I've just fitted a Stack wideband AFR gauge to my cossie - it has a peak recall feature but requires a switched earth at wide-open throttle to trigger the logging function.

I don't want to fit a dedicated switch. I have a SECS monitor and was thinking about using the Water Injection output (a combined MAP and Charge Temp trigger) to do the switching when on boost rather than WOT. Can anybody (Simon? ) assist with this

Failing that I was considering using the TPS - can anybody shed some light on operation of a 4wd TPS? i.e. can I just take TPS signal from the SECS loom and use this directly?

Cheers!

Neil.

 

I too was going to approach Simon about this!!

Simon I can email you the fitting instructions which are fairly detailed if need be

I think it would require a different thing for both 2wd and 4wd though, IIRC it needs an earth when at WOT

 

Boing for Simon or anyone else's ideas

Neil.

 

fook knows

does that help?



steve

 

Yeah great. Cheers Steve!!



Neil.

 

You should be able to do it no problem.. Depends on how the SECS unit is wired up really.. If the water injection control is a switched-earth itself, then you should be able to hook it up straight to the dash.. if it's a switched-live, then you'll either have to use a relay (not nice) or a transistor (nicer, slightly more complicated).. i'm sure mr secs will make it all clear for you.

 

A simple transistor circuit could be an idea actually

Will wait for Simon

 

I've sent a PM to Simon, so hopefully he can reply

 

i don't understand why it needs to be at WOT? how does a wideband know anything, or care, about throttle position? can't you just have a switch?

 

Nick, it just enables peak recall / alarm mode when on WOT - so you can recall the leanest value whilst giving it welly.

Otherwise you'd get loads of super lean readings on overrun.

My idea was to use the WI driver on the SECS monitor (only using 0deg ACT and an arbitrary boost level instead of throttle position).



Neil.

 

PS yeah, you could use a switch, but I'd rather have it automatically activated...

 

PF01 - this is a variable resistor but with a switch in series with the wiper so that when the throttle is closed the output goes open circuit. The idea behind this is that the closed position is clearly defined. The sensor must be set up so the slightest movement will close the switch and the voltage will change from 5v to 4.4v.(the voltage decreases to 0.35v when the throttle is fully open). The disadvantage is that the most likely fault is an open circuit due to wear or a wiring problem, which cannot be identified by the ecu and so will not flag up a fault. A faulty output could cut the fuel during normal driving causing misfires or an engine which won't rev. The setting up of the switch position is critical as the throttle does not have to open very far for the revs to rise and the ecu must realize that it is the throttle controlling the revs and not the idle speed control valve, the result may be surges or stalling.

PF09 - This sensor is just a variable resistor and the extra programming capacity in the level 8 ecu is able to automatically calibrate the closed throttle position. The calibration takes place during normal driving by detecting the lowest stable voltage from the tps (which should be the closed position) and it then sets the threshold to that value plus a few millivolts. Because the voltage should never be 0v or 5v, unlike the PF01, then an error can be flagged up if they do to show a tps error and the program modified to ignore it. The tps is wired with the supplies reversed compared with the level1 / level6 so the voltage increases with throttle angle.



don't know if that helps your quest atall, looks like you can't run it off the tps

 

i see Neil, that makes sense. no point logging irrelevant data

 

Right, the WI pump O/P is pins 1 & 3 of the connector adjacent to the main connector on the SECS PCB.

It's not a pair of contacts as I'd hoped, it's a +12V and GND. So a relay or other circuit will be required. According to the manual the max current is 200mA and the circuit is UNPROTECTED.

Just looking for a suitable relay now

Note that the minimum setpoint for the ACT is 20deg so this won't work if your charge temps are below that.

Neil.

 

SHIT HAPPENS Latin