[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

5kt Boost Problem Solved

Well finally managed to fix the wastegate frequency valve and recover stock performance, ye ha.

To debug the problem I connected a LED to monitor the operation of the wastegate valve and soon determined the ECU would never vary the duty cycle to the frequency valve. This limited boost to 2-3psi. I ran all the input and output tests and didn't find any problems. I then disconnected the WOT switch and shorted pins 2 and 3 of the connector this should have caused the LED to flicker on. It didn't. After tracing the wiring I found that the wire going to pin 3 of the connector had broken free, probably due to either the switch itself being removed, or more likely the pipe running from the FD to the turbo being removed.

I fixed the wire on the connector but still no duty cycle at the frequency valve. Since I had just replaced the WOT switch I decided to probe out all the inputs and outputs to the ECU. No  problems there. So, I made up a short wiring harness to fit between the WOT switch and the connector, this allowed me to monitor the operation of the WOT switch. With the harness connected the WOT switch always measured closed no matter what position the throttle was in....

So beware, not only do BOSCH make temp senders that are DOA, they also make WOT switches that are DOA.

Regards, Mike

TLA explanation  :)
LED Light Emitting Diode 
ECU Electronic Control Unit 
WOT Wide Open Throttle
FD Fuel Distributor
DOA Dead On Arrival
BOSCH Bits Of Scrap Creating Hate