Hard start at 50-60 degrees

[Benjamis]

She starts right up in one second or less most of the time, except when it is 50-60 degrees F, she cranks and cranks and sputters and starts on 2 or 3 tries. Just above the temperature where the glow plug light would come on. If it is cold enough for the glow plug light to come on, I wait til it goes off, and it starts right up. Good old pre-glow. The glow plugs and relay are new and tested and working as they should. No issues at all starting in warm temperatures or when the engine is warm.

I have the BK ECU and from what I understand the pre-glow cannot be adjusted in VCDS. What to do about this? Rig a switch? It is way way easier to start the car and less smoky when it is 20F than when it is 55F. A fuel prime issue would affect starting at all temperatures, would it not?

 

[garciapiano]

Have you checked your coolant temp sensor? I would also suspect the fuel temp sensor inside the injection pump.

 

[Steve Addy]

I'm not sure if the BK operates in the same manner as what came after, but if you really wanted to force glow then you could install a switch that cuts ground to the CTS, and that way it would force the GP's to full cycle.

OTOH, is this indicating another problem? I can't say for sure, but none of my AHU / 1Z cars glow at all above 40 and they don't have to crank much either.

Steve

 

[Benjamis]

Have you checked your coolant temp sensor? I would also suspect the fuel temp sensor inside the injection pump.

The sensors read ambient temperature with a cold engine and also are in the proper resistance range according to Bentley.

 

[Benjamis]

I'm not sure if the BK operates in the same manner as what came after, but if you really wanted to force glow then you could install a switch that cuts ground to the CTS, and that way it would force the GP's to full cycle.

OTOH, is this indicating another problem? I can't say for sure, but none of my AHU / 1Z cars glow at all above 40 and they don't have to crank much either.

Steve

I would prefer to find the other problem that it indicates instead of forcing glow. I do have a somewhat weak battery, but the fact that the car starts in one second at 20 degrees on multiple occasions makes me feel like that is not the problem. It's just very interesting that it only does this around 50 degrees.

 

[turbodieseldyke]

I would also suspect the fuel temp sensor inside the injection pump.

The fuel sensor would kick a CEL, wouldn't it? I think mine did. Also had worse MPG til i replaced it.

 

[Mcgink]

Shouldn't need glow at 50-60 degrees IMO. Maybe some other issue. Thermal T letting any air in? Got air bubbles in your return line? Timing? Crank sprocket?

 

[Benjamis]

No air in fuel lines, timing is advanced almost to top line of the graph and is mechanically spot on, crank sprocket was replaced less than 20k ago. I would think all of these would affect starting at all temperatures.

Maybe it is the fuel temp sensor. It reads 2 or 3 degrees higher than the CTS with cold engine. The resistance graphs in Bentley for the FTS and CTS are the same, and the last I measured, the FTS was 2790 and CTS 3110 ohms, which I thought to be within the spec on the graph for the given ambient temperature, although it is a large difference. I didn't think this would be huge deal with starting, but maybe it is. Will have to monitor it more closely. Also one time last summer I went to check timing on VCDS and it said fuel temp was too hot, it was just off the graph, but I was low on fuel, and that hasn't happened since, so I don't know...

 

[burn_your_money]

What's your compression?

Try boosting the car with another car or hooking it up to a battery charger and see if that makes any difference when it's in the 50s.

Have you done voltage drop checks to make sure the battery cables are sufficient?

 

[Benjamis]

Compression is good, I hope. You're right, I should check it though, I suppose I haven't because I haven't found a free loaner gauge yet. I have not done voltage drop checks, the entire car probably needs that. Thanks for the input, will report back soon.

 

[Benjamis]

I'm getting a voltage drop of 0.21 volts from the positive battery terminal to the positive starter post while cranking on a 35 degree day. Connections are clean and tight, just had the starter off last winter and cleaned it all up as well. The battery holds a charge of 12.6 volts in cold weather. I would think if there was a problem here, it would have a problem when the glow plugs are cranking when it is 20 F out or below as well, but she fires right up when there is pre-glow.

The FTS and CTS resistance readings are in spec at 35 degrees ambient, a little less the 2 C. VCDS readings for FTS are 2.8 C. CTS is 0.0 C, IATS is 1.8 C. I wouldn't think this would be a problem, or is it?

I might have a compression tester lined up here shortly. Or maybe I should just buy one for the 3 times I might use it. What's another 50 or 100 bucks. Sigh.

 

[burn_your_money]

What the voltage drop from the negative battery terminal to the starter housing?

How quickly and to what voltage does the battery drop to while cranking?

 

[Benjamis]

Voltage drop from starter housing to negative battery terminal is 0.21 V as well but I did it several times and saw a 0.36 V max once. I'll check the battery voltage while cranking next time I get a chance at 45-60 degrees. All this past week, whenever I started the car in the morning it is 25-30F and it starts in 1 second without fail. When I leave work to go home, it has been 40-50 degrees, and it cranks and cranks and sputters and takes 3 tries to start it. The crank speed in the morning seems very weak, but either way it starts immediately. In the afternoon, it cranks strong but doesn't start well. It cranks strong and starts immediately with a warm engine. I've meant to check cranking rpm but every time I did with VCDS it starts too quick to tell, but didn't think to disconnect the FSO solenoid and see, will do that on a cold morning and also at 50 degrees and see.

 

[jdulle]

Perhaps it is a sensor, if it was a compression problem, it wouldn't start better in the cold.

 

[Benjamis]

The battery did die on me one cold morning, so I put a charger on it and it fired up. Then it slowly started becoming a regular occurrence, even with battery voltage of 12.6. However, on cold mornings it would often be at 12.2 V, and the crank was weak, and I had never bought a battery since I owned the car, and the battery's date of manufacture was November 2015. So I bought a group 49 battery, and the next cold morning, she won't start! So I took a large stick and lightly hammered on the starter, and she fired right up. A few days later, I got a wretched squeel when I tried to start it, which had happened twice before in the past year. When I pulled the starter, the gear could be spun easily in both directions, probably not the only thing wrong with it. Not the original, but was a Bosch and had the sticker of the remanufacturer on it.

I bought a brand new Valeo starter with no core for cheaper than a Bosch reman. It cranks strong and starts instantly on the coldest of mornings. So now the weather is warming up, and we're getting a lot of those good old 50-60 degree starts. Brand new oversized battery, brand new starter with strong and fast cranking, and it cranks and cranks and sputters and dies and takes several tries to start. Brand new professionally calibrated injectors. No bubbles in clear fuel lines. Timing mechanically spot on and advanced in VCDS as many here do. Fuel/coolant/intake temp sensors in spec in resistance graphs and within 2 or 3 degrees C of each other with cold engine. No CEL, no codes in VCDS.

Warmer temps, thinner fuel, check valve not checking? I have an intermittently working fuel gauge now. And when it works, it reads low, then slowly climbs to what it should be, then goes off, then repeats the cycle.

Any other guesses before I get to checking check valves and all that business down there? Once again, this is a temperature dependent issue, and the temperature sensors all check out like they should, the car runs very well once started, and starts no problem with a warm or slightly warm engine, and cold starts in 1 second or less whenever it is cold enough for the glow plug light to come on.

 

[ToddA1]

I’d almost discourage you from messing with the check valves at the sender. That plastic is old and things like to snap. Maybe install a couple temporarily at the filter barbs to do the same thing.

FWIW, I’ve taken apart fresh Bosch remanufactured starters and wasn‘t too impressed. Rusted parts, little to no grease, etc... seemed more like rebuilt, but expected better. I’m sure it depends on the person who’s actually doing the work…

-Todd

 

[Abacus]

I’d almost discourage you from messing with the check valves at the sender. That plastic is old and things like to snap. Maybe install a couple temporarily at the filter barbs to do the same thing.

FWIW, I’ve taken apart fresh Bosch remanufactured starters and wasn‘t too impressed. Rusted parts, little to no grease, etc... seemed more like rebuilt, but expected better. I’m sure it depends on the person who’s actually doing the work…

-Todd

I've never had an issue with the check valves coming off but do use hose removing pliers.

They make things so much easier and don't damage the components.

As to starters, I have also not been impressed with the Bosch remans and instead sent my own to an independent local shop to be rebuilt. I have never had luck with the "lifetime" Valeo ones and stay clear of them now after having to replace every one of them early.

 

[Benjamis]

Well, if I don't figure out this hard start issue that may be my valeo's fate. I figured though, I got it for cheaper than any bosch reman I could find, and I still have my bosch and can rebuild it. I searched for a local shop but only 1 place of the many I called seemed remotely interested in working on it. Every one of the certified Bosch shops I talked to said they "send them out".

 

[Benjamis]

I’d almost discourage you from messing with the check valves at the sender. That plastic is old and things like to snap. Maybe install a couple temporarily at the filter barbs to do the same thing.

Where do you buy your check valves? They seem a little pricey, even at local parts stores.

 

[ToddA1]

I still have my bosch and can rebuild it.

Take it apart if you’re the curious type…. I am. There’s really not too much in there… parts can be found online.

Where do you buy your check valves? They seem a little pricey, even at local parts stores.

I’ve never had to buy them, but I’m sure you can find some that’d be suitable, even if its only for short term testing. Try Amazon, eBay, etc, if you don’t like what you see locally.

-Todd

 

[ToddA1]

Verify the size.

Amazon.com

If you can be lazy like me, your temporary test may become a permanent repair…

-Todd

 

[Benjamis]

Thanks. Could call it lazy, or practical. It's happened before, I would do it again. I would be very ok if I installed these by the fuel filter and left them there for the life of the car.

That's a nice looking starter by the way. Maybe next winter I'll rebuild mine, I started looking for parts a while back and seemed I could only find genuine bosch parts from europe on ebay. I forget his name but there was a guy on here too supplying rebuild kits for both valeo and bosch.

 

[ToddA1]

If you open your starter, it’ll probably be obvious what’s wrong with it.

The first starter was used, but the 2nd was the Bosch remanufactured. I only took them apart to paint and plate the hardware. I’m glad I took the 2nd apart… ended up cleaning parts, adding grease, etc.. Remanufactured used to mean all new internals… supposedly that term changed definition.

-Todd

 

[Benjamis]

Sounds about right.

So the fuel supply line is 5/16" (8mm) and the return is 1/4" (6mm), so I should probably stick with those sizes, or I guess I could get a 2 pack of 5/16 and used an oversized one on the return if it saves a few bucks, which nowadays means $10 or more. Will probably install one on the supply only first to see if there are any changes. There is about a 1 inch bubble in it right now after sitting for a few days, never thought that would be a problem, but maybe a sign of fuel going back into the tank or air entering somewhere, but no diesel leaking or smell of diesel anywhere from what I can see or smell. I don't see any bubbles in the fuel lines with engine running.

I found these pierburg check valves are in the $10-15 each range, would rather buy those, but of course the 5/16 seems to only be found in Europe, plenty of 1/4" available here on many sites though...

https://www.kmotorshop.com/document/tecdoc/5/PI-1547_E_1569085.PDF

 

[Benjamis]

I installed a check valve in the supply line and also in the return line between the fuel filter and injection pump a few months ago. There has been no change whatsoever at any temp, but with higher summer temps, starting isn't a problem, but every once in a while the overnight lows have been dipping into the 50s, and that means a rough start in the morning. To recap, she starts instantly when it's cold enough for the glow plug light to turn on. She starts instantly when it's 80+ F, and she starts instantly with a warm engine. She takes 2 seconds to start when it's 70-80F, a few more it it's 60-70 F, and at 50-60 F, she cranks and cranks and sputters and takes a few tries and lets out a massive cloud of smoke. Any other thoughts or ideas?

 

[Steve Addy]

You shouldn't have any trouble starting when it's 50 out, and I think I said it before, you don't get glow, unless you modified the parameters, until it's under 40 degrees. I'm not sure what's causing this issue but it's strange.

As for the fueling issue you are running a vented tank or a vented cap?

Steve

 

[Benjamis]

Hmm, not sure about the vented tank or cap. I have not had to mess with that yet since I bought the car 5 years ago, but I believe it is all stock equipment down there, I'll have to look into that.

I have the BK ECU and from what I understand the glow parameters cannot be altered. From what I recall, I see the glow plug light for a half second or maybe a second or two when temps are in the 40s, I'll have to double check on that this fall.

 

[Benjamis]

As for the fueling issue you are running a vented tank or a vented cap?

Oh yea, the vented tank... I remember reading up on that a while back, I never tried it out yet though, I just fill up til it automatically stops and call it good. I have a Stant fuel cap that has a spring loaded vent on the underside, came with the car. Seems to work, I don't smell diesel when it is on. Could a bad fuel cap cause a fueling issue on the B4V?

 

[sbnm99]

Hi there, mate. I know it's been a while since this thread was updated, but I'm being driven crazy by my 2010 common rail TDI. It's doing exactly what you're saying, starts perfectly under 10°C, when the glow plugs fire up, when it's over 25°C out, and when it's warm.
If the ambient temperature is around 15-20°C and the car has been sitting for a few hours, or even if the coolant temp is at around 20°, it does this hard start, cranks for a long time, then puffs out grey-blueish smoke. It's been almost 3 years since it's been doing this, and I've just run out of ideas. Battery and starter are good, injectors are new, timing is done perfectly. I just don't know what to do anymore.
Did you manage to get yours fixed?

 

[Benjamis]

Oh yea, I've been meaning to update this thread. I inadvertently fixed this when I was chasing oil pressure issues, I replaced the intermediate shaft bushings, and "while I was in there" decided to remove the cylinder head to replace the valve guides and stem seals in hopes of fixing the billowing smoke issue. Not sure if this had anything to do with the problem:

20230617_171612.jpg

• Benjamis
• Jan 15, 2024

20231114_141508.jpg

• Benjamis
• Jan 15, 2024

That's about a pint and half of baked oily soot chips that I got out of the intake ports. The intake manifold was similar, so I cleaned that as well. Maybe it just wasn't getting enough air. The EGR was "deleted" by a previous owner, and it has smoked an embarrassing amount on cold starts ever since I bought it over 6 years ago, so this must have been old crud. The exhaust valve guides were barely still in spec so I replaced them all, along with the stem seals. It turned out I had several valves that were out of round, so I replaced all the valves as well, and fell the rest of the way down the slope and did the lifters and cam.

Now she starts quickly in any temp and smokes very little in comparison. This morning she fired up in 1 second at 7 degrees F, smoked a decent amount but still not nearly as bad as the old 50F starts before.

I have a sneaking suspicion but not totally sure that either the cam or the the injection pump was off by one tooth as long as I have owned the car. When I did the timing belt the first time, I marked where the old belt was, and put it on the same. I used a stack of sawzall blades as my cam locking plate, and the cam would smash the blades towards the rear of the car, but it's the only way I could figure out to get it all together, and that's how it was on there before. When I put the head back on and did the timing belt this time around, I did it the same way but thought it wasn't right so undid it and did away with the IP lock pin and used my pulley counterhold tool on the IP sprocket and got it all where it needs to be. No more smashed sawzall blades from the cam. I thought it was perfect before but it seems it wasn't. I read in other threads that people have trouble getting the cam fully in line with the IP and crank. Fuel economy is the same as always for me, upper 40s, low 50s on occasion, and seems to run the same, just starts way better and no smoke and do have more power and better acceleration, but as for exactly why, it's hard to say, might have been many factors, but generally speaking smoke issues are going to be either timing or valve stem seals and/or guides, or bad fuel. Wouldn't hurt to change all the filters first. How many kms on the vehicle?