800 revs not 8000

 

So you are saying that traveling 9mph-in 2nd gear of a manual transmission car-that when you put your foot on the brake that braking force is not enough to slow the car below 9mph when turning a corner? I must be missing something because if that was the case, how do you stop your car at all otherwise? At 800 RPMs the engine is barely turning over and is all but ready to stall out the way it is. If you are going that slow to turn a corner I would guess you would probably be on the verge on having to push in the clutch and either put it in neutral or go to a lower gear to even keep it running. Maybe it is different with a diesel. I have a 3.0 petrol manual X-Type for seven years and never had an issue like you are describing, but I am guessing I must be missing or not understanding what you are saying.

 

In second gear it prob goes up to around 1,000 to 1,100 revs and yes I have to depress clutch and brake so car can go round a right angle turn. Even if I change down to 1st it's still pushing along at 9mph. If I give it a rev with clutch depressed, it seems to clear the speeding issue and speed drops as it should, so this makes me think it's the throttle body valve needs cleaning.

 

Diesels do have a bit more grunt at the bottom end apart from that you are correct in your thinking.
Guy now says his car does rev too high in first which obviously is a problem. Why did he noy say that before. I am too confused to bother any more. I fear it's too close to April first.

 

Fella there's no point in getting upset because there's some misunderstanding. The thread did begin that it travels to fast in 1st. So don't understand why your upset. Anyway thanks for the input, it's appreciated.

 

Jaymo, see if you can try this: Get the car rolling around with the video cam going. Start out in first, get it up to second, step on the gas a little bit, then at some point slow down to shift back to first gear (seeing if the car will maintain the 9 mph in 1st gear). I am curious what it looks like. From what you are describing, if the car is maintaining 9 mph in 1st gear after pressing on the gas pedal, then this pretty much has to be a stuck throttlebody. The only other thing that I could possible think it could be is a stuck injector. But, this should not be dependent on the position of the throttle, more on the temperature of the engine as the injectors are perpetually opening and closing and only inject more fuel by changing the amount of open time relative to close time.

 

Thermo, I'm off work tommorow so will give that a try then post the vid. The fuel injectors were all done about 8 months ago so could be throttle body.
Thanks

 

I'm a newbie to jags and admit it but I'm trying to learn... Anyway I popped the bonnet open today and intended to clean the throttle body valve. But I couldent find it . So I'm adding some pics to see if anyone can point it out.
I feel stupid asking this but I don't know, until I know.

 

Jaymo, I keep forgetting that you have a diesel engine. Diesel engines don't have a throttlebody. They regulate the air flow by engine speed. The engine speed is regulated by the amount of fuel admitted to the engine. So, your engine can run lean or rich and it won't care. You can tell that you are running rich if you see your car start belching out black smoke (ie, unburnt fuel).

If you did have a throttlebody, it should have been just downstream of the accordian piece in the intake (to the left of where the brake fluid reservoir is in your first pic). I would try cleaning the MAF sensor (the piece sticking up in the intake just in front of the accordian piece).

 

Thermo,

They don't have Throttle body in Desiel? No wonder I couldent find it. I bought the can of cleaner as well and spent last few days watching YouTube vids on how to clean it. Back to the drawing board for me. Thanks for other suggestion, I will give that a look when off next.

 

I'm quite confused, like one of the other posters. Some of the statements are incomplete or seem contradictory.

Single question- when the car is going too quickly, what is the engine RPM?

 

MIkey, just to add some clarification as I am understanding things: the car moves fine when in first gear at an appropriate speed (4 mph), when the car is shifted to second, it will speed up to 9 mph (correct for that gear). Where the problem lies is that when the car is in first gear and the gas is depressed to speed the car up, the car will then maintain 9 mph. This leads to the question of what is causing the car to move too fast after depressing the gas pedal.

 

That's how I read it too Chris, but the videos seem to show something else.

 

Thermo, you explained it exacty as it is. For some reason I cant view the videos as in bad internet area at work, but if I remember right the vids show it all running fine but 99% of the time it shows the speed issue.

 

How about simply answering the single question I posted.

What RPM is the engine at during the problem.

 

Well I tried to capture the RPMs whilst the problem occurred but for some strange reason the car performed an normal, problem free. So I've posted 3 vids to show my findings. I will have to record again when the problem reappears.

Video 1


Video 2

 

Hi Jaymo. I don't want to be rude but it looks to me as if your diesel is behaving exactly as it should.
You have an ECU that is insisting that the tickover in whatever gear does not drop below about 800 revs.
This does not happen on an older none ECU petrol where if you brake you can drop below tickover and it will not fight you.
Also I am afraid if you don't know that a diesel does not have a throttle to clean the bonnet is perhaps best left closed, unless you can find some help.

 

Dunks, thanks for your advice. I don't take it as being rude at all. I've never had a Desiel before or a Jag, so it's a new learning curve for me. At 56 I've only ever driven petrol vehicles before so just trying to learn a little bit about this car. I thought the forum might be a good place to do this.
I have picked up a lot of info I didn't know a couple of months so so I'm grateful for everyones input. I think as it's a Mondeo engine rather than Jag , I should be able to take it to many a garage to have it looked at so maybe I should do that.



The sun actually showed itself today in London so maybe I will clean the car instead :-)

 

Perhaps best idea and get them to have a drive whilst you explain what you think is wrong.
Your engine is possibly the most common diesel in the Uk at present. In the Mondeo of course but also in a zillion ford transit vans and a million or two London Taxis.
They will all drive very much the same re engine characteristics.

 

I think lots of garages will be be happy to take your money off you for a problem that isn't really a problem. You have to ask yourself, what trouble is this causing you, is it dangerous? Is it making driving difficult? I'd have to ask why you are driving around in 2nd with the clutch engaged and then changing to first, and then engaging the clutch again. I don't understand why you'd want to go down the gears like that. You've got discs brakes all round, excess engine braking is not really needed these days.

Years I ago I worked in a few garages and people would come in with statements about their cars. Such as my car vibrates when I rev it when stationary at 5000rpm but it doesn't do it when I'm driving and get the revs up to 5000prm. The answer was, don't rev it when stationary then.