try to start it. I have tried cycling the key twice to see if it just needs some more heat and that doesn't seem to have an effect. I should also mention that when the car is hard to start, when it finally gets enough firing to not hold the key it smokes significantly (white) until the idle smooths out and then it will clear up.

Thanks for the quick reply!

Generally, a failing IP will cause more struggles when warm.

Timing could be bumper to be a little more advanced.

Wonder what your CTS (Coolant Temperature Sensor) is like, whether it's partially failing. Might see how things respond when that's unplugged.

If the engine is cranking over really fast it "could" be a sticking ASV. If one close the ASV up entirely there's next to no compression.

The IP knows to adjust for fuel temps. It's got an internal fuel temperature sensor. Sometimes these can go wonky; however, without hooking up to a diagnostic tool (VCDS is the favorite) it's really hard to say.

Scanning for codes would likely help.

You didn't mention changing the fuel filter. And come to think of it, this is all sounding mostly like a fueling issue, but rather of being cold fuel I'm thinking it might be due to air incursion. If you have a clear fuel line to your IP (most do, but not all) then look to see how much air there is in it. If a lot then that's more likely the source. Warmer cylinder temps PLUS warmer fuel temps are more able to overcome any built-up air in the fuel system. I'd look to replace the fuel filter, which also means replacing the O-rings that are on the thermo "T"- these things are known to be sources for air leaks: sometimes the "T" itself is cracked and is the thing responsible for allowing air to enter. Also make sure to use an anti-gelling additive. Might be that you're also having some gelling happening inside the fuel filter and that as the warm fuel quickly passes out the return lines and into the fuel filter canister that the gelling is eliminated.

UhOh,

I am planning on doing the timing when i do the TB after the new year. After reading about other peoples issues I thought the timing was a sure suspect but with it in the factory suggested (but not cold start suggested) setting I didn't think it would cause an issue when the temps are 20 degrees or so.

I have scanned for codes with VCDS and the only codes I have are a bunch for Airbags (lower priority right now) and a couple for the radio. But none for the powertrain. For the fuel filter o-ring, my fuel filter does not have it in the box. Do you have a part number off hand by chance? I will look for one and post it if I find one.

I will look up a thread on how to monitor the fuel temp sensor and go check it on VCDS when I next start the car.

Thanks for the suggestions!

All filters should come with a small plastic packet containing the two o-rings. Not sure if you can get them separately (or what their spec might be to track down some generic ones- though they have to be diesel fuel rated). Filters are fairly cheap; I'd just pick up another one: make sure that the o-rings come with it; if it's a local parts store and they're selling filters w/o o-rings then I'd point this out to them.

Do you have a clear section of fuel line to the IP?

Another thing to scrutinize is the fuel return lines. Might be getting leaks here as well; generally, however, if they're not sealing well you'd tend to see fuel leaks.

1) Are you sure that your glow plugs are actualy working?
A quick and easy test is to throw a little snow around each glow plug, on a cold engine, then glow the plugs a couple times without starting it....you should see the snow starting to melt around the base of each glow plug if they are heating.

2)Advancing the timing closer to the top of the graph helps cold starting.

3) are you sure it is cranking over fast enough?
A slightly tired starter may sound good but still not fast enough for cold starts.

4) As mentioned above....you need to make sure there is no air getting into your fuel system. A blockage/restriction in the fuel pickup/sending unit , in your tank, can cause air to be sucked in at the fuel filter connections, the thermo "t" or inj pump seals.

5) and lastly you need enough compresion....if all else checks out a compression test may be worthwhile.

Thanks everyone for the suggestions! yesterday I had some time and the engine was cold enough to try starting it and watch the transparent fuel line from filter to IP. On the 4th attempt to start (only did 15-20 second attempts) with the throttle slightly depressed, I saw one small air bubble. It only happened once in the total 6 tries. Hopefully today or tomorrow I will be able to try again with VCDS hooked up to log cranking speed, fuel temperature vs coolant vs IAT, and to throw the snow on the GP and cycle the key to see if it melts. I will report back when I do that. I did get to take a gov't car into town for an appt so I also grabbed a new fuel filter with the o-rings so i will install that.
-Mike

You could bring the motor to tdc at the flywheel and see where the IP alignment hole is.
(A true time check you also need the cam at tdc). The IP hole should be within roughly 1/4".
Said you just bought it, many folks don't make the effort to properly time these cars.
Sounds like it's getting fuel, hence the smoke. Disclaim: Often white smoke is burning oil, next time give it a whiff, see if doesn't smell like fuel.

The injection pump hole is 5mm (iIrc)
I prefer to test the glow plugs with an amp meter, not resistance.
They should all be the same amps depending on how good the battery is.
Never heard of the snow test but I guess it should work.
The white smoke could be pump timing slightly retarded.
When you do the belt you have to lock the pump and cam at #1 cylinder TDC.
When you have the flywheel at TDC you should be able to insert the 2 locks.
Watch the pump hole, it has a fool ya hole that the lock wont go in all the way.
There are good threads with the steps in order to do here. Someone might post their favorite one.

I've stuck in the fool's hole before, that was 9 years ago, love these cars.

So I just went out and started the car. It was unplugged all night with temps around 17 F. Checked the GP with the snow method, I think I put too much on there because I couldn't see it melting but I could here what sounded like melting (sounds stupid but true). I watched voltage, fuel temp, air temp, coolant temp, and engine speed before and while cranking. All temps were in a few degrees of each other, 12.45V to ECU, and cranking speed was around 240. Looking on the forum some people think it is acceptable and then others claim that 300 rpm is the minimum.

If it is unacceptable, is a rebuild generally sufficient with our cars or is it better to go the reman route? From reading, I know to make sure to get a 1.8kw or higher starter that is meant for TDI with a manual.

Tomorrow take a quick look if you see an air bubble in the highest point of the clear fuel line before you try to start it.
I'm wondering if you have an air leak and the fuel syphoning back to the tank.

NorthLights said:

So I just went out and started the car. It was unplugged all night with temps around 17 F. Checked the GP with the snow method, I think I put too much on there because I couldn't see it melting but I could here what sounded like melting (sounds stupid but true). I watched voltage, fuel temp, air temp, coolant temp, and engine speed before and while cranking. All temps were in a few degrees of each other, 12.45V to ECU, and cranking speed was around 240. Looking on the forum some people think it is acceptable and then others claim that 300 rpm is the minimum.

If it is unacceptable, is a rebuild generally sufficient with our cars or is it better to go the reman route? From reading, I know to make sure to get a 1.8kw or higher starter that is meant for TDI with a manual.

Click to expand...

You should have seen the snow melt......I would investigate further....check for voltage at the harness or could be your harness is no longer making a good connection to your glow plugs....common problem.....the sound you heard may be electrical arcing between the harness connector and the glow plug post.
You have classic symptoms of non working glow plugs.

Well maxmoo with the answer! Glow plugs tested -> yep they are good, positive connection to glow plugs -> yep good. Fuse on top of battery-> nope, burned through on the internal eyelet section of the fuse. The nut on the power supply side was missing so the fuse had next to no surface area to transfer 40 amps (assuming the combined draw of 4 GP's) and burnt up. Will post picture when I figure that out. robbed the fuse and nut from the coolant GP wire (shouldn't need, car is plugged in religiously and all cooling wholes are blocked off on front). Gave it a shot to start up the car at 20 F, maybe 3 revolutions of the crank shaft and it stumbled to life. GP's have probably been unplugged for a year or longer.

BUT, all the other possible culprits are going to be addressed as some good preventative maintenance.

wonneber, no air bubbles in the clear tube at all feeding the IP.

Thanks everyone for helping with this! Input on the starter speed would be very much appreciated, it seems that it may be on it's last leg but I am not sure.

Not bad, less than a week! good work.
Interesting that that fuse didn't trigger any response from the ECU.

NorthLights said:

wonneber, no air bubbles in the clear tube at all feeding the IP.

Thanks everyone for helping with this! Input on the starter speed would be very much appreciated, it seems that it may be on it's last leg but I am not sure.

Click to expand...

I've had a small bubble in the clear line before starting on all the VW diesels I ever had.
Maybe the fuse will clear things up.

NorthLights said:

Well maxmoo with the answer! Glow plugs tested -> yep they are good, positive connection to glow plugs -> yep good. Fuse on top of battery-> nope, burned through on the internal eyelet section of the fuse. The nut on the power supply side was missing so the fuse had next to no surface area to transfer 40 amps (assuming the combined draw of 4 GP's) and burnt up. Will post picture when I figure that out. robbed the fuse and nut from the coolant GP wire (shouldn't need, car is plugged in religiously and all cooling wholes are blocked off on front). Gave it a shot to start up the car at 20 F, maybe 3 revolutions of the crank shaft and it stumbled to life. GP's have probably been unplugged for a year or longer.

BUT, all the other possible culprits are going to be addressed as some good preventative maintenance.

wonneber, no air bubbles in the clear tube at all feeding the IP.

Thanks everyone for helping with this! Input on the starter speed would be very much appreciated, it seems that it may be on it's last leg but I am not sure.

Click to expand...

Great to hear you've found the source of the problem.

Cranking speed on the starter is fine. I'm wanting to say that Bentley says minimum 150. I think that 200+ is good. With the GP issue resolved it should really fire up now.

NorthLights said:

Well maxmoo with the answer! Glow plugs tested -> yep they are good, positive connection to glow plugs -> yep good. Fuse on top of battery-> nope, burned through on the internal eyelet section of the fuse. The nut on the power supply side was missing so the fuse had next to no surface area to transfer 40 amps (assuming the combined draw of 4 GP's) and burnt up. Will post picture when I figure that out. robbed the fuse and nut from the coolant GP wire (shouldn't need, car is plugged in religiously and all cooling wholes are blocked off on front). Gave it a shot to start up the car at 20 F, maybe 3 revolutions of the crank shaft and it stumbled to life. GP's have probably been unplugged for a year or longer.

BUT, all the other possible culprits are going to be addressed as some good preventative maintenance.

wonneber, no air bubbles in the clear tube at all feeding the IP.

Thanks everyone for helping with this! Input on the starter speed would be very much appreciated, it seems that it may be on it's last leg but I am not sure.

Click to expand...

Great news!

As far as starter speed goes these starters do tend to gradualy get sluggish with age....if your starter looks like it may be original or a cheap aftermarket one you may well benefit from a new/rebuilt starter.
Since you have had trouble starting your engine for a while you may very well have overheated/damaged your starter.

Have you seen these two threads.....
http://forums.tdiclub.com/showthread.php?t=234337
http://forums.tdiclub.com/showthread.php?t=338845


The way that I test starters is I use an inductive clamp on amp gauge (a neat tool that I've had since the early 70's) that you hold on to one of the main battery cables while someone else cranks the starter......anything over 300 amps and I replace the starter.
http://www.hoytmeter.com/index.php/600-amp-analog-induction-starter-current-indicator.html

Something else that I find useful in cold climates for diesel engines are oil pan heaters......imo properly installed they work better than zero start heaters for getting the heat to the right place efficiently.
This is the one we use on all our tdi's....
https://www.proheatproducts.com/product-page/model-512-csa

maxmoo said:

The way that I test starters is I use an inductive clamp on amp gauge (a neat tool that I've had since the early 70's) that you hold on to one of the main battery cables while someone else cranks the starter......anything over 300 amps and I replace the starter.
http://www.hoytmeter.com/index.php/600-amp-analog-induction-starter-current-indicator.html

Click to expand...

I have a similar one from back then.
Took a beating, still working.