Another “surging idle” problem

[07GtS197]

Not necessarily, as in my case, the voltage was too high. All I mean to say is different sensors will read differently, hence the need to adjust the blade sometimes.

That’s true but the point is you don’t need to get a certain value for closed throttle. Maybe some aftermarket sensors are scaled wrong so when they are at rest then read too high voltage for the ecu to be happy. On the other hand, that can also happen because the mounting point is fixed but the blade can be adjusted causing a different than stock reading when someone messes with the blade stop because they’re having issues. Most of these cars have probably had the throttle stop adjusted causing issues for the next owner.

 

[ttocs]

correct me if I am wrong but doesn't the ecu measure the voltage across the sensor while starting and sets that reading to its zero point/closed throttle? If this is correct is there an upper or lower limit that causes problems?

 

[95opal]

correct me if I am wrong but doesn't the ecu measure the voltage across the sensor while starting and sets that reading to its zero point/closed throttle? If this is correct is there an upper or lower limit that causes problems?

Above 1v and the ecm considers the throttle open.

 

[Terrorist 5.0]

That’s true but the point is you don’t need to get a certain value for closed throttle. Maybe some aftermarket sensors are scaled wrong so when they are at rest then read too high voltage for the ecu to be happy. On the other hand, that can also happen because the mounting point is fixed but the blade can be adjusted causing a different than stock reading when someone messes with the blade stop because they’re having issues. Most of these cars have probably had the throttle stop adjusted causing issues for the next owner.

Yeah there is no set value. Just in the ballpark. The Foxbody guys with their 0.9 something volts or it’s no good are just chasing their tails.

 

[Daryl]

.9 was the # on the YouTube vids I saw

 

[07GtS197]

Like Scott said the ecu uses the lowest value at key on as closed throttle but there is a range, something like .8v-1.1v. Out of that range and the ecu doesn’t know what to do. Then people start messing with either the sensor or throttle stop to fix this and cause more issues.

 

[96blak54]

I remember having to set the tps voltage by clocking the sensor when I swapped out to a bigger throttle body on my 1988 crown victoria 5.0l. Back them the obd1 wasnt as intelligent as the obd2 system. I also remember having to elongate the tps holes to clock the correct voltage.

 

[Daryl]

I remember having to set the tps voltage by clocking the sensor when I swapped out to a bigger throttle body on my 1988 crown victoria 5.0l. Back them the obd1 wasnt as intelligent as the obd2 system. I also remember having to elongate the tps holes to clock the correct voltage.

This was also eluded to in one of the YouTube videos

 

[95opal]

KOEO tps voltage should be above .53 and below 1.27 if that checks out you should be fine. You can also apply throttle as you take readings and look for a smooth linear increase. PCM considers WOT at 4.5

 

[1BadSVT]

Bear with me on this. Check the connection of all of your fuel injectors for a loose wire.

 

[ttocs]

I think if I were in that deep and disconnecting the plugs I might just have to take one out to see what it looks like. A pic of that can tell us a lot.