Good Evening, It's been a while since I have posted here. I have heard that some of the older Jaguars are stubborn and a little hard to start. I was told that it is natural for my car to be like this. I don't believe my car has ever started on the first time turning over, it is usually the third. Is there a reason for this and is there anything I can do to correct this problem or is that just the nature of this beast?

 

I am not as familiar with the AJ6 engine, but I don't believe you are correct. I don't believe these cars should be stubborn to start.

It sounds like your fuel rail probably does not stay pressurized? Someone will come in and help, but it is not a common problem.

 

I have the 4.0 engine and have never experienced the car not starting on the first turn of the key. So your engine shouldn't be doing this.
Not sure what the problem is though.

 

Definitely not " the nature of this beast". Should start easily.
Hard starting can be caused by many things.
I'd start by checking the state of the battery. spark plugs, fuel pressure, etc.

 

93xjs6cyl,

Can you give us a bit more info? When you say that it doesn't start "on the first time turning over", do you mean that it just doesn't catch immediately? Or do you mean that it doesn't start, you then stop turning it over and try again, and then it does start?

Paul

 

Every time I get in the car in summer or winter I will turn the key and it turns over but will not fire up. Some times, but not often it will on the second try but usually I can count on the third. If I drive somewhere, stop the car and 5 minutes later I try to start the car, it starts right up. Can anyone tell me where to find the timing marks so I can try to see if the timing is ok? It has a new battery, new plugs, new rotor and cap. The plug wires seem to be good. When I bought the car, I noticed the seals that protect the spark plugs were letting oil drip down on a couple of the plugs and I noticed that the valve cover was not tightened down. I just cleaned all that up and tighten the cover. I have the Jaguar service manual, but I doubt that it's an original.

 

93xjs6cyl,

When you turn the engine over on the first time, what does it do? Is it trying to fire at all but not quite catching? Or is it just turning over withut any indication of firing? How long do you crank the starter for before you let go?

As mentioned, it could be a drop in fuel pressure in the fuel rail. Try the following:

- turn on ignition, see if you can get someone to listen for the fuel pump operating in the boot as you do this. Leave ignition on for 5 seconds
- turn off ignition, wait 5 seconds, turn on ignition again for 5 seconds.
- turn off ignition, turn on ignition again and now turn starter. What happens?

Paul

 

Ok. It's been a while since she and I have been out. I took her out to run some errands and she made a liar out of me at every stop (I'm glad to say...lol). It must have been getting a little oil past the plugs and running as a two stroke. It probably took a little to clean up the cylinders, but she started first time every time. I still would like to check the timing on her.

 

I think it's more likely to be residual fuel pressure dropping which is why it takes longer to start from cold, but then is ok from warm. Try my suggestion which will make the fuel pump run for a few a seconds each time with the ignition, before turning the starter.

Cheers

Paul

 

I just went and started it up after it has been sitting for several hours and she started right up. ptjs1, I will try your suggestion on cold starts in the morning. I also noticed that when it's cold she will thump a little. That also, seems to go away when she warms up. What I am thinking of trying on a cold morning, is turning the ignition on for 5 seconds, turning it off, then try starting it. It might just need a little extra kick. Like I said, it been about 8-9 months since I driven her, so we are getting reacquainted with each other. I stepped on the gas on an open road and it didn't seem to be what I remembered. Then I remembered the "sport" button and that is what I remembered. It was like I pissed her off.

 

Drive it more often and report back. Often long cranks have to do with the check valve in the tank failing. If this is the case you can install an external check valve.

 

Brewtech, What exactly am I looking for?

 

Before I get into explaining the fuel check valve. Does the car start right up first thing in the morning?

 

I will find out tomorrow morning. What I can tell you is that I haven't started it in about 12 hours and I just went in the garage and it started up on the first try.

 

Good morning, Well, what ever the problem was, it seems to have went away at least for now. At 6:45 a.m. I went into my garage, the temperature was about 74 degrees and it started right up. I will probably have to wait until the temperature drops some more and it is cold to see if she will become a bit grouchy in the morning. So far, so good.

 

93xjs6cyl,

There are a few potential causes of the problem. One is a potential loss of pressure in the fuel rail. And naturally this will manifest itself based on time since last start, rather than the mabient temperature. Cycling the ignition twice before trying to then start the car will cause the pump to run and reprime the pressure.

Another potential problem is the CTS (Coolant temperature sensor which influences the fuelling. That is morelikley to manifest itself as a problem based on the engine temperature rather than the time since last started. If the sensor is failing and causing an inappropriate fuelling (which could also cause rough running), one helpful way to diagnose that is to bridge the terminals on the plug and bypass the sensor signals which will cause it to use the default fuel map.

Cheers

Paul

 

Looks like finding original parts is not going to be easy. I found two Coolant temperature sensors that are suppose to fit my car, but they have different part numbers. My manual has about half a page on the cooling system and it doesn't say much. So, where can I start looking for this sensor?

 

Im going to assume that the internal fuel check valve was sticking open, allowing fuel to return back to the tank when you first got her going. Having fuel go through it may have unstuck it, so now its back working. Its not uncommon to add an inline check valve at feed line connected to the rail. My XJ40 has one because of extended cranking times irritating me. I have a write up on the XJ40 forums.

 

I will keep the internal fuel check valve and the Coolant temperature sensor in mind if I start having any more problem with starting. I am about to put up another post on an issue I was working on today and I could use your help. Thanks!

 

There are 2 sensors fitted in the thermostat housing on the 4 litre.

One is the CTS that sends a signal to the ecu to influence the fuelling. The other one is a temperature transmitter that sends the signal to the temperature gauge. Perhaps that's why you're finding 2 part numbers.

Always use Jaguar's own parts website to get the right part numbers, even if you purchase elsewhere. See here for the coolant sensors:

https://parts.jaguarlandroverclassic.../brand/jaguar/

Cheers

Paul