2001 TDI hard to start when cold, starts and runs fine when warm

[Lew]

One thing I do is add Power Service to my fuel. Pick up the white bottle, not the gray bottle since you are in the colder climate....The white bottle of Power Service will help keep the fuel from gelling and keeps the injectors clean, etc. Not to mention it boost the cetane in diesel fuel. I add 8 oz on a full fill up. Stop by Wal mart, it cost about $6. It's a good thing

[cnemo]

Good News. This morning the blinking glow plug indicator went away on it's own. I'm not sure if the auto clear takes place after a certain number of engine starts or temperature cycles with no errors, but in any case it is gone, at least for now. With temp at 39 degf this morning, I thought the start was still sluggish, so I still need to check the glow plug circuit, which I will do this weekend. And, I still have the CEL which I assume is still the fuel temp sensor short to ground. Will check that again with vag-com this weekend as well. I did add some Power Service last time I fueled up. That was about 100 miles ago.

[kcfoxie]

These are all good signs!

[janitz]

Originally Posted by Lew

One thing I do is add Power Service to my fuel. Pick up the white bottle, not the gray bottle since you are in the colder climate....The white bottle of Power Service will help keep the fuel from gelling and keeps the injectors clean, etc. Not to mention it boost the cetane in diesel fuel. I add 8 oz on a full fill up. Stop by Wal mart, it cost about $6. It's a good thing

I concur! And watch where you get your fuel, if large trucks go there, that fuel is likely not good for your little diesel. The Cetane value of that fuel is often no better than 40. Your diesel engine wants a value of 49 if I recall correctly in order to operate optimally.

No matter where you go, if you're far enough north to encounter Winter Diesel, you want/need to add a Cetane boost.

For those people too far south to get or know about winter diesel, up here in Canada from October to March (approximately) the fuel stations sell diesel fuel with an anti-gel component added to it.

However what many people do not know is that the Cetane values of winter diesel are much lower. Co-Op here has decent diesel, Cetane value around 47-49 so it doesn't need much if any of a boost, but once they switch to winter diesel the cetane value apparently drops to around 41-43.

As an example of the difference the boost makes on fuel economy, my beetle hasn't any modifications* to its engine to boost economy, and during the summer will easily reach 1000KM per tank using the Co-Op fuel with no boost. During November my fuel tank only lasts for around 850KM without a Cetane boost. If I boost, it goes up to around 950KM.

* There are a number of modifications that can be done to the engine to boost its fuel economy, some folks at TDI club have their car reaching 70+ MPG when combined with good driving habits.

[cnemo]

Dec 23 update-

This morning I removed the glow plug header and verified I was getting 12V when I turned on the key. Also checked the resistance of all the plugs. I don't have an accurate meter, but they all seemed to read about the same resistance and none were open.

With temp at 37 degf the car started after about 6 seconds of cranking. Idled smooth and no smoke. Hooked up vag-com. Only error is temp sensor short to ground. Drove about 30 miles at both in town and interstate speeds and it ran well. Logged data during the drive.

[AndyBees]

Fuel economy suffers during the colder winter months regardless of fuel additives due to a number of reasons!

[cnemo]

December 29 update-
As of this morning (Thursday the 29th), I have put about 350 miles on the car since replacing the fuel filter, adding Power Service, and topping off the tank at a truck stop. I put some 70 MPH miles on it driving the Interstate last Friday and Saturday, and I have been driving it to work each day. It has been running fine, as good as it ever has since I got it, best I can tell. Starting is still not like it was earlier this year however. I still have to crank it longer than, say, 6 months ago or last year at this time. For example, yesterday morning, with ambient temperature of 35 degf, I had to crank about 4 to 5 seconds before it started. When it started, it idled smooth right away and I drove off and it ran great. This morning, with temperature of 40 degf, it started with about 3 seconds of cranking. From the research I've been doing, I'm beginning to think there might be an air leak somewhere and the IP is loosing prime. I thought I noticed several months ago that it was taking more cranking than before, but I wasn't positive since I was no longer driving it every day. Anyway, I don't think this is a problem I introduced when I changed the fuel filter, it was the original problem I was having, but it is not as bad now as it was before the filter change, so the old filter and possibly bad fuel was contributing to the problem. The hoses seemed to be in good shape, no cracking or dry rot that I could tell, and I put new O rings on the temperature valve that clamps into the filter.

As of last Thursday, December 20, the Quantity Adjuster error code cleared on it's own, however I still have the CEL because of the "fuel temp sensor short to ground" error. The Quantity Adjuster error did not come in again until Monday evening when I started the car after it sat for about 48 hours. I had to crank it about 5 to 6 seconds before it started, and then about 30 seconds later the the glow plug light started blinking. It went out the following day after three starts of the engine and has not returned. One of the responders to my posts suggested that the QA max's out because the ECU keeps trying to dump more fuel to the engine because it is not starting. Sounds logical to me and seems to agree with my experience that it comes in when I have to crank excessively, then clears on it's own.

I'm thinking the issue with the fuel temp sensor is probably a bad sensor. This error came in for the first time on December 14 when the engine would no longer start, and has been in ever since. I was hoping it might clear on it's own, but it doesn't seem like that is going to happen. I'd like to verify that it is the sensor before doing the replacement. I have a number of questions so it might make more sense to begin another thread specifically related to that issue. I'll post on this thread if I have an update related to the hard starting and/or when all problems are resolved. I'll call the new thread "2001 TDI ALH Fuel Temp Sensor Troubleshooting". Thanks to all for the help.

[cotterniu]

Originally Posted by cnemo

December 29 update-
As of this morning (Thursday the 29th), I have put about 350 miles on the car since replacing the fuel filter, adding Power Service, and topping off the tank at a truck stop. I put some 70 MPH miles on it driving the Interstate last Friday and Saturday, and I have been driving it to work each day. It has been running fine, as good as it ever has since I got it, best I can tell. Starting is still not like it was earlier this year however. I still have to crank it longer than, say, 6 months ago or last year at this time. For example, yesterday morning, with ambient temperature of 35 degf, I had to crank about 4 to 5 seconds before it started. When it started, it idled smooth right away and I drove off and it ran great. This morning, with temperature of 40 degf, it started with about 3 seconds of cranking. From the research I've been doing, I'm beginning to think there might be an air leak somewhere and the IP is loosing prime. I thought I noticed several months ago that it was taking more cranking than before, but I wasn't positive since I was no longer driving it every day. Anyway, I don't think this is a problem I introduced when I changed the fuel filter, it was the original problem I was having, but it is not as bad now as it was before the filter change, so the old filter and possibly bad fuel was contributing to the problem. The hoses seemed to be in good shape, no cracking or dry rot that I could tell, and I put new O rings on the temperature valve that clamps into the filter.

As of last Thursday, December 20, the Quantity Adjuster error code cleared on it's own, however I still have the CEL because of the "fuel temp sensor short to ground" error. The Quantity Adjuster error did not come in again until Monday evening when I started the car after it sat for about 48 hours. I had to crank it about 5 to 6 seconds before it started, and then about 30 seconds later the the glow plug light started blinking. It went out the following day after three starts of the engine and has not returned. One of the responders to my posts suggested that the QA max's out because the ECU keeps trying to dump more fuel to the engine because it is not starting. Sounds logical to me and seems to agree with my experience that it comes in when I have to crank excessively, then clears on it's own.

I'm thinking the issue with the fuel temp sensor is probably a bad sensor. This error came in for the first time on December 14 when the engine would no longer start, and has been in ever since. I was hoping it might clear on it's own, but it doesn't seem like that is going to happen. I'd like to verify that it is the sensor before doing the replacement. I have a number of questions so it might make more sense to begin another thread specifically related to that issue. I'll post on this thread if I have an update related to the hard starting and/or when all problems are resolved. I'll call the new thread "2001 TDI ALH Fuel Temp Sensor Troubleshooting". Thanks to all for the help.

hi cnemo, I'm luigi from Italy. I 've got a new beetle 1.9 tdi 90cv, (engine code ALH), and I've your problem too: in the morning the starting takes too time (5-6 seconds). when is very cold outside. how do you resolved this problem? please, I need your help. thanks, luigi.
my email address is:
luigimarti0@gmail.com

[cotterniu]

Hello man, I think that I found the solution for the problem ( hard to start). I bypassed the n-valve on fuel filter, and yesterday and today, with -2°C, the starting were good!I think there were air into fuel circuit, in particular into return line. LOOK THE PHOTO.

[cep]

That's fine if the weather isn't too cold but the filter relies on warm fuel being returned to it to keep the filter from clogging when it's cold.

I would replace the "T" valve and see if that helps. They're not very expensive.

Also, I don't think I saw anyone else mention this, but white smoke means you have unburned fuel going out the exhaust. Black smoke means partially burned; white smoke means it didn't ignite at all in the cylinder. That is a sign that one or more glow plugs are not doing their job OR the compression is down on one or more cylinders. It's also an indication that fuel delivery is not the cause of the problem.

Yet another thing--much has been made of the condition of the fuel that was drained from the filter. I didn't see any mention of which side of the filter this fuel came from. If it came from the filtered side, you have problems, but I would expect the fuel drained from the unfiltered side to have water and look dirty. That's what the filter does--trap water and dirt.