Getting a pain to start

[NineNails]

If the cars not been run for 2 or 3 days it's getting a pain to start.
I will occasionly need to crank it for a good 10 seconds and even then it sometimes only starts and idles very rough untill I switch off and start again (sometimes another 10 sec crank, sometimes not) then all will be fine. It's fine if it's run every day. Like I say, this only seems to happen after it's been stood a while. I checked for codes and there's nothing.
Any clues at all?
Thanks

 

[Bradderz_1988]

Sounds a bit like the immo problem mine did it awhile ago when its was cold never done it since tho.

 

[NineNails]

Nah not immo related. I've had that on another Audi.
keep the ideas coming though

 

[Arrkon]

Fuel pump? Fuel could be draining back when left for a prolonged period, which would explain the poor running until key off and restart....

 

[CHEZ]

glow plugs? as its cold.....................
*edit* just checked, its not a diesel..................... defo not glowplugs mate lol

 

[CHEZ]

as its not a derv, i would punt a bet on your MAF then................ as its cold

 

[OldRedEyes]

Temp sensor?

 

[Ste_Nova]

scanned it for fault codes?

 

[NineNails]

Thanks for the suggestions lads but would I not get a fault code if the maf or temp sensor was at fault?. Someone has suggested a leaky injector. They reckon sometimes an injector can constantly drip into a cylinder and cause this after a couple of days. I may try some of that cleaner in the tank. I know it's not had a fuel filter since I've owned it, about 40k now and probably more before i had it. Plugs were changed about 20k ago.
[Edit]: Yeah Ste, no codes mate

 

[Ste_Nova]

i had an injector stuck open on my 106, it still started easily but lots of black smoke

 

[hades-]

id go for fuel pump draining back or leaky injector
CTS dont always bring a code up

 

[Bradderz_1988]

Crank sensor maybe ???

 

[shaggy0072]

Hey, I've had this problem myself. 97 2.8 quattro manual was becoming very difficult to start, and even after ignition it would just hack and cough until the excess fuel cleared out of the cylinders... After pulling most of my hair out, I figured if I just unplugged the fuel pump fuse beside the dash (killing the fuel supply.) It would fire after about 2 seconds of starting whilst holding the throttle wide open. When the engine began to smooth out after a few seconds, just plug the fuse back in the holder. This problem for me was intermittent, and it didn't matter if it was cool outside. It would do it at 100F or 20F. It wasn't picky... The fuse trick worked well for me, and the problem has pretty much fixed itself since then... Good luck.

 

[aragorn]

stick a new CTS in for a start, they're cheap enough and cause all sorts of funny issues when they're failing.

MAF is a similar story, but obviously a lot more expensive, however you can try simply unplugging it and seeing how it runs.

Bear in mind you'll only get fault codes if a signal is out of range. If the CTS has failed and tells the ECU its -20 or +105 when its actually 15c you wont get a fault code, you'll just get an incorrect fuel mixture. The ECU might eventually notice if it stays stuck at -20 forever.

Same goes with the MAF and various other sensors, if the maf provides readings within the expected range, but that bear no relation to the actual airflow, it'll run like crap but the ECU wont notice or care.

If its fuel pump related its usually obvious from listening to the prime cycle, the pump sounds very different pumping against pressure than it does pumping free.

 

[Ste_Nova]

cts is a service part really, my passat had 3 in 10 years

 

[NineNails]

Thanks for all the replies lads
I have had an incorrect fuel mixture fault before but a long time ago and a new stat seemed to sort that. I think I'll try a new cts first then because as said, I know they can cause some random faults.
I've just scratched by forearms to buggery changing the heater pipe at the back of the head but it's not fixed the leak so will probably have to change the plastic flange pipe thing anyway... Don't look fun
I really need to change the fuel filter too but I just get sod all time!
Do the injectors pull out easily enough, or does something tend to break? I've started to notice lots of plastic bits & bobs have started to go brittle with age now. I can pick up a set of second hand injectors on ebay cheap enough and maybe send mine away to be cleaned? I think there would be a benefit in doing this anyway at 170k miles.

 

[aragorn]

If you want to pay the postage i've got a set of stock injectors in the garage that you can borrow, just return them when your finished.

 

[NineNails]

That's ****** good of you mate, thank you I'll bear that in mind. I've got a cts coming so will try that. The thing is, I normally use the car daily so this problem is not really a problem until I take a couple of days off work if you know what I mean. I've not even looked yet on the cost of injector refurb, I've no idea as to how much that would be. Like I said, I guess at 170k it would be a benefit but with xmas and all that... However, I don't want this to get worse as I do need the car daily!
Is there anything to lead you to believe that if it is an injector it will get worse this side of xmas at all?

 

[Chriscooke]

I have a similar issue, in fact I started a thread on here with a video iirc. I've changed the stat and the cts and although it's better I can't help feel its a furling issue. I'm planning on changing the fuel filter when I get time to see if that helps.