Discovery td5 won't fire

Hi everybody help needed please got D2 auto was running fine had leak on fuel cooler took off repaired replaced start straight up not used a couple days now just cranking and won't fire even with a spray any ideas or help please

Hi, first of all charge well the battery cos even if it's cranking well if the voltage drops below 10.5V it will hardly start as the ECU doesnt have enough power to manage the injectors. Measure the voltage while cranking to make sure you have above 10.5V then othervwise you might try in vain

Hi thanks for reply fully charged battery and reading 11v on multi meter whilst cranking .connected computer and cranked live reading max rpm209 do crank sensor just go because was running good

You need at least 250 rpm to start well, any sensor can work well then fail just like that, it's valid for all the parts.... can you hear the fuel pump running?

Hi can hear the pump running it was a little low on fuel have put more in still can hear pump but bit less .the wires to the crank sensor is stiff should I get any readings from clip with multi meter and can I test the sensor

You can't rule out the sensor with a multimeter as long as it's still working but youcan do this for the pump: Check Td5 fuel pump HP

Will check the pump but
wouldn't it fire with a spray down inlet if was just fuel

If it doesnt fire up on spray it's cranking too slow or there is a compression issue as the spray doesnt explode, on spray it shoud run even with the ECU unplugged... let's hope the timing chain is not snapped, or something, can yo see the crank pulley turning while cranking? my knowledge kind'a ends here

sierrafery said:

If it doesnt fire up on spray it's cranking too slow or there is a compression issue as the spray doesnt explode, on spray it shoud run even with the ECU unplugged... let's hope the timing chain is not snapped, or something, can yo see the crank pulley turning while cranking? my knowledge kind'a ends here

Click to expand...

Yes the crank pulley is turning and just run another live test and rpm only 200 max so think try cps got little fire with easy start but not running on it

Can you post a video of it cranking over ?

tilly2 said:

Can you post a video of it cranking over ?

Click to expand...

Iam analogue mate struggle with technology. But just tested fuse f10 and only drawing 11.3mv so thinking hp pump as have had firing on spray the other thing the rpm is only 200 max on live whilst cranking?crank sensor

Wilf g said:

But just tested fuse f10 and only drawing 11.3mv

Click to expand...

You must replace the pump to rule it out, it's possible that the cranking speed is around 200 in reality while the sensor reads well but if it ran for few seconds on spray the rpm should have go up i think and if it was enough fuel pressure it should have keep running. IMO untill you dont get correct power on F10 the rest is irrelevant, the first suspect is the pump but if with new one you'll get the same voltage it's possibe to be a bad contact on the circuit somewhere...let's hope not cos it can be a nightmare to trobleshoot

Just run live whilst on spray shot up over 400 rpm so pump ?

It seems likely to be the pump, but you can get a better idea by seeing if the HP line into the FPR has a good flow.... attach some more hose and run that to a bucket, if it's working a lot of fuel is going to flow... You can also make up a line with a pressure gauge in, should be seeing more than 4 bar of pressure there, the FPR regulates it down to 4.

Cheer will try that pipe thing not got a gauge or would have checked pressure but I'm pretty sure the flow is poor

There is a flow but doesn't seem to be under much pressure could have put finger on end to stop, when I undone it there wasn't any pressure in it slight drip of fuel

https://www.ebay.co.uk/itm/142501581112?epid=2231498769&hash=item212dc19138:g:5BYAAOSwwoRfoa9D&amdata=enc:AQAHAAAA8MflUVBUkWNRnMHTGnGKpmScNOWqlaC6vHTTbiJ0QHaAuTzCJflFdGZIN5HRZ0uwJIidairnj+PcafQmbGSgk/kgP45taTZkGRsLVBy8Dc8dXfmNd4Jh48UiEtA6TC1TUeg8SUJsf1UgYg3fN0kmtjfGKl/znfWNh7MsUTqFm/yEHxBkc/y7m8GLCCEJMiySs5YLfb/IBV9HPK3iC6ulgRM/5avC3xPTmGpY0vYB2qbGyIz3a3Auab1CTFGR5RN7yUSUjQK++qapKGdJYqMOroyT72zwP9NwPaBzbhcXUB4mG+TV9zLsLpPhiRVfcMPtwg==|tkp:Bk9SR57XhMivYQ



One of these fuel test kits are essential for testing your fuel pressure on a TD5. Remove the temperature sensor on the Fuel Pressure Regulator, and screw in the tester. You should get 4 bar. At £24 delivered, its cheaper than shelling out £350 for a quality pump, and finding it wasnt faulty....

Wilf g said:

There is a flow but doesn't seem to be under much pressure could have put finger on end to stop, when I undone it there wasn't any pressure in it slight drip of fuel

Click to expand...

You shouldnt be able to stop it with your finger unless the pumps jiggered.

Cheers I'll send for one of them and go from there

Fuel pressure test......