[Diy_efi] Problem with TPS on aftermarket ecu

[Ernest Buckler]

Damian,
Mostly I lurk and learn on this group, but on this subject I may have some 
relevant experience, since you are looking for a non-obvious answer (having 
covered all of those already, heh.)  A few years ago I was trouble-shooting 
some intermittent sensor wiring, and got it down to one wire.  Connectors 
were good on both ends, but still no continuity.  Frustrated, I broke that 
wire out of the bundle, expecting to find a hidden break, but nothing 
visible, argh!  Knowing that I was going to replace it anyway, I began 
cutting into it in segments and testing each section, until I reduced the 
non-continuous run to a span of a foot or so.  Then I stripped that section 
inch by inch - to find a clean break in the solid copper strand, a perfectly 
square cut, no damage visible even under magnification.  Meaning that it had 
been mfgd that way, difficult as it seems that would have been.  I can 
imagine that as-new continuity testing would have passed, since the ends 
touched.

Anyway, I send this not as a likelihood, but merely as citation of a very 
rare example.  So weird that I must proclaim my own present sanity [:oj and 
restate the factual nature of the tale; I was an instrumentation tech at 
Edwards AFB, so, while not an engineer by any stretch, I've got a pretty 
good grasp of the basics.  Meaning that I know how unusual such a 
discontinuity is.  But it did happen at least once.  Meaning that it could 
happen again, even tho I've never heard of anyone else finding such an 
anamoly:  Bad splices, loose crimps, hidden corrosion, yes, but never a 
clean square shear INSIDE undamaged & unmarked insulation.

Ernie B.




----- Original Message ----- 
From: "Damian Long" <bigcow_610 at yahoo.com.au>
To: <diy_efi at diy-efi.org>
Sent: Thursday, March 29, 2007 2:58 AM
Subject: [Diy_efi] Problem with TPS on aftermarket ecu


> Hello,
>
> gee its quiet in here.
>
> 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.
>
> thank you
>
> Damian
>
> Send instant messages to your online friends http://au.messenger.yahoo.com
> _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> Subscribe: http://lists.diy-efi.org/mailman/listinfo/diy_efi
> Main WWW page:  http://www.diy-efi.org/diy_efi
>
>
> -- 
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.446 / Virus Database: 268.18.20/736 - Release Date: 3/27/2007 
> 4:38 PM
>
>