A little slow to start but no fault codes - any thoughts?

W

Will

A2OC Donor
2004 1.4TDi

This past week or so my car has been a little slow to start. Maybe requiring an extra crank or two to fire. But once started it idles smoothly.

Knowing the car was on the original battery I bought a replacement. But this does not seem to have improved matters.

So I plugged in my Ebay vag-com cable and used VCDS-Lite to read for any fault codes. None were found.

So a couple of questions.

Is it possible the budget cable and VCDS-Lite can not read all the possible fault codes?
Assuming there are no fault codes what are the possible causes? Fuel filter maybe? CPS would come up as a fault code I assume?

Many thanks.
 
Symptoms read like crankshaft position sensor failing. About £180 to get sorted at Audi.
 
Hi Will
If it becomes harder to start the longer the car is parked up then it may be loss of fuel system prime due to a problem with the fuel filter. The filter housing is plastic and the cap can crack if overtightened. Any fuel leaks or smell of diesel from the back end of the car?
The other possibility is the camshaft position sender or crank speed sensor (as Alan suggested) Key differences are -
The cam position sensor allows the engine to work out which cylinder is on the firing stroke for start-up. If this sensor fails the crank speed sensor is used as a back-up BUT the engine can take several revolutions to sort itself out and fire up.
The ECU uses signals form the crank speed sensor for fuelling and ignition timing. There is no back-up for this sensor so if it fails the engine won't run. In the early stages it may cause poor starting or stalling but this is more likely to happen when the engine is warm.

Cheers Spike
 
Thanks guys.

Are there any experiences using replacement parts from ECP?

FAE - camshaft sensor £70
no brand - camshaft sensor £30

Being transverse I'm using access to the CPS is not so difficult?

My car is due a fuel filter change anyway. So I'll get that and take it from there.

Thanks again.
 
I would hope the glow plug light would start flashing if there was an issue. As it is it turns off within a few seconds even when below 0.

Glow plug would be a nice problem to solve, being quick and easy. If the symptoms persist I may just change them anyway. £20 isn't so much.
 
Given the time involved in replacing the cps, I'd play safe and go for the oem part.
 
Last edited:
I'd quite like confirmation from a fault code that the CPS has failed before attempting that job.

I'll get out the multimeter and check the glow plugs first. Start with the easy and cheap things first, then work my way up to the difficult and expensive jobs is my DIY methodology.
 
For info, the CPS is located behind the top cambelt cover, roughly at the 5.0 clock position reference the camshaft pulley.
I'd always buy genuine sensors but if cash is tight it could be worth trying the cheap CPS as failure does not disable the engine. If on the other hand you need a crank speed sensor, go for the genuine part.

Cheers Spike
 
A new filter filter plus the warmer weather seem to have brought the car back to normal :)

I can't tell you which of the two was the solution. If I had to guess I'd say the warmer weather.

Thanks for the reminder on this thread - as I never did get around to checking the glow plugs, which I'll try to do sooner rather than later.
 
Hmm thanks for that. I had all my filters done 3k ago so I'm probably OK on that score. Just had the throttle body cleaned - reported to be filthy and mechanic started car 'on the button' 5 times before he handed it back. I get in just now and still having trouble starting, although the engine seems to 'breath' easier somehow. Again once under way, it's fine. I have to floor the throttle to get it to fire and no clouds of smoke emerge from the rear end which I'd expect, so maybe, hopefully not, a fuel pump issue (but again, no fault codes for anything). Thought it might be the cam sensor but again, no code so I left well alone.
 
Aha! Just noticed a pool of diesel under rear passenger side door so, rather than mop it up, onto forum and oracle points to a broken fuel filter housing. This probably won't throw up a fault code and will make starting harder as air needs pumping out of system so matches symptoms. Filter housing to be swapped out on Friday.
 
You must log in or register to reply here.
Back
Top