Is there a way to get your a/f close?

[OrangeMustangGt]

Whell, ive been messing with my FP all the time, and i would like to know if there is an easy way to find a sorta close a/f ratio. I know about widebands, but there cash! see, i know i should get a tune etc however, is there a way to just get it close for now, hmm like buying one of those a/f ratio gauges and welding in another 02 senser? has anyone done this and is it close? i really want to dial in my FP for now so as i dont do any damage.

 

[mikenstang]

Without knowing what Inj size you have I can only say what worked for me. I have my FPR set to around 42psi (no Vac) If you put the vac on I am around 39 to 40psi. I did find that clearing my KAM after making adjustments helped the car run better as well. Always take the car for a ride after making a change to let the computer relearn the settings. Your EEC will always try to obtain the correct A/F ratio from what info it gets from the MAF and O2 sensors. This won't be perfect but it will get you close.

Then after all that I finally gave in and bought a Tweecer RT and ---
Thay are worth the money to get a HCI working correctly

 

[Ray@VSK]

No, you can adjust up & down lean will pop & cackle alot, rich will burble & backfine, put it in the middle wich in theory would be right, right ? NO, Even @ that once you put it on a dyno with widebands you'll probably be off the charts, this is a very delicate procedure that can not be done by eye or ear.

 

[OrangeMustangGt]

hmm, damn i thought so, but just for my combo, im using 19lb explorer injectors. is there some sort of guage i can set up? also, the computer only adjusts in closed loop right, so you must set your a/f for idle and WOT?

 

[mikenstang]

You can buy a fuel presure gauge at most auto parts store around $30.00 it goes on the schrader valve on the front of the passenger side fuel rail.
Just to be clear you are not adjusting you A/F.... only your fuel pressure. The EEC will try to set the A/F. with 19lb Inj you shouldn't need much more than 39PSI of fuel pressure. If you are still runnig rich then you need to look at somthing else causing the rich condition. Check for codes possible bad O2's???

Closed loop is when the processor utilizes the readings from the oxygen sensors to continually adjust fuel delivery.

Open loop ignores the oxygen sensors and relies on environmental readings and calibration data to calculate fuel delivery.

Factory oxygen sensors only work when heated to approximately 600 degrees. Also they are used by the processor to help acheive an emissions friendly 14.7:1 ratio.

The processor typically operates in closed loop only when the engine is fully warmed up and not under much load when a 14.7:1 air fuel ratio offers the most benefits. The processor will operate in open loop when cold or under load when either the sensors are not functioning or a different air fuel ratio is desired.

 

[HISSIN50]

the puter does use the adaptive strategy for open loop operation, as well as WOT operation. it just does not use the O2's for that tuning.