air charge temp sensor

[greaseyfingers]

when my ranger's 2.9 engine is cold, it idles at 1300 rpm's, unless I unplug the air charge temp sensor... then the idle will come down to, approximately, 900 to 950 rpms...

if I don't unplug the air charge temp sensor, after the engine has warmed up, the idle will, usually, drop down, by itself, to 900 to 950 rpms, if the engine has had a chance to run for, at least, 15 minutes...

sometimes, the idle won't drop down, by itself, after the engine has warmed up, even if it has had a chance to run for, at least, 15 minutes... unless, I turn the ignition key off, re-start the engine, immediately, and then within a couple of minutes, the idle will, usually, drop down 900 to 950 rpms...

what do you think is causing my ranger's engine idle problem, as I've described... anyone have any good ideas...

I've, already, tried using a new air charge temp sensor... thinking that would correct the problem... but, the engine's high idle problem reacted the same way, as before...

I've, also, replaced the engine's coolant temp sensor, and the 02 sensor, with new ones... replaced the tps sensor, map sensor, and all of the other sensors, with used ones...

I've checked for vacuum leaks, too... and there are none, anywhere, that I've been able to detect...

do you think the new air charge temp sensor, I tried, was faulty... or, do you think there is something else, that is causing my ranger's engine to idle too high...

I noticed my fm 145 transmission's sensor, that is located on top of the transmission, just in front of the shifter, has two wires that are broken off, at the very base assembly of this sensor... it was like this, already, when I got my ranger, from a previous owner...

is that sensor, a neutral sensing switch sensor, or a vehicle speed sensor... do you think that could be causing my engine's high idle problem, by the wires being broken off, this sensor, making it inoperational for whatever purpose it was designed for...

 

[IMenriched]

Others Im sure will confirm that if there is a missing return signal to the engine computer, (weather it is engine or transmission), it will give it the opertunity to give out misguided information back to the managing componets.

you could simply have a sticky throttle cable, seems that you have tried/tested everything eles, and with all your new sensors in place it maybe time for a tune up and timiming adjustment.

the only other item that isn't listed is the AIC (passanger side uppertake), which directly controls the idle...if it is abit sticky it also can give high/erratic idle. This maybe one of the componets that fall under used in your list of things replaced.

remove and spray with good carb cleaner, let dry and replace.

do you have cruise control?? did you check it for vacuum leaks?

 

[Jspafford]

The switch on the transmission tells the ECU that the truck is in neutral. I supposed it could cause the problem. Why not just scotch lock the wires back together and see what happens.

If the sensor had no purpose, they wouldn't have put it there to begin with.

 

[greaseyfingers]

Others Im sure will confirm that if there is a missing return signal to the engine computer, (weather it is engine or transmission), it will give it the opertunity to give out misguided information back to the managing componets.

you could simply have a sticky throttle cable, seems that you have tried/tested everything eles, and with all your new sensors in place it maybe time for a tune up and timiming adjustment.

the only other item that isn't listed is the AIC (passanger side uppertake), which directly controls the idle...if it is abit sticky it also can give high/erratic idle. This maybe one of the componets that fall under used in your list of things replaced.

remove and spray with good carb cleaner, let dry and replace.

do you have cruise control?? did you check it for vacuum leaks?

I've, also, replaced the AIC, which I forgot to mention... a ford mechanic thought that was the cause of my engine's high idle... but, replacing the AIC didn't help, as the ford mechanic thought it would...

my throttle cable doesn't seem to be sticking, either...

I don't have cruise control... however, the wires to my transmission's neutral sensor have been broken off, ever since I've bought my ranger, from the previous owner...

I'd solder them together, but these wires are broken off, right where they come out of the neutral sensor assembly, itself... unless I can, some how, tap some small screws into the base of the neutral sensor, itself, where the wires are broken off and attach the neutral sensor wires to these small screws...

I have new bosch platinum plugs, and new autolite plug wires...

the engine timing sounds like it's pretty close, starts easy, revs quick, and doesn't ping any under heavy acceleration...

 

[greaseyfingers]

The switch on the transmission tells the ECU that the truck is in neutral. I supposed it could cause the problem. Why not just scotch lock the wires back together and see what happens.

If the sensor had no purpose, they wouldn't have put it there to begin with.

the wires to my transmission's neutral sensor have been broken off, ever since I've bought my ranger, from the previous owner...

I'd solder them together, but these wires are broken off, right where they come out of the neutral sensor assembly, itself... unless I can, some how, tap some small screws into the base of the neutral sensor, itself, where the wires are broken off and attach the neutral sensor wires to these small screws...

some people I've talked to, don't think the transmission's neutral sensor is causing my engine's high idle problem...

but who knows, maybe, it is... as you said, if the sensor had no purpose, they wouldn't have put it there, to begin with...

thanks for your input... I think your opinion might be right, as I've been kinda thinking there must be a reason for this neutral sensing senor, too, as you mentioned... which might be the cause my engine's high idle problem, when this sensor isn't being utilized for sending information to my vehicle's computer management system...

 

[greaseyfingers]

The switch on the transmission tells the ECU that the truck is in neutral. I supposed it could cause the problem. Why not just scotch lock the wires back together and see what happens.

If the sensor had no purpose, they wouldn't have put it there to begin with.

the wires to my transmission's neutral sensor have been broken off, ever since I've bought my ranger, from the previous owner...

I'd solder them back together, or scotch lock them, as you mentioned I should...

however, I can't, these wires are broken off, right where they come out of the neutral sensor assembly, itself... unless I can, some how, tap some small screws into the base of the neutral sensor, itself, where the wires are broken off and attach the neutral sensor wires to these small screws...

some people I've talked to, don't think the transmission's neutral sensor is causing my engine's high idle problem...

but, who knows, maybe, it is... as you said, if the sensor had no purpose, they wouldn't have put it there, to begin with...

thanks for your input... I think your opinion might be right, as I've been kinda thinking there must be a reason for this neutral sensing senor, too, as you mentioned...

which might be the cause of my engine's high idle problem, when this sensor isn't being utilized for sending information back to my vehicle's computer management system...