Hi everyone. I just got myself a X300. My first jag, and I am not really a mechanic so it's a bit scary. In D, N and R the engine runs normally around 700-900 rpm but when rolling slowly in Drive )walking speed) it falls down to 300-400 rpm and dies.(Unless I keep my foot on the gas to slightly adjust) Having read a lot of similar posts here I decided to get a new battery. It removed the warning lamp for the transmission, but that was the only difference. Next up I checked the transmission oil level, and added half a litre as it was a bit low. It did not help any.
I then changed the engine oil with Castrol 05-40W and the airfilter (the old was extremely dirty) and I fitted new NGK iridium plugs. The coils were "made in japan" and the plugs were the original champion RC9CC ( they were black and sooty) I also tried cleaning the MAF but there is still no improvement. I was kind of hoping these things would solve the problem, but now I have to look elsewhere. Maybe I will try clening the MAF again with a O2 spray this evening, or order a new fuel filter, as it's probably an old one sitting there.

So, do you have any other ideas I could try? Is it possible to simply adjust the idle and set it a little bit higher? I also notice a bit of a rough idle in the 2000-3000 range. Hard to describe it but its like a rumble, or a misfire. Or is it just supposed to sound that way?

Any thoughts and ideas would be appreciated. Greetings from Norway

 

Some suggestions from down here, and not knowing where you call home.

1) Some markets have an EGR (Exhaust Gas Recirculation ) system, they carbon up, and I have read of this reeking havoc with the idle integrity. We did not get it thankfully.

2) Fancy spark plugs are NOT liked by the AJ16. I run standard spec NGK, and no issues at all.

3) The idle is controlled by a stepper motor, and is ECU controlled. They carbon up, related to (1) above.

4) The intake trunking has a hole in it, especially from the MAF to the throttle body connection.

5) The throttle body and disc are coated in the infamous "black goo". Use a solvent soaked rag and wipe it out until it is CLEAN.

6) The trans is waaaaay overdue for a fluid freshen up, and this can have issues with the torque convertor NOT doing what it should, until it locks up 100%, and your wallet gets smacked.

Others will have their ideas.

 

I would start with reading the car with an OBD2 scanner and check if there are any stored codes. secondly try unplugging the MAF and run the engine, see if it makes a big difference in how she runs and responds.

 

Hi, and thanks for the advice. This is kind of driving me crazy. I will by the way be purchasing an OBD tool, but I have not found out which one to get for this car yet. Any idea??

I tried to disconnect the MAF and then drove it, and it didn't stall, but it still idled at around 400 rpm in drive. The engine shakes a bit and almost chokes.
The engine was warm at this point, and i have a feeling that improves the idle.

When I arrived home I took out the throttle body and cleaned it, (it didn't look too bad actually), and I cleaned out the contacts for the MAF sensor and the stepper motor.
I just took it for a quick spin, and it kind of choked right away. After 5 minutes of driving the rpm was at around 600, occasionally dropping down to 400 but without stalling. Not sure if it's an improvement yet.. I'll try to take a longer drive tomorrow.

 

Could well be a outgoing MAF or O2 sensor, but its just a guess.
That its not stalling anymore when unplugged says something.
When you unplug your MAF the ecu takes a standard profile, I think it even discards the O2 readings.

There are many different tools out there, but when you go look for one it will t need the ISO 9141-2 protocol in order to work I believe. I have not much experience with these tools, maybe someone else can give you some good advice on what brand/model to buy.

Excellent color on the jag btw! Blue steel look ;-)
Same interior as mine I think.

 

You did not mention how many miles are on the car. And did the car run alright when you first got it or was it in this condition right off. Do you have any history as to what has been done to the car.

When it dies ignore the transmission warning. Also, probably won't get any codes that mean much. If the car has a lot of miles you probably need new coils, plugs, throttle body cleaned, and cam cover checked for oil on plug wells.

 

The car has around 84000 miles (135000 km) and all services done at Jaguar Norway up to 60000miles. After that a couple of independent dealers changed the oil.

I changed the plugs and cleaned the throttle body yesterday. Same problem this morning though. It did not stall however, but the rpm's drop to 400 occasionally in Drive, almost choking the engine. It drove well when I bought it. I filled a full tank and drove home, and the next day it started...

I will try to get a hold of an OBD tool today.


Does anybody know how many O2 sensors that's attached and where? Mine was imported from Germany in 1998..

 

I believe European market cars only have 2 O2 sensors, North American cars have 4. Use NTK 25018 sensors, that's the OEM sensor. At the mileage you have, if they are original they are probably in need of replacement. if you buy them from an autoparts store they will be much cheaper than a Jaguar dealer. Where I am it's about 1/10 the price.

They will be on the exhaust pipe, right side of the engine bay. Just follow the wires back to the connectors that are at the back of the engine and very difficult to access. It's easy to get the connectors confused, so change one at a time

 

Isn't this significant? What grade of fuel? Usual supplier that you have used for petrol before?

Mike

 

True Mike.. But the manual says 95 unleaded and that's what it got. The quality of fuel is very good in Norway. Would there be any consequences by giving it unleaded 98 instead? I know shell stations have the nitro unleaded 98 option designed to "clean" the engine etc..

This is btw how the old spark plugs looked after removal..

 

I just put regular UK fuel in which is 95 I think. I did try a 98 once and it made no difference at all one way or the other that I could see apart from costing more.

Thing is it's the one thing that's changed between running OK and running not so well. Was the tank very low? If so perhaps a load of crap was mixed into the fuel and is now sitting in that fuel filter which I don't think you've changed yet.

Incidentally, changing the fuel filter is easy enough but treat the steel pipes with respect as after 20 years sitting exposed to water and maybe salt off the roads they may be a little fragile and the union nuts may be quite reluctant to release.

I suppose that plug does look a bit black but it's not caked in carbon like some I have pulled

Mike

 

I had similar problem, stalling, rough idle, misfires coughing around 1200-1500 rpm. After stalling could not bring her alive again. With the maf unplugged, still rough idling, some misfires, but no more stalling.

I replaced the MAF and she was alive again, without any issues.
Thats why i suspect something in that region, since you say it does not stall anymore when it is unplugged.

 

I am loving this forum... The tank was half full when I bought it. I have noticed that its using a lot of fuel though, so I am beginning to suspect O2 sensors or the MAF. I will order the parts and try.

It seems the car has a high level of Co2 at idle. I am not sure how to interpret these figures, but I am guessing the O2 sensor (Lambda) might be faulty...
(In Norwegian though, but I guess you might be able to read the numbers better than me. )

 

You have to be careful about which O2 sensor you get. The cheap ones may not be suitable, someone more expert will be along shortly. I think you can simply disconnect them anyway and see if it makes any difference.

I tried changing one of mine and it made no difference at all.

Fuel doesn't sound like the problem.

I think people will ask about long term fuel trim real soon now

I love this forum too. Everyone is always so upbeat and helpful.

 

*Pro tip:
Try to find a scrapyard nearby that has a x300. ;-)
There are always nice goodies you can plug from it if its not parted out yet.
Also saves alot of money instead buying it from partshops.

 

That's running very rich. I have seen lower emissions on a 1960's car. Definitely change the O2 sensors, then possibly the coolant temperature sender. MAF may be a culprit, but they don't tend to fail.

Does the temperature gauge come up to the mid point on the dash gauge? If the thermostat is stuck open and the car doesn't come up to temperature that can cause a similar condition.

 

You have to get the Titanium/Titania O2 sensors not the cheaper Zirconia ones don't you? Even some parts catalogues list Zirconium ones for the X300 but that seems to be a mistake. Or am I mistaken?

Mike

 

Just for information purpose.
For early models there was a tsb about the maf.

The maf I replaced was made in 94.

 

Yes. Only Jaguar and Land Rover used them (that I am aware of). Most sensors change voltage in response to changing O2 levels, these change resistance.

 

So.. I had a short drive today. In the morning it almost stalled, as expected. On the way home after work I drove it warm with some frequent kickdowns, and it actually improved the idle. I know the car has not been used a lot the last year. Could it actually be possible to "wake up" the O2 sensors again by simply letting out some steam? O2 sensors has been ordered anyway, so hopefully I will have this fixed soon. I am also going to try the method of spraying some startgass along the vacuum hoses while running to see if there is any reaction from the engine.

Jagboi64 : Thanks for your input. The temperature comes up to a mid point after a while.

DrMike : I ordered the O2 sensors from britishparts, and I have no idea what kind they are. But I had a look in the engine bay and realized it will be hell to change them

I will order a new MAF probably if my next fixes wont work out..