Topic

Been ages since I posted anything. I've pscaned some live data from an M. O. T. Failure.
Emissions is the reason for failing. Everything else passed.  
Anyone want to tell me where I should be looking 
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First off, the stepper motor position at idle should be 21 steps, not 97. Adjust throttle body adjuster screw until closer to 21 steps. Reset TPS and then test. It may take several goes before steps at 21 with RPM at 875 rpm - throttle open degrees at idle should be at 4-5 degrees.

For the rest, I would need to check my Pscan readings where I now have the default spot on.

The oxygen sensor (AKA Lambda probe) voltage should fluctuate between 0.1v and 0.8v.
Yours is showing 0v.
Everything else works off this sensor so if the ECU sees no reading it will automatically run rich which is why the stepper motor is high.

DO NOT CHANGE ANYTHING UNTIL THE OXYGEN SENSOR IS CORRECT.

James

Your readings appear to have been taken when the engine was off (ie RPM deviation should be zero, not 875)!

Before you do anything get the engine hot.

I have a series of readings (where significantly different from yours) when hot (incl oil) and idle at 875 rpm:

1. O2 from 0.58v to 0.87v. Ov not right
2. Throttle angle 4-5 degrees. 
3. Steps 21-25
4. Coil charge time 1550 ms
5. Loop sensor closed
6. Battery voltage 13.3-13.5V
7. Crank status Okay



 

Thanks Julian you are of course right. I now have all readings more or less matching yours. The coil is the the only query. Is your reading 1.550? Milliseconds. My 1998 mgf has a distributor. Don't know if that makes a difference

There are different readings for the MEMS 1.9 non VVC cars like yours which have a distributor.

On the mk1 VVC with MEMS 2.0J there are 2 small remote coil packs, mine give around 9 whatevers on one and 12 whatevers on the other.

Mine is an MK1 VVC. I have 2 new coil packs at circa 1550ms (the old ones were closer to 1300ms each but I had the original length spark plug leads).

The other thing to note is that I have an oil cooler that takes the place where the coil packs were originally. The coil packs are now located in the top part of the engine + I had made much shorter spark plug leads (exactly to length) with the new coil packs; I have no idea whether the latter points make a difference to the coil charge time.