tps problem

matthunter1448 · Post by **matthunter1448** » Wed Jun 08, 2016 7:12 pm

so i have a tps problem i have tested all the wiring and it is all good as well with the sensor.
what happens is it shows 18% when i start the car and wont change with throttle movement. It has a voltage of .82 on the signal wire( even with it disconnected from the tps sensor.)
it sometimes goes away when the car is running and then the tps magically works fine like it's supposed to
i don't have any issues with any other sensors
i have tested it on the stim and it works fine on it but just not when i plug it in to the car plug
wondering if anybody can help please
i am using a 3.0 board with ms3x i built all of it and have looked over everything and can't seem to find any problems
t

billr · Post by **billr** » Wed Jun 08, 2016 9:18 pm

It is likely that something is wrong with the wiring or sensor, despite your testing. I believe people can "see" things the way they know they are supposed to be, not the way they actually are; so repeated checking/testing is useless. You either need to get somebody else to check it, or walk away for a week or two and check again with "fresh eyes".

matthunter1448 · Post by **matthunter1448** » Wed Jun 08, 2016 9:21 pm

I don't think so. I cut the signal wire. Going to the tps just to be sure and it's still has voltage. On the megasquirt side of the wire. And I've triple checked it. And it works off and on which is baffling to me

Sent from my SM-N920T using Tapatalk

DaveEFI · Post by **DaveEFI** » Thu Jun 09, 2016 1:51 am

I'd probe the output from the tps while connected normally, and measure the voltage to ground. It should rise smoothly as you open the throttle. You don't need to run the engine for this.

matthunter1448 · Post by **matthunter1448** » Thu Jun 09, 2016 6:33 am

I have. When it is working it works like it's supposed to. When is stuck it's at a direct .82 volts

Sent from my SM-N920T using Tapatalk

billr · Post by **billr** » Thu Jun 09, 2016 6:55 am

I would expect some voltage reading at the MS TPS input pin when the TPS is disconnected. That doesn't prove anything. The fact that the TPS responds OK with a Stim, but not on the car, is a huge hint that you gotta be open to the possibility that you may be making a mistake in you checking/testing.

matthunter1448 · Post by **matthunter1448** » Thu Jun 09, 2016 6:59 am

It shows the same connected as well when this is happening

Sent from my SM-N920T using Tapatalk

matthunter1448 · Post by **matthunter1448** » Thu Jun 09, 2016 7:16 am

I look at it again tonight. It has me stumped but I'll start from the top again and see what I can figure out

Sent from my SM-N920T using Tapatalk

DaveEFI · Post by **DaveEFI** » Thu Jun 09, 2016 7:51 am

matthunter1448 wrote:I have. When it is working it works like it's supposed to. When is stuck it's at a direct .82 volts

Sent from my SM-N920T using Tapatalk

In the stuck condition, did you check 5v and ground were present too? That very low reading suggests a short somewhere.

matthunter1448 · Post by **matthunter1448** » Thu Jun 09, 2016 9:24 am

DaveEFI wrote:
matthunter1448 wrote:I have. When it is working it works like it's supposed to. When is stuck it's at a direct .82 volts

Sent from my SM-N920T using Tapatalk
In the stuck condition, did you check 5v and ground were present too? That very low reading suggests a short somewhere.

I did check both. They have both

Sent from my SM-N920T using Tapatalk

Megasquirt Support Forum (MSEXTRA)

tps problem

tps problem

Re: tps problem

Re: tps problem

Re: tps problem

Re: tps problem

Re: tps problem

Re: tps problem

Re: tps problem

Re: tps problem

Re: tps problem