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-   -   2003 XK8 4.2L cranks but no fuel (https://www.jaguarforums.com/forum/xk8-xkr-x100-17/2003-xk8-4-2l-cranks-but-no-fuel-279181/)

Shane Goldsmith Apr 11, 2024 03:56 PM

2003 XK8 4.2L cranks but no fuel
 
In need of some help here, shut car off and would crank but not start. Replaced fuel pump still no start. found no power after initial key on when cranking. No codes from ECM. Verified Ignition spark, replaced cams sensors, crank sensor and inertial switch along with fuel pressure sensor and fuel pump control module. No change in car. Shipped ECM to rebuilder in Jacksonville and was told it was done and would have to be replaced. They offered a reman but no programming available to them. I am struggling to know what can be replaced to get vehicle to run without additional programming. Many different answers from folks, thought I would ask the seasoned vets on here. If the speedo, ECM, BCM and ignition key/module from same donor vehicle is all installed at the same time, is additional programming needed to make car run? My availability here in the Florida Panhandle have netted poor results. This was my late wife's prized possession and I would love to get it back up and running. The car only has 107K miles on it and is in pristine condition. Many thanks in advance for all of your help and assistance.

JagV8 Apr 11, 2024 04:58 PM

Before buying such, maybe there's hope. I'm very surprised to hear about the "ECM" as they are very robust.

Have a look for posts about the PATS light.

Also, what codes are there? You should at least have one of P1000 / P1111.

Y2KJag Apr 12, 2024 12:06 AM

Don't take this the wrong way, but stop firing the parts cannon at it. That approach almost never works.

How much diagnosing was done? When it first failed, did you check fuel pressure before replacing the pump? After? How do you know you have spark? You can't have spark if you have a bad ECM. Or if the anti-theft has immobilized you.


Shane Goldsmith Apr 12, 2024 09:54 AM


Originally Posted by Y2KJag (Post 2739911)
Don't take this the wrong way, but stop firing the parts cannon at it. That approach almost never works.

How much diagnosing was done? When it first failed, did you check fuel pressure before replacing the pump? After? How do you know you have spark? You can't have spark if you have a bad ECM. Or if the anti-theft has immobilized you.

The very first thing I did was to screw in a fuel pressure gauge and found no fuel pressure at the fuel rail on the intake. I then checked the fuses and replaced fuel pump relay with a known good one. Still no fuel pressure. Hooked meter up to power wires for the fuel pump and cycled the key, it would run initial 3-5 seconds on key on. Thought maybe I had plugged fuel filter, replaced fuel filter, still no pressure at the fuel rail. Thought it was pump at this point. Pulled old pump out and found bypass hose on fuel pump canister had a broken clip and hose was hanging halfway onto the fitting. Thought, ok here is the problem and replaced the fuel pump and buttoned it back up. Tried to start and no fuel pressure, dug into it a little deeper and thought maybe the inertia switch was bad or tripped as I had just picked the car up from the detail shop. I worked in a shop years ago and our detail shop from time to time would trip the inertia switch when they were aggressively vacuuming the floor and would hit the foot panel where the switch was housed. I reset the switch and it felt like it wouldn't stay depressed but still tried to start it once I reset It. Still no start so I replaced the switch and same result. The whole time this has all been going on, there has not been any DTC codes on the reader. My next test was to see if I had power to the pump at cranking, which indicated I have positive but no ground coming from the harness at start up. I have positive and ground at initial key on but not while cranking. If I provide a ground then I have fuel pressure at crank and pressure at the fuel rail. Still no start condition. In reading some of our threads someone indicated the fuel rail pressure sensor being an issue at times which can shut down the fuel pump signal so I purchased a new unit. No change. Next device that has no test that I know of is the fuel pump control module, I replaced this unit as well and still no start, still no fuel pump power in craning position. For the sake of trying something different I replaced the crank sensor and both cam sensors. No start. Next check was to plug in a replacement ignition coil on one of the coils and cranked the engine, I have physical spark on multiple coils but still a no start condition. From what I could tell at this point was, I have fuel pressure when jumped, I have spark when cranked and I have compression so the only thing that could possible be missing now is the injectors are possibly not firing. It has to have a signal from the cams sensors, crank sensor and oil pressure sender for the engine to allow fuel pressure to start and the fuel pump to run and the injectors to fire. All of which are verified present and working. The missing negative at the fuel pump is controlled by these inputs thru the ECM correct? In looking at the wiring schematic, that is what I thought was the case. I have all key sets for the car and I have tried all three in the ignition and nothing changes this. What am I missing? Thought it was a possible ECM so I sent it to a company in Jacksonville Florida and boy did I ever regret that. They said it was corrupted and not repairable and offered to sell me a reconditioned unit that would need programming once I received it. Their reconditioned units were in the $1300.00 range and still would have to be programmed. I found their pricing to be less than favorable than other sources for a reman. Everyone of them all stated the replacement ECM would have to be reprogrammed once it was replaced. Fast forward, I found a company locally here in the Panhandle that does this programming service and $685.00 later in labor and a $200.00 rebuilt unit and it still is not running. He believes the immobiler circuit has been triggered on my original ECM and that is what has caused the no start situation and he doesn't have the tools to program the replacement ECM. Now you have the full story, My confidence in the local Jaguar dealer is not there as it took six months the last time I took the car in for body work. Have I missed something in diagnosing the no start situation? I am open to all suggestions of advice here. Now you understand why I am asking what needs to be replaced if you do loose an ECM and is it possible to buy all of the items from the same donor car and do install on my car and run the car? I know the vin numbers in the ECM will never match at this point. Many thanks in advance for listening and reading my long drawn out details. I look forward to all of your thoughts and assistance.

michaelh Apr 12, 2024 10:49 AM


Originally Posted by Shane Goldsmith (Post 2740023)
The very first thing I did was to screw in a fuel pressure gauge and found no fuel pressure at the fuel rail on the intake.

Fuel pressure is available over OBDII on the 4.2L cars.

Fuel pump will run for 1-2 seconds after the key is turned to position ii (on)

Do you have B+ on the injector Black/Red wire(s)? Check F18 (10A) in the Engine Management fusebox.

Module replacement is much more involved on the 4.2L cars. See the attachment on this post from motorcarman:
https://www.jaguarforums.com/forum/x...8/#post2719259

Which modules have you changed, and do you have the originals?

Shane Goldsmith Apr 12, 2024 01:43 PM

All original modules are still on the car. I have checked all fuses in all boxes and non have been blown. Will check B+ on injector wire as recommended when I get home today, will let you know what I find out. Thank you for the assistance, I greatly appreciate it.

xalty Apr 14, 2024 06:09 PM

do you have injector pulse?

bladerunner919 Apr 15, 2024 03:36 AM

It would be worth just looking inside the fuel tank again to make sure all is well. I had a fuel pump failure recently, fitted a new one and still had no fuel pressure. Turned out that the output hose had come off the pump, despite me being certain it was securely attached. The new pump was running, but just squirting fuel around the tank. One thing I did notice was that after each crank attempt, there was pressure in the tank, and a whoosh as I removed the fuel cap, presumably as a side effect of the pump running. Might be worth just checking for similar.



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