DS vs LM1 readings

[Fuelie600]

Had a chance to finish installing my LM1 rpm cable this afternoon. I am recording rpm, tps, boost, and a/f ratio. Problem is, the LM1 readings do not jive with the DS readings. LM1 TPS is a bit low at idle ( .38-.40 vs .42 for DS ). RPM's are also off, with the LM1 showing 100-150 more at idle and 500-600 more at a 55mph cruise. I set the rpm's for the LM1 with the motor at 2,000 rpm. Anyone else with similar descripencies. The rpm cable is grounded on the body just above the ECM ( don't know how critical ground location might be ) Thanks Brian

 

[ijames]

Innovative recommends not using the ground connection on the rpm cable so try lifting that wire off and see what it does. On my car, with the power wiring run as I have it, there is a 0.20 V offset between the ecm ground and the LM1 ground. Go into the setup for the tps channel with the key on, engine off, and both logworks and direct scan running. See what ds says for tps, then set that voltage in the lm1 setup and use the right click to assign that voltage to the current reading. Then floor the gas pedal, hold it til everything is rock steady on ds, and repeat for the other end of the scale in the lm1 setup. I have something like -.2 V = 0 V displayed and 4.7 V = 4.8 V displayed, and now over the full range of idle to wot both ds and logworks agree. You can do the same for the map signal - one point is easy, key on engine off is 1 bar or 14.5 psia. I teed a bicycle tire pump into my boost gauge and map sensor line and pumped it up to about 28 psig to set the upper point. Don't know anything you can do about the rpm offset but ungrounding the rpm converter might help.

If you or anyone else wants to go over this stuff in person at Cecil Co. in October I'd be happy to show my setup and help with yours.

 

[Fuelie600]

Thanks again Carl. I grounded the rpm cable because Innovate instructions suggested it, if sensors other rpm were going to be hooked up. I certainly will diconnect it and see what readings I get. Will also play with the other settings. With key on engine off, my TPS jives with DS. When the engine is running, it shows low. Maybe the ground is an issue. Brian

 

[Fuelie600]

Well, I went out into the shop and pulled the RPM cable ground. I lost .15 volts on the TPS signal ( from .39 to .24 ) engine running. Might try gong to the ECM for a better ground source. Later Brian

 

[Worthog]

I just calibrated my TPS to a percent value of full throttle and called it done. I grabbed a ground directly off of the ECU harness and my TPS voltage is within .05 of what Turbolink shows. It does say something in the documentation about having to use the ground when you're using the other inputs besides RPM.

Also, try using the soundcard method to calibrate your RPMs. Mine match Turbolink almost exactly.

I did have to run a wire directly to the 3-bar MAP sensor to get accurate boost, for some reason with the Turbolink boost sensing harness the voltage on the MAT line at the ECU was 2.26 volts at 1-bar (atmospheric) instead of the 1.6 volts at the sensor.

 

[Fuelie600]

Tomorrow, I am going to transfer the ground from body to ECM. I also recalibrated the rpm's from the sound card with little difference. The signal I'm picking up on is crank sensor high, and the LM1 programer is set at " crank 3 pulses per rev. " 6 cylinder----non waste spark. Later Brian

 

[Worthog]

I'm using the tach output from the connector just behind the alternator for mine, works like a charm.