in tank fuel pump faulty or not?p38diesel

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cvloenen

Member
Posts
29
Hi all,
I suspect something is not right with the feul system of my car and would like to know what thoughts there might be on the symptoms I see.

I can confirm that the pump is operating - when cold & ignition switched on the pump is pumping to FIP. Its not blasting out fuel but pouring it out reasonably fast I think. There has been a lot of forum discussion on the tank pump and I would like to know if there is a fail safe way to determine if the tank pump is faulty.
Fuel tank is quarter full.

Symptoms are
- car starts perfect when cold
- when hot its reluctant to start requiring lots of cranking
- idle sometimes dropping intermitendly and engine adjusting to correct
- engine will just stop all of a sudden when idling or coasting or when little
throttle applied
- sometimes lacks power
- when engine stops I am sometimes getting dash board faults such as alarm fault/gearbox fault, but I don't suspect there is a problem with any of these.
- I hav'nt noticed air bubbles in the fuel line, but am checking this

looking forward to hearing some thoughts on this, tank fuel pumps are expensive and I don't have cash to waste unecessarily replacing expoensive components that are not faulty.

Ian
 
cvloenen said:
Hi all,
I suspect something is not right with the feul system of my car and would like to know what thoughts there might be on the symptoms I see.

I can confirm that the pump is operating - when cold & ignition switched on the pump is pumping to FIP. Its not blasting out fuel but pouring it out reasonably fast I think. There has been a lot of forum discussion on the tank pump and I would like to know if there is a fail safe way to determine if the tank pump is faulty.
Fuel tank is quarter full.

Symptoms are
- car starts perfect when cold
- when hot its reluctant to start requiring lots of cranking
- idle sometimes dropping intermitendly and engine adjusting to correct
- engine will just stop all of a sudden when idling or coasting or when little
throttle applied
- sometimes lacks power
- when engine stops I am sometimes getting dash board faults such as alarm fault/gearbox fault, but I don't suspect there is a problem with any of these.
- I hav'nt noticed air bubbles in the fuel line, but am checking this

looking forward to hearing some thoughts on this, tank fuel pumps are expensive and I don't have cash to waste unecessarily replacing expoensive components that are not faulty.

Ian
Click to expand...

Those messages are usually a symptom of a battery or alternator problem which could affect all the cars systems. Check the battery is good and the alternator is charging correctly before you worry about the other problems:)
Also check the under bonnet fuse box for signs and smells of burning and that all connections earths etc are clean and tight.
 
Remove fuel feed pipe from filter place in suitable measuring vessel. With ignition OFF remove fuel pump relay (relay12). Take wire from positive side of battery and power number 5 contact on relay socket for ten seconds, in this time a minimum of 180Ml of fuel should be pumped. Number 5 is the connection which is contrary to the other three.
 
You have an intermitent alternator/energy problem. Same thing happened to me and it was the alternator. When it fails there's not enought power to run the pump and you'll get a loss of power. It could also be something as simple as a loose/bad connection.
 
Datatek said:
Those messages are usually a symptom of a battery or alternator problem which could affect all the cars systems. Check the battery is good and the alternator is charging correctly before you worry about the other problems:)
Also check the under bonnet fuse box for signs and smells of burning and that all connections earths etc are clean and tight.
Click to expand...

Thanks, battery has plenty kick and has been charging well of alternator when runnning. fuse box seems ok.

This morning the car for the first time was reluctant to start from cold! Also, only ran for 30 secs and decided to stop. So, thats it now, not relaible to drive around anymore.

Now when I put key in ignition it comes up with "Alarm Fault" on the dash, goes out when key is turned.
I am wandering if low keyfob battery could be the issue, anybody any experience with that issue?

Ian
 
wammers said:
Remove fuel feed pipe from filter place in suitable measuring vessel. With ignition OFF remove fuel pump relay (relay12). Take wire from positive side of battery and power number 5 contact on relay socket for ten seconds, in this time a minimum of 180Ml of fuel should be pumped. Number 5 is the connection which is contrary to the other three.
Click to expand...

Thanks, originally when I checkede fuel pump just switching on ignition the pump was dispensing about the said quanity of fuel in that time, but I will check this again, also powering the pump directly. Now things have got a little worse overnight I am more confused about where the main problem is.
Car now no longer easy to start from cold, and stopped after about 30 secs running.
Ian
 
mcapinha said:
You have an intermitent alternator/energy problem. Same thing happened to me and it was the alternator. When it fails there's not enought power to run the pump and you'll get a loss of power. It could also be something as simple as a loose/bad connection.
Click to expand...

Thanks,
but did your car also still have plenty of kick in the battery? could be a bad connection, but checking all connections is big job. Did you also have starting difficulty when car is warm - such as still plenty crank power from battery but not firing till about 6 + secs?
Ian
 
Last edited:
cvloenen said:
Thanks,
but did your car also still have plenty of kick in the battery? could be a bad connection, but checking all connections is big job. Did you also have starting difficulty when car is warm - such as still plenty crank power from battery but not firing till about 6 + secs?
Ian
Click to expand...
Hi , have a search for the hot start fix,common fault on p38 diesel.

The gearbox fault will come up if engine dies when your are driving,but should reset when you restart the car.It's only because all the electrickery in the car gets confused cos the engine is not running but you are still in gear an on the move;)
 
cvloenen said:
Thanks,
but did your car also still have plenty of kick in the battery? could be a bad connection, but checking all connections is big job. Did you also have starting difficulty when car is warm - such as still plenty crank power from battery but not firing till about 6 + secs?
Ian
Click to expand...

Plenty of kick in the battery as you put it does not mean that you have 12.8 volts or more that is needed for the electronics. Have you actually metered the voltage? You should have 14.2 to 14.8 volts at 2k rpm and 12.6 to 12.8 volts after the car has stood overnight.
There are only 4 or 5 crtitical connections to check in the first instance, battery terminals, alternator feed, fuse box positive feed engine and battery earth. If there is a fuse box fault, the ignition relay (I know it's a diesel) could drop out shutting off the fuel etc.
Poor starting from hot is a well documented issue and probably nothing to do with your other issues.
 
Hi, I had soem time this afternoon to look at the car again. Initially tried a start and the motor started reasonably quick, idle again not absolutely steady, motor died after about 30 seconds.

I then checked the fuse box and its relays visually/smell for anything suspect, checked and wiggled connections underneath fuse box, battery terminals, alternator connections, and FIP connections. Then tried the car again and it started straight away with a steady idle, took it for a little run and it felt fully powered. It appears to be fine again. I can only assume there must have been a bad electrical connection in one of the areas I was tinkering with. Either that or there is some intermittent fault.
Should have tinkered one area at a time and started the engine inbetween investigations, then I might a least of had an area to concentrate on.

Can anybody tell me about the key fob battery so I can maybe eliminate it as an area of suspision. If the batteries are flat will this cause engine issues? The batteries are probably quite old I think but they do still operate the central locking satisfacorily.

Ian
 
If fob batteries are getting low the message center will tell you and they should not affect the running of the engine.
 
cvloenen said:
Hi, I had soem time this afternoon to look at the car again. Initially tried a start and the motor started reasonably quick, idle again not absolutely steady, motor died after about 30 seconds.

I then checked the fuse box and its relays visually/smell for anything suspect, checked and wiggled connections underneath fuse box, battery terminals, alternator connections, and FIP connections. Then tried the car again and it started straight away with a steady idle, took it for a little run and it felt fully powered. It appears to be fine again. I can only assume there must have been a bad electrical connection in one of the areas I was tinkering with. Either that or there is some intermittent fault.
Should have tinkered one area at a time and started the engine inbetween investigations, then I might a least of had an area to concentrate on.

Can anybody tell me about the key fob battery so I can maybe eliminate it as an area of suspision. If the batteries are flat will this cause engine issues? The batteries are probably quite old I think but they do still operate the central locking satisfacorily.

Ian
Click to expand...

It would be a good idea to take the fuse box out and look at it properly before it lets you down, it is a well documented failure item. You can't always see the problems unless you remove it.
 
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