How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Matt Your Own Question
Matt
Matt, Engineer
Category: Jaguar
Satisfied Customers: 21482
Experience:  Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
12772297
Type Your Jaguar Question Here...
Matt is online now
A new question is answered every 9 seconds

My 2000 jaguar s type looses power after about 20 minutes of

Customer Question

my 2000 jaguar s type looses power after about 20 minutes of running when the engine is cold. it will idle but when i give it gas it will not accelerate. if i shut it off for about 5 minutes it will start and run with power for about 3 or 4 miles and loose power and can barely go 5 miles per hour. no trouble codes
JA: Has the vehicle turned into a gas hog? And how does it start -- same as usual?
Customer: it is a 4.0l
JA: What is the make/model of your car?
Customer: it is in my first paragraph
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: the engine was just rebuilt
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 7 months ago.
Category: Jaguar
Expert:  david craig replied 7 months ago.

Hi Im David, you said after running the engine for 20 minutes the engine is cold?

Expert:  Matt replied 7 months ago.

Hello

another expert here

This sounds like a lack of fuel and could be a lack of fuel pressure from the electrical pump at the tank.

1st thing to try is to remove the fuel filler cap and then flick the ignition on whilst listening for the brief ‘buzz’ of the pump

If the connections to the pump are corroded or damaged then the pump could stop at any time or could not be running at full speed. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse,

Ideally measure the pressure at the injector rail (should usually be around 3Bar / 45psi +) and if this is low check the pump as described and also consider changing the fuel filter as if this partially blocked this too will reduce pressure.

You can also get this issue with contaminated fuel , if there’s water or dirt in the tank then either the petrol floats on top of the water or the filter sock on the pump is choked up – so if the other things check out then I’d consider pulling out the fuel pump and cleaning the filter sock

And one other thing to try is to loosen off the fuel filler cap, as there’s a 1 way valve built into the cap to let air into the tank and so prevent a vacuum from being created as the fuel leaves the tank to the engine

If this helps then replace the cap with a new item

Ideally I would pursue getting a scan tool plugged in so you can monitor the engine readings and see if there's any lodged fault codes

Expert:  Matt replied 7 months ago.

Hi

do you still need help?

Bear in mind that the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. I am only paid for my work on this question if you rate my answer, using the star system at the top of the screen. Please do not forget! Thank you