2010 Sportswagen TDI No Start!

Hello members, I am hoping to get some good advice on resolving a no start issue. A VW dealership gave a false diagnosis of zero bar fuel pressure and then a minimum quote to drain and purge my fuel lines of six grand. I opted instead to have the my car towed back home were I first started my diagnosis to verify the fuel pressure issue on my own. I began by checking for restrictions of my fuel beginning at the intake side of the fuel filter and found that fuel was easily drawn from the tank with a vacuum pump. I change the fuel filter and activated both the tank pump and auxiliary pump and got pressure. 10 p.s.i. at the outlet side of the filter and my 100 p.s.i. gauge pegged from testing at the outlet side of the auxiliary pump. Since I do not have a gauge for testing the output of the HPFP, I merely loosened a nut on the fuel rail to verify that I had fuel pressure.
The glow plug light goes out within seconds when the ignition is switched on. I am not getting any sign that the car wants to start as the motor turns while operating the starter. The next step was that I checked continuity of the glow plug wires with a test light. I switched the test light clip to the negative battery terminal to test voltage of the center wire of the glow plug wire when the ignition was switched on. To my surprise the light did not glow very bright and within ten seconds the circuit was cut and I heard a clicking noise when the light went out. I assume this is a relay from the ECU. I am not sure about the exact location but assume the ECU is near the firewall under the hood. Now I am wondering if there is indeed a problem with the glow plugs or not as I have read that the glow plug operation may be intermittent and dependent on a temperature sensor for my year and model car. I would greatly appreciate if anyone has some good suggestions and steps I can take to troubleshoot the no start situation of my vehicle. Cheers, David

Inspect/clean/tighten grounds (known problem area). One is under the airbox. This is free if you do it and is good preventative maintenance.


Then perhaps the battery is bad? http://forums.tdiclub.com/showthread.php?t=421570&highlight=grounds&page=2

I am very suspicious that you have a failed HPFP. I think your car should start without glowplugs just fine except for maybe a little smoke.

I take it the car is not ‘fixed’ and thus under warranty for fuel system failures. Might be anyway. Time to start reading...

The fuel rail should be under enough pressure to cause risk of injury when released.

A happier option is that the ECU doesn’t know the engine is cranking. Does the tachometer move? I’m pretty sure mine shows something before the engine fires.

You need someone who can pull codes which will tell what is wrong. Unless you have a VCDS or equivalent to do that you are unlikely to find the problem. The engine management system is much too complex. Throwing parts at it is a waste of money.

Hooray Success at last.

I persevered and the result was the car finally started. After a verification that I still had zero bar after the HPFP, I decided to verify that fuel was pumping by first turning the ignition to crack the car with a loosened #4 feeder line to the injector. A little fuel came out. So I then just decided to run the two fuel pumps on their own enough to force fuel through the common rail. About 4 ounces came out and I retightened the high pressure fuel line. I then cranked the car and in less than six seconds the car started to run without any problems. For some reason everything that I read about using VCDS to prime the fuel lines never mentioned cracking open a high pressure line to purge air. I assume the procedure were the VCDS operation of the two pumps (tank pump and the auxiliary pump) for three intervals of up to sixty seconds each time should have sufficed to prime the fuel lines. Clearly this did not do the job in my case. Am am glad that I persisted because no trouble codes came up and I easily verified that the glow plugs were functioning and in good condition. Thanks for your suggestions.

no codes were stored?

I did not see any fault codes with the exception of immobilizer and certain other features that I do not have installed. When the VW dealership said I initially said that I had to replace my glow plugs and possibly injectors, I knew immediately suspected the dealerships integrity.

Good to hear. Your initial post didn’t provide much background or that you had vcds so I assumed you didn’t. Sorry about that.

For what it’s worth in two filter changes and a 2 micron install I have never done more than run the pumps for a few minutes and the car has started pretty promptly after. Maybe 5 seconds of cranking. The RossTech instructions suggest the pump should turn off after 30 seconds but mine don’t so I just time it.