2.0 ltr petrol Beetle ( 2000 ) Cold start issue

[Roy Mac]

Looking for some inspiration here guys, I’m losing the will to live.
The car has cold start issues, I’ve regualarly checked for codes and cleared as I’ve gone along.
The car will run for about 3 or 4 seconds then fades. Starting from the back, I’ve checked fuel pump, ok. Replaced fuel filter, replaced plugs, leads and coil, replaced MAF sensor, replaced temperature sensor, replaced lambda sensor and replaced the throttle body and I’m still getting a P158200 code. If I can keep it running when the car hits about 50°c it’ll run “normally”, but when cleared the code returns straight away.....HELP !

[Crasher]

Have you cleaned the throttle body and performed basic settings 060? Which engine type code does it have?

[Roy Mac]

It’s a new tb fitted with an AQY engine

[Crasher]

So you have fitted a new VW 06A 133 066 H (assuming it does not have cruise control) at £849.60, Pierburg 408-236-111-007Z at £260 ish or an ERA 556198A at £80? When fitting a new tub there are two critical steps to getting it to work correctly, firstly the throttle cable must not be too tight, holding the throttle open and secondly the tb MUST be adapted to the ECU using a diagnostic computer, firstly to clear the learnt values and then adapt the tb potentiometer outputs for Max and min movement the range of movement available to the stepper motor. This is done with the engine not running but ignition on in Basic Settings 098 and the battery must be fully charged so really a charger needs to be connected.

[Roy Mac]

All done, battery showing 12.6 v, even changed the oil today and although it hasn't worked with the running problem, the fault codes have completely cleared and staying clear

[Crasher]

Can you describe the running problem?

[Roy Mac]

It’s starting for 1 or 2 seconds at a time, spluttering really bad, then fades. No codes

[Crasher]

Check the value from the coolant temp sender in Engine 01, Measuring Blocks 08. Can you still get it to run well when hot by keeping it going?

[Roy Mac]

Brande new temp sender in it. When it gets hot it runs well...

[Crasher]

When you start it, watch the rpm display in measuring blocks to see if it fluctuates.