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Diesel 75 runs for 20 seconds then cuts out

15K views 23 replies 4 participants last post by  FLYER 
#1 ·
Hi
My 2002 Rover has just had its in tank and under bonnet fuel pumps changed after being towed home by the RAC. The RAC man diagnosed faulty pump so I changed them both with a lot of help from this site. Car started no problem but then cut out. If you leave it for a while it will start again but then cuts out. Anyone got any ideas?
Many thanks in advance
Paul
 
#2 ·
Sounds like it could be a vacuum problem.......not sure where the breather is on the 75 tank.....but if thats blocked the pumps will only be able to overcome a certain vacuum before the engine is starved of fuel......
Maybe try running the engine, (with the car stationary!!!!!) with the fuel cap off......
 
#3 ·
Thanks for the thought James. Have just tried the car with the fuel cap off, starts then after 20 secs or so cuts out. Worth a try though. Used to do this back in my boating days, start the outboard, get 200 yards offshore and the thing would cut out. Undo the air vent and off we go.
Paul
 
#4 ·
Oh well, worth a try.....the only other suggestion would be a blocked filter/line. Change the fuel filter, and whilst its off use an air line to blow the fuel back into the tank until you can hear bubbles from the filler cap. Not very technical I know, but its what I would do before paying for professional help.
Good Luck!
 
#6 ·
my first thought is that the power to the underbonnet pump is being cut off by the ecu as you say it is around twenty seconds , get someone to start the engine while you put your hand on the pump to see if it stops running after the twenty second spell , also listen for a click if it stops this is the ecu turning it off , you have to start somewhere so try that first . flyer.:2c:
 
#7 ·
start from the rear pump and work forward.

Is the rear pump pumping fuel (you do have enough fuel in the tank?) (ive been there myself :D (check at the rear pump)

if adequate fuel from the rear pump, move to the front pump, and check fuel is getting to the front pump

if front pump checks out, then its onto the diesel pump /injectors etc

have you checked the diesel filter isnt blocked or broken down?


btw whan you say it runs for 20 secs then stops, is it a gradual stop ie missing / hesitancy? or a hard stop (as though youve turned the ignition off)

it may be an ignition/ diesel pump solenoid issue where the car thinks the ignition has been turned off

hope this helps

mart

Just had a thought...

long shot... it could be the pick up round the ignition barrel is on the blink, and thinks wrongly that the key has been removed, hence the car stopping

mart
 
#8 ·
start from the rear pump and work forward.

Is the rear pump pumping fuel (you do have enough fuel in the tank?) (ive been there myself :D (check at the rear pump)

if adequate fuel from the rear pump, move to the front pump, and check fuel is getting to the front pump

if front pump checks out, then its onto the diesel pump /injectors etc

have you checked the diesel filter isnt blocked or broken down?


btw whan you say it runs for 20 secs then stops, is it a gradual stop ie missing / hesitancy? or a hard stop (as though youve turned the ignition off)

it may be an ignition/ diesel pump solenoid issue where the car thinks the ignition has been turned off

hope this helps

mart

Just had a thought...

long shot... it could be the pick up round the ignition barrel is on the blink, and thinks wrongly that the key has been removed, hence the car stopping

mart
could be any number of things mart so as you say easy stuff first [remember the und bonn doesnt need the intank to be working] and its just been renewed anyway . flyer.:broon:
 
#10 ·
Hi Guys
Many thanks for all the interest. In answer to your questions, car was running beautifully with under a quarter of a tank of diesel, stopped for the wife to go shopping, started the car and pulled away, 100 yards down the road car cuts out. No juddering or misfire (if you can have that on a diesel) just as if the ignition had been turned off. Tried to start the car to no avail, turned over but wouldn't fire up. Called the RAC, he took out the back seat and pronounced the pump not working although 12v present, towed me back home. Next day car started up and I drove maybe 3 or 4 miles filled up to the brim with fuel and thought it had cured itself. Tried the car about an hour later and nothing. Changed both pumps, had to pump out some fuel via hose under bonnet, very slow so obviously pumps knackered, to change the in tank pump. Now we are at the 20 second cycle, no missing a beat or lumpy tickover, just stops.
When we first had the car, about 3 years ago, we had a problem with it not starting and a mechanic just tapped the under bonnet pump and away it went. No problems since then!
Thanks Paul
 
#12 ·
Hi again
Ran out of room in the last post. Mileage is 95k, no work done other than routine servicing and an offside sensor on the front wheel to cure the ABS light staying on, this about 2 years ago. Wondering about the fuel filter, as it doesn't look very new, but would this cause it to stop without coughing and spluttering a bit? Have disconected the fuel pipe from the pump side of the filter, and fuel comes out like a power shower. Have ordered a fuel filter so can change that when it arrives, can't do any harm.
Thanks once again
Paul
 
#17 ·
The filter doesn't look like its ever been changed, i'm sure it must have been.....I think. When I switch on the ignition the pumps run for about 20 seconds and then stop - same length of time as the engine runs for. So could it be an electrical cut out that shuts off the fuel as Flyer suggests. Where can I find that relay? Got the corkscrew out now!!!!!!
Paul
 
#19 ·
the pumps will run for a set period say thirty seconds then if you dont start the engine the ecu turns them off , when you start the engine the pumps run constantly , your relay could be wonky , or the pressure sensor could be faulty or the filter could be blocked or or or or or ??? you just have to work your way thru or get it on T4 which is hard for you as you cant move the car , read rover rons diesel forum for a better understanding of what could be wrong , also a [75 fuel pressure sensor ] search will bring up similar symptoms others have had . flyer.
 
#23 ·
Do you have a spare key for the car?

Try starting it with the spare...;)


Its sounding more electrical than fuel at the mo.

if i recall, the starting sequence is.

Ignition on - energises fuel pump (the whir you year when you turn the key to pos 1)

if the key is turned to pos 2, the following occurs

the ecu looks for signals from the cam / crank & ignition module sensors to confirm engine running. if none received, it shuts down the fuel pump.

It sounds like yours is starting then deciding you've turned the ignition off.

Or its not seeing the transponder in the key and turning off the cut off on the injector pump

Mart
 
#24 ·
Do you have a spare key for the car?

Try starting it with the spare...;)


Its sounding more electrical than fuel at the mo.

if i recall, the starting sequence is.

Ignition on - energises fuel pump (the whir you year when you turn the key to pos 1)

if the key is turned to pos 2, the following occurs

the ecu looks for signals from the cam / crank & ignition module sensors to confirm engine running. if none received, it shuts down the fuel pump.

It sounds like yours is starting then deciding you've turned the ignition off.

Or its not seeing the transponder in the key and turning off the cut off on the injector pump

Mart
one things for sure the ecu is shutting the pumps down , prob due to dodgy sensor . flyer.
 
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