Possible head gasket and turbo problem

[Big Lee M]

Sorry I didn't see this before but the V6 4motion Mk4 Golf share the same POS's/Ignition module. Just a bit of info for when someone when they do a search. The brown one is a mk4 golf POS and it has a 'A' on the end of the part number, if I'm thinking right?

[jamie9048]

ALL FIXED WOOOHOOO COOLAND FLUSHED AND RENEWED IGNITION COIL MODULE FITTED AND WORKING

[jamie9048]

ignition modules are they the same or do they differ? also what cars share these as a common part?

[jamie9048]

[jamie9048]

[jamie9048]

right I`ve had a chat with chris from thurso and it turns out he had a similar problems with an electrical component of which there are two of, he changed one.

its located near the o/s strut top on the bulk head pic to follow

[prj]

Check for boost leaks - as first issue.

[neebover]

Just to add a brand new maf and lambda sensor were replaced when I had the car as I had a few running problems. Receipts for these in the history Jamie. Not sure what the issue is then?

Chris.

[A80Avant]

you are right Dmitri, it could be just the map i had. I believe jamie's car is stock tuned, so may well be the maf then

[aelred]

Why a lot of cars run hot is because the auxillary rad has been removed and if they have air con they will tend to overheat due to the AC rad being in front of the main water rad, also you find air diflectors to channel the air to the rad are missing on a few cars.
I dont know if this is the case in your car.

[prj]

Dimtri, when you go part throttle, is your lamda out of the loop?

i say this, that on my engine i had this problem twice with the lamda sensor when i was using motronic. Maf was the same, or replaced with a new unit, car behaved the same, and once i changed lamda, everything went back to normal. Also the car was reaching full boost and ran nicely only on WOT. So perhaps Jamie is having a different problem, i dont know. But im sure on part throttle my lamda was causing problems up to 1-1.4bar if i remember correctly.

It depends heavily on the software you run in ECU.
But in stock ECU and in sensible mapping, the load threshold where the engine goes open-loop is very low.
Of course I have seen some funny chips which mapped the lambda threshold way too high...

Lambda is basically only active when you are "holding" it at a speed. The moment you start to accelerate, even a bit, it gets ignored.
The only way you get issues with lambda, is if your fuel trims are way off. But I don't think it uses fuel trims when it runs open loop either.
But all this is very, very easy to test. Just disconnect the lambda sensor and reset the ECU

[A80Avant]

Dimtri, when you go part throttle, is your lamda out of the loop?

i say this, that on my engine i had this problem twice with the lamda sensor when i was using motronic. Maf was the same, or replaced with a new unit, car behaved the same, and once i changed lamda, everything went back to normal. Also the car was reaching full boost and ran nicely only on WOT. So perhaps Jamie is having a different problem, i dont know. But im sure on part throttle my lamda was causing problems up to 1-1.4bar if i remember correctly.

[jamie9048]

right I`ll check it tomorrow where is the plug located on the s2?

[prj]

Lambda will NEVER ever cause such issues on stock Motronic ECU. You can unplug it and Motronic will NOT go into limp mode. Furthermore, lambda in Motronic is only used on cruise, the moment you give it even a BIT of throttle, it is ignored completely.

If any sensor is to blame, then having a dead range with no power between 2500 and 4500 rpm points to broken MAF or bad contact within the MAF plug.

Have you read codes? If not, stop guessing and read them.
Somehow I doubt any sensors are to blame. Even if you disconnect almost all sensors, your temp will not go over 90 degrees.

As for boost getting pulled - boost gets pulled on heavy knock. Thrashing the car when there is an obvious and possibly serious problem, will just lead to an engine rebuild.
In fact pressure test your system and make sure, that there is no leakage betwen the MAF and turbo, where unmetered air can enter. Lean mixture due to MAF-Turbo hose failure + detonation is a pretty common fault.

Easiest way to test - unplug the MAF and see how the car drives. If it's better, then you have an issue with unmetered air (read: leak).

[A80Avant]

your lamda may be at fault as well. Do you have any way of looking fault codes? if not, i have a vag reader and we can read it that way if you like