Have to use glow plugs when starting.

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.

Radar1946

Active Member
Posts
362
Location
Lichfield, Staffordshire
Hi, The engine starts first time when cold, but every time after even when hot I have to wait for the glow plug light to go off, and it starts straight away. Any ideas or do the rr bmw engine always do this?.
 
If your waiting for the glow plugs to go off when the engine is warm it sounds to me like you have a Hot Start kit fitted. The glow plugs should normally only operate on a p38 when it is cold first thing in the morning for example once the engine is warm they dont come on until the engine become cold again.

These engines do suffer with a Hot Start issue which is down to wear in the Fuel injection pump and timing chain stretch

hope that helps

W
 
Last edited:
If the glow plug light is on when your engine is hot it sounds as if you have a hot start fix fitted. This is usually because the motor is hard to start when hot. This is caused by your timing modulation out of limit's due to the timing chains stretched or your pump timing is out.:)
 
You can get the timing altered but usually the wear falls outside the tolerances, changing the chain is tricky!!! Hence Hot Fix Kits!
 
You can get the timing altered but usually the wear falls outside the tolerances, changing the chain is tricky!!! Hence Hot Fix Kits!

If you have chain stretch that cannot be adjusted with the available movement on the pump you should be thinking new chains before one breaks and put you completely in the ****. ;)
 
Hi, Thanks for the info. Thinking about it ,the chains do sound a bit noisy. Is it a job I can do myself? I used to be a mechanic in my younger days in the 1960s, but in them days everything was easy to get to.
 
The BMW M51 is a straight-6 Diesel indirect injection engine

It should need heater plugs to start. Same as all indirect injection engines of yesteryear :)

The one I had would always start, hot or cold, if you turned the key....it wound until it started :) If you gave it a bit of heater plugs it fired straight away.
 
Hi, The engine starts first time when cold, but every time after even when hot I have to wait for the glow plug light to go off, and it starts straight away. Any ideas or do the rr bmw engine always do this?.

Same with mine. I have a hot start box bolted just behind the engine ECU (front left (as you look at the engine) behind the battery).

Is your timing modulation out that far when you check with diagnostics?
 
The BMW M51 is a straight-6 Diesel indirect injection engine

It should need heater plugs to start. Same as all indirect injection engines of yesteryear :)

The one I had would always start, hot or cold, if you turned the key....it wound until it started :) If you gave it a bit of heater plugs it fired straight away.

Direct injection engines also use glow plugs. ;)
 
Direct injection engines also use glow plugs. ;)


Yes....more to control emmisions though...indirect injection diesels need the heater plugs to start :)

It would be easier to use the heater plugs as they were intended rather than adding hotfix boxes or timing chains. It says in the manual to wait until the glow plug light goes off before starting :)
 
Yes....more to control emmisions though...indirect injection diesels need the heater plugs to start :)

It would be easier to use the heater plugs as they were intended rather than adding hotfix boxes or timing chains. It says in the manual to wait until the glow plug light goes off before starting :)

Yes but the glow plugs don't come on when the engine is warm unless you have the hot start fitted. Indirect injection was developed to help stop diesel knock on smaller engines. You didn't want a car sounding like a bloody tractor. Everything was direct injection at one time, direct injection is a lot older than indirect injection so the yesteryear comment is a little silly.
 
Yes but the glow plugs don't come on when the engine is warm unless you have the hot start fitted. Indirect injection was developed to help stop diesel knock on smaller engines. You didn't want a car sounding like a bloody tractor. Everything was direct injection at one time, direct injection is a lot older than indirect injection so the yesteryear comment is a little silly.
All the Di engines of yesteryear were low revving, the problem was to create small high revving Di engines, I think Ford were the first with a sucessful one in the Transit, it had no glowplugs. My current Transit is also Di, it has glow plugs but starts fine without them except in extreme cold.
 
All the Di engines of yesteryear were low revving, the problem was to create small high revving Di engines, I think Ford were the first with a sucessful one in the Transit, it had no glowplugs. My current Transit is also Di, it has glow plugs but starts fine without them except in extreme cold.

Is it common rail? They are much kinder on cold starting than mechanical injection because of the greatly increased injection pressures. Different manufacturers tried different set ups. So there are lots of variations out there. Nearest some of the old direct injection engines got to glow plugs on a frosty morning was a burning news paper held in front of the venturi whilst cranking. Been there done that got the T shirt and cap. So when someone makes a sweeping statement that direct injection engines start straight away without glow plugs that is nonsense, modern common rail ones may but it doesn't matter if it's a slow revving or high revving engine it still has to fire on a cold morning.
 
Is it common rail? They are much kinder on cold starting than mechanical injection because of the greatly increased injection pressures. Different manufacturers tried different set ups. So there are lots of variations out there. Nearest some of the old direct injection engines got to glow plugs on a frosty morning was a burning news paper held in front of the venturi whilst cranking. Been there done that got the T shirt and cap. So when someone makes a sweeping statement that direct injection engines start straight away without glow plugs that is nonsense, modern common rail ones may but it doesn't matter if it's a slow revving or high revving engine it still has to fire on a cold morning.
No, not common rail, uses a mechanical injector pump, the original Tranny Di also used an an old style injector pump, just much higher pressure and a complex inlet manifold designed to cause inlet air swirl.
The old Volvo marine Di engines would start in any conditions short of waxed diesel, hand cranking was easier on a rolling boat with a squirt of Easy Start:eek: (in the intake, not into me LOL)
 
No, not common rail, uses a mechanical injector pump, the original Tranny Di also used an an old style injector pump, just much higher pressure and a complex inlet manifold designed to cause inlet air swirl.
The old Volvo marine Di engines would start in any conditions short of waxed diesel, hand cranking was easier on a rolling boat with a squirt of Easy Start:eek: (in the intake, not into me LOL)

Old ones used to start by banging loads of fuel in, hence the clouds of smoke that surrounded them on frosty mornings. Can't do that anymore it ain't allowed. Used to saw the top off old pistons, put two or three of grooves in the squish band and polish them to make ash trays.
 
This thread is not about how diesels work.....though I could go on but I wont.

Its about an indirect injection BMW diesel that you are supposed to wait until the glow plug light goes out on before you start it....as stated in the user manual...the same as almost every other indirect injection diesel.....

To save you checking wammers...as you obviously dont know ...the pcm controls the heater plugs and the light...if it decides it needs to use heater plugs based in input from sensors the pcm switches them and the light on for a predetermined time....the driver waits until the light goes out, then starts the engine. #### all to do with the hotfix mod.

The very diesel that the question is about seems to me to be starting as it should....it says in post 1 that it starts if he waits until the glow plug light goes out it starts straight away. That is the instructions in the user manual.


Me personaly couldnt give a toss if Radar1946 fits hotfix mods or timing chains but I think its a waste of his money :) But its up to him if he wants to believe some internet copy n pasters or the manual that should have come with the car. :)

Radar1946...not all internet experts are really experts...a lot of them just like their own typing :)
 
This thread is not about how diesels work.....though I could go on but I wont.

Its about an indirect injection BMW diesel that you are supposed to wait until the glow plug light goes out on before you start it....as stated in the user manual...the same as almost every other indirect injection diesel.....

To save you checking wammers...as you obviously dont know ...the pcm controls the heater plugs and the light...if it decides it needs to use heater plugs based in input from sensors the pcm switches them and the light on for a predetermined time....the driver waits until the light goes out, then starts the engine. #### all to do with the hotfix mod.

The very diesel that the question is about seems to me to be starting as it should....it says in post 1 that it starts if he waits until the glow plug light goes out it starts straight away. That is the instructions in the user manual.


Me personaly couldnt give a toss if Radar1946 fits hotfix mods or timing chains but I think its a waste of his money :) But its up to him if he wants to believe some internet copy n pasters or the manual that should have come with the car. :)

Radar1946...not all internet experts are really experts...a lot of them just like their own typing :)
Think you are missing the point, the glow plug light should not come on when it is hot. The fact that it does means that it probably has the hot start fix fitted. This is fitted to mask an underlying problem, timing out or stretched chains which puts the timing out. He either lives with waiting till the light goes out or does something about it.:)
 
Think you are missing the point, the glow plug light should not come on when it is hot. The fact that it does means that it probably has the hot start fix fitted. This is fitted to mask an underlying problem, timing out or stretched chains which puts the timing out. He either lives with waiting till the light goes out or does something about it

very good if thats what you think thats fine.

"The fact that it does means that it probably has the hot start fix fitted"

whats the probably for? it either does or it doesn't :) What your trying to say the light/glow plugs are probably on? maybe not on, sometimes on....

but we'll go with that...the glow light is on and theres no hotfix fitted...so what now?

I'll point out now that I have a P38 2.5 diesel that does NOT have a hotfix mod :) It starts just fine....just like it always has
 
Back
Top