4.0 hc stalling when hot - HELP
Discussion
Hi
I was wandering whether anyone might be able to help me.
I have recently aquired a 4.0 hc which stalls quite often when hot and changing down gears when I am slowing down. It starts again immediately and runs perfectly again and then once again it will stall. Also, sometimes I get a faint glow from the bottom red light on the dash (I think it is the oil pressure light) yet the pressure on the guage is always very good and never drops.
I can still drive it with a quick blip of the throttle which stops it stalling but it is a little disconcerting. Thought it might be an idle problem on overrun but I'm not very handy with the spanners.
Also my speedo has just stopped working.
Also would anyone know the nearest specialist/garage to Shrewsbury in Shropshire
Many thanks
Mark
I was wandering whether anyone might be able to help me.
I have recently aquired a 4.0 hc which stalls quite often when hot and changing down gears when I am slowing down. It starts again immediately and runs perfectly again and then once again it will stall. Also, sometimes I get a faint glow from the bottom red light on the dash (I think it is the oil pressure light) yet the pressure on the guage is always very good and never drops.
I can still drive it with a quick blip of the throttle which stops it stalling but it is a little disconcerting. Thought it might be an idle problem on overrun but I'm not very handy with the spanners.
Also my speedo has just stopped working.
Also would anyone know the nearest specialist/garage to Shrewsbury in Shropshire
Many thanks
Mark
Ive seen this issue when something like a failing AFM is causing the engine to run too rich, or it could be something like the ignition amp failing under heat. You need to start by removing one or more spark plugs and checking the colour or if they are sooted up. This needs to be done with the engine cold, but after it has died on you when the plugs may have fouled. If you do it after an OK run the colour may be completely different.
This happened to my Chim, what I discovered was that the ECU needs a speed signal to stop the car stalling at junctions.
The ECU cuts fuel when your foot is off the throttle; this is a design feature to save fuel.
To ensure you don’t stall at junctions the ECU reinstates the fuel at a pre-determined speed (5mph I think).
The system has a number of components that may be at fault & works like this.
A pickup just forward of the diff sends a pulse signal to the speedo.
The speedo turns the pulses into a reading on the gauge (but it doesn’t end there).
The signal then comes out of the back of the speedo to a black box.
The black box turns the pulse signal into something the Range Rover ECU can understand.
The ECU absolutely must have the speed signal, without the signal it will not reinstate the fuel as you slow down approaching a juction.
The result is......... YOU WILL STALL!
So you need to investigate the following:
1) The pickup at the diff end (you would have no speedo or erratic readings)
2) The speedo itself (again no speedo or erratic readings)
3) The black box
4) The ECU
5) Any bad connection along the chain
In my case I was lucky, making good the connectors at the back of the speedo was all it needed.
The fact that your speedo is also not working indicates to me it's something to do with the above & nothing to do with the stepper motor.
Most likely its 1, 2 or 5 in my above list.
Check the pickup at the diff end first and work your way towards the ECU.
Steve Heath offers some diagnosis & sensor kit that will help you locate, and ultimately solve the problem.
https://delta.securesslhost.net/~shenglt/catalog/p...
Or you may get lucky like me & find a bad connection on the back of the speedo.
Good luck & let us all know how you get on with it.
The ECU cuts fuel when your foot is off the throttle; this is a design feature to save fuel.
To ensure you don’t stall at junctions the ECU reinstates the fuel at a pre-determined speed (5mph I think).
The system has a number of components that may be at fault & works like this.
A pickup just forward of the diff sends a pulse signal to the speedo.
The speedo turns the pulses into a reading on the gauge (but it doesn’t end there).
The signal then comes out of the back of the speedo to a black box.
The black box turns the pulse signal into something the Range Rover ECU can understand.
The ECU absolutely must have the speed signal, without the signal it will not reinstate the fuel as you slow down approaching a juction.
The result is......... YOU WILL STALL!
So you need to investigate the following:
1) The pickup at the diff end (you would have no speedo or erratic readings)
2) The speedo itself (again no speedo or erratic readings)
3) The black box
4) The ECU
5) Any bad connection along the chain
In my case I was lucky, making good the connectors at the back of the speedo was all it needed.
The fact that your speedo is also not working indicates to me it's something to do with the above & nothing to do with the stepper motor.
Most likely its 1, 2 or 5 in my above list.
Check the pickup at the diff end first and work your way towards the ECU.
Steve Heath offers some diagnosis & sensor kit that will help you locate, and ultimately solve the problem.
https://delta.securesslhost.net/~shenglt/catalog/p...
Or you may get lucky like me & find a bad connection on the back of the speedo.
Good luck & let us all know how you get on with it.
Edited by Chimpafrolic on Monday 19th September 18:37
Thankyou so much for the advice, I am very grateful. The car was running perfectly when the speedo worked so I think you have hit the nail on the head. I'll have a butchers under the bonet and see how I get on.
I have contacted Mark Adams regarding a tornado chip which I believe may be a good upgrade, any opinions on that one?
Many thanks again
Mark
I have contacted Mark Adams regarding a tornado chip which I believe may be a good upgrade, any opinions on that one?
Many thanks again
Mark
Marksayuk said:
Thankyou so much for the advice, I am very grateful. The car was running perfectly when the speedo worked so I think you have hit the nail on the head. I'll have a butchers under the bonet and see how I get on.
If the stalling coincided with the speedo failure it's almost certainly a speedo/pick up issue.Get the speedo working again and your stalling issue will disappear.
There is nothing under the bonnet that will help you solve a dead speedo.
Step 1: Take the dash top off & check the connections at the back of the speedo (Worked for me)
http://www.parkersteve.dsl.pipex.com/techinfo.html
Step 2: Investigate the connections from the speedo to the black box
Step 3: Check the pick up at the diff end (failure here is common problem)
Good luck & let us know how you get on.
Marksayuk said:
Thankyou so much for the advice, I am very grateful. The car was running perfectly when the speedo worked so I think you have hit the nail on the head. I'll have a butchers under the bonet and see how I get on.
I have contacted Mark Adams regarding a tornado chip which I believe may be a good upgrade, any opinions on that one?
Many thanks again
Mark
Mark, there is a very comprehensive Search Facility button up top (use the advanced bit).I have contacted Mark Adams regarding a tornado chip which I believe may be a good upgrade, any opinions on that one?
Many thanks again
Mark
Just putting in Tornado Chip, 2-years and TVR Chimaera gives you the following threads.
http://www.pistonheads.com/gassing/search4.asp?h=0...
Happy reading and welcome to the TVR pages!! Bet you wish you hadn't asked!!!
HTH
Trev
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