[Diy_efi] Problem with TPS on aftermarket ecu

Robert W Hughes rwhughe
Thu Mar 29 18:45:44 UTC 2007


> I have a problem with my TPS and I'm running out of ideas. Perhaps someone else on here knows whats going on.
> 
> The TPS is not reading correctly in the ecu. The ecu is a Walbro BIKE400. Probably haven't heard of it but thats not real important as it uses basically the same principals as most ecu's when it comes to TPS.
> 
> I have wired the TPS correctly. It is a standard GMH 3 wire TPS. +5v, GND, TPSsig.
> 
> The throttle movement is correct. I could calibrate the opening 0% and 100% without problems. In the datalogging software, the throttle movement works correctly. WOT logs 100% throttle etc. The problem is that the 'dthrottle' value does not change. It remains at 0 with the occasional movement to 1 or so. Just like little blips of interference (noise). Basically the ecu thinks that, although the throttle is moving, there is no change. The result is no accellerator enrichment. 
> 
> If anyone knows why it is doing this, it would be a great help.

> I have a problem with my TPS and I'm running out of ideas. Perhaps someone else on here knows whats going on.
> 
> The TPS is not reading correctly in the ecu. The ecu is a Walbro BIKE400. Probably haven't heard of it but thats not real important as it uses basically the same principals as most ecu's when it comes to TPS.
> 
> I have wired the TPS correctly. It is a standard GMH 3 wire TPS. +5v, GND, TPSsig.
> 
> The throttle movement is correct. I could calibrate the opening 0% and 100% without problems. In the datalogging software, the throttle movement works correctly. WOT logs 100% throttle etc. The problem is that the 'dthrottle' value does not change. It remains at 0 with the occasional movement to 1 or so. Just like little blips of interference (noise). Basically the ecu thinks that, although the throttle is moving, there is no change. The result is no accellerator enrichment. 
> 
> If anyone knows why it is doing this, it would be a great help.

The simplest explanation is that TPSSig is either not connected or 
poorly connected to the ECU.
-- 
Robert W. Hughes (Bob)
BackYard Engineering
29:40.237N, 95:28.726W or perhaps 30:55.265N, 95:20.590W
Houston, Texas "The city with too much Oxygen"
rwhughe at oplink.net




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