So today I was out pulling the plugs off each sensor and then starting the engine to see what happens. I'm trying to determine if there is any change in the way my engine is currently running in association with a possible bad sensor. I got to the IACV and pulled the plug and started the engine. The engine ran normal like it has been for the last few months. The idle was a bit high as normal. Now correct me if I'm wrong but should the engine even be idling without the IACV. I removed the IACV and watched it atuate in and out while I turned the key. This part is the only part I can think of why my engine will not idle at normal operating temperature. But it moves in and out like it should. The only thing that makes me question it is my engine ran the same with it connected to power and without. Any thoughts?

 

isnt the IACV the one that has the super important positions to it. Im not describing it right, but i thought i read a while ago that if the IACV wasn't set to the right depth at idle or something that it would completely throw your **** out of whack. Like it needs to be zeroed essentially, so if you're pulling it out and watching it move it's def fubar'd now. because it has a default position that is important to its operation.

Fact or fiction?

 

now about those snorkels....

 

Yes. But when you install it, you can 'zero' it manually. I'll have to pull up the info for here.

 

The IACV is basically a computer stepper controlled vacuum leak. When not working, usually they cause vehicle to crank and idle high. I went through replacing several, and finally replaced ECU, and it worked. Not sure if my old ECU just could not re-learn the replaced sensor. And what's worse, I believe it (IACV) may actually be shared with a Jeep model.

Also - the coolant temp sensor, the one monitored by the ECU, not the single wire gauge sensor, it is used by the ECU to determine changing the injector timing (pulse width, not relationshiip to piston position) when warmed up to adjust fuel flow. When unplugged, mine makes the scanner read -40 degrees. Might be something to check, as well as fuel temp sensor. If no scanner, unplug and check for change? Or measure resistance both cold and warmed up, to see if sensors are actually changing. Not sure if RAVE has expected values.

 

Below was taken from the RAVE. I thought the IACV was normally closed, but it appears that the ECM opens the IACV at engine shutdown. So if you install a new IACV, you should be able to(theoretically) open the IACV by:
1. unplugging the IAVC
2. turning on the power(without starting the engine)
3. plugging in the IACV
4. Turning off the power
5. repeat until you feel the IACV is fully open.

Main relay

The main relay supplies the power feed to the ECM
with a tap off to feed the fuel injectors (8 amps) and
air flow sensor (4 amps). This relay is controlled by
the engine management ECM. This enables the ECM
to remain powered up after ignition is switched off.
During this ’ECM power down routine’ the ECM
records all temperature readings and powers the
stepper motor to the fully open position. Failure of this
relay will result in the engine management ECM not
being switched on resulting in engine not starting due
to absence of fuel and ignition.

 

The only thing that will make this engine any worse would be an open fuel line and a match. Would an intermittant faulty IACV cause poor fuel econemy? I'm thinking that when the engine warms up it somehow disrupts the IACV which may be causing my stalling at stops, rough idle when warm and rich running. Does this sound close? I would heve never thought about this part because it does move in and out with the key turned. I figured that it was working properly. Does anyone have the correct procedure to re-install the IACV. I'll try that and see if anything works. I wonder if my problem isn't with the ECU also. I have tried my 97D1 ECU and it runs my engine at lower RPM's but same 6-7 MPG fuel econemy, and warm engine stalling at stops. Turf, I would like nothing more than to consentrate on aftermarket gismo's. But right now I have a sick engine and it is the deciding factor if I continue with Land Rovers.

 

i forget that justbecause my landrover doesnt need attention (for the first time in it's life) doesnt mean you have the time to build my free, prototype, flat black snorkel. Get your IACV right and then build my snorkel.
Do what chris told you. You just need to find the default off position for the IACV and make sure it gedts back there, and also be sure that the ECU KNOWS it's in the right position

So if you install a new IACV, you should be able to(theoretically) open the IACV by:
1. unplugging the IAVC
2. turning on the power(without starting the engine)
3. plugging in the IACV
4. Turning off the power
5. repeat until you feel the IACV is fully open.

Maybe that'll help? Im at work still so not sure if the rave has a more detailed procedure.

 

From what I have read, I would also look at going ahead and replacing that two wire coolant temp sensor that feeds input to the ECU. I remember Spike saying he had a problem with that, replacing the sensor was cheap and fixed his running rich problem.

It probably would be worth doing to at least rule that out.

 

Yeah I replaced that already. I'm going to try a few parts and then if this repair work does not do it, it is sold to the first bid. I'm ordering 4 new O2 sensor, IACV, Timeing chain and sprockets, new CAM. My money is on the O2's right now. I went down to the auto shop and all O2's were codeing, along with a misfire.