running rich

[scottyMIz]

checked the voltage reading on my o2 sensor and it's running rich all the time.Voltage was about .950volts it would change and drop some but mostly stayed there.How can i lean it more with the stock system?I've adjusted the afm some i'm not sure if i can adjust it anymore.Anyone got any suggestions?

[Scottie-GNZ]

Scotty,

 

if you are running an adjustable FPR, then here is something you might try. The SVO injs are rated at 36psi pressure. First make sure the FPR is set to 36psi. The fuel pressure is best checked and adjusted with the signal line off, covering the line with your finger to keep a good idle. Of course the fuel pressure will drop when the line is connected. Those injs are good for 325hp at a conservative 80% duty cycle. Since you are not making 325hp, yet , you should be able to adjust the pressure down to 34psi and see if that makes a difference. You should still have enough fuel at full boost.

 

This is not necessarily the best way to correct the problem, but unless you can find someone who truly knows how to recalibrate the AFM, you are faced with one of the prime reasons for getting a programmable system.

[TimZ]

Here's a thought...

The flapper meter was used in lots and lots of vehicles through the eighties. Take a trip through the junkyards and see if you can find one with a larger diameter bore. Maybe one of the big BMWs or something.

 

This would give you greater airflow for the same AFM reading, which is just what you need. You may have to swap the electronic 'guts' from your old meter to remain compatible, but this might give you the extra range that you are looking for.

[Drax240z]

Early 80's BMW 530i. I've read about a guy swapping his 280zxt AFM internals into the body of the very much bigger bore 530i AFM. I've seen them both (thsoe 530i's were great cars! just Baaaaaaaaad on gas) and they look identical except for the size. You'll be wanting to get a bigger TB at the same time I think. If I had to guess I'd say that the BMW AFM has a 60-65mm bore compared to the 50-55mm one for the 280zxt.

[scottyMIz]

I forgot to check the pressure while the line was off.I can do that easy i got the af gauge coming i found one on ebay for 58 bucks shipped to my door!So that's next plus opening up the exhaust made a huge diff in the performance i'll have to check it after i get the new gauge and see if the exhaust made a diff on the fuel mixture.Hopefully tomorrow it will not rain so i can make a few passes at the track.Bad news on something else though i was driving after the new exhaust was installed(sounds great )and second had no problem setting the car side ways and third well it reved up then the clutch cought up with the engine.So a center force clutch is in order for the over winter mods.It sounds so sweet and has alot more balls.The guys who did my exhaust are just blown away by the power that little six cylinder has They got to drive it from my work to the shop and i told the guys to be careful the boost takes you by suprise.I got to the shop to talk to them and they said they barely gave it any gas and it was gone.I told them it was quick but they didn't believe me now they do and have a new respect for the imports.I'm getting a magnaflow exhaust it's coming in next week it's a sweet muffler with tip all stainless polished.I'll try to post pics when it's done the 3" is just nice looking.I get everyone's attention now but no cops yet Hope i don't get their's either the muffler will be in soon and it will bring the noise down some to toletant levels.I'm going to save for a programable unit for the fuel and ignition so the stock one can get sold and away from me.

[SleeperZ]

Couple ideas come to mind. I don't believe you can get an adjustable fuel pressure regulator that will go below 30psi, but it's questionable that the injectors will perform that low anyway. Further leaning out of the AFM may result in much more intake restriction, as you will be tightening the s**t out of the AFM spring. Last idea before going to a different ECU is a metered air bypass. Get a small air cleaner and adapt a 1-1/2" or 2" PVC pipe to it, run it through a ball valve, than insert it into the intake before the turbo. Then adjust the ball valve until you get somewhat close to a good mixture, and fine tune it with the AFM. Keep in mind, I have NOT done this -- it should work, but it will be ugly. My solution to this, once I install my 370cc injectors, is to reprogram the chip in the ECU with a different injector table. But I am running a 300ZX ECU.