The Diesel Stop banner

1 - 8 of 8 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
My gf has a 97’ 7.3 and we keep having a problem with the throttle response. I can push the pedal down at the very slightest and the rpms will jump up to about 1000 or so. Could it be the TPS that needs to be changed out?
 

·
Super Moderator
Joined
·
25,204 Posts
That could be the problem. You can unplug the Accelerator Pedal and check with an ohmmeter. The resistance of the potentiometer should change smoothly as you push the pedal down. If it's jumpy, you can probably conclude that it needs to be changed.
 

·
Registered
Joined
·
1,772 Posts
Mine has the opposite behavior: ForScan mobile shows the TPS/APP increasing smoothly as I press the pedal slowly to ~23% before there's any change in RPM.
 

·
Super Moderator
Joined
·
25,204 Posts
Mine has the opposite behavior: ForScan mobile shows the TPS/APP increasing smoothly as I press the pedal slowly to ~23% before there's any change in RPM.
That's the point where the Idle Validation Switch changes state. Until it does, the APPS has no effect on RPM. That's normal.
If you monitor IVS at the same time, you'll see the switch point at the same time the RPM's start to rise.
 

·
Registered
Joined
·
1,772 Posts
Is it possible to adjust the IVS position so it's closer to the bottom of the pedal travel? Is it possible the OP's symptom also has something to do with the IVS/APP relationship?
 

·
Registered
Joined
·
10,578 Posts
It could, probably more in your case than the OP's. It can be adjusted by bending the tab (I think) so the IVS closes a bit sooner in your case. Using some electrical contact cleaner while cycling the switches may help with operation, although I would probably be on the safe side and disconnect the IVS and TPS (APPS) before doing that. Cheers!
 

·
Registered
Joined
·
6 Posts
Discussion Starter #7
That could be the problem. You can unplug the Accelerator Pedal and check with an ohmmeter. The resistance of the potentiometer should change smoothly as you push the pedal down. If it's jumpy, you can probably conclude that it needs to be changed.
Awesome, thank you very much for the help. So if I test the resistance through the pressing of the pedal, what readings should I get from barely pressing it to fully depressing it
 

·
Registered
Joined
·
10,578 Posts
You would probably be checking more for a smooth change when depressing the pedal. The service manual doesn't show resistance they use a voltage curve. See the attached for tests you can do. The graph in the introduction will probably be the most useful and you would probably have to backprobe the AP wires to measure the voltage (unless you have a scanner and can access the PID. Cheers!
 

Attachments

1 - 8 of 8 Posts
Top