Car is slow to start,whines a little ,can run fine for a while then will sputter and stall, will restart but then stalls again ,relay under glove box clicks a lots,loss of power I geuss, have replaced fuel pump and fuel filter and checked and cleaned all electrical plugs under bonnet,it is a loss of power of some sort.Any one had a same problem. Help

 

Laza,

What model year and engine are we discussing? Were the same symptoms present before and then after the fuel pump change?

 

1988 Daimalr VDP,Yes,the problem was there before I changed the fuel filter and fuel pump, I bought the car a while ago 3 months maybe, drove it around no problems then started to cut out abit but only got worse,the only thing I have changed is the radio cassette for a CD player and of coarse the fuel pump and fuel filter, I thought it might be a bad earth but it still there

 

Sorry it's a 3.6 litre
Thanks
Laza

 

Laza,

Two things come to mind, the first is the Throttle body and it's TPS (throttle position sensor), the other is your Crankshaft Position Sensor. Not sure of your mechanical ability in diagnosing a problem, but the first suggestion is something the DIY'er can do with little or no expense, except of course, if the TPS need to be replaced.

In regard to the first item, it is a matter of removing and cleaning the throttle body and the TPS, re-installing and then adjusting the TPS correctly. Note: the TPS needs to be re-installed properly so it provides the appropriate voltage to the ECU in the throttle closed position.

In regard to the second item, Crankshaft sensor, the sensor can produced symptoms you described if not working properly. I have no experience with this component, so hopefully someone who does will chime in on this post.

There are a few other electronic components which could produce the symptoms, but are usually not the main contributors.

Process of elimination, do you have either the JDHT service cd's or a Haynes manual?

 

Your losing fuel pressure and/or spark. As noted above get yourself the CD's or Haynes manual. If you are not a fly by night Jag owner, and plan on working on your cars, start getting some tools. CPS you'll need one very long 3/8th's extension or 2 together. I believe it's a 8mm hex, 8 or 10 from memory. You will need a fuel pressure gauge as well.

If your car has been sitting, it's probably water throughout the system. It needs to be drained. Sounds to me like water. If you haven't done so go introduce yourself in the new member section. After you get some posts under your belt you can use the search functions within the XJ40 section. Plenty of info here on your situation, I'm one of them.

 

Thanks guys . I have drained the fuel tank when I installed the fuel pump no water but did have water around the fuel filler one day it rained I then cleaned the drain hole,Replacing dizzy cap leads and plugs today and will look into these issues and get back to you Thanks again Guys

 

Laza,

One other item I overlooked earlier is the oxygen sensor. It will also produce symptoms as described when not operating correctly. I had to replace mine several years ago. I would be running along just fine, then suddenly the engine would go into a type of "lull" (not stall), then back to full power, then repeat the behavior, then would stall out eventually. Usually happened after the engine warmed up.

Not sure if you're new to the XJ40 (as in owning one before), but it is well worth the effort of going through the trouble shooting process before buying components. If you don't have them, get either the Haynes or the JDHT Cd's to assist.

A few other items to investigate would be the MAF (seriously doubt this is the problem), or you may need to pull the fuel rail and service the fuel injector's.

Again, process of elimination.

Good luck, keep us posted.

 

Yup, that will do it, there is water in your system. Fill that tank with fresh fuel and put a pint of dry gas in there, keep starting it, eventually she will go. Unless of course, that's just one of your issues.

 

Hi,

Seconds Robs suggestion. Had exactly same problem. Changed Fuel filter and Oxygen sensor. Fine after that.

 

Laza,

If you want to put the water issue to rest, go to your auto parts store and purchase a product called "Heat" in the fuel additives section. It's in a yellow bottle w/long neck, blue label. I have used it on occasion when I definitively knew water in the fuel was the issue (loose fuel cap, my fault). You'll need to turn the engine a few times to work the additive through.

If it is water, the Heat will eliminate it and all should be fine. It's not expensive, and much easier than draining or siphoning the fuel tank out.

We have very similar models, a little water in the fuel filler latch box assembly does not immediately conclude water got in your fuel tank. If you cap is tight, water shouldn't enter the system. This latch box assembly is an area where you want to monitor, call it poor design, but the drain hole does plug easily with debris.

Since we're on the subject of water/moisture, is your boot in good to great shape? Is there signs of an excessively damp conditions in the boot, such as the mildew aroma, the carpet kit has been stained/mildew, or there are signs of rust under the carpet kit?

 

Ok guys Ill look into it you have given me lots to thing about and check and yes the boot was wet, carpet medew and fuel filler did have water around the cap after rain,items changed so far fuel pump,fuelfilter,fuel relay,spark plugs still waiting for plug leads and cap.
This is my secound Jaguar first was a 1978 XJS lovely car and yes I do have a both Manuals but new to Electrionics Cars XJS was much easier to work on, but hey Iam learning...
Thanks Larry

 

Laza,

Taken from my own painful experience, thoroughly investigate the source of moisture in the boot. I had to pull my fuel tank this past summer due to a leak caused by rust on the bottom of the tank.

I had two places where water entered, first was the rubber gaiter in the latch box assembly had some finite cracks which allowed seepage into the boot, the other was the finish strip located near the bumper/boot lid. It's more visible when the boot lid is open, it runs between the tail light assembly's. If yours is like mine, you will see four set screws holding this plastic strip down. Water seeps under the strip and then through the screw holes and finds it's way into the boot.

What happens is the water condenses and fills the boot with humid, moist air and it settles everywhere, especially on and under the fuel tank. If you do find cracks in the gaiter, you might as well pull the tank and examine it as a precaution. You're going to have to loosen the tank anyway to replace the gaiter. It's almost impossible to replace the gaiter without disrupting the tank, though I have heard of some doing it, and I think it was an 88 MY where it was accomplished.

 

A couple of weeks ago my '94 4.0L started hesitating at stop-lights when I gave it gas, just a momentary thing which only happened when cold - but two days ago it wouldn't rev up from idle when I first pulled out of the garage and sputtered and missed unless I backed off the gas, almost stalling out. Tickling the throttle it finally picked up and drove normally as it warmed up.
I pulled the hoses off from the throttle body and associated breathers today and found a bunch of oily muck between the MAF sensor and the throttle body, mainly in the big hose but also in all the breathers, return hoses and around the air temperature sensor.

After a good cleaning and reassembly, she runs great again with no hesitation or miss...I don't think this gummy muck is unique to my car so may be something to check if she's still running rough and you've eliminated the water/electrical problems.

 

here's a link to a diagram of the bits I'm talking about, good luck

http://www.jaguarclassicparts.com/uk/ja ... -4-0-litre

 

Lawrence,

What do you think the "gummy muck" was? I had my MAF off a few weeks ago for the first time in years and didn't run across anything like what you described.

 

Hey Rob,

It was brownish and milky - kind of a mix of thick old oil residue with water making it milky.
I think the oil was from the valve cover breather, looked like it hadn't been cleaned out in years - the water? not sure - maybe the damp atmosphere up in the pacific northwest?
I don't have any water in the sump or any trace of it on the dipstick so I'm guessing it came in via the air intake OR there was a problem with the head some time in the past and after they did the head didn't bother to clean out the throttle body?
The big fluted hose is where most of the guck was, it's the low point in the system so I guess it would be natural for it to sit down there in the flutes.

What do you think?

 

Lawrence,

Not sure what it is, glad you found it before you had real serious problems. Sounds like your theory with having previous head work done has good reasoning for the source of the substance...... must have been quite an event to blow oil back to the MAF. Wow.

Did you pull the throttle body and TPS when you made the discovery?

Laza....sorry to hijack your post....we're still here to help

 

No Rob, I left them in place, the throttle body wasn't too bad, I was able to clean the butterfly up without removing it and didn't adjust the tps. The muck didn't go back as far as the MAF, the elbow was about the limit of the stuff and was pretty caked up.
When I first got the car the oil level was way overfilled - don't know how long it had been like that - maybe some of the excess oil got pushed up the breather and back into the intake?

 

Hi Guys
Could not find any product call Heat!! to get rid of the water , not sold there but Methylated spirits has made a differents will check the MAF senor next.
Thanks Guys