Id like to preface this by saying that im not a mechanic, I do mechanic work because I can literally turn a wrench and I'm familiar with the complex orchestra of physics that bring an internal combustion engine to life, but im not a mechanic by any means. I have no training and am not good with diagnostics or just about anything electrical


As the title says, I changed the clutch in my dads 2000 2wd 2.5 manual ranger and now it idles a bit high. Its the bargain bin utility model which doesnt have a tach so I had to use my scan tool to read the rpm.

During the clutch job I also removed a disconnected subwoofer cable from the + battery clamp. I changed the tranny fluid(obviously). I changed the clutch master and slave cyls. I disconnected the downstream o2 sensor(and reconnected it). I removed the egr valve and pipe(to more easily access the two trans to engine bolts on the top of the transmission). I checked the air filter(it was good). I mention this so that you know everything that has been done since the engine was previously running fine, even though im sure most of it is irrelevant at least you know I didnt leave anything out(unless im forgetting something)

So far I've checked/tried:

tested brake booster for vacuum leaks by pinching off hose.

Changed egr gasket in case it was causing vacuum leaks.

disconnecting iacv electrical connector.

disconnecting tps electrical sensor.

shaking the pcv valve(it rattles) and pinching off pcv hose to test for leaks.

checked the dipstick for vacuum leaks.

Double checked air filter housing was closed correctly.

double checked for electrical connectors I may have unplugged during clutch job.

crossing my fingers

Inspected throttle body to make sure it closed all the way and wasnt getting hung up on the pedal or something.

and just checking any suspicious vacuum hose for leaks


If I think of anything else I'll post it

Any help on this would be great 👍

 

Welcome to the forum

Well not sure how separating transmission would cause high idle but it has

Your testing makes a lot of sense, good job

An Engine is an air pump, if you give it more fuel you get a flooded engine, if you give it more air you get higher RPMs

And its not an electrical problem, for sure

So with the IAC Valve unplugged(no power) RPMs don't change?

Above 2,500rpm would mean a pretty big vacuum leak

There is the PCV Valve and its hose under the intake, not sure how it would get disconnected by doing the clutch, but its the same size vacuum hose as on the brake booster, so could certainly cause very high idle

Have a look here: https://www.ranger-forums.com/genera...-valve-112336/

2.5l is disassembled but you should be able to get location
The 1st picture is the PCV Valve
2nd picture is the intake with brake booster hose and then PCV Valve hose attach to underside at the bottom of picture

 

Well the trucks battery is dead(probably from starting it over and over again all day yesterday). So I didmt get a chance to test anything else. However I did take off the iacv and i did notice that its wide open, I dont know if its supposed to be wide open when off the vehicle and not receiving voltage but I thought I should mention it. When the battery has charge again in going to try starting it with the iacv removed and the holes where it mounts blocked off. I figure if it has a low idle in this state then the iacv may be to blame and if the problem persists then it should rule out the iacv as the source

 

So I started the truck up with the iacv blocked off and the truck idled at about 1200 for a while then slowly dropped to about 650 as it warmed up and then after 10 minutes of idling it stalled out. Am I correct in assuming that the iacv was the cause of the high idle in this case? Was it just stuck open?

 

Yes

IAC Valve should be closed when unplugged, there is a spring inside that should push it closed with no power applied, its internal, can't be seen

 

good I hope thats the problem.
I just went to autozone to buy a worthless *** duralast iacv. If it fixes the problem then I'll order a motorcraft iacv off Amazon but for the meantime I need my dads truck outta my driveway lol.