I think my engine is running a higher idle than it should be...it runs around 900-1,000 rpm,I'd like to know if that's adjustable or not..I'm not quite sure what it should idle at but it seems a little high...doesn't surge or any other issues just seems to idle a bit high.


Thanks

JC

 

Idle is not adjustable. It is controlled by the IAC (idle air control valve). Appears yours may not be working, or may be disconnected. A disconnected will idle faster than the usual idle, which on my 93 3.0 liter V-6 is about 700 rpm. You can search this forum for test procedures, or do a Google search (for example, "ford ranger test idle air valve"), or find a Chilton's or Haynes manual. On my V-6 it is attached to the fuel injection throttle body.

 

Thanks for the reply..I'll do a search for that and test procedures..much appreciated.


JC

 

Is the engine temp sensor in good working order? You have two, one for the guage cluster (single wire harness) and the second is used by the ECU to adjust the idle as pw2buz mentions with the idle air controller. If this temp sensor is not working, the ECU may think the engine is still "cold", and will keep the idle high.

 

Both sensors seem to be working...gauge on dash seems to be working ok stays right in the middle and doesn't jump around at all...is their a test procedure or resistance check I can do on these? I did pull the IAC off and cleaned it but really didn't drop down the idle much still right around 900-1000,although I haven't really driven it very far so am not ure after its cleaned if it needs to re-learn or not. At almost $90 for an IAC I'd like to be sure if that's what it is or not.

JC

 

The dash gauge reads off a different sensor. On my 3.0 liter V-6 (93 Ranger) the one used by the PCM (power control module) is next to the housing for the thermostat and has a connector for two or more wires. The temp. gauge sensor is nearby (I forget where) and has only a single wire. Test procedures for the first (PCM) sensor should be in Haynes or Chilton manuals.

If you unscrew the sensor, be careful to not break the plastic part at its top, to which the multi-wire connector attaches. It is rather fragile!

 

Not sure of a test for the PCM/ECU, but the guage cluster can be checked (sort of) by removing the single wire connector. With the key "on", the guage should be at the cold mark. Ground the wire, and the guage will read full hot. This lets you know that the cluster guage is good, along with its wiring.

If the sensors are old, it would not hurt to replace them both. They are only 10 to 15 bucks each. As it has been mentioned in other threads, do not use any type of tape sealer on the bottom of the sensor threads; they require a good ground contact. You can place a small wrap of tape sealer at the top of the sensor threads.

 

On my 96 3.0 there is a screw on the throttle linkage that when turned clockwise opens the throttle plate enough to increase RPMs. What is that adjustment screw called?

 

Does anyone know if the procedure for the 2.9L is also used on the 3.0? There is a sticky thread at the top of the TRS 2.9L forum. It involves disconnecting the IAC connector and setting the idle quite low using the stop screw for the TB butterfly. From that point the EEC uses the IAC to let in more air and adjust the idle.

Did your idle recently change? If so there is probably something else that needs to be fixed. Changing the idle by messing with the stop screw only makes sense if you think a previous owner messed with it.

 

That may primarily be to take up slack as the cable stretches. Is there also a stop screw for the butterfly?

 

Sorry, submitted twice by accident.