[T3] Bad day at the (FI) office

[Daniel Nohejl]

>Have you tried setting the pressure sensor adjusting screw back to
>where I calibrated it? That's where I'd start. I'd also take out the
>resistor, since that's telling the brain that you're not fully warmed
>up, so it will richen the mixture.

For my commute home, I removed the 100 ohm resistor and didn’t touch anything else. Within a few blocks, the engine could barely hold an idle. It kept hunting up and down and the AFR numbers (I know, I know….) were extremely lean, anywhere from 17 to 20 when 13 or so is the supposed target number. Acceleration was poor with some bucking. After a few blocks, of this, I pulled over and put the resistor back in place just so I could drive home with some peace of mind. I’d rather be getting bad gas mileage than heating up the heads while driving too lean. This leanness was with the MPS still adjusted to a richer position than the original calibration. 

For fun, when I got home, I checked the resistance of the temp sensor with the resistor in place and it was 153 ohms. Without the resistor, it was 82 ohms. Clearly, my 100 ohm resistor is only giving about 70 ohms of resistance. I know that Jim says the resistance number isn’t that important here, but 70 ohms made a huge difference in idle, drivability, and AFR. Should this be so or does this point to another issue?

In any case, we’re kind of back to where we were a month or so ago, with three options:

—keep the resistor and lean out the mixture a bit at the MPS  (back towards original calibration)

—remove the resistor and richen the mixture at the MPS (further away from o.c.)

—remove the resistor, return MPS to o.c., and do something else that I’m unsure of. I’d have to do something though because if removing the resistor made it as lean as it did today, then recalibrating the MPS to original would make it even more so as original is clockwise from where I am now. 

I’m definitely stumped!



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.vwtype3.org/pipermail/type3-vwtype3.org/attachments/20160322/ffdda3b5/attachment.htm>