Tuning questions/help
 

Hi
I have spent most of the weekend driving around with a wideband attached tuning my FD Rx7.
I have a few questions:
- I get a lot of popping on deceleration. Decel cut-off is disabled. If I enable it will this remove the popping? Is decel fuel cut-off ok on the RX7. I quite like the popping but I doubt the cops will when they hear it.
- I have played with the throttle pumps. I had to increase them quite a bit from the base map from the Ricemobile site. I now have 36,22,34,19,22,13. I have another map with the pump values far in excess of these. I remember a previous comment on my map from the list saying the pump settings were too low. How do these settings look and compare.
- I am having issues with the TPS readout. If I change maps will it require calibrating each time. It only seems to work properly after recalibration. Not sure if I have a dodgy sensor.
- I want to link the wideband to the spare A/D on the haltech. The 2 wires from the FJO need to be joined to the A/D plug wires? The plug has 3 pins. The 3rd requires a ground? So it looks as if I will be wiring in 5v from FJO, ground from FJO and chassis ground. Does that sound right?
- The spare A/D is set to general atm. It reads 0.47v and is not connected. Is that ok.
Thanks in advance.
Martin

Martin,

Point by point for your questions:

The popping is due in part to air being drawn into your exhaust system. If you've got any exhaust leaks or you've got a smog pump injecting air, you'll have that problem. There's a couple things you can do to fix it, one of course is the decel cut-off. When you're coasting down, the engine cannot ingest enough air and fuel at the nearly closed throttle angle to support complete combustion. Therefore, the air/fuel mixture leaves the engine unburned, where it can be ignited within the exhaust system if there is enough heat. If you've got a turbocharger, you've got a virtual always-on spark plug in your exhaust just waiting to ignite that unburned mixture. If you're not running the oil injection pump, and are running pre-mix instead, I wouldn't do the decel cut-off. That would be. . . . bad

The popping in your exhaust has nothing at all to do with the accel pump settings. You're better off developing your own map if you've got a wideband, and compltely disregard other people's maps.

The TPS has nothing to do with the map you use. If you've got a TPS which changes its closed throttle position value by more than 2%, I'd look for another sensor.

There is a way to connect your wideband to the spare aux input on the Haltech. The thing you must be careful of is avoiding a ground loop. Make sure that the negative connection from your wideband has the same potential as the negative connection on the Haltech. In other words, connect the ground of the FJO output to the Haltech ground. I won't waste a bunch of space explaining why, but it's impoartant that the wideband and Haltech share the same ground potential, or else you can damage either or both of them, and you will most certainly get inaccurate readings.

Good luck,

BK
BMEP Fuel & Tuning