There aren't any resistance values given for the digifant knock sensor that I can find, all you can do is check that the wiring is intact and that it is correctly torqued up. If it has been overtightened then it will be damaged and need replaced - it should be tightened to 20Nm. The oxygen sensor on the digifant can't be tested until the car is properly set up, i.e. the CO levels etc. have been set correctly - which yours won't be if it is putting out too much fuel. The wires to the sensor quite often get damaged though. To check the wiring you need to unplug the ECU and test the resistance between terminals 2 and 13 on the wiring harness connector (see here for pin numbers) Digifant pin numbering There should be infinite resistance between the pins, no continuity. If there is continuity then there is a short to earth in the sensor wiring. Next disconnect the sensor harness plug and short the green wire (on the harness side of the plug) to earth. There should now be continuity between pins 2 and 13 on the ecu harness connector. If not, there is a break in the sensor wiring between the harness connectors. That oxygen sensor stuff was straight from the Bentley manual by the way, UK cars don't normally have oxygen sensors - so don't blame me if it's wrong!
Thanks I tried to unplug the ECU a couple of days ago but I could not. I did not try harder as I was afraid not to damage it. How can I unplug it - should I take out the whole unit or it can be done with the unit in place?
Easiest if you wiggle the unit backwards so the metal mounting frame disengages from the holding lugs, and them you can tilt the whole unit and get better access to it. You need to pull back the metal spring clip, and then pull that end of the plug out until the plug is at about 45 degrees to the ecu - then you can unhook the other end of the plug. It's much easier after you've done it once and seen how the plug is shaped.
I will try it tomorrow. When I tried to do it 2 days ago I was unable to detach the unit. Perhaps it is stuck and I will have to push it back a little bit harder. Thanks
I would try a new engine temp sensor first, it the Blue one on the water pipe coming out of the head ( grey in colour if its a early digifant). That may sort your hot starting problem and perhaps the fuel in oil.
Well, it probably helped, but it did not solve all my problems. The gas leaking will probably stop, I have to check again tomorrow, but the car still dies at idle and it is hard to start it when the engine is hot. The rpm at idle play between 500-1500 and it often stalls. Any suggestions as to what is the cause?
Before these problems started have you had the gearbox out at all? If the earth lead on the gearbox isn't connected correctly it fries the ECU on the 8v. Usually happens after a clutch swap or whatever. You can re-set the ECU on the 8v Digifant. http://www.btinternet.com/~gvk_motorsport/diduphart.html Check all the vacumn pipes and make sure the grommet in the rocker cover for the PCV valve is intact for your idle isuues.. Edited by: G_V_K
It does, you should be able to hear it click as you move the throttle lever from it's stop. Check the connections to the throttle switches as well, they often break. If they are broken or the switch isn't being actuated (might need adjustment) then you'll need to reset the idle speed after you've fixed that.
I checked these and they seem fine. They are both clicking, but the rpms "play" at idle b/n 500-1500 and it often stalls. I disconnected the switch of the idle stabilizer valve while the car is running and the rpms stayed firm at 950. But then the car starts quite difficult, but when it starts it again stays at 950 firm. What do you think?
Your idle stabiliser valve probably needs cleaned out, and the CO level set up properly. But as GVK says, that won't be causing the overfuelling. The resetting the ECU GVK mentioned is only really for setting the timing, all it does is cancel the "cold start" function until the next time you start the engine.
Well, I am not sure, but I think the overfueling is at least less, if not gone. Right now the problm seems to be the idling. How can I clean out the idle stabilizer valve?
Good stuff if the overfuelling is gone! Clean the ISV in petrol or methanol, leave it to soak overnight and clean the innards out with a toothbrush or whatever you can. A bit awkward to get at the innards. You should also clean the idle speed control screw on the throttle body (unscrew it completely, clean the end of it with petrol or carb cleaner) and spray carb cleaner into the idle speed control screw hole to clean that out. Also check that the o-ring on the screw isn't cracked or perished.
I already cleaned the screw. I am not sure about the overfueling, because the oil level has risen 3mm, but it might be of the oil change. But it seems like nothing compared with the 7 litres of oil and gas that were in the oil compartment. What are these innards in the valve ? How do they look like? Can the ISV be causing the hard starting?
It can if it's sticking - they sometimes get a lot of carbon buildup inside them. You can see the innards once you take the valve off - it's just a motorized air valve, but you can't dismantle it to clean it so you just have to clean it as best you can through the openings. People sometimes say to use carb cleaner on it, but in my experience this is too harsh and usually makes them fail completely before long.
