New High Idle when Warm Problem (2 Viewers)

[Malleus]

I've been staring at the same cable appearance for years, wondering when it was going to give me trouble...

 

[davesax36]

So how much gap should there be between the TPS screw and the stop plate at idle? I'm working on crazy idle issues ranging from 800-1800 in P and 650 (YAY) and 1000 in D. A pic of someone's 80 idling would be awesome. I'll do the TPS feeler gauge check thing, of course. When the FSM says, "apply vacuum to the TPS" does it just mean open the throttle? I don't see any vac hose coming out of the TPS. I've made bonehead mistakes before, though, so there's that.

 

[mudgudgeon]

I've just picked up a new to me 93 FZJ80, idle when at running temp was at around 1100rpm, barely changes when AC cycles on/off

@BILT4ME did new throttle cable fix this for you? or something else?

@CJF from your comment, sounds like its likely to be something mechanical related to the throttle plate position?

 

[BILT4ME]

I've just picked up a new to me 93 FZJ80, idle when at running temp was at around 1100rpm, barely changes when AC cycles on/off

@BILT4ME did new throttle cable fix this for you? or something else?

@CJF from your comment, sounds like its likely to be something mechanical related to the throttle plate position?

I haven't installed it yet. Still having intermittent high idle. Each time I can open the hood and pull toward the DS and it will drop the idle back down for a number of cycles.

 

[mudgudgeon]

Checked out my throttle cable/throttle body tonight.
Throttle cable had too much tension on it. I've backed it off so it has just a touch of slack in it, but not enough to feel it through the gas pedal.
Will see how it goes.

 

[Tools R Us]

Checked out my throttle cable/throttle body tonight.
Throttle cable had too much tension on it. I've backed it off so it has just a touch of slack in it, but not enough to feel it through the gas pedal.
Will see how it goes.

Proper throttle cable adjustment should be done at WOT. Pull the wadded floor mats, gummy bears, etc, out from under the pedal, confirm it goes all of the way to the stop. Under the hood, slack the adjustment nuts on the cable, have a helper hold the pedal to the floor. Under the hood, pull out on the cable sheath, adjust the nuts so the throttle plate just touches the WOT stop.

If the WOT stop is adjusted to primarily using the stop at the throttle body, this is a leading cause of cable wear/stretch, etc. There needs to be cable play at idle, the amount is irrelevant. Occasionally lubing the cable is helpful to life, our favorite is silicone dry slide. Disconnect the cable at the throttle body, remove the dust boot, hold the cable vertical, spray, work the cable in and out, repeat. Have recovered several slightly sticky cables this way and anytime we are working on the cables, always lube them.

 

[davesax36]

Does anyone else's pedal seem like it hits the floor/carpet really fast? Almost like the tunnel is too wide. Also, I'm new at this, so be kind if this is totally normal.

 

[mudgudgeon]

Proper throttle cable adjustment should be done at WOT. Pull the wadded floor mats, gummy bears, etc, out from under the pedal, confirm it goes all of the way to the stop. Under the hood, slack the adjustment nuts on the cable, have a helper hold the pedal to the floor. Under the hood, pull out on the cable sheath, adjust the nuts so the throttle plate just touches the WOT stop.

If the WOT stop is adjusted to primarily using the stop at the throttle body, this is a leading cause of cable wear/stretch, etc. There needs to be cable play at idle, the amount is irrelevant. Occasionally lubing the cable is helpful to life, our favorite is silicone dry slide. Disconnect the cable at the throttle body, remove the dust boot, hold the cable vertical, spray, work the cable in and out, repeat. Have recovered several slightly sticky cables this way and anytime we are working on the cables, always lube them.

Thanks for the tip, I'll have another look at it when I have more time.

A tip for you, use graphite powder for lubricating cables, it's slippery AF, and 100% dry, so it won't pick up dust at all.

 

[Tools R Us]

Thanks for the tip, I'll have another look at it when I have more time.

A tip for you, use graphite powder for lubricating cables, it's slippery AF, and 100% dry, so it won't pick up dust at all.

Graphite powder depending on where it's used, can work as a lube or abrasive, have had problems with it. Also, silicone, soaks, travels farther down the cable, the "dry" version doesn't collect dust, overall have had better results with it. The "dry" version comes in a liquid carrier, that quickly evaporates.

 

[ajax1]

So how much gap should there be between the TPS screw and the stop plate at idle? I'm working on crazy idle issues ranging from 800-1800 in P and 650 (YAY) and 1000 in D. A pic of someone's 80 idling would be awesome. I'll do the TPS feeler gauge check thing, of course. When the FSM says, "apply vacuum to the TPS" does it just mean open the throttle? I don't see any vac hose coming out of the TPS. I've made bonehead mistakes before, though, so there's that.

If you pull iac valve off you will see a vacuum line going to the tps billow where the set screw is, line is about 2inches long

 

[Bleu62]

I had a very similar issue with my cruiser. I tested the throttle position sensor iaw the fsm and it was the culprit. $60 fix. FSM is priceless