What's the impedance range for a 2.5L TPS? (Page 1/1)
David Hambleton JAN 25, 09:08 PM
The FSM specifies voltages for checking a TPS while installed - I think a smooth rate of impedance change might be a suitable bench check.
I have 2 that range from 1500 ohms to 7000 ohms as the lever is moved. I suspect they're both ok, but maybe there are acceptance values available...
pmbrunelle JAN 26, 12:32 AM
Sounds good. The precise value isn't important.

You can also measure between the pins at each end; based on your data, this should be a constant 8500 ohms or so, regardless of lever movement.
Blacktree JAN 26, 05:47 PM
I'm not sure what the spec is for resistance. But the important part is to have a smooth sweep. If there are any 'hiccups', that would indicate a bad spot in the resistor.
David Hambleton JAN 26, 06:41 PM
I was looking for the source of some erratic 84 SE 2.5L behaviour and was contemplating (among other things) the possibility of an uncooperative TPS. Didn't seem likely but...
Then I noticed lightning from under the rubber coil wire cap to the coil core as the throttle was opened quickly, and suspected the current was taking the path of least resistance.
The path of least resistance shouldn't be there, so I looked a little further. The pic is the distributor cap with the coil wire post exposed. I stopped looking for the problem, lol!



Anyway, it's easier to check for a smooth resistance change than a voltage check if the TPS isn't installed; I suspect my investigation provided the range since the engine is ok now...
theogre JAN 27, 12:06 AM
Above happens when Water and whatever crap it carries runs down wires under dist boots and/or work up between towers and boots.
Can coat the tower "pins" and inside of boots w/ silicon grease.
A Thin coat is enough. Do not fill boots on wires on either end or ends can pushed off as grease expanse w/ heat.

As for topic...
Total TPS resistance can change between batches etc at factory.
It doesn't matter because ECM sees volt out on the wiper.
total = 5000 10000 even more still output same volts on wiper as wiper moves.
The pot is just variable Voltage Divider.

Like Blacktree said...
look for drop outs.
But don't bother taking it out...
Key on Engine Not Running
Back prob to Connect volt meter ground and wiper and slowly turn throttle open.
Is easier w/ analog meter or digital w/ "analog bar." Cheap meters are slow to display and make this harder and often fake bad TSP.
Note that wiper Doesn't reach 0 or 5v. Idle ~ 1.2v WOT maybe ~ 4v (Not digging thru note right now.)

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