Engine won’t lean out

[Jonty]

Thanks David - really appreciate your help

[Ron]

Pressure check is a good next step.

+1

Since the dwell was off after it suddenly went south, you probably have to fix why before you can get it to stay in closed loop. Nothing is screaming electrical so I'd confirm the primary and control pressures. (Could be the PPR o-ring or a dozen other things.)
Once that is done, get a decent initial setting as Dave T mentioned. Basically, you put the easy injectors in a bucket and make the pump run continuously. Quickly turn the adjustment screw until the injectors start to spray then back it off until they just stop. Put everything back to normal and it should fire up. You may have to baby it or adjust the dwell screw so it will idle and warm up, allowing you to set the dwell. It is always the last setting and touchy so turn it in increments a small as you possibly can or it may go 'out of bounds' and make you think it is not working.

[Bitsyncmaster]

+1

(Could be the PPR o-ring or a dozen other things.)

+1

The PPR o-ring can go bad suddenly.

[Jonty]

Thanks Ron and Dave. I did reset the injectors as you describe and still no joy so defintlay control pressures next on the list. Will let you know result in case anyone else has the issue.

Cheers both

[David T]

While it can't hurt to check the pressures, if they are way off the motor wouldn't run. More important to check the injectors for opening and closing pressures and spray pattern. BTW, sticking an O2 sensor after the catalytic convertor and trying to adjust the mixture screw is not the way to do it. Either follow the procedure or remove the O2 sensor and measure BEFORE the cat. (I am assuming you measured post cat with your O2 sensor).

[Jonty]

Thanks Dave - he’s checking from behind the Cat.

[Jonty]

I did call in today and noted he was tuning the mixture without a bung in so took my old bung down that I drilled a hole in to slip over the Allen key. My car is super sensitive to the bung being out (it will die instantly if it’s out). That hopefully helps him.

[Ron]

That's odd. I have never seen one that would die because of the adjustment hole being open...usually it doesn't even take it out of closed loop. With yours running rich enough to trash the plugs, I'd think it would like it going a little bit lean...

[Jonty]

Hi Ron - that’s exactly why this thing is throughly confusing me. It’s just not behaving normally as what you suggest was what I initially assumed. Something is messing with the mixtures so that’s why I’ve sent it in for someone to reset then start working through it. When it fouled the plugs it was running in closed loop perfectly the day before!!

[Jonty]

Ron the one other symptom I haven’t mentioned was that when it was tuned and went into closed loop particularly you often heard what could be described as a “clattering” noise that would come and go. I’m starting to wonder what out of adjustment valves might be contributing?