need help, cranks, and fires but doesn't start, drove fine for last 2 months, drove last night, but this mroning doesn't want to start. possible things i can check? i'm assuming fuel is the problem

 

do the tanks contain gasoline? Often overlooked fact.

place the shifter in First gear, turn ignition switch to START and hold it there for 4 or 5 seconds, can you hear the fuel pump humming / whirring in the trunk?

 

there is gas in tanks, at least the gauge is reading almost 1 half. I will check if i hear a hum tmmrw, thank you for replying!

 

had my ear right down in the trunk carpet, not hearing a humm or whirr. am i to assume fuel pump is bad?

 

It's a fair assumption. But, double check by bypassing the fuel pump control circuit. In simplest form this could be done simply running a long wire from the battery "+" post to the fuel pump "+" post. If the pump still doesn't hum, then it's no good. If it does hum, then we can help you check the circuit.

Or, if you don't have a long enough wire, unplug the fuel pump relay from the socket. Take note of how the wires are arranged in the socket. Jump the white/green wires to the white wire. This will supply 12V "+" voltage to the pump with the key turned "on"

Cheers
DD

 

yes, the fuel pump makes a buzzing or humming or whirring sound when it is running. You can hear the pump just sitting in the driver's seat with the shifter in first gear or in Drive and turning and holding the ignition switch to Start. The engine will not crank in first gear or Drive but the fuel pump runs.

follow Doug's test above but also check the Inertia Fuel Cutoff tripper. Located in the passenger side, under the low end corner of the dash, behind the kick panel, a black box with a pushbutton on top and a plug with wires at the bottom. Push the pushbutton down to see if it "clicks". If it does, it was tripped and the engine will start.

If normal, the pushbutton will spring back, no click.

another test will be the Cold Start Injector. But the Start Relay test is important.

 

Does the engine seem to start when you turn the key to "Start", and then die when you release the key to "Run" position ?

 

i can hear a click near the trunk when we put it to start, and when the engine was cranking i could hear the fuel pump hum when i had the trunk carpet and spare cover off. i will try the inertia cutoff switch. it will crank, fire and every few cranks will actually start up and run at idle for a couple seconds then die off, could it be a clogged air filter? how do i change or clean the filter

 

today we trie again to start, when we had one crank the engine, we had one at the trunk to listen for the fuel pump, i heard it hum loudly when the engine cranked

 

doesn't sound like a fueling problem to me, if the fuel pump is humming, it is pumping. Did you click the inertia switch button?

 

going to try it now, so i should see if it clicks when i push down? what if it doesn't spring up?

 

okay tried inertia switch, it is pressed down. when i put it in drive and turn key to start, i do not hear fuel pump in trunk, but can hear it when i crank.

 

a couple times it started up and ran for a few seconds at idle speed, even after key was released to run

 

Okay, sorry for my confusing messages, this is one of our dailies so very stressed and cold outside. We put it in drive, and put it to start, 03. we could hear the fuel pump from drivers seat. so pump is fine. not the inertia switch because it is starting and runnign for a moment then dying.

 

it looks like it is not an issue with fueling.
Since you drove it the night before it is puzzling.
​​​​​​Must be an electrical component, like the coil or the ignition module, or even the ignition switch itself.

try this: when you get it to start, grab the ignition key and turn it very lightly towards the start position, (towards the right), but very lightly, to see if the engine stays running as you hold the key.

 

ok i will try that now, just going to wait for the battery to charge back up. majority of time it is cranking and firing, but not starting up, and then a few times it will start for a sec and die. if i short the white connector by the fuel rail, i am able to squirt fuel in and get it to run at idle for like maybe 3 seconds, but then hope falls as it dies again. could it be a fuel filter?? if not that all i can think of is some kind of electrical malfunction. could a camshaft position sensor cause it not to idle for long? i even took out the air filter and cleaned it, hoping maybe it was that. if i can't fix it myself in the next few days i am going to take it to a european car shop near me, hoping they can get it fixed easily

 

Hi XJ6_1984, have you changed the fuel filter to check for rust/crud coming from tank. Have you tried switching to the other tank? This sounds like classic fuel starvation to me. I know you started the thread by saying the car ran the previous day and then wouldn't start except for occasional firing/brief run. A cruddy tank screen or nearly plugged fuel filter or plugged pump inlet screen (if it has one) might just have had "the straw that broke the camels back" between the previous day and the following day. Sounds pretty sketchy, but we all know that a filter or screen will eventually plug up if fed enough contaminants and if it isn't that time now, when will it be?

Post #9 "hum loudly" might be normal for a Jaguar fuel pump or it might be a worn out rubber mounting bushing or it might be a pump that is cavitating due to not enough fuel supply. But every once in awhile, it sucks enough fuel to fire a cylinder or even let the engine run for a few seconds.

Is the fuel pressure acceptable at the regulator, using a test gauge? Does the pressure hold for a reasonable amount of time? You mention early-on "at least the gauge is reading almost one half full". Did you actually stick a string, dowel, small chain, piece of old vacuum hose, or something down into the tank and verify that the tank you think the pump is supposed to be drawing fuel from has fuel in it? More than one of us have fallen for that old "....the gauge said...." trick.

All this being said for not enough fuel, it could also be that the engine has become flooded, but you would need to pull a couple spark plugs to see if they are wet, literally wet. I'm putting this condition farther down the list of possibilities only because your first attempt to start, the following morning, should have been successful even if the mixture was rich. It might have quit running quickly and then would surely have not started completely there after if the rich condition remained.

In my opinion, your first (next) step is to put a fuel pressure test gauge on the pressure fuel line (not the return line) and see if you have pressure when the pump sounds like it is running. How much pressure and how long does the pressure last after the pump stops.

Dave

 

That's what i am thinking now, maybe fuel filter? i don't know what else it could be. I will try to change filters and then see. I will also stick something into the gas tank to verify there is gas. the gauges have read accurate (at least as far as old cars go) until now, but one tank is near empty and one has about half, so i will put gas in other tank and see if the other pump can get her going. if it matters when i opened the gas caps earlier i did not hear a pressurized gasp as i have every other time opening caps, could fuel line not be pressurized?

 

when i put it in drive and turn key to start, i can hear pump from driver seat, and while cranking as well.

 

I believe the pressurized gasp comes from a fuel return valve that is not working on the same tank the pump drawing from. In other words, if the left tank is chosen with the dash switch, the change over valve, just before the fuel pump, should toggle to the left tank and the fuel return valve for the left tank will open so that the fuel is with drawn and returned to the same tank. The return valves are located in-board of the rear wheels behind a little plate. The return valve for each tank toggles on or off to match the same tank as the change over valve.........unless it doesn't. If the change over valve(s) don't work properly, the pump is drawing from one tank, but the excess fuel is being returned to the other tank.

You don't say what your history with the car is, if you are not familiar with the upkeep and maintenance, a thorough inspection of the fuel system should be one of the first three things I would do. Rust in the fuel tanks is very common, which then flakes off and plugs filters, etc. and in worst case can leave pin hole (leaks) in tank. When you remove the current fuel filter, tip it up and drain it into a pan and look for bits of rust, bugs, dirt, and anything else besides pure gas. That will help point you in a direction. Checking the fuel pressure when cranking and just after you stop cranking will still give you the most "bang for your buck", in my opinion. However, changing the fuel filter is probably easier as a first thing to do.

Others with more experience than me will chime in.

Dave