Sluggish Cold Starts

[bacillus]

Here to join the club. Lately, past few months, mine has failed to run on the first start attempt.
I have a seat_key in ignition_shut the door and buckle up_turn the key_let go of the key thinking it can take over on its own_and nothing. Turn the key again and it starts right up.

Had that problem with mine and it eventually turned out to be the starter motor becoming faulty.
No issue now with a new starter motor...

[ROH ECHT]

Was yours like mine is; turns over and sounds like it should be running but when I let off of the key it's not running? That's with holding the key in the start position a bit longer than normal.

[bacillus]

Was yours like mine is; turns over and sounds like it should be running but when I let off of the key it's not running? That's with holding the key in the start position a bit longer than normal.

actually not!
Mine intermittently did nothing on first turn of the key but started on the second turn.

[ROH ECHT]

I tried unplugging the MAF before starting it today...and it started right up. Not certain if it was a fluke, so I decided to try every other day now, starting it with the MAF plugged in and not. I'm wanting to make sure before replacing it. I also need to log its mass air while doing a quick throttle snap so I can graph the data....looking for a straight line during the incline with no arch or swell. If trying it unplugged every other day fails to show consistency, I'll probably try unplugging the relay and check morning pressures.  We'll see.

[ROH ECHT]

I will update this post every day while going every other day starting it with the MAF unplugged. A new MAF is more than $220usd if genuine VW...not sure I want to spend $160usd for a Hitachi (but made in GB and sold by FCP Euro with a lifetime warranty)....with others costing much less. The Hitachi is very tempting though because of the lifetime warranty.  I bought the new K04 from FCP three months ago because of their lifetime warranty. FCP is great for their lifetime warranty...they even cover oil filters, wiper blades, gaskets, brake pads and all consumables. But you have to first send the parts back and wait for the replacements to arrive.

Tues. - MAF unplugged and started right up.
Wed. - MAF plugged in and it did the same ol' "turns over but not gonna run until the 2nd attempt."
Thur. - MAF unplugged and started right up.
Fri. - MAF plugged 'in' and it started right up. Actually started the best yet of the four days.
Sat. - MAF unplugged and it started right up.
.......*Interestingly, the past two days have started better than it has in a long time. Before Friday's start-up...I messed around with VCDS O2 Readiness on Thursday, following the morning start-up. I wasn't able to get the test procedure down for the test to actually work, but still something may have changed. I have spent some time trying to resolve my issues with performing the Readiness test, as it remained on "Test off" no matter what I tried, and am now ready to try again. We'll see.*
Sun. - MAF plugged in and it didn't start the first attempt.

[pudding]

Don't forget the Intake Air temp sensor from the diagnosis list.  Coolant and air temp compensations have quite a big influence on cold starting.  Cold starts need a LOT of fuel and if these sensors misread i.e. the ECU 'thinks' it's summer, the fuel supply will be lower than it should be.

FWIW, mine developed a sluggish and lumpy cold start, and replacing the IAT sensor has solved it.  £40 from VW.  The sensor is unbranded, so I don't what brand to suggest in the aftermarket.  It's definitely not a Bosch sensor as they don't list one for the EA113 engine.

[ROH ECHT]

OK, thank you. I will keep the IAT in mind and would replace it with VW if needed.
I really don't think mine is having an 'only when cold' start issue. It's just been having a non-start issue on every first attempt. Until the past three days. With the last two starting up nicely for whatever reason. Our night weather here has been quite consistent since early June....with low temps dropping to 58°F to 65°F. And mine is parked in an insulated garage. I think today will be the last day I report on whether it starts or not the first try. Unless it not starting returns again.

[pudding]

Have you done a tumble flap delete?

Unless there are other mechanical oddities/worn parts, I can't think of anything else that would affect startup consistency.  Older engines with reduced compression don't tend to start as smoothly as a new one either.

[Mk5gti]

Did anyone ever manage to fix this cold start issue

[ROH ECHT]

Nope...mine returned to cranking over but then nothing. If I hold the key at start longer than normal, it cranks and starts to run. But the initial moment of it running is briefly rough before it smooths to a normal running condition. I am hoping an upcoming VVT service will help. To include; chain__tensioner__cam phaser__I don't think it needs three new phaser rings, nor the N205, because I replaced the chain cover (06F103107G) recently for being stripped after a dozen CF swaps__and clean the N205 screen.

I don't believe it needs a new IAT sensor because its VCDS IAT data shows the intake temp to be near what the MFD does on the dash before starting. But I do have a new IAT sensor sitting on a shelf to try.

I believe 'Pudding' mentioned, on another topic, he recently changed his VVT bits...and he stated he noticed it now starts more like new.

[Yusufterzi]

Nope...mine returned to cranking over but then nothing. If I hold the key at start longer than normal, it cranks and starts to run. But the initial moment of it running is briefly rough before it smooths to a normal running condition. I am hoping an upcoming VVT service will help. To include; chain__tensioner__cam phaser__I don't think it needs three new phaser rings, nor the N205, because I replaced the chain cover (06F103107G) recently for being stripped after a dozen CF swaps__and clean the N205 screen.

I don't believe it needs a new IAT sensor because its VCDS IAT data shows the intake temp to be near what the MFD does on the dash before starting. But I do have a new IAT sensor sitting on a shelf to try.

I believe 'Pudding' mentioned, on another topic, he recently changed his VVT bits...and he stated he noticed it now starts more like new.

Did you solve the issue?