Volkswage Passet TDI Hard Starting when warm
 

First I apologize for adding a non-Benz item but I'm pulling my hair out trying to figure this issue out.

1. Car starts perfect when it cold or has sat. However, if it is warm and sets a 10-15 minutes it cranks and cranks - finally starts and then white smoke
2. I have had the car into my favorite shop and they have done everything possible
a) Compression great
b No error codes
c) Timing belt replaced a few months -- preventative maintenance
d) New fuel and air filters
e) glow plugs are ok

The only item that they thought could contribute was that the operating temperature was a little cool about 10 C less than what it should be.

Does anyone have any suggestions.


Please and thank you

3pointstar

What year is this car?

Try VWVortex - The Volkswagen Enthusiast Website or Fred's TDI Page. TDIClub.com. VW TDI Enthusiast Community
I have an 06 Golf tdi and rely on both of these forums.

Look into timing. If I remember with my 1.9l tdi's when the timing belt is changed you generally have to have the timing set again (guy did it with a computer on mine.) My thought is maybe something is off from that. Just a thought.

which year ...98-02?

I had Vectra DTI year 2000, with exact same issues...VP44 Bosch pump (electronic part) has failed totally after month or two....

do you also tend to drive on low tank? :)

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Yes, need to know the year... the suggestions change vastly depending on which engine you have.

One thing to check is the starter. Does it crank as fast when warm as when cold?

FYI, I'm quite active on Fred's :cool:

-J

Everyone -- THANK YOU SO MUCH FOR THE RESPONSES

The car is a 2005 Passat TDI. It has approximately 72000 miles. Other than a sporatic hard start when warm the car is perfect. It runs like the wind and fuel economy has been great. I called the guy who works on the car and mentioned the starter potential....but he was at a loss to determine how to measure the rpm of a starter.

I personally think it is the starter or a bad ground.

again thanks for everyones help

3 pointstar

The only known common issue with a PD warm starting problems are battery, starter, crank speed sensor, clogged EGR causing it to stick, or bad fuel related.

If you have an original Varta battery, then it should be nearing the end of it's service life. You might want to upgrade it to a bigger 80Ah battery. The original is a physically smaller 72Ah battery and an upgrade requires new a hold down clamp.

Regarding the fuel, has this problem been occurring with multiple fill ups from different fuel stations?


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Non-contact Photo Tachometers do not cost much.

You need a straight with the beam of light that it projects at the piece of reflectorized tape that you stick on the Surface of the rotating item you want to measure and you press the button and get a digital rpm read out.
On My Volvo I cleaned off a spot on the Vibration Damper on the Crank Shaft.
About 5 years ago I paid $16 for it.

hobby king - turnigy IR 10$ shipped good for under 30 000 rpm. I use one. Set the number of the blades and off you go...


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Another concern with this car is the chain driven balance shaft module - vw has not and probably will never figure out how to do a chain drive properly. The chain wears out, the tensioner snaps in half, and the balance shafts stop. The bigger problem is that the oil pump is driven off of the balance shafts - so the oil pump stops too.

You can measure the RPM of the starter with the VCDS scan tool.

A weak crank position sensor will cause hard starts. You can also see this with the scan tool - it will show 0 rpm while cranking.

Another thing to check is the in tank fuel pump. It should run for a moment when you turn the key on then turn off, you should be able to hear it.

A slightly different problem: PD TDI's Hard to Start First Time in the Day, No Problem Thereafter All Day - TDIClub Forums

One of the experts suggests: "Another thing on the PDs that can cause a long crank is a flakey Coolant Temp Sensor (CTS). They behave more like the gassers do when the CTS wigs out rather than how the VE does. The engine will rarely record a DTC, but often times the Instrument Cluster will, so always check there too."

Again, break out the scan tool. With the car cold compare all the temp sensors. They should read the same. Check again when warm. The cluster temp should match the ECU temp (they use different sensors).

Thanks,

-J

I have a 2005 Passat TDI Variant.

I highly recommend the coolant sensor, cheap and easy to do and can impact several points of engine mgmt. The CPS is also a big thing. For some reason, the wire for this sensor (dull gray rubber jacket) is very popular with mice. I finally found that mine had been slightly chewed through and one wire was bare and occasionally ground out. This caused some bad starts.

And if you have not had the BSM replaced with the gear-driven upgrade, DO IT NOW. Not tomorrow, not next week, NOW!! It's about $1000 worth of parts/labor, but well worth not tanking the entire engine...

I have over 120k on mine. PM me if you ever have questions. And make sure to frequent tdiclub.com

-Andrew

Emergence of the overly complex diesels although there are benefits. There are also downsides. We will not be buying current versions.

Complexity with absolute reliability might be fine but without the absolute reliability I think we will continue passing them by. The new fuel supply systems are not particularily happy with certain fuels either. What is coming out of the refineries has changed in many not so positive ways. It is rumoured that even just one really bad batch of fuel can damage things.

In the newest common rail cars that is the case, the PD motors weren't quite as sensitive.

-J

Had any issues with your Passat TDI? Ours has been ok so far but only has 7k on it....pretty sure I don't want to be its owner when its out of warranty. Are you planning on venturing out of the warranty zone? :eek:

I will say I am not a fan of the VW drive by wire....it tends to lurch/buck when going along at lower speeds in 3rd gear....like it can't decide if it should be fueling or not.