BEW being a bewstard!

[bmali98]

BEW. P0726. P0725. P2637. I caused P0727 when I disconnected the crank position sensor. I replaced the sensor already. Didn't fix.

So, my 04 golf ( my primary but only running car) has always been difficult to start in the cold. This is the second winter I have owned it. I have put on 110000km on it relatively problem free. I've had glow plug circuit codes rarely but nothing an extended crank couldn't get me out of. Nothing too crazy. Just the ol' crank and stumble a couple times. "Probably didn't have the update, whatever". It only did this on -15C mornings or worse.

Couple days ago it just cranks forever like the injectors aren't squirting. Cycle a bunch of times. It says no,no,no,no,no,no,kick,no,no,no,no,.......... Every time I cycle and crank. while cranking, glow light flashes while the low oil light flashes and the tach hovers in the 0-200 rpm area until it suddenly stumbles to immediate life and all is ok except for the check engine light. Codes p0726 (crank signal range/performance) p0725 (eng speed circuit malfed) and p2637( tq management feedback signal A) which makes for no guts. Clear everything and it runs fine for forever, everywhere, all the time perfect, until it's left overnight and it gets cold. So I replaced the crank sensor when it left me stuck after 2 days of ****ty starts when cold. The first time I cranked with the new sensor, of course it starts fine when it's in the warm shop. Go to leave work 3 hours later and it pulls the no fire thing again. It starts eventually so I head home with it so I can look into it at home. Runs 100% perfect, not a stumble or fart or surge or knock.


This thing is going to give me trouble in the morning, I know it.

I tugged at the Wiring while running. I replaced the crank sensor already today. I even disconnected the new crank sensor while running and it can't run without it... When I did this it set P0727(no signal) If it is warm even the least bit it starts perfect. It's not a glow plug problem.

Any ideas?

 

[stamp11127]

I can't offer any help for your problem since I'm new to the TDI world. But I do have some experience with big diesels and have a question for the guru's about your problem.

Is there a minimum cranking rpm before the ecm will allow the injectors to fire? I know on a CAT C7 we need to be above 250 rpm or we will not run.

 

[Dimitri16V]

If the car will not start/run with the crank sensor disconnected , the cam sensor maybe be giving erroneous signals

 

[bmali98]

Is there a minimum cranking rpm before the ecm will allow the injectors to fire? I know on a CAT C7 we need to be above 250 rpm or we will not run.

If so that could coincide with my tach needle. If the ecm isn't seeing the rpm to send fuel. The needle does seem to spike to about 500rpm when it kicks even just once.


How does the sensor pick up rpm on my engine? Is it a chopper wheel with a tdc tooth, a magnet on the crank?

 

[AndyBees]

The crankshaft can be rotating at the "rate" of 500 rpms and it will not be reflected on the Tach..... I've had situations where I thought my ALH in the Vanagon was not going to start as the battery was drained from other issues, then just when I thought it was over, sha-zam, it fired up. I was watching the Tach it was basically on zero.

So, in my opinion watching the tach for that magic number (over 250 rpms) is nothing more than hope!

 

[pruzink]

Do you have vagcom? There are two things that I would take a close look at. One is your engine coolant temperature sensor data. When my coolant temp sensor failed my car wouldn't start without long cranking. The other is torsion value (timing). Where the torsion value is set can have a big impact on how the car starts & idles.

 

[shak911]

BEW. P0726. P0725. P2637. I caused P0727 when I disconnected the crank position sensor. I replaced the sensor already. Didn't fix.

So, my 04 golf ( my primary but only running car) has always been difficult to start in the cold. This is the second winter I have owned it. I have put on 110000km on it relatively problem free. I've had glow plug circuit codes rarely but nothing an extended crank couldn't get me out of. Nothing too crazy. Just the ol' crank and stumble a couple times. "Probably didn't have the update, whatever". It only did this on -15C mornings or worse.

Couple days ago it just cranks forever like the injectors aren't squirting. Cycle a bunch of times. It says no,no,no,no,no,no,kick,no,no,no,no,.......... Every time I cycle and crank. while cranking, glow light flashes while the low oil light flashes and the tach hovers in the 0-200 rpm area until it suddenly stumbles to immediate life and all is ok except for the check engine light. Codes p0726 (crank signal range/performance) p0725 (eng speed circuit malfed) and p2637( tq management feedback signal A) which makes for no guts. Clear everything and it runs fine for forever, everywhere, all the time perfect, until it's left overnight and it gets cold. So I replaced the crank sensor when it left me stuck after 2 days of ****ty starts when cold. The first time I cranked with the new sensor, of course it starts fine when it's in the warm shop. Go to leave work 3 hours later and it pulls the no fire thing again. It starts eventually so I head home with it so I can look into it at home. Runs 100% perfect, not a stumble or fart or surge or knock.


This thing is going to give me trouble in the morning, I know it.

I tugged at the Wiring while running. I replaced the crank sensor already today. I even disconnected the new crank sensor while running and it can't run without it... When I did this it set P0727(no signal) If it is warm even the least bit it starts perfect. It's not a glow plug problem.

Any ideas?

cranking the engine for extended seconds, uses lots of power, and causes battery voltage to drop, electronics get confused and throw false codes.

I,too had cold start issues with my 04 Bew, I tried so many different things to fix it, of course the last thing I tried was a frost heater, I purchased a 1500 watt model, and I just recently tested it at -25C, after only plugging it in for just 30-45 minutes, it is thermally controlled, I think the make was Zero Start.

so if you have access to 120V where you park, that's is the best way to go, to me it was the only thing that worked.

strange, my 2012 starts just like a healthy gasser if not better, no need to plug it in. I am amazed at the difference between the 2, even cabin heat is faster than a gasser...

 

[bmali98]

Do you have vagcom? There are two things that I would take a close look at. One is your engine coolant temperature sensor data. When my coolant temp sensor failed my car wouldn't start without long cranking. The other is torsion value (timing). Where the torsion value is set can have a big impact on how the car starts & idles.

I don't have vagcom but I am due for a timing belt. Maybe the cam is off from a stretched belt? I already have a kit to put on...

The shop near me has vagcom. What would I be looking for in the timing? With the temp sensors I guess I would be looking to make sure fuel, coolant, air at same ambient temp on a cold start?

 

[bmali98]

cranking the engine for extended seconds, uses lots of power, and causes battery voltage to drop, electronics get confuses and throw false codes.
I,too had cold start issues with my 04 Bew, I tried so many different things to fix it, of course the last thing I tried was a frost heater, I purchased a 1500 watt model, and I just recently tested it at -25C, after only plugging it in for just 30-45 minutes.
so if you have access to 120V where you park, that's is the best way to go, to me it was the only thing that worked.
strange, my 2012 starts just like a healthy gasser if not better, no need to plug it in. I am amazed at the difference between the 2, even cabin heat is faster than a gasser...

It still cranks like a rockstar. If this weren't a sudden issue I would just get a block heater but this is way out of the normal. I work as a truck mechanic and have started a lot of tempermental cold engines. Mine is missing more than just compression heat.

I borrowed a gasser to get home yesterday. I like how it started this morning. Lol.

 

[shak911]

It still cranks like a rockstar. If this weren't a sudden issue I would just get a block heater but this is way out of the normal. I work as a truck mechanic and have started a lot of tempermental cold engines. Mine is missing more than just compression heat.

I borrowed a gasser to get home yesterday. I like how it started this morning. Lol.

the way I read your post, the car has no issues starting when engine is warm, or when the weather is warm (not freezing), but you have difficulty starting it when the outdoor temperature is very cold and car has sat for >3 hours.

do I have it right ?

 

[cooter2]

If your getting glow plug codes and long cranking I would try two things.

1. Replace the glue plug harness and test all the glow plugs.
2. Check/ replcee Replace the lift pump

Both had an impact on the child start cranking of my new jetta. Both were bad.

I also had similar symptoms, long cranking and rough start. I also got occasional crank sensor codes. All had now been resolved.

 

[Wilkins]

If the first glow plug recall was done but not the second it will be hard starting below about -12.
If you have Vagcom, I think block 54 gives the rpm readings from the crank sensor and the cam sensor. Mine takes a couple of seconds before they both read right, it's just the sampling rate of the device.
If I recall right you need about 250 rpm to fire, which isn't much.
If the cam sensor isn't working I think it takes maybe five seconds longer to fire because it can't tell which piston is the one that needs the fuel and doesn't inject. A BEW won't run without a crank sensor. BRM will.
If you disconnect the temperature sensor it defaults to very cold - if that is the problem it should start easier with the sensor disconnected.
Is the lift pump working? Should hear it below the back seat when you turn the ignition on. Runs for five seconds then shuts off until car starts. If you don't hear it pull the fuel line off the filter to confirm. Should get fuel squirting out when the ignition is turned on without cranking the engine.
Read http://pics.tdiclub.com/data/517/PD_fuel_delivery_check.pdf

 

[bmali98]

Thanks all. It started great this morning at -15C but I didn't do anything. It was only -5C when it wouldn't start yesterday after I did the sensor.

Cooter2 and Wilkins, I will check the lift pump. I changed the filter a couple days ago but didn't use the pump to prefill it. I will check for this first. It started poorly before the filter change but it was due for one so the filter was my first thought. Thanks for the link Wilkins.

As for the glow plugs, I'm guessing vagcom will tell me what update it has on it if any? How can I tell if it's the current update? I went to vw hoping to get it updated but they told me that campaign ended for my car in 2012 and they don't have record of it being done but thats not to say someone else didn't. I don't think the glow plugs are my main issue though. This is a sudden issue that I had before I changed the fuel filter (it's not likely air in fuel at the filter)

I'm going to hopefully be able to check temperatures, timing, crank vs cam rpm while cranking and what glow plug program it currently has via vagcom from my neighbourhood vw shop. Thanks again all! Any new thoughts please keep posting.

 

[JB05]

Is the thermal T on top of the fuel filter in tact?

 

[bmali98]

I wasn't able to get to the other shop to get some vcds use but I did use our snap-on solus to monitor some stuff. Coolant,air and fuel temp are all within 2C of one another and the crank sensor picked up engine rpm just fine and it started right away. The symptoms aren't present right this second. The lift pump is not working. I pulled the filter inlet line and no flow with key on. Fuse 28 is ok. Will have to look into this... Thanks again Wilkins for the link. I will troubleshoot this later when I get some time.




Update: The lift pump itself is defective. I used my power probe to feed power and ground to it and nothing. I will replace the pump and see if that fixes it. Mind you it hasn't been cold and won't be for the foreseeable future so I may not know until next winter if the lift pump solved the problem.

 

[bmali98]

K, so an update in case anyone has this problem in the future....

I replaced the lift pump today and the car starts much better. By the time I unfold the key, it's already running. It starts immediately and makes a larger poof of blue smoke when cold and immediately is smoothed out ready to go. The car used to stumble for about 10 seconds regardless of temperature. I will have to see how it cold starts next year but I feel it will likely start a lot better. Aside from starting better, the ass dyno says it also has better under 1000-2500 torque and smoother high rpm power. It has a stage 1 tune only but now I feel I never knew what the tune was capable of due to probably never having a functional lift pump the last 1.5 years. It runs so different the auto Trans had to adapt at first as it was shifting clunky/at odd rpm but now shifts are perfect and smoother than before now that it has relearned. The car also had a problem where it would double downshift at 100kmh to 3rd and have no power and would barely build speed. Now the double downshift is working properly as to now it actually goes with great pickup in that situation. I can't honestly believe the bad Trans shifting, hard starts, rough/inconsistent power was all caused by the inop lift pump some would argue is unneeded. Thanks for the help all who contributed.

 

[bmali98]

Another update!!!!

Did it again! Cranked forever and got an engine light. Didn't scan yet as I gotta get to work. Probably same codes...Lift pump can be heard running..... Bah!

 

[RT1]

The car will not run without the G28 (engine speed/crank sensor). That's by design. The crank sensor is the fall back if the Cam position sensor G40 fails otherwise the ECM has no idea what cylinder is in position to fire. There is a "quick start" function that uses signals from the G28 and the G40 to activate the correct injector without having to synchronize with the first cylinder. Switch out the G40 and see if that doesn't fix the problem.

p.s.There's no argument you needed the lift pump. The tandem pump was not designed to suck fuel through a filter from a tank through ten + feet of tubing. The tandem pump is for pressure after the pump, not suction.

 

[bmali98]

Thanks for that. So if I'm getting a no start with a crank code, it's already not using the cam sensor? Or is it that they don't agree with one another and the crank is calculated to have the issue? I'm going to do the cam sensor in a week then when I do the timing belt.

No argument about the lift pump anyway. It definitely performs better in general. Can't really ensure a measurable difference just better overall.

 

[Wilkins]

Id be happy if someone were to correct me but I thought the cam sensor on the BEW only provided info for a hot start but on the BRM it also functions as a backup for the crank sensor. If so it won't affect a cold start.
Could be a crank sensor, but since it is intermittent check the wiring at the plug, located somewhere near the vacuum reservoir if memory is correct. Two skinny little wires with next to no protection. Might be a damaged wire or bad connection. If the crank sensor fails I suspect it stays dead.
Crank sensor is also much less expensive than cam sensor, plus fairly easy to change.

 

[bmali98]

Thanks Wilkins but I already did the crank sensor. Also went around and tugged all the wiring to it while running and not a hiccup or stumble. Also disconnected the sensor while running to ensure the engine needs it while running, it does. It is the small wiring near the vac reservoir. The cam sensor wiring is right above it. Shook that too and no reaction.

 

[tjsean0308]

I realize you are getting different codes, but you do have an 04. Was the TSB in this thread done? I noticed a big difference on my 04 wagon once I added the ground to the ECM in this TSB.

https://forums.tdiclub.com/showthread.php?t=328868

 

[bmali98]

I have only had this car a couple years but I doubt this tsb was done. When I get a chance I'm going to pull the harness apart and see. Thanks for this link.

This seems a possible cause of this problem. I wouldn't dream of doing a wiring connection without a crimp or solder or a proper terminal connection. How does the equivalent of wires twisted and taped together as a lazy ground source become mass produced?!

 

[kosamatic]

Have a 2004 Jetta TDI BEW Automatic. Has always had a longer start than my ALH, weather is cooling off and having hard time starting. I'm getting these same 3 codes on a cold start was there any resolution to this issue?

 

[osesu96]

Have a 2004 Jetta TDI BEW Automatic. Has always had a longer start than my ALH, weather is cooling off and having hard time starting. I'm getting these same 3 codes on a cold start was there any resolution to this issue?

What codes are you getting with your 2006 Jetta?

 

[AndyBees]

I believe Kosmatic is talking about an 04 Automatic with the BEW engine that's not on his TDI list!

 

[DuraBioPwr]

Not to beat a dead horse here but just adding some more input for others having issues with crank no start conditions related to the crank position sensor.

The TSB was done on my car a number of years ago. Long before I purchased it anyways. Since owning it I have had on and off issues with the 'crank no start' and eventual P0727 code. I have put probably 4 CPS sensors on it. All OEM. Works for awhile and then randomly does it again.

I tore the harness apart at the ECM to inspect and it all looked fine with the proper butt splice connectors blah blah blah.. I hate butt connectors and decided to fix with a solder joint and proper heat shrink. So far so good and has not done the random crank no start again, yet anyways..

Butt connectors can be dodgy. Oxidation, vibration etc.

 

[BobnOH]

I usually solder repairs as well, but the butt connectors is the recommended method because a solder joint can crack if it binds and moves enough.
Issue is most of us do not own a proper crimp tool, at least I don't. As time goes on we see more and more issues with wires/connects.

 

[PRtime]

Recently received P0727 code on my 2005 Jetta TDI w/BEW engine manual transmission. So where is this crank sensor located? What is the trouble shooting procedure? Internet videos have been somewhat helpful but also have led to these questions.

 

[Destro]

Its the gray connector on the front of the motor mounted down on the block. Mine started having intermittent issues at zero throttle shutting off the engine and preventing restarts without the accelerator pressed a few years ago that were solved by securing the wires into the connector with rtv to reduce their movement as I have stiffer engine mounts, replacing the sensor is easy if that does not solve the issue. After it reoccurred that is what I did.