Hello,

I need your help guys. I have strange problem with my car.
When I try to start engine sometimes everything is fine, sometimes not. Engine is cranking but after 1s rpms are going low and he dies. After second or third launch engine is Working, has power, no issues...
The problem appears on warm engine after 5-10min brake, but sometimes on cold.

Sometimes starter is launching engine with 1s brake a with metal knock and then it is starting and run perfectly. Do you know what is going on?

Crank Sensor is ok, New sparkplugs and coils. The problem is more visible in 20 and more C degrees whether.

 

I forgot to add that starter has been checked 2times and all parameters looks fine. I have checked all ground point in the car and no errors found using obd scanner

 

Hi Sceleton,

Welcome to the Jaguar Forums. It's great to have you with us.

I'm sorry to hear you are having trouble with your X300. Difficult starting when the engine is hot after being shut off for only 5 or 10 minutes could be caused by a failed Fuel Pressure Regulator (FPR), which is supposed to maintain approximately 40 psi of fuel pressure in the fuel rail. If the FPR no longer holds pressure, when a hot engine is shut off the fuel in the rail experiences a sudden loss of pressure, which boils or vaporizes the fuel. This creates classic vapor lock and the engine won't start again until all the vapor has worked its way through the injectors until liquid fuel has again filled the rail, or until the vaporized fuel condenses back to liquid.

One definitive test of the FPR is to pull the vacuum hose off and, while cranking the engine, look for wet fuel at the hose fitting which indicates the diaphragm in the FPR has failed. But even if the FPR isn't leaking fuel through its diaphragm it can be no longer able to maintain the proper pressure.

A failed FPR can also cause problems when starting the engine cold.

How did you confirm that the crank sensor is working properly?

Another thing to be aware of is that if the battery voltage falls much below 11V while cranking, the Engine Control Module (ECM) will not trigger the ignition to fire.

For other ideas, check out all the possibilities at this thread, compiled by our member aholbro1:

https://www.jaguarforums.com/forum/x...ngines-120221/

Also, since we're a friendly group, please visit the New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum and post an introduction so we can learn something about you and your Jag and give you a proper welcome.

Cheers,

Don

 

Thank you Don for your detailed information. I will check it then.
What about Fuel filter? Could it caused the same symptoms? I'm not sure when it was replaced but I will also check it. I think if the fuel filter will be dirty then I should notice a performance problems in hi revs, but after start engine is working normally with huge power I have to mentioned that engine is not working perfectly. I see random vibrations in idle but also during revs. My collegue told me that it can be caused by cracked exhaust manifold.

 

How did you confirm that the crank sensor is working properly?
We switched the sensor by new one from Lucas and sympthoms are the same


Another thing to be aware of is that if the battery voltage falls much below 11V while cranking, the Engine Control Module (ECM) will not trigger the ignition to fire.
I have new battery since one year, alternator is producing 13,9-14,1V on warm engine, sometimes is going lower on hot days 13-13,5V. before I'm start the engine the Voltometer on dashboard is showing only 11,5V on cold even 11V but I guess it is not so precise.

 

Hi Sceleton,

You should replace the fuel filter to rule it out as a possible contributor to your symptoms. The filters are inexpensive and easy to replace.

Regarding your battery voltage, it really doesn't matter how new the battery is if it is not being properly charged. A common cause of poor charging is corrosion on various power connections throughout the car (alternator, starter, bulkhead power connection, fuse boxes and fuse box protection modules, battery terminals, and the related ground points).

Unfortunately, you can't rely on the voltage gauge on the instrument cluster. You'll have to test the battery voltage across the battery terminals while cranking the engine, preferably with an analog voltmeter that can react quickly to show the true voltage sag, or have it professionally load tested by someone with the proper equipment.

You mentioned that you have checked all the ground points. Did you just inspect them visually, or did you disassemble every ground connection, clean the stud, wire terminals and nut with a wire brush and zero-residue electrical contact cleaner, and then reassemble? It doesn't take much surface corrosion to reduce current flow to ground, which can cause all sorts of electrical gremlins.

Cheers,

Don

 

Hello,

Yes I will change the filters. I've downloaded the pdf file with electronic connections and all have been checked, disassembled every ground connection, cleaned with zero-residue electrical contact cleaner but without wire brush. After that I have always 14,5 v on cold. Before that I had 14V.

 

Ok, filters replaced. Problem still exist. I know how to simulate it.
Examppe: When I drive to the gas station and tank fuel on warm engine. fter 5min when I try to start engine, he starts but then rpms are going up and down between 300-500rpm and engine dies after 2-3seconds. Next crank takes 3s and nothing. after third crank engine starts perfectly.

So should I check the regulator now or maybe something else?

 

Guys,

One more thing! Probably I found the root cause. What are symptoms of not working properly immobiliser. I found the P1621 code by OBD Scanner.
Where transmitter is located? in key or in pilot? I think that randomly there can be issue with immo sync. That is why the engine starts and is dead after 2-3s. Rest of fuel is comming to engine and nothing more because of fuelpump cut? key is removed from ignition switch and after second time engine starts and works correctly. what should i check? dashboard or pilot?

the question is: If immo is not working should starter crank and only fuel pump is cuting the pressure or the started should even not move?

 

Sceleton your theory about the immobiliser is interesting. I once got caught out by a Mercedes which would crank and start but as soon as you released the key from the crank position the engine would die. Eventually we realised that we were using a spare key which did not have the RFID chip. When we used the right key the car started and ran normally.
In the Jag the fuel pump is switched on by a relay driven by the ECM. The ECM is connected to the Security Module "fuelling inhibit" line.
The starter is controlled by the BPM which also is connected to the SCM.
Maybe you could monitor the voltage at the fuel pump wires to see if it is energised or not when you get the problem at startup?

 

Problem solved. Fuel Pressure Regulator replacement thank you for help.

 

Well done, and well done Don B; called it on the first bounce. Impressive, and hats off!

 

Hello,

I didn't had time to post a message, but I didn't solved my issue. I thought that regulator solved the problem but I was wrong. It seems that it is related to engine temperature.
On hot days to simulate this issue I had to wait 10-15min. On cold days like now we have in europe the issue is visible in 5-10min after engine is turned off.
so: Engine is starting to 1100 rpms going down to 500 and next to 0. Second start is impossible. I have to wait 5-10seconds and third attempt - the engine is starting in 1 second! I don't understand why? Could it be related to temperature sensor or what?
usign OBD temparture looks ok, the same on dashboard...


I've checked OBD codes and only one result: P1621

What about Coils and spark plugs? Can they cause such sympthoms? I've changed spark plugs 1 year ago but they are not "champion". Probably other brand. Don't remember.
Also coils have been changed to new ones but not Jaguar original (Some substitute).

 

Dear All,

I need your help. My problem has not been resolved yet. During the Autumn & winter problem was not visible due to cold days. Now, when the weather is better and we have warmer days problem came back with double size.

When the engine is hot after 3-5min (on gas station etc.) I'm not able to launch the engine. After first turn engine starts and is dropping to 200rpm and he dies. next cranks gives nothing. I have to wait 10-15 min to launch the car back and then everything is fine. There is a power and car works perfect. Ok.... maybe there are little engine vibrations on idle but rpms are not waving.

What has been checked:
- crankshaft sensor (was replaced 3 years ago 40 000km) but it is working fine
- camshaft position sensor - works
- temperature sensor - shows 90 so seems that works fine and 30 on cold.
- AIr temperature sensor - works
- sparkplugs are new (but after replacement nothing changed (NGK V-Line) - previous sparkplugs looks ok after 20 000km (grey color)
- coils are new
- pump is working
- p1621 - immobiliser?
- oil level is fine
- fluids are ok
- nothing bad from exhaust (no blue or white color)
- pressure regulator - new
- TPS is showing 11,4% during crank and it is working fine in all range
- Fuel and air filter are new


Please help

 

Sceleton,
I would look back at Don B's earlier reply. This sounds like fuel vaporisation, which would only tend to happen on a car with fuel injection if the fuel system loses pressurisation.
I have only experienced it in a classic car with carburetors, where the system couldnt cope with the much lower boiling point of modern fuel. Symptoms exactly as you describe, but fuel system working on much lower pressures than an injected system. Pressurised fuel has a much higher boiling point.

 

Yes, it looks like fuel vaporisation, but you sure that engine will not start after 3-4 attempt if there will be vaporization anyway?

What about sparkplugs? maybe sparkplugs are flooded after first crank on warm and I have to wait 15min to dry up?

My mechanic said after sparkplugs replacement that they are white gray which can means that there fuel/oxygen mix is too lean, but i don't think if this can cause the issue above.

Other idea is that there is an ECU problem iself maybe?

this issue is repeatable only on specific condition when engine temperature is around 85-90degree. On winter when car is cooling down in shorter period is really hard to simulate this behavior.

 

Hi Sceleton,

I'm sorry you're still having trouble with this issue.

The component that works together with the fuel pressure regulator to maintain pressure in the fuel rail is the check valve, or non-return valve. If the check valve loses its ability to prevent backflow, then the fuel rail is pressurized only when the fuel pump is running. When the engine is shut off the fuel pressure immediately dissipates, leading to vapor lock. These are the same symptoms as a failed fuel pressure regulator, and it's common for both the FPR and check valve to lose their proper functionality over time.

The best next step would be to check the fuel pressure at idle, when revving the engine, then for about 30 minutes after shutdown. If the pressure falls immediately after shutdown or falls significantly within 30 minutes, suspect the check valve since your FPR is new.

On an X300 the check valve is part of the fuel tank outlet hose fitting, so it is not replaceable. A more convenient option is to add an additional check valve in a rubber section of the fuel line somewhere between the tank and the fuel rail. I haven't done this on an X300, but I did it on our '93 XJ40 using inexpensive parts from McMaster-Carr. If I had to do it again, I would have just left the check valve at the inlet side of the fuel rail instead of moving it to underneath the fuel tank. I didn't notice much difference in performance.

I tried to add a link to my photos of the new check valve installation but the jag-lovers.org link isn't working at the moment. See the link to my photo albums in my signature and maybe it will be working again later.

Cheers,

Don

 

Thanks Don for your feedback! I will also check this non-return valve. I found yesterday this movie:
I have the same sympthoms so maybe I should also check the injectors?

 

Hi,

Issue has been solved - I hope ......It was faulty Blue (fuelpump) Relay .
We checked relays but wrong one - brown in the past.

After replacement everything is working fine - so.... environment's temperature has impact on metal inside the relay (was not contact properly when key was switched to ignition, or worked randomly)

 

Don't know why I didn't think of this a few days ago...but beware, failing fuel pump relay is often a sign of impending pump failure.