won't stop running rich
 

At the GRM challenge we had what we thought was a injector stuck open, the AF went into the 8's

Well , I swapped to RC 370's (from 450 talons) and took out the resistor box... Still doing the same thing

Swapped the P28 (chipped with a basemap) to a stock P06.... Still Rich...


So the injectors and ECU's are good , but I can't get it to run at anything but mega rich.


Philstubbs ran the ostrich , disabled the O2 in crome , still rich , he was able to mod the fuel ratio , but not enough to lean it out, we could adjust the IAC with no issue either

what else could cause it to run so rich?


J.M
89 Si , Vitaras , TT rods , ARP's , Talon 450's , T04E , Gutted ...ect..ect

Re: won't stop running rich
 

Bad O2 sensor?

Re: won't stop running rich
 

I'd say with an 02 sensor or bad coolant temperature sensor?

Re: won't stop running rich
 

But I think that you could still lean it out if it had a bad coolent temp sensor.

Re: won't stop running rich
 

Philstubbs disabled the 02 sensor in crome when we were tuning it , it did nothing...

coolant temp sensor makes sense..

Re: won't stop running rich
 

even with a bad temp. sensor i would think you would still be able to get better ratios then 8's

Re: won't stop running rich
 

Just a thought....Whenever the 02 sensor for my wideband goes out, it always starts pegging out to the rich side....

Re: won't stop running rich
 

Yeah it seems like Bosch widebands like to go rich as they start to die.

If it's not that I'd check your fuel pressure regulator. On a Prelude I worked on the car would run in the 10:1 area when the car got hot and the regulator wouldn't open. When the car cooled down and the regulator worked it would run like it should.

Re: won't stop running rich
 

Checked your plugs to see if you really run that rich?

Re: won't stop running rich
 

FPR, replace it! Before you replace it make sure both vacum sources and the line are in good condition. How are you reading your AF? Maybe a bad wideband sensor.

Reading plugs FTW!

Re: won't stop running rich
 

You are most likely thermally shocking the sensor - leaving it on for long periods with the engine off, so when you start the engine water vapor that has condensed in the exhaust as well as the vapor that is a byproduct of the combustion reaction comes along and hits the sensor's heater circuit. The heater is ceramic. The mental image I am trying to paint is chucking a hot ceramic frying pan into some dishwater. Yours usually rattle when removed, yes?

My widebands typically become lazy, or if exposed to racegas they won't read past 11.5-12:1 AFR no matter how much fuel is thrown at them. I have had the full-rich syndrome, but it's a lot rarer.


Correct, you can.



Single cylinder roughness, eh?

Check to make sure IACV/purge solenoid/IAT plugs aren't mixed up. I think you have an 88-91 chassis ? so the purge is located on the firewall harness and not a problem, but you might have a spare DPI plug or the like that got tossed into the mix.

Check the IAT to make sure the tip isn't melted.

Check the ECU board and make sure there are no burned components.

Re: won't stop running rich
 

the car was running good, then like flicking a switch it went to barely running and tons of black smoke out of the exhaust, while running. we didint change anything. if i leaned insanely, it would finally lean out, but then die. i couldnt get it in a place where it would run without a ---- ton of smoke and a bunch of skinny pedal.

the issue here has nothing to do with what the wideband says. the car wouldnt run. any issues with the wideband are useless at this point

John, did you say you put a stock P06 in there? like no chip? if so that will cause it to run exactly the same with those big injectors. try to scrounge up some 240's and put in there. i bet it will run smooth

Re: won't stop running rich
 

So it wents from running correctly, then *click* rich, then *click* fine?

Sounds like bad injector(s). The overbored eBay Keihins are great for that.

Re: won't stop running rich
 

it was running good then "click" running like ---- and never got good again. If it sits for a few min. it will start like normal, but after second or two it will run like ass again. He had DSM 450's. I usually hear of those sticking closed, not open.

I could make it idle by setting the iacv all the way open with Crome. It was at like 1500 rpm and a bunch of black smoke, but it ran.

Re: won't stop running rich
 

did some investigation on the weekend..

I think everything is fine, the problem lies in a 89 with a 1991 dash harness spliced in..

Turn the key , the fan cycles for a sec , turns off , then runs constant....

something is fucked...I am gonna pull the dash harness from an 89 this weekend and swap it out...

we changed it before the challenge when we had electrical issues... fixing the lighter revealed a mess of wiring under the dash with marettes and speaker wire spliced in...

Re: won't stop running rich
 

had similar problem when I had an exposed v-tech wire touching the cover to the ecu.