Anyone else solved this before? 2002 Montero Limited, 180,000 miles. I'm racking my brain.

This is what I've done or checked:

Confirmed the water in oil from possible head gasket.
Battery disconnected and fully charged. Battery left off for 1 hour to try resetting anything.
Cleaned air intake.
Confirmed it has fuel.
Tried spraying lots of starter fluid into air intake.
Water in the oil is from presumed blown head gasket because it also started to overheat at idle the last time it ran about /weeks ago. There is not oil in the radiator or reservoir.
I pulled a spark wire and confirmed spark to plugs (well at least one).
It has oil (about 1/2 to 3/4 qt overfilled, possibly due to coolant).

There's no noises of broken metal pieces or anything while cranking. I've checked all the motor harnesses and vacuum routes. All look good.

I want to get it running so I can try Steel Seal or Blue Devil head gasket sealer. I hear they work very well for smaller fractures in head gaskets.

Could it be an alarm?

 

If you have spark, then it is not very likely to be an alarm. Many alarms work by disabling the ignition system. It is possible that an alarm would interrupt fuel injector signal, but can't vouch for it. Couple of clarification questions:

1. What do you mean by "it has fuel"? Fuel in the tank or pressurized fuel at injectors?

2. What kind of compression readings do you get on all cylinders?

3. Does the engine "catch" when you spray starter fluid into the intake while cranking?

 

It has fresh fuel in the tank. I can smell unburnt fuel coming out tailpipe though.

I haven't checked compression in individual cylinders yet because I want to try all else before the 1-2 hours to get to spark plug openings. When I remove the intake air cleaner tube and put hand over the opening I can feel very good suction into the motor..wants to suck hand in. Plus after 3-4 seconds with hand on tail pipe it builds up outward pressure too. I figure I should have plenty of cyl compression in at least 4 cylinders (with average worst head hasket leak) to make her start and run rough at least. This is my experience anyway.

After 24 hrs of battery being disconnected I reconnected today and still same thing. I locked doors from inside, and the dash alarm light turns on and is steady. I unlocked both front doors with key and that didn't help. So I left battery plugged in to see if letting her sit with power for 24 hrs makes a difference (like as surpasses a safety no theft time period of stock alarm)?

I've tried getting in and putting gas pedal all to floor and then cranking but still same.

My 2003 Montero Limited (3.8 L) did the EXACT same thing about 5 months ago. Sat for 3 weeks and refused to start. I though it was the Cam Shaft Sensor but it wasn't. One day I got in and it started and that problem didn't return.

In my 2003 Limited disconnected and reconnected the battery but I wasn't paying attention what I did exactly. I'm wondering if 2002 Montero Limiteds have alarm that is problematic and there is some sequence of button pushing to reset the alarm and release any no-start theft program it has?

Is there a known bug and home-grown way to fix alarm if it is bad? As in make it release any grip on starting it may have?

It will sometimes stuble or act like it almost will start but doesn't. When I put starter fluid in it, it does not "catch". It acts like nothing is being added at all.

I left it unplugged for 24 hours (no battery connected) and then reconnecting battery and letting it be on for 24 hours to test alarm theory. My alarm is not sounding aloud but I'm not sure if there is an alarm reset process I should try anyways.

 

Did you try spraying starter fluid into the intake while cranking? Any reaction to that? If you have spark and it is good and at the right time - it should catch. It is possible that fuel is not getting metered correctly - ether too little of it or too much is getting dumped into the cylinders.

 

Yes I've tried starter fluid straight into throttle bottle several times and no change. It doesn't catch or help it at all.

No codes either. My 2003 3.8L did exact same thing a few months ago for several days and then suddenly ran fine ever since. It's really weird.

When the alarms do malfunction, or legitimately activate, what is the anti-theft mechanism? What does the computer change to prevent vehicle use at that time? I'd like to check that and see if I have it.

 

Can't help you with the alarm system - no experience there. I suspect you have an issue with ether spark, spark timing or compression. There is no way the engine that has a proper spark would not at least "cough" when you are using the starter fluid.