I have a 1970 Mini with a B16A2 drivetrain swap. I am running E48 DTA standalone, but the engine is completely stock. The existing tune runs pretty well at heavy throttle but is extremely rich at idle or cruise. I may just tune it myself, but if I find a reputed local tuner at the right price I may go the dyno-tune route.

Is anyone else running DTA on a reasonably stock setup? I'd love to talk specifics on idle settings, etc.

-E

 

I've used DTA S-series software for a while.

DFE Ent (DonF here on H-T) in Florida has used both E and S series DTA's for a long time.

If you have a wideband, take some datalogs of idle and cruising and post them up.

 

I do have a wideband. Unfortunately my laptop with a serial port just died, so I am waiting for my adapter for the new laptop.

I have a gauge in the dash, and it is pretty much pegged all the way on rich during idle and cruise, and it smells like a go-kart. Sooty exhaust, which I am hoping has not fouled the wideband during the years the PO drove it like this.

I'll post up some logs once I get the adapter.

One question I have: Is idle valve frequency secs just a loop frequency setting, or something I need to actually know about the idle control actuator?

 

Is the idle valve a PWM? If so, you just adjust the pulse width and/or magnitude until you get a nice smooth idle. At least that is how it has worked for me in the past.

I don't know if the E48 has a target lambda map, but one thing the new S-series units have is the ability to run closed-loop off the wideband sensor. So you can turn on closed loop and build a target lambda map and let the ECU do the compensation on the fuel trim. I would think this is an easier and less expensive solution than paying someone to re-tune your car, especially since you say the WOT fueling is spot-on. I just don't know if that feature is available on the E-series.

 

I just did a bit of reading on the DTA forum:

http://dtaforum.psycode.com/

It looks like that after a certain hardware version # and firmware version #, wideband inputs were added.

Check to see what firmware you are using, and what hardware version you have.

Also, poke around that forum a bit. They are all DTA users.

 

So the adapter came and I've been able to pull down some logs. They aren't much use - I am basically pegged all the way rich on the sensor whenever I am steady at less than about 15% throttle.

I'd like to get my idle sorted first since it idles so rich. I have the E48. I have not actually been able to figure out how idle works on my B16A2 engine. I know there is an idle control servo, but I mean in terms of the DTA settings. It idles at about 1450 rpm. When I look at the idle settings, closed loop idle control is turned off. However, when I look at the fuel and ignition maps, I don't see anything related to idle post-startup. The maps start at 1% throttle, and if I lower the 1% throttle fuel, it doesn't change the steady idle at all, but if I turn the car off and restart it it tends to die, prsumably because it passes through my reduced fuel point and the engine doesn't recover. Additionally, after bringing the 1% throttle fuel level way down, again the idle stays the same, but if I blip the throttle anywhere off the stop, the mixture leans out. Finally, turning on closed-loop idle set to 1200 rpm and a target of 13.5 AFR does not seem to change anything. I still get an overly rich mixture at ~1500 rpm.

So any idea how the idle mixture is controlled on an E48? When I go in to the real time monitoring stuff it seems to show that it is on the 1% throttle column at the appropriate RPM, but as I mentioned, I can make large changes to that point in the fuel map, and nothing seems to change until I touch the throttle.

Thanks!

 

Post the map, and a datalog from startup cold idle to warm idle, then with some light throttle cruising.

I will take a look at it Saturday morning.