My first post although I have lurked for some time.

I have an XJ6 X300 1994/5 3.2 model. I have had it 2 months and I love it. It was to be my daughter's wedding car so I did nothing to it apart from clean it but the wedding is over and was terrific, the car was immaculate. Great day.

So I checked the oil and topped up with some 10/40, about 750cc maybe.

Then on my next 12 mile run I found that after a while the car wasn't pulling well but was happy to trundle along but as soon as I put load on it it misfired etc. I turned round to go home and it got worse so I pulled over lifted the bonnet and it seemed quite a hot engine. You can smell a hot engine and it smelt hot, no leaks although possibly a little steam at the rear of the engine.

The rescue guy arrived, we started the car having checked the coolant which was fine but not very hot. So he followed me home and the the car drove fine and picked up OK although I wasn't dramatic.

We diagnosed water circulation so I changed the thermostats as a first step always go for the cheap option. But it's just happened again. Happy to tootle along but under load it doesn't pull and now back at home on the drive it's misfiring when I rev it up.

The engine doesn't seem too hot, the top hose is warm but not hot, the heater works well and it's a cold day at 6 degrees outside (Celcius).

So, has the oil had some effect? Is that the first place to try?

Or where do I begin?

Many thanks

Mike

 

It sounds like you had to add a lot of oil. Did you leave it to settle down a few minutes before checking the level? Perhaps you have far too much oil in it. It might only be a coincidence. You could drain the sump and change the oil and oil filter in case there is too much or it's in very poor condition. Does the engine have a healthy oil pressure?? Check it asap, should be around the "N".

Good luck"

 

Oil pressure vertical on gauge, I did wonder about adding quite so much so maybe it is over full but would that cause this sort of problem?

I am considering changing the oil. Each time I check the dipstick it looks the right level. I'll take another look now. Today is Jag day

 

If the sump is overfilled, it will show on the dipstick. As to oil pressure, the gauge will read mid scale as long as the pressure is over 4 lbs. It's just a glorified idiot light. I would change the fuel filter, unless you know this has been done recently. It may be the fuel pump is failing, but the filter would be the place to start.
When you have time, please visit the new member area if you have not already done so. Link below:
New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum

 

You are right I didn't think of the fuel system but it could be that it's running very lean. You could also check the spark plugs.

Jag days are the best, I am glad my wife has asked to drive to work this morning rather than cycling

 

Just checked and while the oil is at the top of the hatched area it's OK I reckon.

OK a fuel filter, I'll get one and fit but I'm not sure why that would cause it to not pull after it gets decently warm although of course it might be random but so far it only happens when the engine is good and warm. This last time it was reluctant to start with CEL on. Then I fiddled with the gear shift and the CEL went out and it would start, I hope that's a side issue. But once running it was OK until after 6 miles or so (from warm) it started to play up again. What I have done is rev the engine from under the bonnet using the throttle cable thing.

Rather worryingly I took the air filter out to fit a new one and I found some very old engine oil in there. I was thinking maybe the EGR was clogged but that's a hell of a long way to come back.

Can I clean the air flow meter? Just pop it out and clean up or more to it than that.

I'm trying to think of things that have changed and it's add oil, change headlamp bulb, top up steering fluid and now I have changed the thermostat but that wasn't eh cause of the problem.

Are there any relays and stuff I could have disturbed in that sort of area?

I love forums like this where you get intelligent help.

Mike

 

It could very well be a water temperature sensor. I am sorry I don't quite know where they are in the X300. This happened to me in my other car, and the problem is that it sends a signal to the ECU saying that the temperature is -XX C, which then overfuels the engine massively, but you only really notice when it's warm.

 

I have to say as gut feeling I'd agree with that as possibility. It's fuel economy has dropped and while driving the symptoms appear when the instant mpg goes low for no good reason.

Mike

 

Sounds good. Not quite sure where it is but the first picture in this post might help you, the one that could be faulty (or unplugged...) is the one that sends a signal to the ECU, not to the gauge.

https://www.jaguarforums.com/forum/x...nnector-74641/

 

Sorry for the spamming but if everything is plugged in correctly this is a very quick way of assessing if the sensor is not working. I've copied it from jummbutterworth's website.

"Temperature sensor: the one that controls the ECU - NOT the dash gauge

A new temperature sensor: part no: LHE1600AA

Iced water = 5360 ohms
Room temperature = 2800 ohms
Boiling pan of Water = 195 ohms

Mine: engine cold (10°C) - about 3,000 ohms; engine hot - about 500 ohms so about right"

 

I found that too, took the sensor out and tested it. The resistances were not hugely out although it is just possible they went a bit funny now and then but that could have been my wobbly hands over boiling water

Mike

 

Don't assume that by the sensor giving the right reading everything is ok. In my case it was actually one of the 2 cables in the connector that was broken!

 

Good point. It is after all an intermittent fault.

 

When I read "misfire" I naturally want to begin by looking for an ignition fault and then move on to other possibilities.

I'd pull the spark plugs for inspection or, as long as you're at it, replacement.

Take a good look at the ignition coil boots for signs of burning/arcing. If any boots are burned they can be purchased and replaced separately.

Coil failures are common on these engines and can give intermittant misfires.

Cheers
DD

 

You just want to depress me don't you? I have to say when I got back and it was sitting on the drive revving the engine via the throttle control on the engine bay it was misfiring. I have read so much about coils etc. on this forum I really didn't want to go there but hey ho!

Do you think it's worth pulling the EGR out and seeing if it's gummed up? Is it possible to simply remove or disable the EGR?

Mike

 

I don't blame ya . I've been thru hell and highwater with coils.




I've heard of many EGR problems on these (and other) cars. So, yes, I'd say it's a good idea.

A few months ago my brother's Chevy truck developed a bad misfire. You guessed it. EGR valve. A chunk of carbon was preventing the pintle from seating.

You might wanna investigate getting a new EGR gasket before removing the valve, just in case the old one fall apart when you remove the valve.

As for disabling or removing the valve I'm tempted to say "no". I'm not sure what the ramifications would be as the EGR is integrated into the entire emissions/engine management architecture. No sense in introducing a new variable by removing things.

Others might chime in here.

Cheers
DD

 

Thanks Doug. While we're here which plugs are recommended? I know there is some disagreement about which is best but I can get NGK at £1.80, Bosch at anything between £1.50 and £4. I believe it's a pretty forgiving engine regarding plugs so I'd just go for the NGK but maybe that's not so good?

Mike

 

I've used both NGK (Iridium) and Champion (standard type) in mine and both worked well. I never noticed any difference in engine behavior with either type. As you know some guys have very strong opinions on this subject

About a year ago I was tormented with a weird misfire for a couple months. Ran great cold but a misfire developed every day after about 15-20 minutes of driving. *Very* long story but changing the plugs solved the problem....and the "old" plugs were only a few months old and looked perfect, visually.

I never could ascertain the exact problem with the plugs. Some sort of fluke.

Cheers
DD

 

Now you're trying to cheer me up. I'll get some new plugs after inspecting the coil boots.

It's all good fun really and part of why I bought the Jag as I haven't had oily hands for ages now.

 

I'm still puzzled over this as the problem only started after I added oil. I have yet to see if the plugs are oily externally as the weather has been too wet to get the bonnet up.

But, it occurs to me that the problem may well only occur after 10-15 minutes of driving rather than be temperature related. I have stumbled over information about the Rochester valve which can fail and someone suggested that this in some way had a line that ran up to the front left headlight area which is just where I replaced the headlamp bulb a few days ago. I hadn't used the car hardly at all since then. Could I have disturbed something there? There are that many relays down there it's possible.

I still intend to replace the fuel filter although somewhat carefully judging by comments about corrosion and probably the plugs too although I regard that as sleeping dogs which I for one don't kick.

Thanks again

Mike