RangeRovers.net Forum banner

1 - 10 of 10 Posts

·
Registered
1995-2002 Range Rover P38A
Joined
·
44 Posts
Discussion Starter #1
hi
my range rover p38 diesel has been very hard to start over the winter,have replaced glow plugs and bleed off pipes,car was better but still not right.
after reading quite a few related items on you forum ,it seemed to point to the in tank fuel sender , BUT in the recent warm spell my car started first time every morning and made me wonder if it could be temperature related.any ideas would be a great help


thanks
wil
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
1,851 Posts
Hi

The principle of operation from a diesel engine is to compress the air in the cylinder during this process the air heats up naturally. The injected diesel starts to burn the moment it comes in contact with the hot air. When the weather is very cold it is normal for diesels to have problems with starting. The cold engine parts will extract the heat from the air and the temperature for self ignition might become too low. It is common to use start pilot (ether gas from a can) that is sprayed into the air intake to get the engine started.

On the p38 Diesel there is a temperature sensor in the fuel pump and this sensor tells the ecu if it needs to perform a cold start or a hot start. There are kits on the market to trick the ecu to perform a cold start all the time. These kits are available for 30 to 40 pound on ebay and come with fitting instructions.

Regards

Jos
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
44 Posts
Discussion Starter #3
hi jos
many thanks for the reply,ihave looked on ebay and the only thing i can see are hot start kits ,are these the same thing?if so that is the next thing to try ,thanks again

wil
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
1,851 Posts
Hi

The temperature sensor is often broken and is supposed to tell the ecu that the engine is hot or cold and during the hot start up sequence of glowing, the fueling and timing of the engine is differently performed resulting in long crancking of the engine before it want to start. In the early days when the kit was not yet available, people were throwing cold water over the fuel pump to get the engine to start. I have read a story from an owner that did not dare to top up fuel at the pump because he has to shut down the engine and had been in the embarrassing situation that he could not restart the engine.
This kit bypasses some of the signals for 20 or 30 seconds or so after turning on the ignition and gets the ecu to use the cold start settings.

In your case I would measure the current draw from the glow plugs these should draw a significant amount of amperes. If they do not work properly or the relay or wires are not in good condition it will be most noticeable during cold weather.

Regards

Jos
 

·
Registered
Joined
·
483 Posts
How long does your glow plug light stay on? That is a good indicator of what the sensors are seeing.

When you turn the key to pos 2 you should see a picture of a coil or something similar (they changed the symbol).
You should be waiting until that light goes out before cranking the engine, that is the glow plugs warming up if you are not waiting then there is your problem.
Assuming you wait then on a cold morning the light should stay on noticeably longer than when its warm. If it does then the odds are all the sensors are working OK.

It could be all OK, as mentioned the compression has to get the air hot enough to ignite the fuel. Cold air and cold metal will mean that it can't and has to have a few more tries (longer cranking) to manage. The glow plugs help but they only help, you have to get that air hot. The extra compression and potentially longer cranking is why the diesel has a significantly larger battery.

We use the cold start spray on lifeboat engines and stuff like that on ships but I would steer clear for your car. There should be no need, engines can become almost dependant on it and more to the point you look a right berk with a range rover opening the bonnet, removing the air filter and squirting an aerosol in.

Of course really cold countries they fit engine preheating to stop the problem. Cruise ships we did the same, engines inside enclosed boats and often heated. People don't like to see them struggling to start.
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
44 Posts
Discussion Starter #6
many thanks for the replies,
the glow plug lighty normally stays on for about 5 or 6 seconds,have tried turning back to position one and ,reheating etc.in the winter it could take up to 10 mins to start ,and had to use dampstart.it is still hard to start fist time in the morning but will kick in first time all day ater initial start.at first start it belches out smoke,been told this is unburned fuel,but rest of day its okay
have been reading up about hot start fix on the internet think i will try this next


thanks

wil
 

·
Registered
Joined
·
483 Posts
I would not panic on the hot start kit, you have the opposite and messing with cables right now will just confuse things.

It sounds like it is trying to do the right things. As Jos said checking the current draw on the glow plugs would be good. The light on the dash just tells you they should be on. Ideally see if you can check individually but like the injectors they are a sod to get at with the inlet manifold in place.

Next up would be compression but let's hope its not that. To check you can get (borrow or rent) a compression gauge that replaces the injector, occasionally even the glow plug which is easier. As a short term when did you last change the oil? New oil may just help a bit likewise the filter.

10 mins is certainly way too long, I was thinking 10 seconds.

One other thing worth trying is a full tank. I would not expect cold to have much effect there but the lift pump is in the tank and only runs with the engine cranking or running. There may just be something with the cold causing more fuel to drop back and struggle to prime. I am not convinced but you will use the fuel anyway so its worth a go? That or find the relay, bridge it to brink the pump on, run the pump for a while on a cold morning then try starting.
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
44 Posts
Discussion Starter #8
would a one way valve in the fuel line stop the fuel returning to the tank help
 

·
Registered
Joined
·
483 Posts
I did look at that but I needed a new pump anyway, I decided to just change it instead of trying to delay it.
The simple answer is yes. Do you have the clear plastic fuel lines? If so you will see bubbles in them if that's the problem.
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
44 Posts
Discussion Starter #10
no the pipes are black,my brother is coming over tomorrow to test glow plugs,will let you know how we got on over the weekend.

i will order one way valve anyway(only about 10 pounds on ebay)

many thanks for your advice and quick response
 
1 - 10 of 10 Posts
Top