My 1996 VDP with 130K miles is giving me fits. Recent history is this: about a year ago the car started bucking. After months of trial and error it was determined that the ECU was intermittently not sending the signal to run to the fuel pump. Sent the ECU off and the fault was found but was deemed to be not repairable. I was able to find a replacement on Ebay with the same numbers. The problem went away. When I drove the car home, after maybe six months, the check engine light was on (P1313,1314,0300). I thought no big deal as the car had been sitting a good bit. And it sat outside in the weather. I thought water in the fuel tank maybe. So I put three different fuel cleaners in (three different times) with no success. Historically when that has happened I put in new Champion plugs and coils. I used QYL coils from Amazon. No success.

The CEL comes back on fairly quickly when I erase it. The engine signs/symptoms are periods of time when the engine exhibits something I would call "runs at half power". When it does that, with no movement of the throttle the engine goes back to full power after a few seconds. Like when a turbocharger kicks in.

I bought two extra ECUs on Ebay. None have solved the problem. The engine has a new Jaguar brand CPS, I've switched the TPS with another to no avail, the TB is clean, and a new Denso fuel pump/relay. I've been driving Jags since 1982 continuously. I love them. I've never experienced anything like this.

I'm hoping someone out there knows exactly what it is. Many thanks in advance.

bliving7
I drive the car daily hoping the problem will just go away.

 

Hi bliving,

With random and excessive misfires in both banks, your suspicions about contaminated fuel seem reasonable. The horizontal orientation of the fuel filler neck on an X300 makes it easy for water to sneak in past the gas cap seal in heavy rain, or even in light rain if the rubber gaiter drain is clogged. If there's enough water settled at the bottom of your fuel tank, fuel dryer additives such as Heet may be unable to help all the water to combust in the engine. You can use the car's fuel pump to remove a few gallons or more of fuel to see if things improve. To do so, disconnect the fuel inlet line at the firewall end of the fuel rail, attach a piece of hose such as 5/8 inch I.D. heater hose or garden hose and direct the other end into a suitable catch container. Remove the fuel pump relay in the trunk and use a large paperclip bent into a U to jump the load contacts in the relay socket (terminals 30 and 87 or 3 and 5 depending on how your relay terminals are numbered). The fuel pump will run and pump fuel into your catch container.

In my experience, the OBD system in the X300 is not always able to accurately identify cylinders that are misfiring,

Have you checked for oil in the spark plug wells?

Have you inspected the coil wiring harness for brittle/broken insulation causing intermittent shorts, especially at the rear end of the head where the harness bends?

Have you done a compression test on all six cylinders?

Are you certain your fuel pump is operating consistently and there is no problem in its electrical circuit? Have you replaced the fuel filter?

Have you cleaned the ground points, especially those referenced by the engine management system including the engine ground strap?

I'm attaching the DTC Summaries which gives possible causes of P0300 (and P1313/P1314).

Please keep us informed.

Cheers,

Don

 

Lets get you started with a flood of information and then you can whittle it down into AJ16 engine regulation compartments


http://www.jagrepair.com/images/Trai...20-%202000.pdf

The fuel pump will come on for 4 seconds to charge the fuel rail and then turn off until the ECU sees engine rotation through the Crankshaft position sensor

This will give your # 1 fuel pump the 3rd click on for the duration of your drive

You will most likely not see a CEL code on a lower and not fully failed Crankshaft position sensor failure

The sensor can get metallic and grease debris on it other then a dirty connector in the bad wet environment

To skip the fuel pump relay control logic you can just remove it and jjumper socket 30 to 87

Or just put power on socket 87

The CEL code on a 1996 for Crankshaft position sensor is P0335 ( if it shows ) on page 130 something , my eyes are bad tonight

 

Thanks Don. I'm going to pursue the water in the fuel thing for a bit and see what happens. Today I put a bottle of HEET in then filled the rest of the tank with non-ethanol premium gas.

Bill Livingston

 

Thanks Lady P. I will try easier things first. \

Bill Livingston

 

QYL coils..... Watch the coils... There are expensive ones and cheap ones... and there are cheap ones sold for high prices... The cheap ones fail quickly and often are bad out of the box... go with the expensive coils... get them from a reputable Jag parts house not from amazon or ebay. You'll only have headaches with the cheap ones.

 

Thanks. I bought a new 1995 XJ6. The original coils lasted ten years. I got Jaguar replacements for around $150/per. They lasted another ten years. After that it's been a crappe shoot. But I'm aware of bad coils and replace them readily.

 

I have never had good luck with cheap coils on XJ6. The only ones I found to work reliably were the made in Japan by diamond. My el cheapo coils worked fine for 3-4 months then the car started running poorly and having idle issues. The problems got progressively worse until the coils were replaced again, this time with the expensive coils made in Japan. That cured my idle issues for good.

 

I have been running QYL coils for 2 years now, so far no problems.

 

The latest is that my car's CEL has been off for six days. But the car still suffers from engine sags. But I think that they are getting less frequent and shorter in duration. I'll keep you posted.

Blivingston

 

Looking at the print the Papa Indy 1 and 61 connectors get corroded and was addressed in a Jaguar TSB

There are several engine regulation wires that run though them

 

Where is this connector located ?

 

Behind the right headlamp, near the windshield washer reservoir filler neck, which is visible in Parker's second photo.

Cheers,

Don

 

Hey, thanks. I disconnected those two connectors today and reconnected them. Did not spray cleaner or anything. No change in the symptoms. So I'll keep trying to clear the gasoline for a while since I can't thing of anything else to do.

Bill Livingston

 

Bill,

While you had the connectors apart, did you inspect the metal terminals for signs of corrosion, arcing/burning or melted plastic, and did you check the insulation on the wires attached to those connectors? Problems with those connectors are very, very common.

Cheers,

Don

 

Before you change the Papa Indy 1 or 61 connector you can jumper around it with the suspect wire

The X300 does not have a anti siphoning fuel fill neck and the old fuel can be pulled out

Does the fuel pump relay click with your finger on it ?

The fuel pump relay command wire to the ECU goes through the Papa Indy 61 connector as the Pink / Brown wire in position 7

This is a ground command provided by the ECU so any ground will work




In case the ECU is losing it's 2 power sources swap the RH engine fuse box relay ( ignition positive relay ) with the LH engine fuse box relay ( only runs the horns )

And the large ECU controlled relay with the fog light relay

 

Thanks. Looked there today and there is a white connector there, however, it has only 3 wires. Looked at all other connectors in the area just in case mine are black instead of white. They all looked clean. Now my speed control wires that i looked at made me wonder how it ever worked. Wires to the small motor are bare.
Dumped some injector cleaner in the tank. Couldn't hurt.
Uf i put my meter across the injector leads and check voltage, should i not see a drop whenever the injector is grounded by ecm?

 

The injectors have 12 or B + volts sitting on them with key on through the ECU controlled relay

The ECU provides a timed ground

You may see a bip when grounded

The car can not drop below 11.4 volts or the ECU will not function properly

Now my speed control wires that i looked at made me wonder how it ever worked. Wires to the small motor are bare. ?

 

Yeah, visually all was well.

Thanks.

Bill Livingston

 

The vertical cylinder in front of the square ABS brake module is a traction control throttle retraction motor ( an option not on all vehicles )

It is common that the 2 wires coming out from under the cylinder has the insulation come off

These 2 wire I assume are not powered unless the ABS module sees a increase in wheel speed ( spin ) in a rear wheel relative to the front 2 wheels