My trusty X300 4.0L Sport has developed a problem for the first time in its 2 years and 30,000km of my ownership. It's now done almost 190,000km.

The other day when driving I pulled up rather quick (spirited driving) and it stalled when I came to a stop. First time it had ever stalled on me. No warning lights that I noticed. I started it up and drove off no problems.

Today it stalled on my wife multiple times (not a good thing). When I got in the car to investigate the transmission light was on and the car was only driving in third gear which is why it seemed to want to stall, because it was not changing down to first when you slowed down. I could not select any other gear via manual selection or kickdown.

I then turned off the ignition and restarted the car and the transmission light had turned off, and the car worked perfectly again!

So I am now unsure if an initial engine stall caused the transmission to go into some type of ‘limp home’ mode or if the source of the problem is the transmission itself.

I don’t have a code reader but it seems I now need one. Any suggestions on a good one?

 

That electronic trans can be fickle at times.

My questions (in NO particular order) are:

How long since a trans fluid change?. In 2 years and 30K kms, it should have had at least one.

The torque convertor "may" have failed in lock mode, getting common now, and that caused the initial stall, and the events after have "released" it. Remember, that "lockup" is purely a mechanical event.

So, my suggestions are:

Remove the battery cable, let it all settle down. About a 6 pack in our time. Reconnect that cable, reset your stereo, etc, and see if all is OK. Most times it is.

Change the trans fluid, PLEASE. Simply drop and refill will suffice for now. If that fluid coming out is grubby, you may have found your root cause. Numerous drop and refill's will freshen up the whole system, and just maybe, solve/save the trans.

Others will chime in soon with more suggestions, but I always head down the simple path first and foremost.

 

Howdy Mark,

The stall causes the transmission to go into limp mode, hence the very sluggish 3rd gear operation and the trans fail light. Usually happens when the vehicle is still moving when the stall occurs. Also can be accompanied by an engine code P0727 showing Crank Position Sensor fail. Don't worry, (probably) neither your transmission or your crank sensor is bad. These warnings will usually reset after cycling the ignition.

How old are your spark plugs?

I had a stalling problem with my 96 XJ6 recently. I am embarrassed to admit that it was solved by replacing the spark plugs!! The old ones didn't look too bad, although the gap had widened. But obviously, they had been in the engine much too long. A simple but very important maintenance item that I had neglected for too long!

I had checked various other components, but had not confirmed any failures. I did not end up replacing anything but the plugs! Wal-mart has them. Champion RC12YC. They are known to work great in gas lawn mowers too!

 

I should add that the car ran great on the old plugs, when it ran! The stall happened only at closed throttle or at the first touch of the throttle. It happened when cold, when hot, when in park, when in gear, with a/c on, with a/c off, after ten seconds, after ten minutes, whenever, sometimes never. Very unpredictable. Bugga!

I believe that if a cylinder missed a spark because of the worn plugs, the other cylinders couldn't compensate for it with their weak sparks, hence a stall. Perhaps the coil on plug ignition is more sensitive to the spark plug's condition, than conventional coil ignition?

 

Thanks for the replies Grant and SleekJag.

Grant I am embarrassed to say I have not changed the trans oil in that time. It has been on the to do list the past 6 months and I just haven't got to it. It's now at the top of the list! Thanks for the tip on disconnecting the battery.

SleekJag, I did put a new crank sensor on it around 18 months ago but have never changed the plugs. I've also never changed the coils but do have spares on hand. It's probably time both get looked at...

Any tips on a good code reader? I've been wanting to get one for a while but the car has been running so good there has never been any urgency

 

Lot of choices.

I use an Innova 3130....


.....although mine is an older model and doesn't have some of the feature seen on this one.

Anyhow, something long those lines is fine for DIY work. You can spend hundreds or even thousands .

Others will chime in.

Cheers
DD

 

An update on my random stalling...

I got the local transmission guy to do an oil and filter change. He said it all looked nice and clean but I've noticed the gear change is smoother with the new oil.

Back to the stalling. The car would randomly stall at idle. It was worse when you pulled up quickly rather that a gradual stop. Even from say 40km/hr to zero so I ruled out any torque convertor lock up problems.

Basically it didn't seem like a spark problem, just the idle speed got a little low, dropping below 500 and then stall. If you gave it a little gas it would perk up and run perfectly. I did notice even when not stalling the idle sometimes took a split second to find equilibrium which never used to be the case so I suspected the idle control valve.

I disconnected the idle control valve when the engine was cold which made the engine idle fast once it heated up. No stalling but the idle speed was way too high when hot. So then I disconnected the idle control valve when the car was running at full operating temperature. Thanks to our warm climate the car still starts immediately from cold and idles fine at 500 rpm in gear and after a couple of minutes of driving the idle is up to the normal 700rpm. And after 2 weeks not a single stall, even with the idle control valve disconnected in the 'hot' position.

So I am blaming the idle control valve. I've now got a new one but have not fitted it yet because the car is running great!

I checked my coils and the current ones are labelled Lucas, made in Japan. So I didn't want to remove these coils and replace with my spare no name type unless I had a definite failure. I've also got 6 new Champion plugs ready to go but they might sit in the cupboard a while now.

 

You may be disappointed after replacing the idle control. It's control is tightly coupled to the TPS. Unfortunately, the TPS for these cars is expensive (usually $250. to $$300.). You should check that the TPS is giving a smooth transition of voltage around the idle position and that the throttle plate is getting fully closed to the mechanical limit.
Good Luck

 

Marke,

Remove the intake bellows, and clean the inside of the throttle body. It will be caked with goo.

I use a white rag and carby cleaner. The first time took me about 30 minutes to scrape and brush all that goo out.

My idle was OK, but could have been better.

Once done, it was significantly better.

Now it gets done at each oil change, as I do the filter from the top, and since changing to Synthetic oil it has never been gooed again.

 

Yeah, Grant, I believe the gunk can prevent the throttle from closing completely, thereby negating the ability of the idle control from functioning. I have always wondered why gunk in there should screw up the idle. I mean we all want a clean machine, but the connection between grime and bad operation is not so obvious!

 

Agreed.

This goo is imbedded in my brain from the V12's, terrible build up.

The use of "el cheapo" oils and not changing it when past its use by date, increases the contaminants going down that breather hose straight into the bellows at the throttle opening.

Mine was scraped out 4 years ago, the breather cleaned, etc, etc. It has never re-appeared. Some slight oil residue in the bottom of the bellows at each oil change, which is simply wiped out.

I have never had the idle control valve out.

Also, we do not have EGR down here, so a lot of other gunk never comes back to the engine. Straight out the back where it belongs.

 

I have also seen this kind of stalling caused by a faulty ABS sensor on the rear left wheel. This sensor also provides the only vehicle speed input for the rest of the cars electronics. I guess the gearbox gets confused because it doesn't know what speed you are doing and does't change down?

You say that the stalling is more common on quick stops which is exactly the symptoms I saw with the faulty sensor. I should add that I also saw an ABS fail message which you haven't mentioned, but it's worth consideration.