swisstonihasher

Well, something still isn't right....changed the rear 02 sensor for 2nd hand (very clean) job and decided to run with oe ecu first - glad I did. Improvement, yes, a little...More disco from my led 02 gauge upto 3,000 revs in fact more like disco all the time. Then changed ecu for simtek and back to crap running with revs and very rich - seeing Bob on 17th for clean up of this as it just doesn't make sense. I've got in the back of my mind on original map when I turned around on dual carriage way and went past garage the LED gauge went into red...although its prob just one of those things you think might of happened. Anyway, I've asked Bob to do an "MOT" map with 2nd map and a quick look at original map (full power 1st map) for light throttle as she's way out and the oe ecu picks up no faults with secs monitor so cant think it can be any other sensor on the car. Wont run her now until remap or might fubar replacement 02 sensor, which at mo, looks sweet with oe ecu.

swisstonihasher

Hey Simon, just reading this topic over to try an understand my issue more, you say "rich due to cat fitment" - would a 3" full decat to 3" with single sports cat make that much difference on flow to cause simtek to run rich? My replacement rear sensor seems to of made no difference and I've just checked the plugs (they're black in the middle). I dont need a exhaust sensor to tell she's rich with simtek over oe ecu, same FPR settings, one chugs out loads of smoke all the time. Please pm me if you have time...

Jolly Green Monster

iTrader: (4)

Yes it could well do..

you would have noticed if it were that rich before fitment and any MAP based ecu will not compensate as it cannot see the air flow change etc..

Simon

Jolly Green Monster

iTrader: (4)

thinking out loud.. how is air temp sensor wired? you are unplugging maf and connecting air temp sensor when going back to simtek if the air temp sensor is on the maf wiring?

swisstonihasher

The air temp sensor for simtek is using the MAF, I've not cut any wires etc, not sure if Bob did. If the MAF wires were disconnected, wouldn't the oe ecu run like a dog when re-fitted, plus MAF moved back to pre-turbo location?
MAF now back as "blow through" type location for air temp reading with simtek, the smoke today all the way upto warm temp wasn't good and rich reading well past 3,000 revs (my cams run lumpy upto about 2,500 then clean up), I rev'd over 4,000 and gauge still reading highest rich, .76

Jolly Green Monster

iTrader: (4)

so you don't have an additional air temp sensor added.. it is using the orignal?
then my thought is irrelavent.

Simon

swisstonihasher

Hi Simon,

No, additional temp sensor not added, I have blow through pipework which was made up for original ecu but now used for simtek temp sensor.

Bob doesn't agree with the cat idea, see below:
"Hi, a cat doesn't make an ecu do anything, it "filters" exhaust gas to allow it to pass an emissions level (or help it to) but it wouldn't "make" the ecu do anything. Any ecu running closed loop should run fueling to stoich unless there is something to stop it like a faulty lambda sensor or wild cams etc.

Best regards

bob"

My thinking is then: If oe ecu runs "clean" with cat and wild cams, disco in neutral all the time upto and above 3,000 except base idle (with replacement 2nd hand sensor), reading rear o2 sensor and yet put simtek in and instant rich, how can it be the cams still as they've not changed? None of this makes sense again, cant wait for run to Bob Sat to see what he thinks for 2nd map.

Anyway, my testing with simtek points towards faulty rear 02 sensor (again) or rich map, cant be the cams for all of it as even with revs upto and over 3,000, 4,500 still highest rich level on gauge, confirmed by smoke out exhaust and stink in garage. I'm so sick of this car being an endless money pit...it cant go on.

Jolly Green Monster

iTrader: (4)

No I didn't mean it would make the ecu do anything... that the thing the ecu cannot change, the cams cannot change etc etc.. but the exhaust back pressure has.

my thought being the cat will increase back pressure so with your cams being as they are it has increased the amount of gas remaining from the previous engine cycle and therefore less room for air in the next cycle and therefore richer etc..

but not really sure why we are still worrying about it if you are seeing bob at the weekend I am sure he will sort it.

Simon

swisstonihasher

I sure hope Bob can do his magic because at the mo it looks like my oe ecu is the better device for making her run okay...not nice thought when I've spent all I have this year on my motor with a remaining budget of, well, zero. I'll report back on results.

swisstonihasher

Well, looks like Bob went the extra mile yesterday...put in wideband sensor (his own) and mapped with that (his jack isn't the best, bit worried about him at one point when car slipped). Had nice lambda readings for idle and fast idle and cruise....2nd hand sensor back in and disco all the way back on motorway. Will take her out for normal run today just to see what road manners like, think this is the best she'll be as just got to do final power run early next year with Bob on map 1, cant wait.