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

[cnemo]

I have a 2001 TDI, bought it 18 months ago when it had 89,000 miles. Just turned over 102,000. For the last few months my granddaughter has been driving it and I drive it once a week or so. I noticed that since the weather turned colder that it doesn't start as easily as it did last winter. Last Friday I drove it to work and at the end of the day with temp in the low 30's I had to cycle the key twice to get it to start. As I drove away, the CEL and blinking glow plug light came on. Ran just fine on the way home, a distance of about 17 miles with combo city and highway driving. I felt sure that when I checked the code with vag-com on Saturday morning that it would show an issue with the glow plugs. Instead the fault was:

1 Fault Found:
17970 - Quantity Adjuster (N146): Upper Limit Reached
P1562 - 35-10 - - - Intermittent
Readiness: 1 1 0 0 0

I set up vag-com to log some data and started the car, which was hard to start again with temp in the upper 30's. It idled rough for 10 seconds or so then smoothed out and drove just fine with no obvious change in power, acceleration, etc. IQ at idle is steady between 2.6 and 2.8 with RPM of 903.

Yesterday I did more testing. Before trying to start I had the ignition on for 5 to 10 minutes while I got the logs set up in vag-com. Temp was about 40 degf at this point. When I started it really idled rough with lots of white smoke, This went on for less than a minute when it smoothed out and idled fine. I drove off and it ran as always. After it was warmed up I pulled to a parking lot and cleared the DTC while the engine was running. It said no faults and cleared the CEL and blinking glow plug indicator. I drove back home and it ran fine and the CEL did not come back. When home I turned it off and immediately restarted and of course it started fine when warm, however in about 30 seconds the CEL and blinking glow plug light came back. I checked the faults and it was the same error but now instead of saying P1562 - 35-10 - - - Intermittent, it said P1592 - 35-00.

I decided at that point to try and check the glow plug resistance, but I was unable to get the engine cover off. I have not taken this off myself before. The left nut just turns and turns and does not come off the stud, so I'm not sure what is going on there. Last night I did more research and found that there is another bolt on the rear of the cover that I didn't know about, so maybe that left stud is broken and if I take the right nut off (my right looking at the cover from the front) and that rear bolt, maybe the cover will come off. Otherwise I guess I have to take it to the dealer.

This just seems to me like a glow plug issue, but I am puzzled as to why no glow plug errors show up and I'm getting this Quantity Adjuster fault instead. Any help will be appreciated. I also have several spreadsheets of captured logs if anyone is interested, but I think all they show is that everything is okay when the engine is warm. Last fuel fill was less than a week ago and it was 42 MPG with my granddaughter's all-city driving. It is a 5 speed. Thanks in advance!

[janitz]

Based on my own experience, that doesn't seem to be a glow plug issue.

When I had a bad harness I was losing a glow plug every three months, stupid dealership kept replacing plugs, took it to an independent shop and they replaced the harness and never had a problem since.

When the plug failed, the CEL would come on solid and stay on, I never saw any flashing glow plug light like you mentioned. Other than the CEL, it really didn't have that much problem starting with one plug down.

What you're describing sounds like fuel/air mixture issues, and the codes you're getting support that theory. Could be something as simple as a rotten air hose. TDI Club maintains a list of trusted mechanics, you should check that and go to one near you.

[cnemo]

That has me thinking. A couple months ago before the weather got cold I did make the adaptation change recommended to the EGR to keep the intake manifold from clogging. I could back that out and see if it makes a difference. Thoughts?

[janitz]

Originally Posted by cnemo

That has me thinking. A couple months ago before the weather got cold I did make the adaptation change recommended to the EGR to keep the intake manifold from clogging. I could back that out and see if it makes a difference. Thoughts?

Yes, try that, get it back to factory settings before troubleshooting further.

What change did you make exactly?

[cnemo]

The change to the EGR calibration recommended in the maintenance section of the TDIFAQ's on tdiclub.com. Engine control module, adaption block 3, change from 32768 to 33768. This is supposed to keep the intake manifold from clogging.

[cnemo]

Well, I thought I was zeroing in on this problem, but last evening things got murky. Here is the story-
Evening before last, with temp in the upper 40's, engine started, a bit rough idle at first but smoothed out in less than a minute. Drove a short distance and it seemed ok. Cleared the DTC, which was the quantity adjuster again, and it stayed cleared. Drove a short distance and all seemed ok. Stopped and restarted twice and DTC did not return.

Yesterday morning with temp at 48 degf, started up, no stumbling, no cloud of white smoke, no DTC. Drove 17 miles to work, ran fine. During lunch, with temp about 50, had to crank twice but it started. Let it idle for a couple minutes. No DTC. At this point I was convincing myself that I was dealing with a glow plug issue - either 1 or more bad plugs or perhaps a bad relay or issue in the wiring. I haven't been able to check with a meter because of the cover issue I mentioned in a previous post.

After work, it started but had to crank it a bit longer than usual, CEL and blinking glow plug indicator came on. Made one errand stop on the way home, no problem starting with a warm engine. Got home, shut off engine and it sat for 15 min or so while I gathered up my laptop and vag-com. Checked the codes and had these:

2 Faults Found:
17970 - Quantity Adjuster (N146)
P1562 - 35-00 - Upper Limit Reached
16566 - Fuel Temp. Sensor A (G81)
P0182 - 35-00 - Short to Ground
Readiness: 1 2 0 0 0

Tried to start and then engine ran for just a second or two then quit. Tried it again with the same result. Did another code check and got this:

Fault Codes have been Erased
2 Faults Found:
16566 - Fuel Temp. Sensor A (G81)
P0182 - 35-00 - Short to Ground
17970 - Quantity Adjuster (N146)
P1562 - 35-00 - Upper Limit Reached
Readiness: 1 2 1 1 1

Did some research on the temp sensor fault and as best I can tell this should not keep the engine from starting.
Anyway my plan for the weekend is to wrestle the cover off somehow so I can get to the plugs, wiring, and IP connector to check the fuel temp sensor. I read in one of the after market maintenance manuals that the sensor is an integral part of the IP and to fix it the IP has to be replaced. However on one of the threads on the TDIclub forum it appears if the sensor is the problem, it can be replaced without replacing IP. Which is correct? Hopefully the issue is in the wiring and not the sensor itself. I'll post what I find.

[AndyBees]

I'm thinking there are at least a dozen things/issues that can cause a flashing glow plug light.

MOGolf in the TDIclub, I think did the most of this list, I can't remember who else to credit.

Causes of flashing glow plug light
They are listed with the VW code and generic reader P code.

00741 Brake pedal monitoring - implausible signal
01044 Control unit incorrectly coded
16705/P0321 Engine speed sensor - implausible signal
16706/P0322 Engine speed sensor - no signal
16955/P0571 Brake light switch (F) - implausible signal
17653/P1245 Needle lift sender (G80) - short to earth
17654/P1246 Needle lift sender (G80) - Implausible signal
17655/P1247 Needle lift sender (G80) - Open circuit/short to positive
17762/P1354 Modulating piston movement sender (G149) - electrical fault in current circuit
17969/P1561 Metering adjuster (N146) - control difference
17978/P1570 Engine control unit blocked
18020/P1612 Control unit incorrectly coded
18026/P1618 Glow plug relay (J52) - short to positive
18027/P1619 Glow plug relay (J52) - open circuit/short to earth
18040/P1632 Accelerator position sender - voltage supply
17970 - Quantity Adjuster (N146): Upper Limit Reached
P1562 - 35-10 - - - Intermittent
It also flashes when an interface tool has put the ECM in 'basic settings' mode.

There may be more; these are the ones I found documented.

The brake light monitoring includes the clutch switch (manual transmission cars). It also includes a possibility of blown brake light bulbs. If both left and right brake bulbs are blown, the GP light will flash off and on.



Also, you may want to adjust the Injection Quantity value a little higher to lean out the fueling. I noticed you said yours was 2 something, It needs to be in the 3 to 5 range at normal operating temps at idle (36 to 38 at WOT). Note: If you want less fuel you need a higher IQ value, (use a lower software adaptation number)

I can post a step by step procedure if you need it~!

Hope this helps!

[kcfoxie]

I also agree that your IQ is a little low, and should be adjusted higher....

When it does start, does it rev really high (like abover 1000rpm) and then drop?

I had an issue with my 98 (more than twice your mileage) and it turned out to be a collapsed o-ring in the fuel shut off solenoid.

I googled the resistence code and came up with this thread, note post #4

VWVortex.com - Vag com code: 17970 - Quantity Adjuster (N146): Upper Limit Reached

They say this could be the fuel filter, or a "stuck position sensor" in which case the "Hammer mod" may fix it.

Either way it's fuel delivery, not glow plugs, the cold weather has just made it more of a problem.

I'd start with a new fuel filter and work my way from there. If the new filter doesn't resolve the issue, I'd try the hammer mod and timing adjustment, if that fails then check the shut off solenoid O-ring (Pm me if you want more details on that).

Because the o-ring failure is so uncommon (or may start to become common now in the right circumstances on the right aged cars), it took me a while to find the answer on PassatWorld (96 TDI saved my 98 TDI from an unnecessary new turbo).

I remember the car was a little crankier to start that winter before I started losing power (air getting in the fuel post-pump from the shut off solenoid), so that's something I advocate checking. It'll take a week or two for the ring to come in, it's like $7 from VW.

Good luck my friend!

[cnemo]

Update on my problem - I'll try and make this as brief as possible. As of last Wednesday, car would not even try to fire. Didn't get to do more troubleshooting until Saturday. First step was to muscle the cover off. Problem there was right front stud stripped where it screws into the bracket. Finally got it out and cover off. Visual inspection showed no obvious problems with wiring or connector going to the IP. All hose connections appeared tight and hoses appear in good shape. Tried cranking a few times and it never tried to fire. Loosened the connection at #1 injector half turn and cranked. Got a little fuel but not what I would have expected. Decided next thing was to replace the fuel filter.

Sunday afternoon removed old filter which was an VW/Audi filter made in Austria. Drained it into a pint glass jar and did not like what I saw. About 1 inch of water at the bottom and the fuel on top was cloudy, not at all like the fresh fuel I bought to fill the new filter. Filled the new filter with fresh diesel purchased at a truck stop, put new O rings on the T connection and reconnected all hoses. Cranked a number of times, until battery got weak, and no attempt to fire. Put charger on the battery. Three hours later, tried cranking again. The first few tries same as before, didn't even try to fire. Then I started getting some coughs, but battery was to weak to continue. Put battery back on charge. Three hours later, at 9PM, tried it again. It gradually began stumbling on its own for a few seconds. These periods got longer and longer and eventually it started and sat there and idled smoothly. Let it idle while I rounded up my laptop and vag-com. Checked the codes and the only one in was the fuel temp fault short to ground. Drove the car to the end of the driveway and back, accelerating to about 3000 RPM in first gear and it seemed to respond fine. Parked it back in the garage and turned it off and restarted. It started right up, but the glow plug light started blinking in addition to the CEL which was already on due to the fuel temp fault. Checked the code and it was the Quantity adjuster upper limit reached again. Let it set overnight. This morning with temp at 47 DEGF it started after about 5 seconds of cranking and was a bit rough for maybe 10-15 seconds, then idled smooth. Just a little white smoke during this process. Shut it down and drove my truck to work. Plan for this evening is to drive it more but close to home, and if keeps running, it will be off to the truck stop to put in some Power Service diesel supplement and top off with fuel. It is currently about 5/8 full. I'm hoping the IP didn't get torn up in this process. I did some research on the temp sensor and read that one of the causes of failure is water in the fuel. There was definitely water in the filter, how much of that may have gotten to the IP I have no way of knowing. I got the local dealer to print me the service records, which they did going back almost 18 months before I bought the car. The earliest record was from early 2009 when the car had about 76,000 miles. No record of the filter being replaced at that time, or at any time since then, so it was definitely due. Is it possible for the IP to suck junk/water through the filter?

[kcfoxie]

It's possible, and I don't know what all it can affect to be totally honest with you. I do know these pumps and engines are pretty tough, but a rebuild will run about $900 + core from boraparts.com (I like Aaron, good guy, and he's got a fast turn-around on rebuilt pumps).

Power Service... why it didn't start... you'd lost enough pressure / bad fuel in lines you needed to purge, also it wouldn't have hurt to re-prime the line with a vacuum pump.

I use a Pella-like oil extractor with some hose and fittings, I attach it to the output end of a new filter I've filled as best I can with diesel from a can, I put pressure on it till I get a good fuel flow coming out of the filter and into the pella.

Next is to prime the line. Loose all 4 bolts holding the fuel rail lines to the injector nozzles, make sure the pump and filter are attached with rubber hose, have someone else try and start the car till you get fuel shooting out of all 4 lines. Tighten lines back down.

It should start on the next attempt. I've run both my ALH's out of fuel and had to do this. You need a 17mm to undo the bolt on the nozze/line at the engine.

Glad you got this sorted out -- those filters should be checked every 10k for water and drained periodically. I've never had a large amount of water in my filters, but I tend to replace them every 20k like recommended... they're not that expensive and it's like an air filter, just good to keep it clean.

Good luck!

[MyOtherRidesAVette]

I typically stay away from TDI related posts as admittedly I know very little about diesel engines. That said, I noticed references to water in your fuel. Common with both diesel and gasoline vehicles. Less prevelant with gasoline, however. Diesels have a water separator that as part of normal maintenace are to be drained of water every 10k miles, same as the scheduled oil change. Just saying.

M.

[janitz]

Cnemo, when you changed the fuel filter, did you use a pump to pull fuel through the system to clear air.

I know the first time I did this on my own, I missed that step and my engine would not turn over, due to the air blocking the movement of the fuel.

I think what you may have seen when you took a long time to get it to crank finally was air in the line, and you just eventually worked it out.

My process to change the fuel filter is:

1. Disconnect the incoming lines, pull the pin on the return line T. Pull out the old filter.
2. Remove the O-rings on the T.
3. Clean the T with a cloth and install the O-rings in the correct place. The filter should have come with replacement rings, one should be blue the other black. The black goes on the first, the blue on the second, second being furthest from the end of the T.
4. Install the new filter.
5. Insert the T, clip it in place.
6. Connect the fuel line coming from the fuel tank.
7. Attach a pump to the output, get a bit of vacuum going, not too much just a few psi. This will pull fuel into the filter. I like this better than trying to pour fuel in.
8. Once the filter is filled, connect the line from the filter to the injector pump.
9. Disconnect the return line on the T and attach the hand pump. Get a few psi of vacuum going and pull fuel and more importantly air through and out. I leave it until I stop seeing any bubbles.
10. Connect the return line.
11. Start the car, for the first second it will likely hit a tiny bit of air and get a shudder but after that it's all good.

[cnemo]

I don't have a vacuum pump, so all I did was fill the new filter with fuel before putting on the "T" connection. When I took the lines off the old filter, there did not seem to be any fuel at the outlet pipe of the filter or in the line going to the IP, as best I could tell by just looking. My sense is that whatever fuel was able to make it through that old filter, had already been consumed, judging by the way that the engine died last Wednesday in just a second after I started it, just like it lost fuel. This happened twice then no attempt to fire from then on. The thing that puzzles me is how it had been able to run just fine to that point and then just quit, as though the filter had plugged instantly. I would have expected that flow would decrease somewhat gradually, such as not being able to drive at high speed or the engine would lack power. This was just sudden. I stopped the car after driving home from work and that was it. I am thankful I was home at least, since I had stopped at wal-mart on the way. Thanks for the feedback, and I will keep that in mind the next time, although I would think that if one started a filter replacement after stopping an engine that was running normally, the pump, supply and return hoses to the pump, and the injector pipes, would already be full of fuel, wouldn't they?

[janitz]

Originally Posted by cnemo

I don't have a vacuum pump, so all I did was fill the new filter with fuel before putting on the "T" connection. When I took the lines off the old filter, there did not seem to be any fuel at the outlet pipe of the filter or in the line going to the IP, as best I could tell by just looking. My sense is that whatever fuel was able to make it through that old filter, had already been consumed, judging by the way that the engine died last Wednesday in just a second after I started it, just like it lost fuel. This happened twice then no attempt to fire from then on. The thing that puzzles me is how it had been able to run just fine to that point and then just quit, as though the filter had plugged instantly. I would have expected that flow would decrease somewhat gradually, such as not being able to drive at high speed or the engine would lack power. This was just sudden. I stopped the car after driving home from work and that was it. I am thankful I was home at least, since I had stopped at wal-mart on the way. Thanks for the feedback, and I will keep that in mind the next time, although I would think that if one started a filter replacement after stopping an engine that was running normally, the pump, supply and return hoses to the pump, and the injector pipes, would already be full of fuel, wouldn't they?

They have some, but what happens is you will lose a bit when you take off the hoses. There is some fuel left in the injector pump, but immediately behind that will be a fairly large pocket of air.

You have a 2001 which is the ALH engine design, in the ALH there is not a lift pump in the fuel tank, so the injector pump needs to do all the pulling and isn't strong enough to break an air lock when it occurs. My guess is your continued cranking eventually worked out the air.

[AndyBees]

(Fuel filter related)- For what it's worth, here is my almost 32 years experience of owning, maintaining and driving my VW diesels.

In the early years, I'd drain the fuel filter periodically to see if there was any water ...very very little if any was the typical results. So, I just quit the practice long ago. Then, when I purchased my first TDI, I did do the fuel drain checking for water.....basically same results. So, I don't bother. In the TDI Club, you will read pretty much the same comments from those who have been around for a while.

Changing the filter: I just fill the new one as full as I can get it with fresh diesel using a special funnel! Then I hook up the lines, start the engine and immediately take the RPMs up to about 2000 and hold it there for about 30 seconds! Presto, no problems! I've been doing that from the first filter change in early 1980 to this date! Besides my own vehicles, I've changed a good number of filters for others using the same method with no problems at all! One thing I do is drain the old filter into a glass jar to see what comes out!

It's obvious the original poster to this Thread picked up some bad fuel, based on what he's stated! So, checking the filter to see what may be inside was the right thing to do.

Here is one of those "Believe it or not" stories! My brother let the Original Fuel Filter on his 2001 Jetta go until it had just under 171k miles on it, with no problems. That's definitely not recommended! (He lives northeast of Atlanta, GA)

Lastly, I've always changed mine in late November or early December, regardless of miles on the old one, to face the winter months with a fresh filter! And, I've always purchased fuel where ever and when ever I needed it.....no preference as far as name brand!

[cnemo]

This could have been the original filter as well. All I know for sure is that it hadn't been replaced in the last 3 years.

This morning it started with about 4 seconds of cranking, idled smooth right away and no smoke. Drove it to work and performance seems like it was before all this started. Now, if Quantity Adjuster error will stop after some good fuel and additive goes through the pump, I'll be in pretty good shape. I think the fuel temp sensor is trashed though. The error says short to ground and, although I haven't taken apart any connectors or wiring, it seems to be too much of a coincidence for it to be unrelated to the fuel issues. Thanks for the reply.

[janitz]

Speaking of original fuel filters, the first time I changed it I was in a shock. The filter on the car didn't match the replacement!

The original filter was a one piece unit with no plastic T. The return line was just like the incoming, part of the filter top.

So I had to spend twice as much to do that filter because I had to special order the T.

Early 98, kind of a bit of a one off.

[cnemo]

December 21 update on my problem-

When I got home last evening I hooked up vag-com. Noted that the IQ at idle was now 4.2, compared to the 2.2 to 2.6 before the filter change. Checked the error codes and the QA upper limit reached now said intermittent. Cleared codes and of course still had fuel temp sensor short to ground. I put the adaptation for the EGR valve back in. Did note that at idle the EGR valve position and MAF value seemed to vary more at idle than it did before this whole episode started.

This morning with temp at 44 degf the car started after about 4-5 seconds of cranking. Idled smooth immediately and no smoke. However blinking glow plug indicator came on when CEL came on, so the QA error has obviously come back. I've only driven about 50 miles since the filter change. The drive to work was fine. If it wasn't for the errors glaring from the instrument panel, I'd have no idea there was any problem. Engine seems to run and respond as it always has.

I still have doubts if the glow plugs are getting power and want to check that. Is there any special method or precautions to removing that electrical "header" that goes to the plugs? Do the connectors just pull straight off, or is some twisting necessary?

Here is a picture of what I drained from the old filter:

[janitz]

Wow. That is some ugly fuel.

[Smileybug]

I've seen plenty worse. This came out of the tank of my Mk1:


Hard to tell, but it was brown, and full of pieces of stuff. Oh the joy of a full tank of diesel sitting for 4+ years. Whoo!