Hello folks

I have a 2004 VDP 4.2L V8

I posted about few weeks ago that I had a restricted performance upon warm startup.

The vehicle is now currently at a local shop and I was told that the vehicle is running rich. there was white/blue smoke coming from the exhaust but it didn't smell like anything except for gas. It had a heavy gas smell. The shop suggested changing the Fuel Pressure Regulator and if it continues to change the BCM cause that also controls the fuel dumped into cylinders. They also said it could be a broken fuel injector but before I start throwing money on parts wanted to see if memebers here had gone through the same experience and how did they go about fixing it.

Please, any input will help..

Best
Sam

 

Hi Sam,

It sounds as though the shop is just guessing and asking you to pay for parts until the problem is solved. By that method, you may run out of money or patience long before the car is running properly.

Has the shop scanned for stored diagnostic fault codes (DTCs), and if so, can you please post the codes they scanned so we can help with the diagnosis? The codes will be in the form of the letter P followed by at least four digits, such as P0172, P0175, etc. Knowing the codes will help us know if only one or both cylinder banks are running rich, and help narrow down possible causes and will also probably explain the cause of the Restricted Performance you were having.

I assume the shop must have said that if replacing the FPR didn't work they would replace the ECM (Engine Control Module), since an X350 does not have a BCM (Body Control Module), and on the earlier Jaguars that do, the BCM has nothing to do with fueling.

By the way, it is very rare that an ECM needs to be replaced.

Please post all the codes that were scanned and we'll try to help.

Cheers,

Don

 

Get it towed to a qualified Jag shop (dealer or indy) but they need to be qualified or it's going to get very expensive fast, and the bills will keep coming as they keep guessing.

 

It is easy enough to pull the fuel rail off and bench test the injector's. To me this is either fuel regulator or injector issue. Without codes it is very hard to troubleshoot. I have a full service manual for the X350.

 

Sam, a couple of things to consider and check. When a vehicle is already warm and left to sit for a while and you come back and restart and find it flooded by fuel, you will more than likely find that injectors are allowing fuel to pass. Jaguar does not use a return line to the tank, so there should be residual pressure left in the rail. I would suggest that you check for pressure in the fuel rail after allowing it to sit for a bit, and if pressure is gone, start thinking about a set of injectors.

This issue can also manifest itself at idle, and the condition is generally seen by watching lambda and as it sits there and idles, you'll see a huge sudden jump to the rich side, the idle will stumble and slowly return to normal. It can also be experienced at warm restart and it won't idle well, if at all, and throw codes of misfires on any or all cylinders.

A set of new injectors can run from around 400~450 depending on who you get them from. Injector issues is not that uncommon.

 

Why hasn't the shop checked DTC's. A simple scan tool can check fuel rail pressure's, injectors, etc without pulling out a wrench. Sounds like they are just willing to throw YOUR money at it to fix it.
Don and Box are right on the money with the fuel systems low failure rate. Get the car read, or use the mech's checkbook.
Let use know what the codes, and data is.