Diesel Hot Starting Fault P38

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Hi. I own a 1997 P38 DSE and thought for 2 years that I had a hot start problem and was looking at this fix. However, I changed the battery to the recommended one which whizzes everything around much quicker and now starts brilliantly hot or cold. Just a thought in case it helps.
 
mgmayo said:
Hi, I have added some pics to explain my earlier post. The grey/blue wire to splice is in the black box behind the battery. Cut it and to each wire attach a wire which you feed to the dash.
These extend into the dash area and are fitted with a normally closed push button or a spring toggle. I got the push button in maplin.

When the engine is hot you press the switch before turning the key, which will give you the glow plugs, after starting release button and everything is normal again.
It works for me.
Click to expand...

Thanks for that mate.

Has anyone else tried this way of doing it?
 
doncarlyon said:
Thanks for that mate.

Has anyone else tried this way of doing it?
Click to expand...

My P38 diesel was never a bad starter but with a new 135Ah 1000CCA battery it leaps into life hot or cold:D Low cranking speed is a common cause of poor starting on diesels, had the same problem on my tractor, new battery and starter motor (bearings shot) problem solved.
 
As reported earlier I had fitted an interrupt button to the temp sensor wire. However recently the hot starting was taking a noticeably longer time. Based on other threads I moved the FIP towards the block but with no improvement. So yesterday having suspected a lazy starter I took it off. On dismantling it, there was no obvious wear so before bringing to the reconditioners I decided to give the armature and inside the coil a sanding and try it. RESULT: different car!! engine turns over much easier. Today I got to check with the engine hot and like a miracle it starts no problem without the need to heat it. Unbelievable. Maybe persistance pays off after all!
 
mgmayo said:
As reported earlier I had fitted an interrupt button to the temp sensor wire. However recently the hot starting was taking a noticeably longer time. Based on other threads I moved the FIP towards the block but with no improvement. So yesterday having suspected a lazy starter I took it off. On dismantling it, there was no obvious wear so before bringing to the reconditioners I decided to give the armature and inside the coil a sanding and try it. RESULT: different car!! engine turns over much easier. Today I got to check with the engine hot and like a miracle it starts no problem without the need to heat it. Unbelievable. Maybe persistance pays off after all!
Click to expand...

Just to clarify: are you saying you sanded the potentiometer of the quantity servo control unit inside the FIP? (That's on page 305 of my copy of RAVE.)
 
Grrrrrr said:
Just to clarify: are you saying you sanded the potentiometer of the quantity servo control unit inside the FIP? (That's on page 305 of my copy of RAVE.)
Click to expand...

Read it again, this time with your glasses on:rolleyes: Starter motor armature:)
Although if the armature is rubbing the bearings must be shot IMO.
 
Yes, you guys are correct it was the starter I sanded. It just needed the carbon dust build up wiped off. No excessive wear apparent.

A further development as follows. In the build up to this I had moved the FIP twice. (towards the block) Once a little bit, then a bit more without obvious improvement in starting. This led me to work on the starter. So yesterday I adjusted the FIP back to original position. However I have hot start problem again today, so it's the combination that eliminated the hot start problem.
 
mgmayo said:
Yes, you guys are correct it was the starter I sanded. It just needed the carbon dust build up wiped off. No excessive wear apparent.

A further development as follows. In the build up to this I had moved the FIP twice. (towards the block) Once a little bit, then a bit more without obvious improvement in starting. This led me to work on the starter. So yesterday I adjusted the FIP back to original position. However I have hot start problem again today, so it's the combination that eliminated the hot start problem.
Click to expand...

Think to be honest it is the pump movement that improved the starting. If the starter had have been good when you first moved the pump all would have been fine. Moving the pump without special tools is total hit and miss, if you can move the pump without the tools to give 0.035" lift plus or minus 0.001" you're a better man than i am Gungadin. :)
 
I just fitted a kit to my P38. On it's return from my garage (it was having some other work done) I stopped for petrol. It cranked over but would not re- start, just like before! I had to wait 30 mins for it to cool enough to start normally, which it did.
I should explain I live in Cape Town and brought the P38 out with me when I moved in 2003. We are in summer now, so temps average 30c each day, and after an hour's driving at that temperature on Thursday, I knew it would be a test. Subsequently on stop-start driving around it has proved to work fine, so far. The engine is in good condition, new injectors/reconditioned pump, dual batteries so no shortage of power, just replaced leak-off pipes,etc etc. everything done!
I thought I had found the solution, but I now wonder if there is a critical point (temp) where the relay cannot overcome the heat?
Today it excelled itself in testing my temper. I drove to town, stopped for 30 mins, got back in but the car would not start. Had to wait another 20 mins before it would catch. Then this evening, wanting to go and collect my daughter it would not start again. 2 hours later it sprang to life like nothing happened!
I suspect that a quick stop the a start is ok, but park up and leave it and the heat builds up under the bonnet. Question is, which sensor is it that is inhibiting the starting?!?
 
arwinsor said:
I just fitted a kit to my P38. On it's return from my garage (it was having some other work done) I stopped for petrol. It cranked over but would not re- start, just like before! I had to wait 30 mins for it to cool enough to start normally, which it did.
I should explain I live in Cape Town and brought the P38 out with me when I moved in 2003. We are in summer now, so temps average 30c each day, and after an hour's driving at that temperature on Thursday, I knew it would be a test. Subsequently on stop-start driving around it has proved to work fine, so far. The engine is in good condition, new injectors/reconditioned pump, dual batteries so no shortage of power, just replaced leak-off pipes,etc etc. everything done!
I thought I had found the solution, but I now wonder if there is a critical point (temp) where the relay cannot overcome the heat?
Today it excelled itself in testing my temper. I drove to town, stopped for 30 mins, got back in but the car would not start. Had to wait another 20 mins before it would catch. Then this evening, wanting to go and collect my daughter it would not start again. 2 hours later it sprang to life like nothing happened!
I suspect that a quick stop the a start is ok, but park up and leave it and the heat builds up under the bonnet. Question is, which sensor is it that is inhibiting the starting?!?
Click to expand...

Do you mean you have fitted a hot start kit that tells the engine that it is cold? What is the glow-plug light doing whilst this is happening?

I take it stopping for petrol isn't quite what you mean.

The member JohnP38 is in Cape Town and has testing kit.

First time posters usually get a hard time for not introducing themselves. Prepare for your humiliation with a few Castles, a bottle of Tassie and some Klippies.

G~
 
Do you mean you have fitted a hot start kit that tells the engine that it is cold? What is the glow-plug light doing whilst this is happening?

I take it stopping for petrol isn't quite what you mean.

The member JohnP38 is in Cape Town and has testing kit.

First time posters usually get a hard time for not introducing themselves. Prepare for your humiliation with a few Castles, a bottle of Tassie and some Klippies.

Sorry, I have been following the thread since last year, have read all 19 pages three times over, so forgive me, I thought I was old, not a newbie...
Yes, hot-start kit fitted, glow plug light works as normal, wait for it to go out then crank.
Dohh, of course I stopped for petrol, I was following my wife to put some into her car... :doh:

There are, to my knowledge (according to the LR database here) only around six P38 DSE's in South Africa, so my garage guys often scratch their heads under my bonnet, almost better to go to BMW, which they do for some parts...
John P38, we must get together for a chin-wag...
 
arwinsor said:
Do you mean you have fitted a hot start kit that tells the engine that it is cold? What is the glow-plug light doing whilst this is happening?

I take it stopping for petrol isn't quite what you mean.

The member JohnP38 is in Cape Town and has testing kit.

First time posters usually get a hard time for not introducing themselves. Prepare for your humiliation with a few Castles, a bottle of Tassie and some Klippies.

Sorry, I have been following the thread since last year, have read all 19 pages three times over, so forgive me, I thought I was old, not a newbie...
Yes, hot-start kit fitted, glow plug light works as normal, wait for it to go out then crank.
Dohh, of course I stopped for petrol, I was following my wife to put some into her car... :doh:

There are, to my knowledge (according to the LR database here) only around six P38 DSE's in South Africa, so my garage guys often scratch their heads under my bonnet, almost better to go to BMW, which they do for some parts...
John P38, we must get together for a chin-wag...
Click to expand...

hi,if i remember correctly the problem is the fuel pump expanding due to getting to hot and not being able to build up the correct pressure,when it gets cooler it contracts so builds up pressure.only cure is a new pump i'm afraid.:(
 
Thanks, I know there is a fuel pump situated in the tank, is there another just before the diesel injector pump (overhauled twice last year)?
 
The lift pump in the tank supplies fuel to the injection pump. Pre injection pressure is generated by a rotary vane HP pump inside the injection pump, controlled by a pressure relief valve. Final injection pressure is created by the delivery piston pushing fuel against spring pressure in the injector nozzle..
 
Understood, but why would it not function in extreme (at least by UK standards!) heat? It cannot be diesel shortage or it would manifest itself continuously, therefore it has to be some aspect of heat on something that inhibits the starting function???
 
arwinsor said:
Understood, but why would it not function in extreme (at least by UK standards!) heat? It cannot be diesel shortage or it would manifest itself continuously, therefore it has to be some aspect of heat on something that inhibits the starting function???
Click to expand...

because the metal expands and it cannot build the pressure up.this was found out on another thread a few years ago on here.
 
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