Mine has been doing the same thing. First start of the day it takes it a bit to start, after that no problems at all.. somebody said the V6 had an issue with the injectors becoming clogged

Not sure who threw the tip out here, maybe Jay.. Chevron Techron. I added some to an almost empty tank on Friday, 1 bottle to 12 gallons of fuel as per the directions. voila.. Yesterday morning I noticed a huge difference on the first start up.. car idles better and runs up to speed much smoother too..

 

As far as I know, the SAIP system is all downstream of the engine and couldn't affect starting. A vacuum leak would tend to throw a lean mixture/ air leak code. Have you checked what the coolant temp sensor with VAG-COM? Even though you have a new one, I'd still check it.

 

im guessing (chevronTechron) is some type if injector cleaner?

 

I have yet to Vag the car, Im doing so today after work, if my friend is free and I can borrow his laptop

 

OP, what do you mean when you say there's a hesitation when cold starting?

how's the idle when the engine is cold - good, fair, or poor? does it ever hesitate while idling cold? when driving it while the engine is still cold? if there are symptoms as such, Techron (a bottle or two) will usually resolve it. for some reason, the injectors in the 2.8 do get a little clogged periodically, and I've found Techron is the best thing to resolve it. I run it a little differently than Bill stated above - 1 bottle in a quarter tank of gas, and another bottle in a half-tank of gas (or less, if you want) if the first does didn't fully cure it.

 

the hesitation is during the cold start itself (while cranking it seems to want to stall) But always starts on the first attempt - once started the car runs and idles fine.

 

I know the same symptoms dont always have the same cure, but you are describing exactly what mine was doing. and yes, Techron is fuel system cleaner ( Thanks Jay for that tip BTW:thumbup I picked it up from Auto Zone for like $5 or 6$ dollars. It can't hurt to try it and it might resolve your issue.

 

I will be stopping at my local autozone and grabbing a bottle today. Thank you guys. i will post my findings and or results

 

normal cranking the entire time until the motor feels like it wants to stall then it fires up perfectly fine - techron is in my tank as we speak so I will see if it works and or fixes my problem

 

normal cranking the entire time until the motor feels like it wants to stall then it fires up perfectly fine -

Yes but what do you mean by "wants to stall" while the starter motor is turning the crankshaft?

 

while cranking it seems like it wants to die or stall out - either from to much fuel or air - Im not really sure on how to word it other then - kinda feels like its choking itself during cranking - then starts fine on the first crank

 

You sure you got a good CTS? I'd test that puppy, or swap it out again. That totally sounds like a standard bad CTS.

 

You sure you got a good CTS? I'd test that puppy, or swap it out again. That totally sounds like a standard bad CTS.

I didn't jump on that one because the CTS usually fails either one of two ways - either poor cold starts, or poor warm starts - meaning, the enegine has to crank several seconds (20, maybe) before it jumps to life. I recall seeing a couple of instances over the years where a failed CTS exhibted other symptoms, but not sure that I've seen this aside from a clogged injector.

thinking about this also brings another thought to mind. our fuel delivery systems depend on fuel-line pressure being there at startup. anything that might cause a leakage of pressure, or the inability to build adequate pressure, might exhibit similar symptoms. OP, when was the last time you changed the fuel filter? how many miles are on the car? have you ever noticed any gas fumes/smell coming from under the hood, as in maybe a fuel injector o-ring was worn and the pressure was leaking off overnight?

 

Jay, the one-second pre-run of the pump should be all that's required to bring the pressure fully up. Unless gas is actually back-flowing through the pump, or leaking somewhere else as you suggest, the whole fuel system stays full of liquid and pressurizes instantly like any hydraulic system. I test this routinely, as I pull the fuel pump fuse, and attempt a start to dump the pressure, when the Passat is off-limits to my kid. The engine always fires right back up when the fuse is back in.

Also, fuel filters act like resistors in an electric circuit; as they collect dirt, the resistance goes up. The clogging will therefore be most evident when the current of fuel is maximum, at full-throttle. The fuel flow at idle is so much lower that a dirty filter won't be noticed so much.

 

On cold starts is the only issue - warm starts are fine. It mainly seems like it stumbles or chokes during the cranking (still starts on the first attempt after the stumbling) - all CTS sensors test fine and I just ran a bottle of techron thru the car. Im on my first full tank since the techron. The problem is still present and hasnt seemed to change at all. I changed the fuel filter when i got the car at 99,XXX I have 109,XXX on it now. This is the main issue with the car and it wasnt always there, it started kinda outta no where.

 

- all CTS sensors test fine.

How did you test the sensors ? How does the temp reported to the ECU compare with the temp reported to the instrument panel gauge ?

Have you done a full scan with VCDS (VAG Com) ? Post the codes.

 

Im getting the car scanned in the next few days. I will post my findings and or codes

 

i have the same problem on my 2001 passat b5.5 1.8t AWM
on the cold start, sometimes he doesnt want to start, he really hesitates and i have to keep the key turned for prolonged period of time for it to catch it. if i would let the key go car would die but second time car ALWAYS starts
so, fuel injector cleaner you say, guys?

 

so, fuel injector cleaner you say, guys?

Maybe possible, but not likely.

Check or replace the CTS.

 

turns out to be the check valve in the fuel pump is to blame - its back feeding and causing the flow to be slow during the first start of the day (aka cold start) - ordering a new fuel pump this friday -

 

let us know if that fixes it.. the Techron helped my a bit, but I am still having the issue you have described. side note, this morning, first start of the day, I turned the ignition key on for a few seconds, turned it off, than turned it back on for a few seconds, car fired right up just like it does when it is warm. Starting to wonder if a new fuel pump is in my near future too. I have 99K and the pump in mine is original near as I can tell from the service records.

 

Thanks for the report. I know I jumped on the CTS because it's been the cause so often of these poor cold start issues, (I had the same problem at one point) but I think these cars are getting to the point where the mileage vs. total age is starting to crop up a new set of issues.

 

at the point Im at my car only has 109,XXX on it and the fuel pump is literally the only thing I have yet to replace - Ive done pretty much everything maintance wise and this is the last piece to come into play. The car has literally given me no real issues at all. With Luck that trend will continue.

 

It's very weird that its a pump because I replaced my fuel pump like a month ago and have the same problem anyway. Pump is OEM

 

yes that is wierd.. I am in the process of ordering the VCDS from Ross Tech.. and a Bentley Manual.. gonna try to make my life easier diagnosing these things.

 

Yeah I actually might invest in vcds because I believe it would really help me determining problems