C

CDMC

New Member
Seems a common theme about f/l not starting when warm but mine starts when it feels like. Cranks & cranks when hot or cold and (sometimes) eventually fires and runs sweetly. I've read a few threads and removed the fuel pressure sensor (HP) and fuel comes out when ignition on. I've checked the crankshaft sensor which stopped the engine when I displaced the connector so thats working. No change in the cars running when the MAF disconnected. Disconnecting the hp fuel sensor wiring when running make the car run lumpy but OK when plugged back in. I suspect the camshaft sensor but not sure as most threads talk of it being a hot start problem. Anyone any ideas before I go barking :confused: ps-filters are fairly new & pump under wheelarch buzzes ok. Also checked injectors for leak back and all seem ok.
 
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I am assuming that it is a TD4 as you have not specified? (does help)
If running with the MAF disconnected makes no difference then it ain't working as it should.
Could be the MAF is dead, could be the ECU ignoring a good MAF or it could be another fault telling the ECU to ignore the MAF.
If the ECU ain't in limp home mode, when it's supposed to ignore the MAF, then you have a fault thats masking the function of the MAF or a duff MAF.
Sounds like a trip to the stealers/indies to get the codes read on that one.
That may not have a bearing on the starting problem which may be a failing (weak) low pressure fuel pump(s) - you could try rigging up a pressure test with the ignition on. I remember a few posts where some members investigated this and found their pumps were on the way out - hence starting problems? Try a search on fuel pump.
 
Thanks John, I did put TD4 in the title so thought that might be a clue!! I've taken it to the local Landy garage and they got the fault codes for the HP fuel sensor and the MAF sensor. I'd disconnected both once I had the engine running so thought that was the reason for fault codes. Anyhow the dealer talked me in to a replacement sensor at just shy of £ 200. That didn't work :doh:. I checked the fuel pump in the OSR wheel arch today and its pumping through the filter ok - even runs fuel if I crack the No1 injector hp line so its getting to the fuel rail. I've checked the glow plugs today & all OK. Should the MAF sensor make a difference to the engine when its running? I was told that the ECU went into limp home mode iof the MAF failed?:confused:
 
Should have spotted the title oops!:doh:
Late model - only one pump in the wheel arch then.
Removing the Maf does trigger limp home mode but if that is not noticably different than with MAF connected then there is a problem around the MAF as I said above. :whoosh:
As for the pump, it does not have to fail completely to make it not start. These pumps lose the ability to generate enough pressure and then it gets harder to start until they fail completely, you need to check that it is delivering enough pressure or the sensors will inhibit starting until the pressure has built up sufficiently.
Check out this thread - it has some useful info on checkin' fuel pressures. http://www.landyzone.co.uk/lz/f9/td4-fuel-pressure-problem-help-83679.html

Sound like two problems you have :confused:
Hope it helps :)
 
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Thanks for the advice John, I've got a replacement MAF on order from the local factors so I'll give that a try tomorrow. Whats the pressure likely to be on the rail when the LP pump runs? I was thinking I could fit a gauge in place of the HP sensor on the end of the fuel rail to try it?
 
Had a similar problem with my previous car (not land rover) would start when cold and run without any problems until you switched off and tried to restart. All the advice pointed to the crankshaft position sensor which I changed but the fault still remained, turned out to be one of the ECU plugs had not been refitted correctly even though the clip on the top looked correct. Might be worth checking and giving a squirt of WD 40.
 
HI, Here are the descriptions from the Rave (for a two pump set-up) - Should be very simmilar for the one pump version as the HP pump is the same.
The high pressure fuel injection pump is located on the front right hand end of the engine and is driven via a chain
from the crankshaft. The pump has a variable output which is controlled by the ECM via a pressure control valve. The
ECM maintains the pump output pressure to the fuel rail at a level appropriate to the current operating conditions. The
output pressure is measured by a pressure sensor located in the end of the fuel rail.
The pump receives a fuel supply from the fuel filter which is supplied by the primary and secondary LP pumps at a
pressure of approximately 2 to 2.4 bar (29 to 35 lbf/in 2 ). This pressure is controlled by the pressure relief valve.
The injection pump uses the fuel as a lubricant and coolant for the pump internal components. The pump has an
integral control valve which ensures that fuel delivery to the internal components is maintained in the event of a drop
of fuel supply pressure. If the supply pressure falls to below 0.5 bar (7.25 lbf/in 2 ), the valve closes and diverts all fuel
to the lubrication and coolant passages within the pump in preference to supplying the injectors, preventing
irreparable damage to the pump.
The ECM monitors the fuel pressure by a fuel pressure sensor located in the fuel filter. This sensor detects fuel
pressure emerging from the filter and can detect low fuel supply pressure to the injector pump immediately. If the
pressure falls to below 0.8 bar (11.6 lbf/in 2 ), the ECM changes the fuelling strategy to the engine. In this instance there
will be a gradual drop in engine power because the ECM will limit the injector pulse times to preserve fuel pressure
in the rail and allow the vehicle to be driven safely to a stop.
The injection pump delivers a high output which is not required by the engine at all times. Excess fuel is passed from
the pump to the fuel tank via the pressure control valve. At fuel temperatures above 76C (169F), a bi-metallic valve
diverts the fuel through a fuel cooler, located above the engine cooling radiator, to cool the fuel before it returns to the
tank.
The engine requires a minimum output of 200 bar (2900 lbf/in 2 ) at start up and 300 bar (4350 lbf/in 2 ) at idle. The pump
can deliver a maximum output pressure of up to 1300 bar (18850 lbf/in 2 ) to cover all operating conditions.
Have you dowloaded a copy of the Rave - it has most of this stuff in there? :)
Checking the voltages on the sensors seems easier :confused:
Could be a failing pump or a releif valve fault or something else entiely - just some ideas on what to try next while avoiding the stealers :):)
 
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Don't change the maf, you haven't proved that there is a fault with it. Just leave it disconnected, if you still have starting problems without it then that isn't the cause.

What model year is it? does it have one Lp pump or two? check whether it/they are running when you get the non start.

Do an injector leak test.

Can't check fuel pressure at the rail by removing the sensor because it's that sensor that controls the pressure!
 
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ok crude [but it works] lp test ,get a helper to put hand on pmp , switch on ignition [do not start] ,pmp should vibrate for 10-20 secs then switch off as its hit its high pressure , this test can be used for the double pmp system anorl. . . . .if pmp keeps running its not hitting the pressure or the high pressure switch is fooked. . . . .but remember you could still have an intermittent pmp [sumtimes werks sumtimes dunt] :) :) :)
 
Thanks for all the advice, I've been at the lp pump under the osr wheelarch and it's buzzing ok. Also cleaned the sedimenter alongside. Now fitted a pressure gauge in the lp fuel line in the engine bay and it reads 35 psi with ign on and when the engine runs (it will start maf & hp fuel sensor replaced but the things driving me mad. I have tried the leak offs and no fuel came out..... Any ideas now???
 
Sorry almost forgot it's an early 2003 with no fuel tank pump just one in front of the osr wheel then straight to the hp pump in the engine bay. Also checked the ecu plugs when I added the new wiring fix for the hp fuel sensor
 
Hello, I've finally reached the end of my tether and the f/l is going into the local garage we use for work. I did find a "pinched" plastic fuel line between the filter & lp pump so replaced this with some new fuel hose. The engine still doesn't want to go properly so away it goes :(. Anyhow, will post to keep you updated with progress and (hopefully) final conclusion :rolleyes:. Thanks for everyone's help so far.....
 
CDMC said:
Thanks for all the advice, I've been at the lp pump under the osr wheelarch and it's buzzing ok. Also cleaned the sedimenter alongside. Now fitted a pressure gauge in the lp fuel line in the engine bay and it reads 35 psi with ign on and when the engine runs (it will start maf & hp fuel sensor replaced but the things driving me mad. I have tried the leak offs and no fuel came out..... Any ideas now???
Click to expand...

Is it ruining when the car won't start though?
 
Hi Chaser - yes the pump is giving a good 35psi when cranking, I got the missus to turn the key while I checked
 
Absolutely nothing wrong with that pressure. If you still can't start when getting that reading then I'd be looking at either cam or crank signal. Cam sensor is the most common failure.
 
Hi had a call from the garage today to say No2 injector was leaking badly - didn't notice it when I checked but I suppose they have proper equipment to do the test. Replacement on order so have to wait to see if that's cured the problem....
 
Finally got the car back and it needed two new injectors (well refurbs) Apparently no2 was pi**ing fuel and no1 was on the limit. Starts on the button now. Did have a little flat spot when you accelerated after cruising but I put the original MAF sensor back in and it now seems fine:)
 
Does anybody know whether there is a filter in the tank that can affect the pressure from the pump? Leaving an open end from the engine fuel filter and running the pump (new) the fuel does not spurt out. Could this be the starting problem?
 
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