Passenger side bank running rich.

[Jonah 101]

Pretty much as the title says, My Passenger side of the engine is running rich. Exhaust is spitting out black crap.

On top of that it idles way too fast when I start it up and it take ages to wined down to an acceptable rev range, but it just starts surging. If I can't fix it soon Im prepare to block off the IAC and crank the screw in a bit because I have had enough of this.

Please help!

 

[Big-Al]

Oxygen sensors mate

 

[Jonah 101]

Nah can't be that, no VSS signal, car runs rich all the time not just cruising. o2 sensors can't have an impact on fueling if the cars never enters closed loop.

Does the Crank angle signal pass through the DFI module before the computer? I have new plugs, leads, and coils. I only have second hand injectors but I would have to be a very unlucky man to have three **** themselves on one bank.

I will put the G-scan on it tomorrow and see what it says, might be able to throw up some graphs of what the crank signal looks like. I did a fault code check the other day, think it said incorrect fueling or rich left bank or something. I can't help thinking "WELL BLOODY FIX IT THEN IF ITS RUNNING RICH!!"

Stupid cars.

 

[Jxfwsf]

shot injector/s? plugs/leads? o2 sensor? all those things will have an impact of excess/unburnt fuel going out the exhaust......

most trade schools have the right diagnostic equipment, look for a pc in/on a cabinet on wheels with lots of leads, hook it up and monitor the voltage on the spark leads and look for variation between cylinders that shouldn't be there....

 

[Jonah 101]

shot injector/s? plugs/leads? o2 sensor? all those things will have an impact of excess/unburnt fuel going out the exhaust.....

I am confident in my injectors, It would be strange if all three were fked, Brand new plugs, leads, coils, tried a few different DFI modules, No change. So Ignition system is ruled out.

I dont go to trade school any more I have a real job now, no more McDonalds for me.

Hooked it up to the G-scan today, no fault codes. Looked at the live data, LH oxy sensor is stuffed. the boss and I are not sure if thats the problem though, but what is interesting is that that sensor ( same side that is running rich ) is saying lean. I brought up a graph of the signal and there is no change in the signal apart from a VERY minimal up and down, so if the sensor is saying "hey she is bloody lean on my side!" and the ECU says "Holy crap, lets throw some more gas down her gullet!!" could that be the problem?
I am unconvinced, why would it do this in open loop? Would the ECU change the fuel delivery if the ECU thinks it is running the engine dangerously lean? One thing that bugs me is that its my new sensor I put in about 6 months ago. I hooked a air/fuel gauge to it and it was working fine for a while then it is saying always lean. Could my gauge have stuffed it?


So as usual me having a good look into a problem has raised more questions than answers....... So I have gone back to my treid and true diagnostic method, you may not like it. Unplugging ****.
I unplugged my faulty o2 sensor, I did this because I am pretty sure the ECU will go off its base maps. Also seeing as the ECU is not reciving a signal from the o2 sensor and IF it is changing the fuel delivery because of the faulty sensor. If I unplug it and it continues to run rich, I can look elsewhere for a solution, if things improve I will know what is wrong.


Now my second issue, swing idle ( surging ) I lost my rag with it yesterday and ( you guessed it ) unplugged the goddamn IAC valve. No more surging idle for me.

Now does this mean the IAC valve is faulty or does that mean they is a problem with a sensor. OR is it because one bank is running rich?

Aw man my head hurts.....

 

[Jxfwsf]

ecu/pcm monitors the o2 sensor all the time, if it thinks the afr is 1 thing and it's getting the incorrect mV reading from the o2 sensor it'll get confused.... i was getting the cel lighting up due to a rich idle mix on lpg, only happened after i sat stationary for a minute or 2 and went out as soon as i started to drive, didn't happen at wot or cruising... not to mention the stfc & ltfc were going nuts trying to lean out a mixture it had no control of lol

as for iac, get your hands on a tech2 and run the iac diagnostic test, see what it comes up with, while your at it run the injector cutout test and see what results that shows (not saying there is a problem with the injectors but it helps to rule out other things like manifold gasket leaks etc etc, if it cuts an injector and there's sfa difference to how the runs or it's rpm then it helps to chase other issues and what cylinder to look at) there could be a vac leak somewhere which is why the iac is having problems

 

[Jonah 101]

Thanks Jxw.

I went for a long drive with the o2 unplugged. Left bank is not running rich anymore. I will do futher test to see if anything is wrong, then if I find nothing I will get a new o2 sensor.

 

[Folker147]

Just leaving a comment as happened to me after I replaced my fuel injectors a 300k+ vsv6

Although I reset the computer when I did it, within 2 short drives it carbon clagged all my spark plugs.
I replaced all 6 and I thought every was good.
Over the next 10k kms, it started leaving black crap out the exhaust and also drinking about a 1lt of oil in about 3k kms. Also the car park car exhaust fans kicked everytime I came home lol
I checked my spark plugs, Drivers side perfect. Passenger side - carbon build up. Checked passenger side oxygen sensor - covered in carbon.

Auto shop didn't have a replacement on the shelf but suggested to just spray with carby cleaner and that worked a charm.

 

[Draimond]

My ecotec was running rich on the right bank when I bought it a month or so ago.

Bought a pair of eBay O2's, sort by cheapest. No codes now. Runs correctly. For what I paid for the pair I could afford to do it every oil change