1993 XJ40 4.0L finally got the correct fuel pump and replaced it. Real fiddy job. Have same problem. No codes, trans X'ed, starts but sputters if you give any throttle. Don't know if maybe crank shaft sensor or fuel regulator, nothing seems to match in past threads. Any help please. I am very frustrated, I can normally get things working.
Thank you,
ProQuest

 

Have you actually put a pressure gauge into the system to test the pressure?

 

Thanks Steven, I saw your pressure rig post and will have to get some metric adapters so that I can test the fuel pressure. The transmission light on the dash is X'ed out early after starting up. That is got me troubled, also. No codes on the VCM is troubling too. I would expect something to show up. For the crankshaft position sensor, what are the symptoms? Mine starts and seems smooth at 850-900 RPM's, but if I touch the gas it hesitates and drops to 400-500 (barely stays running) then I let off and smooth's out at 850-900 again.
Do you think the transmission is a separate issue?
Thanks for your help.
ProQuest (Richard Dean) Washington State
1993 XJ40 4.0L VIN 669499
1983 XJ6 series III

 

I didn't follow your topic so sorry if i repeat after anyone.
First I would not count on VCM much.
Then maybe throttle position sensor is failing? you can test it with multimeter for smooth operation you can also try to disconnect things like MAF CTS one at the time and see if it changes anything, check FPR for leaks and smells. and spray starter fluid around to see if there are vacuum leaks, you could also try disconnecting one injector at time and see if it allows you to rev higher.

 

Have you checked the fuel filter?
A mostly but not fully blocked filter will allow small amounts of fuel through at high pressure but will block large amounts of fuel and drop the pressure so the engine will not rev up and will try to die.
I had this happen on a Series 3 XJ6

 

xjack, I will try your suggestions, Thanks. Bill Mac, I should have posted in this thread that I had replaced the filter. I had another thread trying to find the right fuel pump for my VIN (went Carter P72222) and looking for the filter O-rings (CAC89682). Systematically working thru the parts to get it back on the road. Have a Seattle Jaguar Club get together 5 August that I want to drive 200 miles or more (depending on if I take ferries). Thank you for your help.
ProQuest (Richard "Dean" Dean)