hi guys happy new year.
i have a disco 1 with the standard 3.5 efi engine with hot wire injection.
it has an odd problem in that when i come to start it it always turns over for about 4-5 seconds before starting and running, once it is started it runs quite sweet all day.
very heavy on fuel 10 at best if that could be part of the problem.
if the engine is started after just a few mins of being stopped it fires up straight away though any thing over 5 mins and its back to 4-5 secs of churning.
i did ask this question on the old forum and was told to check the earth points.
i did this replacing the chassis and body bolts with new and cleaning up the engine bolts to. all to no avail.
any help from you guys will be followed up on as its really annoying problem.
best regards.
starting gremlin
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Check the fuel pressure with a fuel or oil pressure gauge.
When you first turn on the ignition the ECU should prime the fuel rail by turning on the fuel pump. The pressure should reach 36 psi and hold due to a non-return valve in the fuel pump.
If the fuel pressure does not hold the fuel pump non-return valve could be faulty or gunged up.
If the fuel pump does not run properly check the relay and wiring connections.
As for running rich go to the following site and download the testing procedure. There are many possibilities for problems but the tests should highlight something. iF you are not sure of the significance of a test result come back and ask.
http://www.users.zetnet.co.uk/barnes_firsnorton/lr_efi/
(2.2Mb) Testing the RR Classic Lucas14CUX efi set up
jw
When you first turn on the ignition the ECU should prime the fuel rail by turning on the fuel pump. The pressure should reach 36 psi and hold due to a non-return valve in the fuel pump.
If the fuel pressure does not hold the fuel pump non-return valve could be faulty or gunged up.
If the fuel pump does not run properly check the relay and wiring connections.
As for running rich go to the following site and download the testing procedure. There are many possibilities for problems but the tests should highlight something. iF you are not sure of the significance of a test result come back and ask.
http://www.users.zetnet.co.uk/barnes_firsnorton/lr_efi/
(2.2Mb) Testing the RR Classic Lucas14CUX efi set up
jw
hi thanks for the advice we have had an idea it could be due to fuel, will follow up with some checks and get back.
is there a correct place to connect to to check the fuel pressure??
is it possible for the fuel filter to be blocked and cause the pump to struggle up to pressure, its the only filter i havent changed and ive no idea whan it was last done.
thanks again regards.
is there a correct place to connect to to check the fuel pressure??
is it possible for the fuel filter to be blocked and cause the pump to struggle up to pressure, its the only filter i havent changed and ive no idea whan it was last done.
thanks again regards.
The book says to check the fuel pressure at the filter but this assumes access to a proper pressure test kit. The answer is to check the presure at whatever point you can assemble/plumb/kluge the tee for the pressure gauge.
Late 3.9 Discos have a schrader valve on the fuel rail for this purpose, very, very handy.
The fuel filter is the first suspect. Note that a partially blocked filter will also cause the pump to work hard and draw considerable current so relay and wiring connectors are worth looking at.
jw
Late 3.9 Discos have a schrader valve on the fuel rail for this purpose, very, very handy.
The fuel filter is the first suspect. Note that a partially blocked filter will also cause the pump to work hard and draw considerable current so relay and wiring connectors are worth looking at.
jw
hi...
thanks for the info on the pump and pressure checking, ive ordered a new filter to fit this weekend see what difference that makes.
i tried switching the ignition on for about 20 seconds before cranking the engine and that made no difference i thought the pump would have a chance to get up to pressure before the fuel was needed and that made no difference either.
very strange.
it always does start after exactly the same amount of cranking time what ever i seem to try.
will bin the old filter and locate and check the relays.
thanks for the info on the pump and pressure checking, ive ordered a new filter to fit this weekend see what difference that makes.
i tried switching the ignition on for about 20 seconds before cranking the engine and that made no difference i thought the pump would have a chance to get up to pressure before the fuel was needed and that made no difference either.
very strange.
it always does start after exactly the same amount of cranking time what ever i seem to try.
will bin the old filter and locate and check the relays.
hi all
well i have fitted a new filter to no avail it still cranks for about 4 seconds for it to start warm or cold.
where are the relays located so i can check change this.
the engine had been run at aprox 4pm saturday. i took the filter off on sunday morning 9am and the fuel just dribbled out it wasnt under any residule pressure.
could this be afaulty non return valve in the pump, can the pump be dismantled to check the non return valve.
just to wkake the nieghbours after i fitted the filter i turned on the ignition the pump ran fast and i waited till it had gone quiet, turned the engine over it fired then stopped with a bang, turned over and started ok after that ha ha.
the old filter was at least partially blocked i tried blowing down it.
cheers guys look forward to your prognosis.
well i have fitted a new filter to no avail it still cranks for about 4 seconds for it to start warm or cold.
where are the relays located so i can check change this.
the engine had been run at aprox 4pm saturday. i took the filter off on sunday morning 9am and the fuel just dribbled out it wasnt under any residule pressure.
could this be afaulty non return valve in the pump, can the pump be dismantled to check the non return valve.
just to wkake the nieghbours after i fitted the filter i turned on the ignition the pump ran fast and i waited till it had gone quiet, turned the engine over it fired then stopped with a bang, turned over and started ok after that ha ha.
the old filter was at least partially blocked i tried blowing down it.
cheers guys look forward to your prognosis.
Your description fits a worn non-return valve in the fuel pump. Best confirmed with a pressure test even though its a PITA.
A fuel pressure check would be a good move for later diagnosis of your heavy fuel consumption.
The pump can not be dismantled, it comes as an assembly with the fuel level sender. Do not just order one, check the price first!!!!!
The fuel pump assembly is reached by rolling back the carpet inside the back door and lifting the access panel. The assembly requires the use of a special tool to remove it but ingenuity will allow several ways of removing the locking ring.
My fuel pump relay is located at the side of the RHS footwell where my ECU lives, it can be found by locating the relay with a blue/purple connection to pin 85. Mine is a 98 so details may be different. Check you have the correct relay by checking presence of power to fuel pump either when ignition is first switched on or while cranking.
If the price of a new fuel pump assembly frightens you look at the US sites for RRC or Discovery spares where they discuss using common AC/Delco pumps as a replacement.
jw
A fuel pressure check would be a good move for later diagnosis of your heavy fuel consumption.
The pump can not be dismantled, it comes as an assembly with the fuel level sender. Do not just order one, check the price first!!!!!
The fuel pump assembly is reached by rolling back the carpet inside the back door and lifting the access panel. The assembly requires the use of a special tool to remove it but ingenuity will allow several ways of removing the locking ring.
My fuel pump relay is located at the side of the RHS footwell where my ECU lives, it can be found by locating the relay with a blue/purple connection to pin 85. Mine is a 98 so details may be different. Check you have the correct relay by checking presence of power to fuel pump either when ignition is first switched on or while cranking.
If the price of a new fuel pump assembly frightens you look at the US sites for RRC or Discovery spares where they discuss using common AC/Delco pumps as a replacement.
jw
hi jwriyadh
thanks for the advice and info ive looked up on ebay and found a fuel pump for 82 quid plus postage.
paddock spares list them as 65 quid plus vat. same part number at john craddock is 88 plus vat. so a uk part not to bad.
i will check pump pressure with a gauge of some sort next weekend and reprt back.
once i get it starting ok i can address the heavy fuel consumption then.
cheers again.
thanks for the advice and info ive looked up on ebay and found a fuel pump for 82 quid plus postage.
paddock spares list them as 65 quid plus vat. same part number at john craddock is 88 plus vat. so a uk part not to bad.
i will check pump pressure with a gauge of some sort next weekend and reprt back.
once i get it starting ok i can address the heavy fuel consumption then.
cheers again.
