exploder idle issues

[85ranger302]

i have a 92 exploder and last wed i pulled off the maf, throttle body, and iac and cleaned them all real good. ever since last thu the motor idles at 1100-1300 rpm. ive already checked for vacuum leaks and cant find any, anyone else got suggestions on where and what else to check?

 

[88_ranger]

High Idle

Did you by chance remove the Throttle Postion Sensor off the side of the throttle body when you were cleaning it? It sounds like you may have removed it and not positioned it correctly when you reinstalled it. I had the very same issue with my 88 Ranger and adjusting the TPS fixed the high idle.

 

[85ranger302]

no, i left the tps on while i cleaned the tb, could it be possible that carb cleaner got inside it and fried it? cause the only other thing i can figure is that the iac may be bad, but it ran fine after i cleaned it until i got off work the next day

 

[88_ranger]

I don't see Carb cleaner hurting anything on the iac as long as you didn't spray it on the electrical side of it.

 

[85ranger302]

i didnt and ive cleaned the iac twice now, no change. this is really irritating me cause it ran awesome right after i cleaned everything but has been idling hight since i got off work last thursday, and i havent figured it out yet. i did get three codes last night when i scanned it with the KOER test, gave me dtc 411, 412, and 538, you think they might be related?

 

[bronco_lou]

pull the codes and see it the tps is the problem or something else, I cleaned my MAF with vinegar and what a difference it made, no more hesitation.

Louis

 

[adsm08]

This happened to me once. I dunno that it's your problem, but my issue was that my TB had been so gunked up for so long that the computer had learned to deal with it by opening the IAC further. I went and removed the gunk and the computer didn't adjust very well. I had to go and manually reset my idle speed.

 

[85ranger302]

might be my problem too cause my tb was pretty nasty, just disconnected my battery, gonna see if that does anything

 

[85ranger302]

well i just had my battery disconnected for around an hour and didnt do anything.

This happened to me once. I dunno that it's your problem, but my issue was that my TB had been so gunked up for so long that the computer had learned to deal with it by opening the IAC further. I went and removed the gunk and the computer didn't adjust very well. I had to go and manually reset my idle speed.

how do i manually reset my idle speed?

 

[adsm08]

I'll have to look it up at work on monday. I don't have access to manuals that old from home.

 

[85ranger302]

ok, thanx any help is appreciated

 

[85ranger302]

ok, so i was told by a local shop that my exploder was idling so high cause the intake gaskets were leaking and i just got done changing the water pump, upper and lower intake and the valve cover gaskets. and its still acting the same. one other thing its been doin is when im coming to a stop the motor idles at about 1200 and after i stop and the truck rocks backward from the braking motion idle goes down to 1000. anyone ever seen that before?

 

[xr75er]

Don't buy that till you check it yourself. Take some carb cleaner and slowly spray around the intake gaskets and ALL of the vacuum lines. If it changes idle then you have a leak. Take the air inlet tube off and look at / cover the iac inlet hole. If the idle drops it's the iac. As stated earlier the computer has reprogrammed due to the gunk build up. But it sounds like a vacuum leak to me.

 

[85ranger302]

well i put a new iac on the truck and already changed all those gaskets cause they were leaking anyway. and i sprayed all of the vacuum lines and couldnt find one that was leaking. when i unplug the iac and start the motor it starts and idles at 1000 till you plug the iac back in then it jumps to 1200. and like i said when i come to a stop the idle drops to 1000 rpm, and ive never seen anything do that before

 

[85ranger302]

how many different causes are there for this engine to idle high? power steering pump goin out wouldnt do that would it?

 

[AgPete139]

Hm.

• You could get a volmeter and make sure your TPS is at ~.90 - .99? (What you do is get 2 small pins, stick them in the TPS wires, and measure them with your multimeter device. Idle should be around .90 - .99 volts while WOT is going to be well over 4.00 volts.)

Also...

• Did you pull the automotive trouble codes yet?

So, I just thought about these:

• Could it even be oxygen sensors?
• Is it getting really cold where you are, and the motor is compensating?
• If you are absolutely sure there are no gasket leaks, and your vacuum lines are all hooked up, have you considered fuel?

We'll try and get you straightened out. :icon_thumby:



Pete

 

[85ranger302]

i replaced the tps, i pulled codes and all i got was dtc412 which is cannot control engine rpm during koer high rpm test, at one point i got 411 which is cannot control engine rpm during koer low rpm test, and 538 which is three codes in one, insufficient rpm change during koer dynamic response test, unvalid cylinder balance test due to throttle movement during test, and invalid cylinder balance test due to cid circuit failure. and i replaced the o2 sensor when i swapped out the transmission. i also know that the fuel pump sender needs to be replaced though cause my gas gauge is even more untrustworthy than they usually are. and i did the upper and lower intake gaskets about two months or so ago. and this is confusing the hell outta me

 

[85ranger302]

ok so now that it is getting colder my motor is pulling itself up to like 3000 rpm in park sometimes, but not till it reaches operating temp, and its really confusing me now

 

[84bluebronco2]

I wish i could tell you something but my 4.0 just seems to stall immediately after starting rather infrequently. Good luck and hope you get it sorted very soon!

 

[85ranger302]

yeah me too, its really confusing the hell outta me