Year of Manufacture *: 2004 Engine Size and Code *: 3.0 Litre EZ30 ( Optional ) Scanner Used: Launch ( Optional) Fault Codes: Originally multiple misfires
Hi Everyone
This one is a bit of a nighmare. Sent to me from a colleague who had the auto gearbox out, rebuilt the dif and refitted to the car. The car starts perfectly when cold, and as it warms the idle becomes very erratic, and if blipped will quite often stall, or if not it sruggles to keep running, and wont restart without opening the throttle a little. The idle is very low at about 550 - 600 rpm and the fault codes extracted by my colleague originally was multiple misfires. I am now not getting any fault codes, the mass air flow voltage does not seem to rise above about 3.5 volts on wide open throttle, and on tick over both the front o2 sensors are showing about 0.8 - 0.9 volts and dont appear to be switching, although when blipped they do both drop to 0.2volts before returning to 0.8. I tried disconnecting both the front sensors, and the voltage readings out of the ECU according to the Launch still vary and are around the same voltage as with them connected, which seems strange!! I want to check the O2 sensors with a scope, but I dont have a wiring diagram or colour codes for these sensors, although I suspect the 2 black wires of the 4 are the heaters.
Any help or pointers would be appreciated, as this is not a make we normally get involved with!! What I dont understand at the moment, is why the throttle body is not keeping the idle steady, or above the point where it stalls.
Four gas readings taken yesterday are as follows: At 3300 rpm approx - CO=0.02% CO2=14.92% HC=4ppm O2=0.24%Vol Lambda=1.012
At 650 rpm approx - CO=1.04% CO2=14.61% HC=14ppm O2=0.23%Vol Lambda=0.982
I could do with the O2 sensor colour coding to enable me to be sure about these and check them with the scope, and any additional help would be most welcome.
Hello Rodger has the car been driven a good few miles to re learn all new adaptations after the gearbox rebuild ?
You say even with the lamda sensors un plugged they still can vary ? has the car got 4 lamda sensors and the data your seeeing is the after cat lamdas varying.
If there is no inlet manifold leaks it sounds like it needs to re adapt idle speed.
Further to Lee's input, my initial thoughts are: vehicle CO content @ idle is too high and MAF output at WOT is too low. Try Lee's suggestion first and post results. I do not have the wiring colours for the Lambda sensors but I expect to see 2 wires which are earths, one will have battery voltage and the last one will be the signal wire carrying between approx 0.2 - 0.8v at approx 1htz. So their identities should be easy to establish.
Hi Lee & Pete Thanks for your response. I think Lee is probably right about relearning values, but how do you adapt the idle on this, or is it just a matter of trying a decent road test?
I went for a loong road test in this today on 2 separate occassions, and it seems better but the idle is still very low. However it did flag the MIL light while on test, and has set a code P0400 EGR system. I cleared it during the road test and it has returned so the ecu is clearly seeing an issue, and if this is sticking or stuck partly open it might help explain the poor idle. From what I can see, it looks like an electronically controlled rotary unit on this engine, underneath the inlet manifold, so my next question is has anyone had one of these apart? I spoke to a Subaru parts department today, and he was trying to tell me the car doesn't have one, or at least he couldn't identify it in the parts list!!
Is it feasible to remove the EGR valve and give the plunger thingy a good clean from the carbon build-up? I normally use my scanner to activate it to ensure it is fully closing and whilst it is opening and closing giving it a good dose of carb cleaner. If it cannot be activated then you need strong thumbs! I always clean the apertures where the EGR valve sits.
on March 15, 2011, 9:02 pm, in reply to "