Early EDM non-cat 4A-GE 16v Bluetop Fails emissions (high co)

[Rascal21]

I`m at a bit of a loss here.
As the topic states my Early EDM non-cat 4A-GE Bigport Bluetop engine fails on emissions test, should be 1,5% CO.
During the first inspection a couple of months ago it read 6,7% at idle when warm..
During the second inspection attempt a week or so ago it read 6,8-7,2% at idle when warm.
Today it read 8,2% at idle when warm.

During and/or between the last two attempts I`ve been fiddling with the CO potmeter but can only shave 0,3% of the reading (8,2% goes down to 7,9%).
Been trying my hand 3 times at the inspection, at one point even briefly swapped for a different CO potmeter, but same thing, can only shave 0,3% of the 8,2% reading.

The TPS was a bit off position (slightly anti clockwise to where it should be sitting) and as a result I had rev hunt when slowly throttling up to 2500rpm when it`s not in gear, adjusted TPS back to where it`s supposed to be sitting (it was marked) and now no longer have that problem (Have not put it through inspection after this change)-

Runs very rich (Lambda value is 0.800, should be above 1.000, or if thats 800 and 1000, donno anymore, exhaust fumes been killing me), adjusted idle between 1200 rpm and 750 rpm just to see what would happen.

No exhaust leaks, exhaust is pretty new, new muffler etc.

Tried a oil change, spark plug change, checked compression, dizzy cap, rotor, plug leads both when slacked and when pulled etc, also I swapped ECU and igniter+coil+cap+rotor+leads, plugs etc, no difference in behavior.
Coil+ign has good earth, battery is nice and healthy changed it for the lels but no difference, alt charges nicely, again changed it thinking maybe injectors were getting low voltage, again no dice.
Fresh fuel as well, no fuel leaks, no oil leaks, oil pressure good.
You know, all the usual stuff.
No error codes i.e no bad sensors, also manually checked them by pulling the connectors (pull TPS = Engine stops) and so on, also checked them according to FSM (measure resistance/voltage across pins etc) again, the usual stuff, no dice.
Plugs are nice too of course, also installed some black ones on purpose and as expected got unstable idling.

For just driving the thing is great, 4th and 5th gear up inclines at 2000 rpm using 3.9 CWP without breaking a sweat what so ever.
Pulls hard and healthy all the way up to 7500rpm rev-limit, no odd behavior, no noticeable power loss etc, and considering how rich its running I actually get rather nice mileage (compared to the 2T that the 4AGE replaced in the first place)

I`ve had my fair share of tough ones and have accumulated a bit of experience due to that (as you may notice by everything I`ve crossed off the list), but this one is over my head even with what little I do know.
Would really appreciate any suggestions that I havent yet checked/tested/tried out yet, I`m not proclaiming to be the best or anything, just need the daily grocery getter/parts getter to pass inspections so I can keep using it for it`s intended purpose

[ditn]

Oxygen sensor broken?
I think its runs to rich then.

Or maybe the green water temp sensor on the back of the head.
The ecu uses this sensor for how much fuels needs to be injected i believe.

[Rascal21]

As I said this is the early EDM non cat version, instead it has a potmeter to adjust a/f down to about 1,5% CO levels (give or take 0.5%)
Have been checking sensors and no error codes, the green one is OK.
When I disconnect it, I get idle hunts when the engine is cold.

[ditn]

then my only idea is the green water temp sensor at the back of the head.
That sensor ecu uses for startup injection time/post start and water correction
EDM = european domestic market? xd

[d3nso]

Coldstart injector malfunction maybe?

[Bean]

Set up the TPS according to the manual, all you need is a feeler gauge and screwdriver.
Did you remove the EGR?
Idle should be set around 750-800 for idle emissions test.

[totta Crolla]

Read the section 'join the fun' some useful information on the adjuster pot:
https://github.com/sparkiedk/Toyota-PCM-...0Ross).pdf
You might also have a leaking injector or a fuel rail pressure problem.

[Rascal21]

As I said TPS is set (did not say I used feeler gauge, screwdriver and multimeter).
No EGR on my motor (never came with it either), as I said its a early EDM Bluetop Bigport Non-Cat Non-O2 Sensor, bare bones motor as from factory
Idle was set at 750-800 on all the tests, we also adjusted idle UP, with ZERO difference to CO emissions surprisingly.
Used the PDF file for reference and turned mixture screw (A/F Pot) all the way all sides, middle, a bit off middle, more off middle etc, both sides, got a mere 0.3% difference in CO emissions in the leaner direction, but with zero difference in idle speed, the way the engine runs or anything.

I connected test lamp to W pin on ECU, the other end to Earth, put ECU in diagnostic mode (shorting the two pins in the engine bay diagnostic plug), nothing, not one blink, tested lamp on battery, works, so it would appear everything is healthy in that regard also.
Changed ECU to be sure, still no error lamp blinking, tested most wires with multimeter, found no bad ones.
Disconnected MAP engine runs rough/quits.
Disconnect TPS, same.
Disconnect Cold Start Injector, no change in CO or O2 readings (I.e it works only when connected and only during cold start, just as it`s supposed to)
Changed Air Intake Temp sensor, Cold Start Injector, unplugged cold start injector, etc etc, nothing, CO levels always at 6,5% plus.
Installed Tomei FPR and adjusted fuel pressure to 2.4 bars (Minimum factory allowance) and it made a -0.3% difference. but was still at 7,8% CO which again is at least 6% CO too much, adjusted pressure incrementally up to around 2.8 bars (max factory setting) but still no more difference than -0.3% but at least fuel pressure regulator issues are out of the way!
No exhaust leaks, new muffler, new exhaust manifold gasket, no intake manifold leaks, when I block all air intakes = engine stalls.

Emissions should be at 1.5% +-0.5% or in my case at least below 4,5% to conform with 2T emissions (the engine that this 4AGE replaced).
It just gets way more fuel than its supposed to (0.8 Lambda values) and smells like a snowmobile!

Will try injector cleaner etc today, though I suspect that probably wont do much good either.

Again, the engine pulls like a champ, no irregularities, no lumpy idle, no bwapbwap or anything, no backfire despite apparent overfueling, nice brown/red`ish spark plugs and all of them look exactly the same, exactly how they are supposed to be.
And on that note no bigger compression difference across all cyls than 10 psi (within factory allowance).
Green temp sensor also works, when I disconnect it, cold motor idle hunts up and down until engine temps go up which also actually confirms the other sensor at the back of the head works, though I could disconnect it as well just to see what happens?

Been double checking all your suggestions and thanks a lot for chiming in everyone

And that MR2 write-up actually came in very handy for future reference, now I know what the potmeter is supposed to be dialed at and what each direction does
Thanks

Sorry for typing a lot but I don`t want anything left out

Now will check resistance across pins on all 4 injectors.

[pack]

(05-11-2016 04:35 PM)Rascal21 Wrote:  I connected test lamp to W pin on ECU, the other end to Earth, put ECU in diagnostic mode (shorting the two pins in the engine bay diagnostic plug), nothing, not one blink,

Sorry mate... something is wrong.... The light must blink with 2 sec interval repeatedly.

Regards

[totta Crolla]

(05-11-2016 05:53 PM)pack Wrote:  

(05-11-2016 04:35 PM)Rascal21 Wrote:  I connected test lamp to W pin on ECU, the other end to Earth, put ECU in diagnostic mode (shorting the two pins in the engine bay diagnostic plug), nothing, not one blink,

Sorry mate... something is wrong.... The light must blink with 2 sec interval repeatedly.

Regards

Yep.
Connect test lamp as before but this time press the throttle more than half way down.
Post result !

Cam timing ok ? Ignition timing ok ?