Car and motor info at the bottom.

Ok so i have been having problems with the car for a little bit running rich but had just figured it was do to the fact i had been told the car smoked when i acclerated and that it was buring oil.
(friend told me this after fallowing me around town one day) the other day while ridding with the same friend i let a buddy drive my car and as my friend started to point out the "oil smoke" from my car.
I could tell it was Grey and NOT blue. so now that i know i'm not getting oil past the rings and that it is to much fuel I want to fix this.

First thing i'm not getting black plugs. all four are a mid tone of grey. and No Brown at all
also Very Little Blow by when ran with out the oil cap on.

all repair work done After the Mod work.
the Wideband was reading 13.8~15.2 depending on gear and throttle posion and at idel.
For the first 6 months after all the mod work was done.

Wideband now reads 10.0~20.0 (this is Full Sweep) depending on grear and throttle position.
Idel AFR is 11.3~13.2 @ OT 10.0~12.5 @ Cold
Crussing 2500~3000RPM AFR is 12.2~13.5 with dips to 11.2 and spikes to 15.8
WOT in gear and pulling AFR is 20.0 with dips to 18.0

i have read the sensor data from the ECM and the Factory O2 Sensor is reading the same as the wideband

All this and the Car still Has No CEL.

the car ran fine up till this all started i drove home parked the car and the next moring when i started the car the AFR was all over the place.

i have tried 3 ECM's and all there respond the same. No Cel and running rich.

Car: 95 Del Sol Si

Motor: D16Z6

Repair work: New Fuel Filter, Injectors, O2 Sensor, Map Sensor, IAC, PCV Valve, TPS (tested and working Fine) Coolent Temp Sensor (tested and working) Grounds all seem to be connected.

Testing Equipment: DMM and Snap-on Modes Diagnostic Computer with 2010 3rdQ Update (this is the Most current Update for the scanner)

Modz: DC header, High Flow Cat (it's labled a Cat but you can see right through it), N1 Catback, Short ram + K&N, Aem fuel Rail, Adjustable FPR,
Fuel Pres. Guage(38 PSI with vac 48 PSI without vac), MSD blaster SS coil, MSD A6, MSD cap rotor and Wires, NGK Iridium Plugs and Autometer Wideband O2.

 

Have you looked for an exhaust leak near or upstream of the O2 sensor?

 

yes and there is no sign of any leak

 

Is it possible that your visible inspection has missed an exhaust leak?

Have you checked the O2 sensor and heater wires for resistance and shorts using a multimeter?

If the O2 sensor is unscrewed from the exhaust does it yield a stable lean reading with the engine running?

 

i did a visual inspection first. after that i did a pressure test (pluged the tail pipe with a pack of rags and a band clamp) moving my hand around the header to feel for any leaks and listening for any hissing sounds. and found nothing

tested the O2 with my DMM and it checks out. I had a Spare New one and tried that one as well both show a lean state when pluged in but NOT installed in the Header.

fuel press holds at 38 PSI dropping to 36 PSI after sitting parked Not running for 4 Hours.

I find it odd to run so well one day and the next morning to just start running rich with no cell and no sign of a bad sensor.
the motor dosn't surge, stumbal or any thing. if not for the drop in fuel milage and the Wideband i would have no idea there was a problem.

 

clean ur fuel rail injectors and fpr ful pressure regulator

 

Running rich does not generally cause performance problems in the short term. Did you test the O2 sensor wires with the multimeter for an intermittent short or open? You might not detect any wire problems until the problem occurs. Intermittent problems are the most difficult to diagnose.

 

i could see this being a problem if the car was running lean but it's running rich

 

it's late here so i will have to check the motor harness and body harness tomarrow but the wire from the sensor to the connector on both O2 sensors is working ok.

hooked up the meter and flexed the wire to see if i lost contanuity and never did.