Hello every one,
This is my second posting. I hope I am in the right place this time. My Series 3 is very difficult to start (to fire) , both when cold and when hot but will fire after a lot of cranking. I have been reading a lot of answers from both Doug and Grant on this subject.
I removed the Cold Start injector and checked for petrol supply: beautiful and even spray. I installed a new Thermo time switch (EAC1385), a new Coolant Temperature Sensor(EAC3927) but to no avail. I tried a little trick that I read in one of Doug's answers. I removed the connector from the coolant sensor and jammed a steel paper clip between the terminals as Doug wrote: "This will trick the ECU in believing the engine is hot". The engine will still not fire. I now suspect that the wire leading to the coolant sensor connector is broken. With the connector off and the ignition on, should I have 12 volts with my test light? And thank you, Doug, with my first problem regarding the distributor. It worked.

 

The coolant temp sensor doesn't work on a 12v "+" supply.

The black wire at the connector is grounded/earthed. The blue/orange wire goes to the ECU. The sensor provides a variable resistance ground to the ECU.

Broken wires are fairly common.....brittle from heat.

Also, the fuel injection system wires, including the sensor wire mentioned above, ground/earth under a bolt at the very rear of the water rail. Check/clean/tighten this ground point.

Cheers
DD

 

Hi Doug,
Many thanks for these useful infos. Will check them all and come back. You are a man of great knowledge and full of wisdom.

 

Hi there,

Whats the car like when it fires up? does it run well? In my experience if the coolant temp sensor is open circuit the car will run like an absolute bucket of rubbish and stall out after a few seconds of running.

My series 3 was hard to start and it turned out to be the intake gasket leaking coolant into the manifold, I only found it by chance. After checking the above suggestions ide personally check what the spark is like under cranking and go from there. One cause of weak / erratic spark is the earth connection between the ignition amplifier and manifold. The whole ignition system and fuel injection system relies on a good connection here as the ecu is triggered from the coil pulse, and the only earth point of the ignition amplifier is its case against the manifold.

Regards,
Jay

 

Hi Jay,
Many thanks for those useful comments. The engine runs beautifully, very smooth as soon as it fires. This afternoon, after work, I tried everything Doug suggested: I removed the bolt on the water rail, checked and cleaned all earth connections, made sure both wires to the coolant sensor are not cracked or broken. The car has not been started since yesterday, so the engine was cold. The engine did fire but still after a lot of cranking.
How did you find out that coolant is leaking into the manifold? Can you see or hear anything? If this is the case then, obviously, the coolant level in the reservoir would drop significantly, would it not? I can hear coolant still running or dropping who knows where a few seconds after the engine is shut down. Is this normal? Your expert advise here would be greatly appreciated. Tomorrow, with the help of my other half, I will be checking the sparks the engine is emitting.
Best regards,
Gerard.

 

Ide hardly call myself an expert, the likes of Doug and Grant are the real experts!

I was not loosing enough water to notice a drop in the tank,it must have just been working its way in there while the cooling system was pressurized when hot. I only noticed while I was cleaning the throttle body when I happened to peer down inside the manifold only to find a green, oily mess at the bottom. There was not allot of water in there but enough to be significant and after I replaced the gasket, throttle body and manifold it starts much easier whereas it use to be a right pain when hot, but always started right up cold. The water may have been totally unrelated anyway, maybe it had a vacuum leak in the manifold gasket and that's why it didn't start well.

Personally ide put a fuel pressure gauge on and see if it has fuel pressure while cranking. If you really cant find a gauge take an injector or two out, take the lead that goes from the coil to distributor cap and ground it then have someone crank the car while you watch the injectors. they should spray a good even mist right from when the car starts cranking. If they take a few seconds to spray then ide bet that's probably your issue. a better way would be to just stick a fuel pressure gauge on though.

Im still leaning towards weak spark though as at cranking speeds there is far less signal generated by the hall effect in the distributor then there is at idle as its only doing half the speed. If there is a bad earth on the amplifier, bad connections or wires either between the coil and amplifier or amplifier and distributor it could have a erratic or non existent spark and injector pulse while cranking but a full and healthy spark at idle.

You could also use a screwdriver to listen if the injectors are pulsing while cranking. I do this by taking a long screwdriver and resting the blade against the injector body and the butt against my ear, providing your hearing is good you will hear the injectors clicking quite noticeably even while cranking.

Another thing to do would be to check the voltage between the positive side of the coil and ground while cranking. It should be about what the battery voltage is under cranking, if not there is another issue.

Anyway, ill stop throwing suggestions around and give you a change to test them, and others a chance to chime in.

Hope this helps,
Jay

 

I had the chance to check the sparks to-day, all very good. Could not check the earth connection of the amplifier as Jay suggested. Both the air cleaner assembly and the amplifier have to be removed. This week end job.
I tried the car again this afternoon. After a lengthy cranking the engine wants to fire but cannot. Again a second time wants to start but still cannot . Same for the third time. On the fourth time it fired. Does this behaviour mean anything to you guys out there? Any help would be greatly appreciated.

 

Hello Everyone,
It has been a while since my last message. After having so much problems with my Series 3, I have decided to renew both the Ignition and the Engine wiring harnesses. I purchased both from Autosparks UK. Their part nos. XJ6 311 and XJ6 313 respectively. Although I can understand where "most" connectors are fitted, I need some help with the following:
(1) Is there any trick to detach the connectors from the Injectors etc., other than removing those small U shape clips that they are fitted with?
(2) I read. several years ago, that there is a way to fit a new ignition harness away from a hot engine. I would greatly appreciate your help on "how to".
(3) I find the engine wiring harness rather complicated. There are three connectors at the end of the section for the coil area. One male and two female connectors, all three are fitted with insulating covers. One of the female connector wire is fitted with a short "blue" wrapped around tape. Am I right to assume that this connector is fitted to the positive terminal of the coil and the other to the negative? I am at a lost here. And the male connector, to what is it connected to? Any help and advice would be appreciated.

 

Sometimes the connector can be wiggled off...with the risk of breaking whatever it fits onto. Best to remove the wire clip. A tiny screwdriver or pointy tool is useful here to lift the wire clip off and away from the connector. After a couple tries you'll get the hang of it

Jaguar ran a lot of wires so they're in direct contact with the engine, laying flat against it.

I don't know if there's a prescribed method. You may have to use your imagination to position the wires off the engine. A lot of the wiring is held down by clamps with through-bolts. You could put spacers under the clamps to elevate the wiring harness away from the engine.

The coil "+" post gets solid white wires. The "-" post gets white/black wires and the white/slate/blue wire.

If you still have the ballast resistor on your '86 the "+" post is handled a bit differently. One post of the ballast resistor is attached right to the coil "+" post and the white wires attach to the other post of the resistor.

Sometimes ballast is tossed away, though.

Often coils have been changed. Different coils often have different connectors so there's a chance the connectors on your new harness won't be correct for your existing coil

Cheers
DD

 

Hi Doug,
I thank you very much for your advice. I am re-posting this as I am sure my previous message was posted to the wrong place.
Gerard.

 

Hi,
have you tried shifting the transmission to 1st gear, and turning and holding the ignition switch for 3 seconds in order to "charge / Pressurize the fuel system?

Here's how I do it in my 1984 and it starts from the very first crank 99 times out of 100.

1) Place the shifter in 1st Gear, (Doug does it in "D" but I do it in "1" because that's how I was taught to do it).

2), with the shifter in 1 or D, turn the ignition switch as if to start the engine and hold it for 3 seconds, then back to OFF. As you hold the ignition switch all the way to START, you should hear the fuel pump whirring or whinning or humming, this means it is charging or pressurizing the system.

3) do this ignition switch hold two or thre times, one after the other, and each time you will hear the humming of the fuel pump less and less as the system is fully pressurized.

4) then place the shifter in Park and crank that sucker. It should start quickly.