long engine crank

[vserghi]

Hi all, I have a mk4 TDI 130. I am trying to fix an annoying problem when starting the car.

It can take 5-6s before it will start. There is no engine stumble, the battey is good, no smoke and as soon as it starts it runs perfect. This happens with a cold or hot engine.

I don't think it is the glow plugs as I would of thought it would have started and run rough and probably seen smoke coming out.

I have seen posts about the coolant temp sensor being prone to error. But The temp gauge seems to operate correctly and there are no codes stored in the ECU. I have also seen posts on the CAM sensor and air leaks by the fuel filter.

As soon as I turn the ignition on, I can hear a rush of liquid which I guess is the fuel.

Any ideas?

Vas.

[kite]

Try disconnecting the temp sensor and see if it starts easier.

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[adamss24]

Is there any fault pointing to the crank sensor ? I would start by replacing that first, otherwise it's just probably low compression due to worn camshaft lobes but that would manifest by loss of power and strange blowing noises in the intake when the lifters are worn trough. Take the rocker cover and inspect the narrow cam lobes which press on the hydro lifters. If worn then replace the immediately ! Don't be tempted to buy cheap cams in, had a customer bringing me a cam he sourced of ebay and it did not look right to me. It came with non branded lifters and Glyco cam bearings. I fitted it just to find it snap as soon as i turned the engine by hand ! The engine would turn half way then it would stop ? All markings were on and i even took the glow plugs off to ease turning the engine ! The cam just snapped in 2 pieces and one lifter was cracked ! New, genuine parts were fitted after and that cam went straight in the bin ! As with everything in life you get what you pay for !

[vserghi]

There were no faults listed in the ECU.

I'll try changing the temp sensor first, it's pretty cheap to replace and not a big job anyway. Where is the crank sensor located?

[Dave Bonsai]

Had the same issue myself, changed the temp sensor to no avail.
Saw a thread somewhere that it could be the light switch, try turning on the side lights and see if this solves the problem. I did price a replacement switch but decided the cost wasn't justified if it can be sorted by just turning on the side lights.

Dave

[vserghi]

Not heard of this one before and to be honest can't see how this would make any difference. Just for the hell of it, I tried it, made no difference, in fact I had a good 5 second crank before it fire up. I spoke a VW service guy who also recommended a temp sensor change, to start with anyway. he also suggested CAM/Crank sensors. I'll try this first.

Got new temp sensor, I'll replace it tomorrow on a cold engine. Do I need special coolant or will the generic Halfords item do?

Vas.

[geoff eeles]

VW Owners manual 3.2 states on page 34 2only our coolant additive G12 A8D or an additive with the specification TL-VW 774 D.

[geoff eeles]

Halfords | Comma XStream G40 Antifreeze Concentrate 5 Litre

[vserghi]

Thanks for the link. I changed the sensor and topped up with new coolant. It made small difference, but not much I'll monitor it over the next few days.

Thinking about the crank position sensor, would the ECU switch to the CAM sensor, in the event of a bad crank sensor, to get the engine started or would it not start at all? GSF have a crank sensor for around £28. As there is no code stored I'm thinking it can't be this sensor. A new CAM sensor is £58

Does anyone know of resistance values for good/bad glow plugs?

Vas.

[vserghi]

Temp sensor change did not help in the end. I have had a couple of long starts now.

Any ideas anyone? If it was glow plugs, surely I would see smoke and have bad starts.

Vas