I appreciate there are others having non starts in X300's.
Our car 1995/6 with 3.2 used to run fine, then it started intermittently not starting and now 98% of the time it will not start on its own.
If i crack the airbox and squirt a little easy start it will start very easily if you put your foot on the throttle.
I also found after giving all the connectors a clean with electrical cleaner that the car was fine, until it dried off. Although i think this could be convenience as i tried this again and it still won't start.
There is a relay in the engine bay which i thik either controls spark or the fuel injection circuit. I have tried putting new relays in but this doesn't work. However if i quickly plug and unplug the relay in the socket a few times (quickly)whilst cranking the engine starts to splutter a spark and then it will go.
I am thinking the plugging in and out causes a 12V voltage spike which is fouling the ecu and allowing a start. Obviously this is not a fix but i can at least get the car to start to make sure its ok.
Another problem i find is sometimes when i start the car the idle races up and up to ~2000rpm and after a while will come down to ~1500rpm.

So far i have repalced all the temp sensors and this has helped with the car running smoother when the idle doesn't race. I used ot find if the coolant sensor plug was wiggled the idle would race. Now it doesn't with the new sensor if you wiggle the plug.

I have checked that the fuel pump is working and i always get fuel pressure to the rail. I have never been able to get a spark when pulley a plug coil and grounding with plug to ground.

THe tacho also shows ~200rpm on the dash when cranking. So i guess the CPS is ok.

What else am i missing? I am almost getting to the point where i am going to run some wiring to the relays for ground to give them an extra ground and fitting a push switch on the dash so i can trick the ecu mimmicking pulling the relay in and out quickly as described above. It is driving me mad please any advice greatly appreciated.

 

It could very well be your Camshaft position sensor. (not the crankshaft position sensor) If it is the problem, the engine will eventually start if you keep cranking long enough. It may take 30 secs or more of cranking. The CMPS is used by the ECM to identify TDC of the compression stroke of cylinder #1. If the car fails to start with extended cranking the ECM will try to start at 180 deg from that point.

I am a little confused when you say the car will start when you spray easy start but that you cannot get spark at the plugs?

 

It is surprising also that there is no spark when cranking, unless of course it is just too weak to see.
But it goes straight away on easy start, but then again you can run a diesel on the stuff without a spark and without glowplugs pre heating the stuff.

Therefore i come to the conclusion that the easy start gives the engine enough just to start the engine and then the other systems come online when revs are higher?

 

95/96 six cylinder AJ16 3.2 I presume...

A progressively worse ability to start has me first thinking of Spark Plugs. Was there any random stalling whilst driving before? That's a symptom of bad plugs too. The (coil on plug) engine is sensitive to spark plug age and if unknown, or up towards 20k, get new ones in there. You shouldn't have to "pump the relay" to get it to start!

 

Yes 6 cylinder. New plugs in and still the same

 

OK, my suggestions from down here. Found at random with my 3.2.

1) Throttle body clogged with GOO, more common with EGR cars, which I reckon you do not have, but mine was gooey as hell (no EGR down here), and simply cleaning it fastidiously sorted the oddd idle and harder than expected starting issues.

2) Crank angle sensor, YES, I know the 200rpm thingy. I drove the car home, spouse sprang for tea, so back in the beast, NO GO, nothing, fair dinkum, that box of matches came real close to the fuel tank, trust me. Stole the CAS from neighbours car (he was o/seas) and away it went.

3) The plug for the CAS, is vertical, tucked in the front of the timing cover, and GUNK gets inside the vacant holes and screws with the terminals. PITA to get at, but when I sealed mine with RTV, after seperating and cleaning it, the dying of the engine when driving in heavy rain has ceased.

4) The Cam Angle Sensor is whacky. NOT common, but it may also be "mis-timed", and mine was. So I simply re-timed it, and the engine barely rotates once before firing, sweet.

5) The Blue relay in the RH engine bay fuse box is one of many, many IGN relays in the car. This particular one supplies 12v to the RED wire of the CAS, so make sure this is so.

6) Someone in the UK had issues, and he eventually tracked it to the main ECU in the panel adjacent to the accelarator pedal. The loom connector at the ECU was "green" with growth, and once cleaned, car was sweet.

7) Spark plugs, as said, are critical one these AJ16 engines. I run NGK standar spec only, not the fancy electrode type.

8) The front crank pulley woodruff key has sheared, thus messing with the timing seriously. Again, not common, but I have seen a few in all sorts of Jag engines over the years, mainly V12's. My 3.2 was very sad when I did the timing chains, and not far from shearing in my opinion.

I'll stop there for now, but if something startling hits me I will repost.

 

All of the above suggestions are good ones but I'm still confused about the starting right away when you spray starter fluid in the intake.?

As I understood your post, when you spray starter fluid in the intake the engine starts right away and continues to run normally? This must mean that you have spark as compression alone will not ignite the fluid, especially on an engine that is cold.

This to me points to incorrect initial timing which is the purpose of the cam sensor. Once the engine fires the cam sensor has no more responsibilities. Perhaps when you spray starter fluid, you are circumventing the cam sensor? Then after ignition, the crank sensor takes over and engine runs normally.

If the crank sensor was bad, the car would not start at all, no matter how much fluid you spray and certainly will not continue to run.

As Grant suggests, a clogged TB can cause all kinds of problems but you would notice a very poorly running engine at idle, frequent stalling etc. My understanding is that once the car starts it runs normally?

The high idle can be caused by many things, chief suspects would be malfunctioning ISCV, throttle disc not closed correctly (weak return spring or gunk around the disc) or a vacuum leak.

 

Hi Will,

It would be helpful if you could clarify that the engine continues to run after you start it with Easy Start, or does it run briefly and then die?


It would be very helpful to know exactly which relay you are unplugging and plugging to help the engine start. If you do not have the electrical manual, download it here:

http://www.mediafire.com/download/aa...ng_Diagram.pdf

The relays in the right-hand engine bay include the ECM Controlled Fuel Injector Main relay; the Ignition Positive relay; and the Ignition Coil relay. The electrical manual has illustrations which identify which relay is which.

The Starter relay is in the left-hand engine bay near the air cleaner housing.


The ECM determines cold-start fuel enrichment based on the signal from the Coolant Temperature Sensor (CTS), so the problem with the sensor was probably an intermittent condition that was telling the ECM the engine was colder than it really was, prompting over-fueling.


Even though the fuel pump appears to be working, it is possible that the pressure in the fuel rail is low due to a failed Fuel Pressure Regulator (FPR). This is a very common issue and a cause of hard starting. Have you tested the fuel pressure in the rail? I believe it should be in the range of +/- 40psi.


Identifying the relay you are pulling may give us a clue about your spark condition. All six coils receive a constant 12V supply from the Ignition Coil relay (a black relay in a black base in the RH engine bay), and the ECM grounds each coil individually to charge and fire it, determining timing advance and dwell for each cylinder independently.

As others have said, the Cam Position Sensor (CMP or CMPS) signal is used by the ECM to establish initial ignition timing, then it is ignored and the ECM uses the Crankshaft Position Sensor (CKPS) signal exclusively for timing. If the CMP is failing, the ECM will try various timing options based on the CKPS signal until the engine starts, but it can take a lot of cranking before the ECM figures out which crank position represents cylinder 1 TDC on the compression stroke. You might try simply cranking the engine for a good 40 seconds just to see if it will start without pulling the relay or injecting Easy Start. If it does, that could suggest a problem with the CMP (misadjusted or failing sensor, broken sensor tooth, contaminated electrical connector, etc.).

Hope you track down the issue quickly. I have to drive to Indiana tonight to check on the '93 VDP our son drives at college, which has suddenly developed a no-start condition. Jag ownership is always an adventure!

Cheers,

Don

 

Hi guys thanks for the feedback.
The car does continue to run after starting on the easy start. It runs well after starting this way.
I will check the relays, will check wire colours also.
Will charge battery again as has gone flat after soo much cranking.

 

Have you tried cranking for an extended period without easy start?

A problem with the relays would not cause the issues that you face.

 

So i decided to get back on this car and try and sort it out.
We purchased another crank position sensor as i thought it was worth a try. Still no joy.
Anyway since i knew the relay had caused issues before we started with this again.
This time i wired the relay into some splices which i made just before the connector plug. Started the car and all seemed ok to start but then the car would turn off unless you kept it running with the throttle. If you revved the car up it would rev, but after coming off the throttle most of the time the engine would stall. Sometimes it just barely kept running??
Tried this quite a few times and the car kept doing the same but if you left to idle it would idle around 700-800rpm.
Left the car a bit longer and then it stopped starting again!
This time i cracked open the black and white connectors and have noticed they are very green looking so cleaned back, but still no start!
I think i am going to run some wire splices from either side of the white plug for all the wires and see if it is the connector plugs causing bad connection. This car is driving me mad.
Its a shame because the car is now well out of MOT and has been sat going green on the drive because we can't bloomin drive it anywhere.

 

Ok so the electrical manual doesn't seem to have the correct colour of wires listed for the relay which i am pulling in and out to fire the engine.
I think it is either the ECM relay or the air injection relay?
I pretty sure the wire colours are two narrow gauge brown wires with a colour twist. These are obviously power feed for the relay. These work ok as i can feel the relay click as i plug unplug etc.
There is a black wire, think it has white in it from memory(30mins ago!) and the other is a brown wire, both are much thicker gauge than the other two.
What is secondary air injection, am i miss-understanding this?