Car running rich, AFR 11:1 during idle

[Rob Furniss]

My car has been running rich for a while now, I have an AEM wideband air fuel ratio sensor and gauge, after the car has warmed up it goes really rich like 10:1 or 11:1.
Could be my AEM kit is faulty but I don't think so as it's reading what i'm expecting sometimes.
There are no error codes logged.

I have a greddy emanage blue
I have 275cc injectors
Fuel filter was changed last year and I've only done about 2000km's since.

I had a supercharger on but I've temporarily removed it to diagnose this issue, my emanage blue was only adding fuel based on positive boost from the greddy 3 bar map sensor and as i'm no longer getting boost that shouldn't be the issue, I've double checked the map again and can also do a trace and see what cells it's in when having the issue and it's not adding fuel.
I have the injector change settings set in the emanage blue 166 before 275 now so it should be trimming the fuelling to the injectors automatically.

I've just took the car out for 10 mins, AFR had been ok during this time, rich on startup (12:1) and then settled around 14:1 with some fluctuation, got home and parked on the drive with the engine running and watched the afr gauge, idle rpm around 700, AFR was around 14:1 for about 30 seconds and then there was an engine note change and it dropped to 10:1, crept to 11:1 and stayed there, it was as though someone had flicked a switch.

I've so far tested:
Engine temp sensor at different temps with a multimeter and pretty sure it's ok.
Air intake temp sensor, again tested at different temperatures with a multimeter connected and pretty sure it's ok.
O2 sensor, checked continuity between pins 3 and 4 checked out ok, put multimeter on pins 1 and 2 with 3 and 4 wired to battery and engine running, voltage between 0.9 and 1 with some fluctuation when racing the engine but I didn't see anything around 0.6 as it mentions the range is 0.6 to 1volt in the workshop manual.

Wondering now if it's fuel pressure regulator related as I've had the engine running with someone monitoring my AFR gauge while I clamped and disconnected the vac line to the FPR - engine rpm didn't change and AFR didn't change (11:1) - isn't this strange or would it only change when racing the engine?

Or could it be a leaky injector?

It's funny though how it all of a sudden just switches into this rich mode.

[Rob Furniss]

Just pulled the car into my garage to do another test and it's now running fine, idling for 5 minutes and all is good, raced the engine a couple of times and it settles back to AFR of between 14 and 15:1.
Thing is I know this will run rich again, probably next time I take her out.

[Sahin]

Needs a good clear out, worked for the commo

[Rob Furniss]

I've just done some more reading about O2 sensors and maybe I read the results of my test wrong (well looks like I did) or didn't do it right (that too), it's supposed to drop to around 0.2 when lean and up near 1 when rich and it was reading between 0.8 and 1volt all the time.
But I didn't create a lean condition, just blipped the throttle a bit, I should have took a big vac pipe off to let loads of air in and checked the multimeter on the O2 sensor to see if voltage dropped low.
Apparently if an O2 sensor has a faulty heating element it can cool off at idle and read high all the time often resulting in a rich mixture too, it was around 0.9v all the time and hardly changed.

[Rob Furniss]

This looks similar, would it work?
http://www.ebay.com.au/itm/MITSUBISHI-M ... 2ec3415d9a

[Shane001]

So you have an aftermarket FPR. Do you have a guage on it? I'll put my money on this fluctuating your base pressure. Does this occasionally on my racecar as well. Don't know why. I just readjust base fuel pressure when it happens and adjust back again when needed.

Also I never did trust the injector conversion in the eManage Ultimate. Would trust it less in the blue. In the end I didn't use it and just adjusted fuel based on an approx percentage difference until the ecu went into closed loop reliably.

And the FTO will struggle with 275cc injectors. Mines now running 210's. For yours with he supercharger I'd probably look at 240's if 210's are deemed to small.

[destinationtoby]

Needs a good clear out, worked for the commo

[Rob Furniss]

So you have an aftermarket FPR. Do you have a guage on it? I'll put my money on this fluctuating your base pressure. Does this occasionally on my racecar as well. Don't know why. I just readjust base fuel pressure when it happens and adjust back again when needed.

Also I never did trust the injector conversion in the eManage Ultimate. Would trust it less in the blue. In the end I didn't use it and just adjusted fuel based on an approx percentage difference until the ecu went into closed loop reliably.

And the FTO will struggle with 275cc injectors. Mines now running 210's. For yours with he supercharger I'd probably look at 240's if 210's are deemed to small.

Hi Shane, no it's the stock FPR, I had an aftermarket one on the old car and a gauge but I 'heard' that they are a waste of time so didn't bother this time, personally I think they are good for setting the car up after changes and testing stuff like this.
Think I will stick the 166 injectors back in for now until I sort this issue out as the charger isn't on the car at the moment anyway, hell I may even disconnect the emanage temporarily to rule that out.
I am leaning towards the O2 sensor being the issue, going to test it again this evening but properly this time.

[Rob Furniss]

Just done another test, the O2 sensor won't report anything other than 0.9 to 1v even if I take the large vac pipe to brake servo off to induce a lean condition and my understanding is it should drop to about 0.4volts, it hardly moves even when racing the engine.

So where can I get one from cheap and quick? I've found some overseas but don't want to wait and I would prefer not to have to cut wires to fit a universal one, would this one be ok?
http://www.ebay.com.au/itm/MITSUBISHI-M ... 2ec3415d9a
Connector looks the same but i'm not sure of the specs of the sensor - are they all pretty much the same in terms of what voltage the output?

If I can rock up to Repco and get one tomorrow then great but my experience so far with them isn't great.

[yotka]

Hello Rob.
Check here: http://ftoaustralia.com/v3/viewtopic.ph ... lit=sensor


Important Extracts from Ben, etc in there:
Purchase new O2 sensor from repco, supercheap etc Ask for o2 senor (4 wire) for 6A12 galant. ACA brand, Part Number: OX204

Bosch part number is 0 258 986 602 or LS602

Edit: Bosch planar type seems to be the one to get, according to Dras, and I have been thinking about this for a while, and if you end up getting it, let us know how it went.

[Rob Furniss]

Great, thanks Yotka and I will let you know how I get on

[Rob Furniss]

I've been to Repco, Supercheap and Autopro, cheapest was $120 at Repco but it's a universal one by fuelmiser, I thought it a bit expensive for a universal but then I am a tight arse.
Supercheap quoted $300+
Only Repco had one in, the rest would be 5 days.

I've ended up not getting one and looking on ebay now.

[Rob Furniss]

Just ordered this for $55 + postage
http://www.ebay.com.au/itm/MITSUBISHI-M ... 2ec3415d9a

[FTOwnage]

Mines in need of replacement also.

You reckon this one is a decent replacement ? ^

[PHIL069]

I have asked my local Autopro to get me a price on Bosch part number is 0 258 986 602 or LS602.
Their system shows $189, but he is going to call his supplier on Monday.
I will also ask if parts dept at work can get a price.

[FTOwnage]

Their system shows $189, but he is going to call his supplier on Monday.

I will also ask if parts dept at work can get a price.

[Rob Furniss]

I don't know why the local stores are charging so much.
I will post back on here about the Magna one when I've got it and fitted it.

[vipfto]

yeah same issue mine runs rich at idle and actual idle is 1200rpm adjusted maps and also have the 275 injectors and 255l pump only at idle though when cruising and boosting its perfect wondering if its the emanage that causes it (have 3bar map sensor too and timing and fuel harness)

Car runs great just high idle and rich although do have adjustable FPR too. But idle was good although rich with just injectors pump and larger TB before turbo pipe work and tune done.

Think its to do with emanage TBH.

Thinking of going full standalone when funds allow seeing as baby just born

[Shane001]

Guys I'm pretty sure the problem is too much fuel, nothing to do with your narrowband sensor or the factory ecu.

When I was running 275 injectors I had a bugger of a time trying to get it to idle in closed loop. If the engine is getting too much fuel, the factory ecu simply cannot go into closed loop as the afr will be outside the working range of the narrowband sensor. Anything lower than around 13:1 afr and closed loop won't happen.

Easy to test, connect your notebook up to your emanage, warm the engine up, then start taking fuel out at idle and watch your afr rise until it goes into closed loop. At idle you can safely raise the afr all the way to 15:1 if needed, but I think you'll find once you get to around 13:1 the factory ecu will kick in and switch to closed loop.

Then ditch the automatic conversion feature within the emanage, and manually adjust your fuel delivery within your maps. I found on the racecar the auto conversion feature was very hit and miss. Bear in mind this will likely mean a complete retune. Doesn't have to be spot on for closed loop though, only needs to get you in the range and the factory ecu will take over.

[Rob Furniss]

Ok Shane that is sounding like the culprit, I've got an O2 sensor on the way anyway so will fit that and then get into the emanage maps (when I've finished the cambelt change)
I tried 350cc injectors a few years back on the old car and they were really bad, emanage couldn't do a thing with them - super rich all the time but particularly on cold start so I ditched those.
275's are still way over factory standard and i'm not running the charger at the moment either, was just hoping to keep them on for when I put the charger back on, I think like you say somewhere around 240's are a better fit for low boost though.