Has Anyone Had Any Sucess Changing The C.t.s? Unplugged Mine And The Engine Started Straight Away When Hot, Had A New C.t.s Fitted But It Still Doesn't Start When Hot, Glo Plug Warning Lamp Comes On When Cold But Not When The Engine Is Hot It Does However Come On When C.t.s Is Unplugged. Is This Because The Car Is Tricked Into Thinking Its Cold
Diesel Hot Starting Fault P38
- Thread starter tigapiglet
- Start date
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brookediamond said:I THINK THE BASICS ARE THE SAME FOR ALL THE CARS THAT HAVE THIS ENGINE.
UNPLUG SENSOR AND SEE IF FAULT GOES AWAY
iT IS A BIT FIDDLY TO GET AT BECAUSE IT HAS A RETAYNING CLIP ON SENSOR PLUG BUT IF YOU USE A LONG ENOUGH SCREW DRIVER YOU CAN GET AT IT FROM TOP OF ENGINE AFTER YOU HAVE REMOVED BLACK PLASTIC COVERS.
I WILL BUY YOU A PINT IF THIS DOES NOT CURE YOUR FAULT( IM THAT CONFIDENT).
GOOD LUCK AND LET ME KNOW WHAT HAPPENS.
Think you owe me a pint! Changed the CTS and the car is still the same when trying to start from hot. Disconnecting the CTS does make the car start from hot first time, but I think this is only beacuse the car is tricked into thinking it's cold.
Gents,
Unplugging the CTS tells the ECU that it has no input and the ECU uses a default setting of "Barely warm" to enable the fuel system to function.
Simply disconnecting the CTS will effect the running of the vehicle as the system will not know if the engine is hot cold or in between -
This has been posted by me before and comes directly from Land Rover Technical information system.
It isn't often the CTS more usually the dodgy bit of programming by BMW that lets it start witht reduced emissions when new but get a few miles under the old girls belt and.........
Follow tigapiglets mod but with a timed relay and you will have no more problems, it is easy, low cost, and it works
Unplugging the CTS tells the ECU that it has no input and the ECU uses a default setting of "Barely warm" to enable the fuel system to function.
Simply disconnecting the CTS will effect the running of the vehicle as the system will not know if the engine is hot cold or in between -
This has been posted by me before and comes directly from Land Rover Technical information system.
It isn't often the CTS more usually the dodgy bit of programming by BMW that lets it start witht reduced emissions when new but get a few miles under the old girls belt and.........
Follow tigapiglets mod but with a timed relay and you will have no more problems, it is easy, low cost, and it works
Bigstoo
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rrdiver
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Interesting post! Am I right in thinking you are fooling the glow plugs to come by simulating a lower temperature?
Finally got around to trying the mod. I put it on this morning with a standard relay. Sure cures the hot starting issue. But makes the changes much harsher, also the tick over is higher, and also knocks the fuel economy. So have removed the connector to terminal 30, and taped that up.
Now the changes are back to normal, tick over is fine as well. Would have thought by removing that connection the system would be back as before. But with a hot engibe when I started up the glow plug light came on.
Will try a timed relay in, in place of the standard one once I can find one.
Dave
Now the changes are back to normal, tick over is fine as well. Would have thought by removing that connection the system would be back as before. But with a hot engibe when I started up the glow plug light came on.
Will try a timed relay in, in place of the standard one once I can find one.
Dave
I'm too lazy for my car.
I did the mod without the timmer a year or so ago and never had a problem starting since. Only problems i have experienced are high tick over , lower efficiency 5 to 10 % and lots of smoke.
Strongly recommend if you do this mod dont be lazy like me and put in the timmer.
Old crusty engine man told me in the old days , to get the plugs to glow they used a simple spring loaded switch that you press in before starting and it pops out after 30 secs or so.
If anyone finds one please let me know.
I did the mod without the timmer a year or so ago and never had a problem starting since. Only problems i have experienced are high tick over , lower efficiency 5 to 10 % and lots of smoke.
Strongly recommend if you do this mod dont be lazy like me and put in the timmer.
Old crusty engine man told me in the old days , to get the plugs to glow they used a simple spring loaded switch that you press in before starting and it pops out after 30 secs or so.
If anyone finds one please let me know.
chris.stevenson
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Hi,
Has anyone tried the timed relay yet, I can see that this is the only corret way of doing this mod, over-fuelling will destroy your enigne sooner or later, and these beats cost enough to run as it is!
I've found a timed relay at Farnell.co.uk which isnt cheap at £40 but you can set the timer from less that a second to an hour! So I'll try one of these, the operating voltage is a min of 10v so thats ok, and a max current of 8 Amps.
One other 'fix' is to add some veggi oil at every fill, this seems to stop the fuel thinning down too luch on hot starts and halves the number of revolutions needed to fire up the engine.
Chris
Has anyone tried the timed relay yet, I can see that this is the only corret way of doing this mod, over-fuelling will destroy your enigne sooner or later, and these beats cost enough to run as it is!
I've found a timed relay at Farnell.co.uk which isnt cheap at £40 but you can set the timer from less that a second to an hour! So I'll try one of these, the operating voltage is a min of 10v so thats ok, and a max current of 8 Amps.
One other 'fix' is to add some veggi oil at every fill, this seems to stop the fuel thinning down too luch on hot starts and halves the number of revolutions needed to fire up the engine.
Chris
chris.stevenson
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Strange! i wonder if some of the guys on here used the wrong wire, I havnt looked at the loom yet so dont know if there are multiple red/white wires (which I doubt!) What year is your P38?
Gents,
I jave posted here several times before suggesting the use of the timed relay -
the problem is very simple - BMW have programmed the ECU in such a way that once the engine is warm there will be NO Heater Plug operation, NO excess Fuel for starting, No timing advance for starting. So by fitting the timed relay you tell the ECU that the engine is cold and as soon as the timer switches off ( I recommend 20 Secs only) the ECU returns to standard programming.
A side effect is that Cold Starting gets even Better - Please look up my earlier posts if you need any more help
I jave posted here several times before suggesting the use of the timed relay -
the problem is very simple - BMW have programmed the ECU in such a way that once the engine is warm there will be NO Heater Plug operation, NO excess Fuel for starting, No timing advance for starting. So by fitting the timed relay you tell the ECU that the engine is cold and as soon as the timer switches off ( I recommend 20 Secs only) the ECU returns to standard programming.
A side effect is that Cold Starting gets even Better - Please look up my earlier posts if you need any more help
I like vegi oil advice . Reminds me of the time i had a noisy diff . My mates told me to put bananas in it. If that didnt cure it a pair of tights was next.
That didnt cure the noise so after dragging a new diff accross Europe and changing it , it made no difference.
Turned out to be the gear box.
Anyway back to this mod , my car is now running pretty badly. No poke but lots of smoke . What came first i dont know , poor starting or the smoking .
Fit this timmer or it could cost in the long run.
That didnt cure the noise so after dragging a new diff accross Europe and changing it , it made no difference.
Turned out to be the gear box.
Anyway back to this mod , my car is now running pretty badly. No poke but lots of smoke . What came first i dont know , poor starting or the smoking .
Fit this timmer or it could cost in the long run.
revjames
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Tut Tut, everyone knows that the solution for noisy diffs/ gearboxes is sawdust!
I get a number of messages asking about what timed relay I used and how I connected it up so here it all is
..
Basically wire it up exactly the same as for the normal relay ( tigapiglets mod) with the exception that you take the relays feed from the bunched red/white wires in the ECU box instead of from the Glow plug & starter relay timer.
I used a brodersen unic XM relay (available from RS components) Mainly because I happened to have one left over from a control panel job but also because it is adjustable in the extreme the connections for this are
Red/white feed to connection A1
Earth feed _ back to the bunch of black wires in the ECU box A2
Cut the grey/ blue wire in the ECU box, solder a length (8 inches or so) to them and connect them to No15 and No16.
Take the resistor solder approx 2inches of wire to one end wrap with a good insulating tape and connect each end to Nos 15 and 16 as well shaping it tightly to the relay body.
Set the top dial to On-Pulse the second dial to 6-60 sec and the timed to 2
Feed all the wires into the ECU box via the boot for the battery cables
There you go Bobs your Mums Brother
Mine works a treat remember to wait until the preheat light gos out before you try to start the engine.
Good Luck
Julian
Basically wire it up exactly the same as for the normal relay ( tigapiglets mod) with the exception that you take the relays feed from the bunched red/white wires in the ECU box instead of from the Glow plug & starter relay timer.
I used a brodersen unic XM relay (available from RS components) Mainly because I happened to have one left over from a control panel job but also because it is adjustable in the extreme the connections for this are
Red/white feed to connection A1
Earth feed _ back to the bunch of black wires in the ECU box A2
Cut the grey/ blue wire in the ECU box, solder a length (8 inches or so) to them and connect them to No15 and No16.
Take the resistor solder approx 2inches of wire to one end wrap with a good insulating tape and connect each end to Nos 15 and 16 as well shaping it tightly to the relay body.
Set the top dial to On-Pulse the second dial to 6-60 sec and the timed to 2
Feed all the wires into the ECU box via the boot for the battery cables
There you go Bobs your Mums Brother
Mine works a treat remember to wait until the preheat light gos out before you try to start the engine.
Good Luck
Julian
Ladies & Gents,
Having read here and elsewhere that one possibility of the hot start fault is the fuel temp sensor in the injector pump. Has any one replaced this if so how much were the parts and did it work?
I am curious because it may reduce the amount of time needed to be programmed into the relay for the Mod.
Cheers
Having read here and elsewhere that one possibility of the hot start fault is the fuel temp sensor in the injector pump. Has any one replaced this if so how much were the parts and did it work?
I am curious because it may reduce the amount of time needed to be programmed into the relay for the Mod.
Cheers
offroadbaz
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I changed the fuel temp sensor in the pump yesterday, cost £14 including the top gasket. Just ring any bosch specialist with your pump number ending in something like 993, 994 or 995.
Easy job, just had to remove the inlet manifold and modify a 7mm socket to fit the Bosch security bolt.
The result......... Made no difference to cranking time when hot.
Back to scouring the internet for a fix as opposed to a workaround.
Easy job, just had to remove the inlet manifold and modify a 7mm socket to fit the Bosch security bolt.
The result......... Made no difference to cranking time when hot.
Back to scouring the internet for a fix as opposed to a workaround.
