I put 720 secondaries in my 88 T2, and an FD fuelpump. Now the car is running too rich when the secondaries kick.(To the point that the car almost tries to die.) Does the ECU automatically compensate for the increased flow, or do I need an AFC to manage the extra fuel? I have a Greddy Profec B running at 11 pounds.

Any thoughts?

Drew

 

how does the ecu know the injectors just got bigger?

you need a safc, or some other fuel system

 

I thought possibly: the mass air flow sensor plus the O2 sensor would tell the ECU that the mixture was too rich, and the ECU would adjust the duty cycle of the secondaries. No?

Drew

 

What he said. The ECU has no way of knowing how big the injectors are, so the amount of fuel being injected over 3800rpm has increased 15%.

What other fuel mods have you performed? Injectors are the last thing that should be replaced, not the first. If you're running 11psi boost you should already have replace the fuel pump. Bigger injectors won't help if the pump can't keep up. A fuel controller should then be used to add more fuel if required, and the injectors only need to be upgraded if they exceed 85% duty cycle during that tuning.

 

O2 sensor signal is ignored unless you're in high vacuum "cruise".
At WOT, the ECU doesn't care about the O2 sensor.


-Ted

 

So, I need to put my old SAFC in, and figure out how to adjust it. The problem I have is that the boost declines with higher RPMs. I need to think this through! Whoa! This is the reason most of this type of thing is done by the younger generation, computer wiz types!

Drew

 

I really wish life was that easy. but NO you WILL need to control the injectors some how. I would recommend the S-AFC

 

Dunno how old you are, but I'm considered old in here.


-Ted

 

Yep I have an SAFC, just need to relearn it.

I'm 52! And still playing with the boost.

"Wolf300tt" stands for my 300ZX tt with stage 4+ upgrades, and I have 2-10th AE 1988 RX's.

Drew

 

I just put my 550cc's back in, and it runs great! I will research the installation of the SAFC, and reinstall the 720's another time. Thanks for all the help!!!

Drew

 

Stage 4 upgrades......not to flame but I hate when people say "stage this" "stage that", WHAT DOES A STAGE MEAN IF YOU DO NOT DEFINE STAGE. Were not playing Gran Turismo here! Lol, I used to have this friend who would say, man I wanna put a stage 3 turbo on my 300zx, and I would say: "huh" stage what? That doesn't make sense. You just reminded me of my friend, sorry.