HEY GUYS DROVE MY CAR FOR THE FIRST TIME IN THREE MONTHS YESTERDAY, I JUST INSTALLED A BIG BORE TB AND MATCHING TURBO MASS AIRFLOW,AND RISING RATE ADJUSTIBLE PRESSURE REG (SET AT 32 PSI) I LEFT ALL MY OTHER SETTINGS THE SAME (TOTAL TIMING AT 36DEG). NOW IF I REV IT IT POPS THROUGH THE INTAKE SOMETIMES IF I GIVE IT A REV. WHAT CAUSES THAT? IS MY MA SENSOR ADJUSTED CORRECT OR WOULD IT BE SOMETHING ELSE, IF I RETARD THE TIMING IT BACKFIRES A BIT.

 

It's backfiring. You're running rich. Do you have an air fuel gauge hooked up?

 

No I Dont Even Have A Port For A O2 Sensor, I Welded A Bolt In That 4 Years Ago When I Installed The Header, It Is Running Rich, But Its Only 32psi Of Fuel, Could It Be The Little Screw On The Afm? And How Do I Wire In A A/f Guage?

 

What year ECU ya using? I thought all 280zx's should have an O2 sensor...

Anyway, just because the fuel pressure is 32psi doesn't mean it can't run rich, that's the ecu's job & if a sensor is out of wach, then it can run too lean or rich. Start w/ adjusting down the AFM spring. Also check the head temp sensor connection.

 

just install an O2 sensor and then you wire the a/f guage straight to the O2. Thats all there is to it. Well that and wiring the guage up to a power source. But without an O2 sensor you cant wire in an a/f gauge.

 

I should point out though that an alternative would be to hook up an Exhaust temp guage. Works just as good (some think better) than an O2 guage. You'd still have to weld in a bung for the temp. probe though

 

IM RUNNING THE STOCK 1979 COMPUTER, CANADIAN MODEL, ACCORDING TO THE FACTORY MANUAL I GOT, ALL THE 79S AND SOME 80'S DONT HAVE O2 SENSORS. AND THAT INCLUDES FEDERAL AND CALI. MODELS TOO. I CAN ALWAYS CUT THE WELDS ON THE BOLT AND PUT THE O2 IN. AND WHO KNOWS IF ALL THE SENSORS ARE WORKING, IVE NEVER TESTED THEM, CAR SEEMED TO RUN FINE BEFORE, THAT AND IF I SWITCH TO MEGA SQUIRT IT ALL WONT MATTER. ALL MY SENSORS ARE BELOW THE THERMOSTAT AS WELL, THERE IS NO SENSOR ON THE PASS SIDE HEAD LIKE THE 82 ERA. MY HEAD HAS THE PORT, BUT I SWITCHED THAT FROM STOCK, YOU KNOW MORE HP THING.

 

I would suggest adjusting the AFM down. Just mark the cog where it's set, so you know where it was.

 

So Which Part Of The Afm Do You Mean, Is That The Internal Part, I Got The Spring Kinda Loose To Decrease Airflow Loss. Does The Screw On The Side Do The A/f Mixture?

 

That screw allows some air to bypass the metering... I dunno how much effect it has on the system tho.

To adjust the spring, put your finger on the white cog & loosen the screw that holds the spring. I think tighter leans it, looser enriches it... but I'm not sure exactly which way it is, so play around w/ it till it runs right. You only need to go 2 or 3 clicks each way.

 

i would suggest turning off the caps button oh and not all S130's have O2 sensors, just the 82 and 83 i believe.

 

The screw only adjusts A/F ratio at idle. It wont too much affect other than that and at WOT or anywhere near it it wont make a difference at all. If you want to mess with the A/F ratio then you can tap into the air temperature circuit and the engine temperature circuit to mess with the ratio. Wouldn't reccommend it without an O2 sensor though.

 

SOUNDS COMPLICATED TO ME this better

 

If your running the turbo afm on an NA and have not adjusted it I suggest you do. Its not hard,gently pry the black cover off, the you will see the nylon gear with a bolt and tang locking it down. Mark where it is with a sharpy or something. While your holding the gear loosing the bolt and then you can turn the gear one way or the other.DO NOT LET THE GEAR GO or you will unwind the spring which will suck. I do it with the car running so I can hear what it does, for more info try here.. clicky me..........

 

When I Put The Na Guts Into It, I Let The Sring Go, It Really Wasnt That Bad, Ill Tighten It Up Tommorrow And Report Back, I Lowered The Fuel Psi To 30, That Helped A Bit, And My Timing Is Back To 36deg Total Or 20 Initial Which Ever You Understand Better. Im Going To Check My Tps Too, That Could Make It Suck Too