1996 P38 2.5dse auto gearbox problems

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Datatek said:
Every modern auto I've driven has a modified change pattern when cold.
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Ok carry on. If the ECU temp sensor was telling the ECU the engine was cold at all times the glow lamps would be available at all times also. If the ECU temp sensor fails a preset of 50 degrees is used. Diag may or may not tell a tale, if there is nothing on diag it's down to a mechanical problem. As i have said oil, filter, valve block. I have said what i have to say i do not intend to get into speculation. He either takes the advice or doesn't no skin off my nose.
 
The modified change pattern when cold is certainly not down to oil or filter, been changed 3 times in the last 12K miles.
I agree about the glow plugs if the sensor was always showing cold but we do not know if his glowplug light is acting normally.
 
Datatek said:
The modified change pattern when cold is certainly not down to oil or filter, been changed 3 times in the last 12K miles.
I agree about the glow plugs if the sensor was always showing cold but we do not know if his glowplug light is acting normally.
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Auto boxes characteristics alter as the oil gets warm. We will have to wait and see. May just be that the driver has an heavy foot.
 
wammers said:
Auto boxes characteristics alter as the oil gets warm. We will have to wait and see. May just be that the driver has an heavy foot.
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From my understanding of the ZF box the gear changes are controlled by solenoids that operate the shift valves and the ecu gets information from the TPI crank sensor, speed sensor and it also has a sensor in the gearbox itself but that is only for diagnostic purposes and has nothing to do with the operation of the gearbox. so a sudden change of shift patterns has to do with electronic rather than mechanical or hydraulic.
notice that I havn't mentioned the temperature sensor on the list of sensors that control the box as i could not find any reference to it on the information i had at hand when trying to research my problem BUT when I replaced it it cured my problems.
 
ovalandrover said:
From my understanding of the ZF box the gear changes are controlled by solenoids that operate the shift valves and the ecu gets information from the TPI crank sensor, speed sensor and it also has a sensor in the gearbox itself but that is only for diagnostic purposes and has nothing to do with the operation of the gearbox. so a sudden change of shift patterns has to do with electronic rather than mechanical or hydraulic.
notice that I havn't mentioned the temperature sensor on the list of sensors that control the box as i could not find any reference to it on the information i had at hand when trying to research my problem BUT when I replaced it it cured my problems.
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When you screwed one into your engine and actually got one that reported the engine temp instead of the engine bay temp it cured your problems i remember it well. The OP has low fluid level maybe a sign of poor maintenance, the car has not been on diagnostics, neither you nor i know if there are any electrical faults. If there are no electrical faults the problem has to be mechanical. I am not going to get into a long diatribe as to what the fault may or may not be. Without the benefit of diagnostic info everything is supposition. I have stated the most likely scenario he either acts on the info or does not.
 
wammers said:
When you screwed one into your engine and actually got one that reported the engine temp instead of the engine bay temp it cured your problems i remember it well. The OP has low fluid level maybe a sign of poor maintenance, the car has not been on diagnostics, neither you nor i know if there are any electrical faults. If there are no electrical faults the problem has to be mechanical. I am not going to get into a long diatribe as to what the fault may or may not be. Without the benefit of diagnostic info everything is supposition. I have stated the most likely scenario he either acts on the info or does not.
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I can confirm that removal of the ecu temp sensor causes the shifts to occur only at high revs, a default like pattern of shift. I can also tell you that it does not make the glow plugs stay on any more than normal, that I noticed. I know this because I tried removing the plug to see if it had any effect on cold running a few weeks back
 
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wammers said:
When you screwed one into your engine and actually got one that reported the engine temp instead of the engine bay temp it cured your problems i remember it well. The OP has low fluid level maybe a sign of poor maintenance, the car has not been on diagnostics, neither you nor i know if there are any electrical faults. If there are no electrical faults the problem has to be mechanical. I am not going to get into a long diatribe as to what the fault may or may not be. Without the benefit of diagnostic info everything is supposition. I have stated the most likely scenario he either acts on the info or does not.
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I had a nanacom and it did not pick up any faults at all in fact i dont think it reads the solenoid operation and when driving does not tell you which gear you are in only what the gear leaver position I dont know if the faultmate has any more readings on it or any more diagnostic functions for the gearbox.
I agree that low oil can cause the problem and also burnt clutches can cause it as well we will just have to see if it is cured and what cured it if the owner will be kind enough to tell us hen its fixed
 
ovalandrover said:
I had a nanacom and it did not pick up any faults at all in fact i dont think it reads the solenoid operation and when driving does not tell you which gear you are in only what the gear leaver position I dont know if the faultmate has any more readings on it or any more diagnostic functions for the gearbox.
I agree that low oil can cause the problem and also burnt clutches can cause it as well we will just have to see if it is cured and what cured it if the owner will be kind enough to tell us hen its fixed
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You don't get a lot from the auto box ECU with diagnostics:(
 
roccotune said:
I can confirm that removal of the ecu temp sensor causes the shifts to occur only at high revs, a default like pattern of shift. I can also tell you that it does not make the glow plugs stay on any more than normal, that I noticed. I know this because I tried removing the plug to see if it had any effect on cold running a few weeks back
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If the temp sensor fails a preset of 50 degrees is used. No one is doubting that the temp sensor being totally disconnected or the wrong one fitted can cause a shift pattern change. The glow plugs do not come on for the same time all the time. The time they are lit is controlled by temperature. Colder longer, warmer shorter. Until the engine reaches a temp where they are disconnected. If the temp sensor is faulty and the 50 degree preset is being used you would expect the start up characteristics to alter. But not the gearbox pattern. Change the temp sensor by all means if it cures the problem well and good.
 
Datatek said:
You don't get a lot from the auto box ECU with diagnostics:(
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Keith, Overlanders problem was that his temp sensor was hanging on it's connector in the engine bay, NOT connected to the bloody engine. Can't recall but also may have been the wrong sensor. From what i remember he was told to the point of nausea that it should not be hanging free and to fit a new temp sensor in the head and connect it up. He and Grit instead banged on about box ECU and other stuff. When he finally fitted a temp sensor to the engine his problems went away. If a new temp sensor cures the OPs problem well and good. Worth a try i suppose.
 
wammers said:
If the temp sensor fails a preset of 50 degrees is used. No one is doubting that the temp sensor being totally disconnected or the wrong one fitted can cause a shift pattern change. The glow plugs do not come on for the same time all the time. The time they are lit is controlled by temperature. Colder longer, warmer shorter. Until the engine reaches a temp where they are disconnected. If the temp sensor is faulty and the 50 degree preset is being used you would expect the start up characteristics to alter. But not the gearbox pattern. Change the temp sensor by all means if it cures the problem well and good.
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Now now! I was actually agreeing with you that the sensor was an integral part of the gearbox shift pattern. I agree that the preset is used when the sensor goes out of range as you have said. The glow plugs may well come on but they didn't stay on.

Basically op could see if the temp sensor was causing problems as you have said by the glow plugs coming on all the time or disconnecting it and seeing if it drive the same.

I also agree that the likely cause is bad/low fluid and a filter change is in order.

Good day ladies ;)
 
ovalandrover said:
I had a nanacom and it did not pick up any faults at all in fact i dont think it reads the solenoid operation and when driving does not tell you which gear you are in only what the gear leaver position I dont know if the faultmate has any more readings on it or any more diagnostic functions for the gearbox.
I agree that low oil can cause the problem and also burnt clutches can cause it as well we will just have to see if it is cured and what cured it if the owner will be kind enough to tell us hen its fixed
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Problem with any diagnostics is that they can only pick up electrical faults. Sticky shuttle valves they just don't know about. The adaptive ECUs fitted to the petrol models would maybe give more of a clue if something was amiss mechanically, if the changed setting could be read, but not sure that they can be. But the diesels certainly don't have that feature.
 
roccotune said:
Now now! I was actually agreeing with you that the sensor was an integral part of the gearbox shift pattern. I agree that the preset is used when the sensor goes out of range as you have said. The glow plugs may well come on but they didn't stay on.

Basically op could see if the temp sensor was causing problems as you have said by the glow plugs coming on all the time or disconnecting it and seeing if it drive the same.

I also agree that the likely cause is bad/low fluid and a filter change is in order.

Good day ladies ;)
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Bye. :p:p:D:D
 
wammers said:
Keith, Overlanders problem was that his temp sensor was hanging on it's connector in the engine bay, NOT connected to the bloody engine. Can't recall but also may have been the wrong sensor. From what i remember he was told to the point of nausea that it should not be hanging free and to fit a new temp sensor in the head and connect it up. He and Grit instead banged on about box ECU and other stuff. When he finally fitted a temp sensor to the engine his problems went away. If a new temp sensor cures the OPs problem well and good. Worth a try i suppose.
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I know that, I followed the thread. The new correct sensor cured the shift problems as I recall:)
 
Right sorry for the lack of responses...
I have acquired a full filter kit including auto box filter,Lucas auto fix, will be getting ATF this week (sisters wedding this weekend coming up so funds are tighter then I anticipated! )
I have started with the cheap fix's first.
I read somewhere where someone had a bad earth connection on the drivers front inner arch so iv unbolted,cleaned spade/ring connectors and refitted but no better, also checked all fuses in car (under drivers seat and in engine compartment)
I'm going to put replacing gearbox Ecu on hold for now. I'll go and check the temp sensor now if someone could point me in right direction.
It kind of makes sense if it thinks it's running cold could this also affect fuelling? It seems "juicy but I am just putting that down to running everywhere at 2500-3000rpm....
 
Just a thought aswell, when I put it into 1,2 or 3 it doesn't seem to change it's like it's still in "d" would this temp sensor cause this?
As said earlier it drives 100% in lo range in all gears....
 
johnboy429 said:
Right sorry for the lack of responses...
I have acquired a full filter kit including auto box filter,Lucas auto fix, will be getting ATF this week (sisters wedding this weekend coming up so funds are tighter then I anticipated! )
I have started with the cheap fix's first.
I read somewhere where someone had a bad earth connection on the drivers front inner arch so iv unbolted,cleaned spade/ring connectors and refitted but no better, also checked all fuses in car (under drivers seat and in engine compartment)
I'm going to put replacing gearbox Ecu on hold for now. I'll go and check the temp sensor now if someone could point me in right direction.
It kind of makes sense if it thinks it's running cold could this also affect fuelling? It seems "juicy but I am just putting that down to running everywhere at 2500-3000rpm....
Click to expand...

ECU temp sensor is the green one fitted into head between cylinders three and four. STC2299. Like this. Coolant Temperature Sensor for ECU - Genuine Land Rover at www.rimmerbros.co.uk
 
Ok thanks guys, I'm getting the sensor today aswell as the ATF so fingers crossed!
I got the sensor for £6+vat so if it solves it it'll be a cheap fix and one very happy relieved owner!
Once again thanks very much for your info and time in helping me! It's restored my faith in the land rover! As I was contemplating in getting rid of it however if it's something as simple as this sensor and a service I'll keep hold of the old girl and go make some happy memories with my kids in the old girl!
 
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