MacB767

Looking for a little help on trouble shooting a starting issue I've recently developed.
Lately my car will crank long, about 10-15 cranks before it fires. The engine then stumbles a little then idles fine and runs fine. It doesn't happen all the time. Seems to be the worst if I shut it down and try to start to an hour or so after. If it sits over night it's 50/50 that it will happen. Also if it's cold, below 0 no problem starting. above or close to 0 is when it happens.
I replaced my pump and filter about a month ago (pump was making noise) May be related.
Replaced coolant temp sensor. no fix.
Looking at fuel pump relay, crankshaft position sensor, or leaky fuel injector possibly.
So far I haven't tried a vag just because I don't have access to one.
Just looking for some advice from people who may have had a similar issue.
Thanks in advance.

MotorFabrik

What type of motor? If it is a 1.8T, you may be looking at a vacuum leak.

What pump and filter did you replace?

However for a thorough diagnosis, please visit a workshop. VCDS would be able to pinpoint the issue fairly quickly. If you'd like, swing by the shop and we can take a look at it for you no charge

MacB767

Ya, it's the 1.8t. I replaced the fuel pump and filter. I cleaned the MAF and AIT today. MAF was quite dirty and AIT was covered in oil. Will see if that does anything. Won't know till it warms up. What shop exactly?

MotorFabrik

MAFs on Audi/VW are not really meant to be cleaned. The only German brand you can get away cleaning is more or less BMW.

I just noticed you are located in Georgetown...a bit further from you but we are located in Toronto at hwy400/Finch...750 Oakdale, Unit 22. Website is motorfabrik.ca.

Was the intake soaked in oil or just the normal amount you would see on a 10yr old car? No CEL right?

MacB767

Ya, I think I read that before. I took a bit of a chance but I'd rather chance cleaning it than replacing it prematurely. Ran it into work today with no issues (knock on wood!) The intake was not soaked but had a film of oil for sure. I removed the rubber intake pipe that connects to the metal cross pipe (under the rad) when I installed my aftermarket turbo intake pipe last summer and found quite a bit of oil. Probably 1/2 of a cup. That is the lowest part of the piping so |I guess it collects there. I plan on installing an oil catch can this summer when I install my FMIC. I know some oil is normal like you said on an 10+ yr old car. And yes. i have no CEL or pending codes when I run my OBD scanner.

MotorFabrik

The no CEL makes a diagnosis difficult. If its a cam/crank sensor, VAGCOM would tell us right away. Its really odd that the issue occurs at certain temperatures.

I'd like to extend a helping hand...if you can come in, we can scan the car no obligation and figure out whats going on right away.

MotorFabrik

Hey was dwelling on this one over the weekend...have you checked the oil dipstick tube? Is it cracked by any chance?

MacB767

No haven't checked that. I will if you think it may affect the starting. I put in a new fuel pump relay yesterday. Seemed to me that the pump prime was not the same every time I started the car. Sometimes it would prime longer than others. Problem happened again today after about a half an hour if it being shut down. Glad it's not every time I start it. I'd lose my mind.
I'm letting it do it's full prime now before I crank the engine over. Seems to work better that way.

MotorFabrik

If the dipstick tube is cracked, there is a good possibility its contributing to the long crank. Also, can you check the pressure at the fuel rail?

Nivag

Did you figure out your issue? I am starting to have same scenario on same car... Thx Gavin