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Hacking up Honda's ECU
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 Post subject: 100% tps
PostPosted: Thu Aug 10, 2017 2:56 am 
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Hey guys newbie here.

My situation is this. I'm tuning with Crome gold. I have not even been able to get the car to idle. I believe my problem may start with the tps reading at 100% at startup. The value never changes. The voltages appear to be within spec though. Any help would be great.
Thanks


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 Post subject: Re: 100% tps
PostPosted: Thu Aug 10, 2017 12:38 pm 
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Location: chicago burbs
so datalogging shows 100% at all times or just a startup and after starting it works normally?

if only at startup and normal running it works fine:
I'd be checking your grounds, trans to chassis, chassis to battery and ECU ground at thermostat.

if it reads 100% all the time and a meter shows the right voltage, you have a broken connection between the measurement point and the ECU.


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 Post subject: Re: 100% tps
PostPosted: Fri Aug 11, 2017 2:09 am 
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I appreciate the quick response. It stays at a 100% even after start up. So I will take your advice and check all grounds as well as connections.


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 Post subject: Re: 100% tps
PostPosted: Fri Aug 11, 2017 12:52 pm 
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100% even after startup means way more than a grounding issue, likely the wire to the ECU is broken or not connected somehow.
double check the voltage at the ECU pin

is this a new swap or a setup that was working?


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 Post subject: Re: 100% tps
PostPosted: Sun Aug 13, 2017 2:15 am 
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Yeah z6 swap. Which I finally upgraded to obd1. So I figured I'd have some issues at some point. Could you point me in the direction of which pin I should be looking at. I know I'm asking a lot. Thanks :D

I did forget to mention it's an 89 hatch.


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 Post subject: Re: 100% tps
PostPosted: Sun Aug 13, 2017 10:59 pm 
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I guess I should have checked voltage earlier.I have 5v at c20 at idle. I also have 5v at the yellow wire at idle. I show continuity between c20 and yellow wire also. Which makes sense. The weird part is I found a pic on line of the plug and it kind of looks as though my plug wires orientation is wrong. Not sure though. I have included pics. And yes I have changed the tps. Please help guys. Thanks


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 Post subject: Re: 100% tps
PostPosted: Mon Aug 14, 2017 2:31 pm 
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Location: chicago burbs
this post says everything you'd need to know about the TPS:
https://honda-tech.com/forums/honda-crx ... d-2830131/


as far as the ECU side....
what voltage do you have on C11? (that is the TPS input to the ECU)
OBD1 pins to make sure we are referencing the same locations
http://b18c5eg.com/obd1.jpg

if you have 5V on C11 no matter the throttle position, then your ground is not connected
if you have 4.5v on C11 and the voltage changes with throttle position, then your 5V and ground are reversed (mentioned in the h-t thread)

just be careful moving wires around, the wire colors mean a lot less once you do a conversion.
Trace the pins on the sensor to the ECU, this is what matters.
It's possible that the sensor plug is wrong, it's also possible that the ODB0-OBD1 adapter is wrong, it's also possible that someone moved the pins in the OBD0 ECU Plugs so that the 'reversed' wires that the TPS are actually going to the right ECU pin.
Especially if this engine harness worked fine with your previously used OBD0 ECU.


[I hope all that makes sense]


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 Post subject: Re: 100% tps
PostPosted: Tue Aug 15, 2017 1:09 am 
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So I went ahead and reversed the wires at the tps plug. I now have 0% tps at idle which increases with opening the throttle. At least that's what the live data logging says. I will check those voltages when I have time. It does seem to run a little better. I'm still playing with startup milliseconds. At least now it idles. I will check those voltages though. Thanks


Last edited by 89hybrid on Tue Aug 15, 2017 2:39 am, edited 1 time in total.

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 Post subject: Re: 100% tps
PostPosted: Tue Aug 15, 2017 1:27 am 
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So after reading the tps link which you supplied. (Thanks)I believe my tps plug wiring was incorrect. The car started life as dpfi. Which explains the wires being backwards. I will still have to measure signal voltage at the plug, but It does read .18v at idle on the live data log which is low. Again I will check at plug when I have time.


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 Post subject: Re: 100% tps
PostPosted: Tue Aug 15, 2017 4:06 pm 
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I doubt there will be any noticeable difference at the plug, you will have to slot the mounting screws, loosen them and adjust the TPS sensor itself.
(mentioned briefly in the H-T link)


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 Post subject: Re: 100% tps
PostPosted: Wed Aug 23, 2017 1:27 am 
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Everything appears good now. I have adjusted tps to correct voltages. Now I have correct throttle percentages when closed and open also. I appreciate all the advice. Thank you very much. I am certain I will call upon your knowledge again though. I did though discover that the ground and 5v were in fact reversed. I believe this is a result of the original setup. My car was originally throttle body injection.


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 Post subject: Re: 100% tps
PostPosted: Thu Aug 24, 2017 12:05 pm 
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glad to hear it's working correctly now.
did it fix the idle issue?


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 Post subject: Re: 100% tps
PostPosted: Sat Sep 02, 2017 2:38 am 
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Sorry for such a delayed response. I'm working with another guy who has more experience. The problem we are having now is it doesn't seem to show a trace. I think that's the right term. What I mean is it doesn't move around on the table cells. A little history if I haven't mentioned it before. The car was originally an 89 base hatch. It was changed to port injection years ago using a placeracing harness conversion. I have since changed to obd1. I'm not sure if this may be the root of some of my issues. As always any help would be appreciated. I'm not sure how to answer your idle question. So let me see. When the car had the stock injectors in it responded to changes week. We then swapped in no name brand 650s and No matter what change was made it idled terribly. So we concluded the injectors must be crappy. So I bought some 750 RCs. Now on start up with me playing around it runs between 11.5 to 12.5 a/f and idles pretty ruff. My friend who has a lot more knowledge hasn't look at it since. Anyway still trying to figure out.


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 Post subject: Re: 100% tps
PostPosted: Mon Sep 11, 2017 4:28 pm 
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tables are MAP vacuum/pressure and engine RPM.
Do you have a MAP sensor issue or tach signal issue as well?

do you show sensor readings for other sensors? (ie is dataloging working)


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