[mk3glx]

On a cold start my big turbo 1.8T GTI turns over, sputters for a second then dies. I turn it over again and it starts right up and idles fine. If I let the car sit after driving (even up to a few hours) it starts right up on the first try. It runs rich and rough for a few minutes then drives pretty well. I have VCDS, no faults show.

Car: 2002 VW GTI 337 1.8T (AWP engine code)
Mods: GT28 elim turbo, REVO stage 3, SMIC, 3" Catback, 3.5bar FPR, Genesis 415cc Injectors, DV, CAI, VR6 MAF housing
Recent Work: Spark plugs, Bosch MAF, coolant temp sensor, fuel filter, new injectors, air filter, front O2, fuel pump (stock), compression is good

Thoughts on the cold start issue?
- Ignition switch?
- Fuel delivery?
- Anything to check with VCDS?

 

[Mr_Long]

I have the same issue on my GTi........

 

[groggory]

Try an intake pressure test and let us know if you find any leaks

 

[mk3glx]

Thanks, will do.

I would think if anything there could be an air leak after the MAF since it has a bit of a rich condition. No vacuum leaks were detected by the shop I had the car at a month ago, and the boost/vac gauge pulls about 20 in/Hg at idle.

 

[MÄDDNESSS]

FV-QR

Have you check you're coil packs and spark plugs?

 

[mk3glx]

Plugs were replaced twice for good measure (NGK BKR7E). No misfires from coilpacks detected with VagCom. I'm using the bolt down BERU coils as well.

 

[MÄDDNESSS]

FV-QR

I saw you have the old style coil packs, It's why I asked. There's gotta be a false positive somewhere.

Did you check the ignition harness ground?

 

[mk3glx]

I saw you have the old style coil packs, It's why I asked. There's gotta be a false positive somewhere.

Did you check the ignition harness ground?

Harness looks good, someone put a nice heat shield on it at some point so that was nice. Maybe I'll swap out the coil packs since those are such a common failure point anyway.

Thanks for all the thoughts. I hate diagnosing things so this is good motivation to get back at it this weekend.

Just so odd that it always starts no problem on the second pop.

 

[MÄDDNESSS]

FV-QR

Your Atlernator might be getting weak.
Check the contact points in that fuse block on top of the battery. Make sure they're have a good clean contact?

 

[mk3glx]

CHECKED
- Alternator output checks out fine
- Optima red top battery is in great shape
- All grounds and electrical connections are solid

NEXT STEPS
- Waiting on my air fitting to arrive to pressure test my intake
- Replace the coilpacks
- Replace the ignition switch
- Swap in stock ECU (might try the Unitronic 415cc tune as well)

 

[Slimjimmn]

Fuel pump dieng

 

[MÄDDNESSS]

NEXT STEPS
- Replace the ignition switch
- Swap in stock ECU (might try the Unitronic 415cc tune as well)

This is a bit excessive.

Have you checked you're voltage regulator?

 

[mk3glx]

I just remembered to follow up ...

The issue was a very small exhaust leak pre-1st O2 sensor. Seems odd to me but replacing the exhaust gaskets did wonders. Runs like a bat out of hell again.

 

[Mr_Long]

Gooooood to know :beer: