D24TIC Poor hot starting

[tfb]

Ever since I've had the car I'vr had problems starting it when hot. Starting from cold the engine fires on the 1st stroke every time, whether on diesel or 50/50 diesel SVO.

If I stop for about 5-10 minutes after the engine is fully warmed up it can take a good 10 seconds of cranking to get it to fire. This happens if I'm using diesel or 100% veg oil - it doesn't seem to make any difference. If the car is stopped for less than 5 mins or more than 10 (the timing is not exact, but you get the idea) the it starts fine.
The times I notice it most is when I stop at a fuel station to get a cup of coffee and sometimes I worry that the battery is going to give out before it finally fires

If this was a petrol car I would say it is fuel vapourising in hot fuel lines, but that can't happen with diesel or veg oil. Any ideas any one?

TFB

[jor]

I'd like to pretend that this advice was the result of years of personal experience, well I suppose it is, only not my own....

The glow plugs are not coming on when the engine is hot, and it's
a tired engine. The expensive fix is to rebuild the engine. The cheap
fix is to ensure that the glow plugs come on whenever they're needed.
That can be done in a couple of ways.

1. Simply disconnect the brown wire that goes to the glow plug sensor at
the back of the cylinder head. I recommend just pulling it out of the
harness at the connector at the left strut tower. The downside of this
fix is that the glow plug system always thinks that the engine
temperature is something like -40 deg, and so the glow plugs will be on
for a long time and may not go out at all until the engine starts.

2. Install a 0-500 ohm potentiometer in series with the temperature
sensor. Then, every time the glow plugs don't come on and the engine is
hard to start, crank the pot to a little higher resistance until the
glow plugs just come on. This fix is cheap, easy and effective, and it
is the way that I would go if it were my car.



John

[tfb]

It's worth a try, I'll try fitting an overide switch to the glowplug circuit and see if that make a difference.

Regards

TFB

[DLM48]

This must be some sort of fuelling problem i cant see how the glow plugs being activated on a 'hot' engine will help it to start.

Did the car do this before you started to modify it for the Elsbert Conversion?

IF as i suspect NOT it would seem that you have introduced 'something' that is 'interrupting the fuel supply to the pump.

There must also be a fuel cut off that is activated by the ignition key - something that cuts off the fuel supply when you turn off the ignition so the engine will stop. Could that be sticking?

Just a few thoughts -

Be happy you dont have a petrol 850 with the UNKNOWN wont start when hot issue. I have one of them after 18 months it was fixed for a few weeks - it is now getting a new engine to fix an unrelated problem BUT now my mechanic friend is hors de combat with a broken hand - life is fun.

strange that i now know how to activate my glow plugs 'all the time' now from a hot start problem post and not my cold start problem post - giggle.

regards

[tfb]

It has always had this problem. The last few weeks I have been working a lot of nights, so I usually stop halfway up the A1 to get a cup of coffee on the way home and so I notice the issue more. When I'm on days I do the journey non-stop and I tend to forget about the problem.

I'll try attaching a LED to the fuel cut-off valve so I can monitor the status from inside the car. Activating the glow plugs is a simple thing to do and it's worth a try.

Regards
TFB

[craig8661]

is your fuel lines clear have a look when you stop the engine to see if fuel drops back from the pump to filter thinking of mine when it was hot it was worst and it was the rear seal in the pump on the shaft that was leaking air into it

[tfb]

I've got a spare clear in-line fuel filter, I'll try putting that in the line to the pump and check the fuel in there

Regards
TFB

[DLM48]

Originally Posted by jor

1. Simply disconnect the brown wire that goes to the glow plug sensor at
the back of the cylinder head. I recommend just pulling it out of the
harness at the connector at the left strut tower.



John

can you show me where this connector is (a picture would be great) i had a look see and cant easily locate it

thanks

[craig8661]

give me 5 mins will go under my bonnet for you and get photo

[craig8661]

here you go i couldnt find the other lead but look for the wire on the heater take that on of and tape up follow it to the other plug take that of then connect new switched live feed to the plugs so you can manuly turn them on