O/T Misfiring Pug on Bosch EFI

[Peter Carmichael]

I've got a bit of a problem. My Mi16 went from working perfectly to

complete inability to run on all cylinders below 5k rpm in the course

of the last couple of days.

 

It started with a rough idle and got worse and there are now some

very specific symptoms.

 

The engine installation is mechanically sound and all fluid levels

are fine. Temperatures are fine. The ignition system is in a good state. Don't know about

the general health of the fuel system, but suspect its OK. I think

everything comes down to sensors and other things electrical.

 

The symptoms:

 

a) engine refuses to run happily at low revs, getting worse as it

warms up.

 

b) moving away from standstill requires a clutch burning 5.5krpm.

 

c) with the key in the ignition position, the cooling fan runs

constantly (aircon switch is off)

 

d) battery seems to have a healthy charge, but the alternator belt

always squeals on startup

 

e) the Bosch ECU (three row) has reported codes 43, 41 and 33 (knock

sensor, crank sensor and AFM)

 

f) six months ago I had a misfiring incident that I put down to dodgy

fuel (I'm back in England from France for the first time since months

and on the first tank of BP Ultimate bought in the UK it started

showing these symptoms) (probably a red herring)

 

So, how do I go about debugging this? I am used to working with

programmable ECUs where I can monitor all sensor inputs on a laptop.

This old tech Bosch stuff is a bit daunting in its opacity.

 

Why is the fan running?

 

 

 

 

[Peter Carmichael]

Found the dodgy coolant temp sender in the thermostat housing. Might have fixed a few problems in one go with that one.

 

Excuseme talking to myself.