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Old 08-23-2005 | 07:53 PM
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lugebob
 
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From: Waldorf, MD
Default Troubleshooting throttle circuit. Lets compare notes

I am try to troubleshoot an intermittent "RC-OFF" conditions, that I think is being caused by my un-conventional throttle circuit on the Jet powered streetluge. Occasionally, when I let the throttle off quickly while traveling at speeds over 70 mph the P200 flames out. I was able to keep the ECU alive long enough to get back to the pit area a few times and each time the reason was RC-OFF. I have moved wires and banged things around trying to simulate road vibration with it running to see if maybe I had some loose wires or connections, but could not cause the condition. I am beginning to suspect the mechanical to electrical interface that controls the Pulses in to the ECU. Perhaps I do not have enough throttle range (min to max), causing it to be extra sensitive, although it seems like I have plenty.

Short description of circuit- Throttle cable pulls on a spring loaded Throttle Pot (potentiometer 0-500 ohms). Trim switch, switches in a 100 ohm resistor in series to the throttle pot. This feeds a PIC's chip programmed to make very stable pulses (simulates RC Receiver) that feeds the ECU (Jet Cat Version 5.0 )

Here are the numbers I get when doing the Learn RC procedure

Throttle @ minimum =683 to 688 (varies slightly due to mechanical slop returning throttle to minimum)
Trim @ Maximum = 794
Throttle @ Maximum= 1232

My assumption is that when I released the throttle, that the count would have to go below 794 to get an RC-Off condition

Throttle action seems to produce a steady up or down count as I move it throughout the range.

What numbers do you get? is there a norm? I dont think it matters what engine it is, just the ECU and Receiver combo

Thanks in advance for your help.

Bob

If you've missed it, I posted a link to the video of the drag race run from this weekend in the other thread and one of J34 powered jet cars

[link=http://www.jetluge.net/video.html/jetlugedragrace.wmv]Jet Luge Drag Race.[/link]