---===The Official MAFT-Pro Thread===---

[msassoon]

Bob,

I have a customer with a VR4 that is having problems with the idle surging under PT tracking. The TPS stays constant at 0.63V, but AFR will lean to 17.0, PT Tracking finds it and over compensates to 13.0 and then back to 14.7. After a few seconds, it happens again. Any ideas before I see the customer on Saturday?

Cheers

Marc

[TurboBob]

Originally Posted by msassoon

Bob,

I have a customer with a VR4 that is having problems with the idle surging under PT tracking. The TPS stays constant at 0.63V, but AFR will lean to 17.0, PT Tracking finds it and over compensates to 13.0 and then back to 14.7. After a few seconds, it happens again. Any ideas before I see the customer on Saturday?

Cheers

Marc

What size injectors? My guess is the ECU is switching in and out of some sort of backup idle mode. I saw this kind of thing with my 550's in my other car. What is your target AFR at idle?

I assume both O2 sensors are unplugged. It might be interesting to run a logger on the car and see if it is trying to go closed loop. Also, after hunting a few times does the ECU "give up"?

Bob

[msassoon]

Standard injectors with a target of 14.7. The sensors are unplugged.

I will look at the car on Saturday and let you know.

[in-san-e]

Bob,

I have just recently fiitted a new set of RC 550 injectors. Previously the car had 510cc injectors from an EVO 3, with these in it ran fine, with a nice clean steady idle and virtually no need to make any adjustments to fuelling other than the mainscale which was at -29.5.

After putting the 550's in I pulled the mainscale back some more to -34.5. This however resulted in the car running very lean, off the AEM gauge at idle!! with the Pro indicating an AFR of 19!! I had to reduce the mainscale adjustment back to around -14 to get the AFR at 14.5 or so.

From here I re-set the mainscale to a correct -34.5 and started to re-tune by adding fuel in all of the load pages. This has improved things no end, but I have a remaining problem, an answer to which so far eludes me.

When I lift off the throttle completely while the car is moving and still in gear, the AFR goes very lean, at around 17, if I apply a small ammount of throttle, the AFR picks up to around 14 or so. I beleive this problem is related to TPS and manifold pressures and my not having something set right in PT tracking, or am I way off with this?

Any help would be much appreciated.

Best regards,
Steve

[Patryn]

Hey if any of you guys are pretty good with tuning the maft-pro and can log it with a laptop drop me a line if you are around the Washington D.C. area. Car runs fairly fine, but would like to get the best tune I can and need some tips from someone that knows the MAFT Pro fairly well.

[Highboosted]

Originally Posted by in-san-e

Bob,

I have just recently fiitted a new set of RC 550 injectors. Previously the car had 510cc injectors from an EVO 3, with these in it ran fine, with a nice clean steady idle and virtually no need to make any adjustments to fuelling other than the mainscale which was at -29.5.

After putting the 550's in I pulled the mainscale back some more to -34.5. This however resulted in the car running very lean, off the AEM gauge at idle!! with the Pro indicating an AFR of 19!! I had to reduce the mainscale adjustment back to around -14 to get the AFR at 14.5 or so.

From here I re-set the mainscale to a correct -34.5 and started to re-tune by adding fuel in all of the load pages. This has improved things no end, but I have a remaining problem, an answer to which so far eludes me.

When I lift off the throttle completely while the car is moving and still in gear, the AFR goes very lean, at around 17, if I apply a small ammount of throttle, the AFR picks up to around 14 or so. I beleive this problem is related to TPS and manifold pressures and my not having something set right in PT tracking, or am I way off with this?

Any help would be much appreciated.

Best regards,
Steve

550's here, but not running anywhere near the mainscale your running. I think I'm around -28 while still adding fuel all over. Zero out your tune pages and start resetting the mainscale til you got decent running. The fine tune with the low-med-high maps. My car likes lotsa fuel, yours may vary.

[in-san-e]

Originally Posted by Highboosted

550's here, but not running anywhere near the mainscale your running. I think I'm around -28 while still adding fuel all over. Zero out your tune pages and start resetting the mainscale til you got decent running. The fine tune with the low-med-high maps. My car likes lotsa fuel, yours may vary.

Hi, thanks for your reply

I have left the mainscale alone, as a test, and begun tuning using the load pages as planned. The car is now running great! I have no fuel in the high load pages, about +12 across mid, and +18 in the low, but can probably take some more out yet, when I get some more time. The only issue I still have is the lean issue on off throttle overrun.

Cheers,
Steve

[Rogue_Ant]

Highboosted,
Who made your 550cc injectors?


Rogue

[Highboosted]

Originally Posted by Rogue_Ant

Highboosted,
Who made your 550cc injectors?


Rogue

RC.

[Theo_VR4]

I also like the idea of at least 3 tunes (pump, meth, race, nitrous). I don't know if there's any extra wires, but even if you had an aux trigger 2 so you could just put a switch on it to turn on "race gas mode" etc.