1994 high idle
Thread Starter
Instructor
Joined: Nov 2004
Posts: 230
Likes: 1
You lucked out but I'd get the scanner for the next time. That way you practice with it so you are familiar. If I had that scanner, I'd see the IAC counts were 0 and be able to know that there is a leak somewhere otherwise I might be chasing a leak that doesn't exist. Just my $0.02
I tested the TPS and it's been so long I don't remember what the reading was but I do remember that there was no change in voltage.
Should be .5 @ idle and 5 volts WOT.
Anyway got a new TPS, installed it and checked for voltage.
it's 5 volts constantly.
I checked the ground and got a reading but with my meter set on beep mode it would not beep like it would to say the motor, so I ran another wire from the battery ground and tee'd it in to the existing TPS ground.
No change.
Installed another PCM because I have a spare from the time I took the car to the dealer and they had me buy one because they couldn't figure out the problem.
anyway any clues???
I have my FSM out and hopefully I'll find something
Team Owner
Joined: Jul 2004
Posts: 28,352
Likes: 3,253
From: Hartford WI
I'm back!! So very strange , the very next time I started the car the Idle was back up to 1800!?!?
I tested the TPS and it's been so long I don't remember what the reading was but I do remember that there was no change in voltage.
Should be .5 @ idle and 5 volts WOT. Anyway got a new TPS, installed it and checked for voltage. it's 5 volts constantly.
Installed another PCM because I have a spare from the time I took the car to the dealer
I tested the TPS and it's been so long I don't remember what the reading was but I do remember that there was no change in voltage.
Should be .5 @ idle and 5 volts WOT. Anyway got a new TPS, installed it and checked for voltage. it's 5 volts constantly.
Installed another PCM because I have a spare from the time I took the car to the dealer
Maybe you have 2 or 3 issues. Hard to say. Remember, the system is self correcting. That means that it will try it's best to get to what the ECM wants. FOR EXAMPLE, if the coolant is at -20 degrees, the ECM might decide it want to see 1000 rpm so it will try to achieve it. That you corrected the air leak means it takes a bit longer but it will prevail. Kinda why I suggested you get a scanner.Are you sure you are not probing the reference voltage wire? If you had a scanner, you can see what the ECM sees for a voltage which is kinda important.
Was the EPROM correct?
Thread Starter
Instructor
Joined: Nov 2004
Posts: 230
Likes: 1
Don't know what to say. There is no law in the universe to say you can only have 1 problem at a time. Maybe you have 2 or 3 issues. Hard to say. Remember, the system is self correcting. That means that it will try it's best to get to what the ECM wants. FOR EXAMPLE, if the coolant is at -20 degrees, the ECM might decide it want to see 1000 rpm so it will try to achieve it. That you corrected the air leak means it takes a bit longer but it will prevail. Kinda why I suggested you get a scanner.
Are you sure you are not probing the reference voltage wire? If you had a scanner, you can see what the ECM sees for a voltage which is kinda important.
Was the EPROM correct?
Maybe you have 2 or 3 issues. Hard to say. Remember, the system is self correcting. That means that it will try it's best to get to what the ECM wants. FOR EXAMPLE, if the coolant is at -20 degrees, the ECM might decide it want to see 1000 rpm so it will try to achieve it. That you corrected the air leak means it takes a bit longer but it will prevail. Kinda why I suggested you get a scanner.Are you sure you are not probing the reference voltage wire? If you had a scanner, you can see what the ECM sees for a voltage which is kinda important.
Was the EPROM correct?
One ground
one 5 volts
one 1500 mv
scanner huh???
Last edited by llesg; Jan 25, 2017 at 04:28 AM.
Team Owner
Joined: Jul 2004
Posts: 28,352
Likes: 3,253
From: Hartford WI
That sounds about right. There should be a 5V, a ground and another one that changes when you open the throttle to maybe mid 4V. That is the variable one. I haven't probed for eons anymore. I just hook up to a scanner and depress the pedal. It shows up there if you change to TPS voltage. Also gives you a percentage. So you might see 0% throttle angle and on the next screen 0.54V which is what the ECM sees.
Melting Slicks
Joined: Jan 2014
Posts: 2,478
Likes: 254
From: Downers Grove Illinois
