Pre-MOT work

Pre-MOT Preparation

So Yearly MOT was due so decided a last ditch attempt to get Emissions down and running rich.

Had 3 days to complete the work.

Plan was to complete the following:

1. Remove, clean & check Throttle Body & Idle Valve

2. Replace HT Leads

3. Replace MAP Sensor

4. Check and renew all Vacuum lines

5. Re-set Mp9 ECU

6. Attempt Basic Settings

1. Throttle Body

Removed throttle body to check & clean

Spent quite a while working out what the following hole between intake manifold and into throttle body pas the butterfly valve.

Worked out it was actually not used but suspect its an idle bypass allowing air around butterfly valve. (You can see where a screw would have been to adjust idle, just not used on the Brazilian Bay Kombi)

Once sensors (air inlet temp & Throttle position sensor) where removed.

Gave the whole throttle body a good clean. Adjusted closed stop (basically you screw out screw until there is a gap. Then slip a thin piece of paper in and screw in until it touches the paper. Then screw in 1/2 a turn)

Now I decided to test the Throttle Position Sensor (TPS) as from the diagnostics should give 5 Degrees = 0.3V where I get 6.7=0.3V.

Now the specification says the Idle position resistance should be Higher than 1KOhm at idle.

So I decided to fit the new TPS which I had bought BUT it was the wrong part. It only opened to around -45 to 45 instead of the old one which goes from 0 to 90. Great yet another hard part to find.

Anyway refitted the old part and refitted second hand Idle Control Valve. 

2. Replace HT Leads

Replaced all 4 HT leads with ones from VW heritage. They are not as flexible as orginal ones and suspect they are copper and they where a bit long. Just ensure you have good sealing around tin wear as cooling air leaks are bad news for air-cooled engines.

3. Replace MAP Sensor

Replaced MAP sensor. Again it had been tested but I wanted to be sure.

4. Check and renew all Vacuum lines

Checked again for any signs of vacuum leaks around hoses and fittings. Added extra jubilee clips on the ISV pipework etc. Also replaced fabric vacuum lines from manifold to MAP sensor.

5. Re-set Mp9 ECU

After a bit of research the Mp9 has issues with some fault codes and long term memory data. So I needed to reset the ECU. I will write this up when I am sure of the details.

6. Attempt Basic Settings

OK once all work was completed and everything was put back together I ran a log of the Lambda Response again to check if the Lambda was still stuck at 0.8v (Rich)

So the Lambda is still HIGH But it now falls during acceleration and plenty of lean on de-acceleration.

So unfortunately it has only made a difference at acceleration. So nothing seems to affect it at Idle.

I then tried to carry out Basic settings. There is very little information on how to do this. I will write it up when I am sure of the details. It seems that it did not work and I also got another 00533 DTC error code during the basic setting and had to reset the ECU again.

So to conclude - All the work made hardly any difference at Idle. So Off to the MOT on Monday expecting it to fail again.