TVR (rover V8) Injector Problems
Discussion
Hi there, My engine has the LH bank injectors permanently open as soon as ignition is on (as you can imagine this is quite dangerous). I have disconnected the lambda sensors (no change) when tracing back the signal to open them it is shown at the emu and is permanently present on the pins going to LH injectors. When I change the emu the new unit is the same!!! Any ideas where to go now??
What sensor is only for the LH bank injector signals apart from the Lambda and, can be giving this problem?
All help is gratefully received
Clive
What sensor is only for the LH bank injector signals apart from the Lambda and, can be giving this problem?
All help is gratefully received
Clive
A company called Avilec used to have a diagnostic website under the name carelectronics.demon.co.uk.
Covered common faults with a number of vehicles & the Rover V8 was one of them.
Unfortunately that seems to have disappeared but your problem does ring a bell & IIRC one of the causes was a wiring fault with a break in the wiring allowing a short to earth & where wires pass through holes in the bodywork was a common location.
There were another couple of things which I can't remember.
They're still in existence & it might be worth giving them a ring.
http://www.avilec.co.uk/
Covered common faults with a number of vehicles & the Rover V8 was one of them.
Unfortunately that seems to have disappeared but your problem does ring a bell & IIRC one of the causes was a wiring fault with a break in the wiring allowing a short to earth & where wires pass through holes in the bodywork was a common location.
There were another couple of things which I can't remember.
They're still in existence & it might be worth giving them a ring.
http://www.avilec.co.uk/
more background and history needed.
Has it ever ran right ? Is the vehicle totally standard ?
And the lambda sensors do not control the injectors. They may influence what the ecu does with the injectors, but that's it.
If all injectors are stuck open...most likely a wiring fault, or less likely but possible, injector driver fault in the ecu.
So are they actually "stuck" open, or being commanded 100% open ?
Has it ever ran right ? Is the vehicle totally standard ?
And the lambda sensors do not control the injectors. They may influence what the ecu does with the injectors, but that's it.
If all injectors are stuck open...most likely a wiring fault, or less likely but possible, injector driver fault in the ecu.
So are they actually "stuck" open, or being commanded 100% open ?
Edited by stevieturbo on Wednesday 30th March 20:06
The injectors are high side driven from the ignition on relay (12v supplied to injectors whenever ignition is switched on) and the engine ECU low-side drives (grounds) them when it wants to open them. The RV8 uses banked injection where injectors are fired in two banks of four.
That means if an entire bank of injectors is open as soon as the ignition is one that either:
1) the low side wiring between the injectors and the ecu has become shorted to ground
or
2) the low side driver in the ECU has shroted to ground.
Unplug the ecu and see if that stops the injectors being opened, if it does, then the ECU has failed, if not, the wiring has failed
That means if an entire bank of injectors is open as soon as the ignition is one that either:
1) the low side wiring between the injectors and the ecu has become shorted to ground
or
2) the low side driver in the ECU has shroted to ground.
Unplug the ecu and see if that stops the injectors being opened, if it does, then the ECU has failed, if not, the wiring has failed
stevieturbo said:
more background and history needed.
Has it ever ran right ? Is the vehicle totally standard ?
And the lambda sensors do not control the injectors. They may influence what the ecu does with the injectors, but that's it.
If all injectors are stuck open...most likely a wiring fault, or less likely but possible, injector driver fault in the ecu.
So are they actually "stuck" open, or being commanded 100% open ?
Hi, thanks for the reply,Has it ever ran right ? Is the vehicle totally standard ?
And the lambda sensors do not control the injectors. They may influence what the ecu does with the injectors, but that's it.
If all injectors are stuck open...most likely a wiring fault, or less likely but possible, injector driver fault in the ecu.
So are they actually "stuck" open, or being commanded 100% open ?
Edited by stevieturbo on Wednesday 30th March 20:06
injectors are closed without ignition so not stuck on
1/ Car was running fine and then this happened, I was informed that this had happened a few years ago with the previous owner but he had to work away for a few months and when he returned the car was fine (until now)
2/ Agree about lambdas but that is the only sensor that is one for each bank of 4
3/ With ignition on the signal (earth) is being sent to energise the LH bank injectors from ECU
swapped out the ECU, earth signal for LH bank is still there at the pin on the replacement ECU (would not think 2 x ECU with exactly same problem??)
I am just mystified and that is why I was thinking " what else could cause the ECU to switch the LH bank on?
Max_Torque said:
The injectors are high side driven from the ignition on relay (12v supplied to injectors whenever ignition is switched on) and the engine ECU low-side drives (grounds) them when it wants to open them. The RV8 uses banked injection where injectors are fired in two banks of four.
That means if an entire bank of injectors is open as soon as the ignition is one that either:
1) the low side wiring between the injectors and the ecu has become shorted to ground
or
2) the low side driver in the ECU has shroted to ground.
Unplug the ecu and see if that stops the injectors being opened, if it does, then the ECU has failed, if not, the wiring has failed
Wot 'e said.That means if an entire bank of injectors is open as soon as the ignition is one that either:
1) the low side wiring between the injectors and the ecu has become shorted to ground
or
2) the low side driver in the ECU has shroted to ground.
Unplug the ecu and see if that stops the injectors being opened, if it does, then the ECU has failed, if not, the wiring has failed
This is where you should be diverting your time.
E-bmw said:
Wot 'e said.
This is where you should be diverting your time.
As I said earlier in this threadThis is where you should be diverting your time.
when tracing back the signal to open them it is shown at the emu and is permanently present on the pins going to LH injectors. When I change the emu the new unit is the same!!! Any ideas where to go now??
What sensor is only for the LH bank injector signals apart from the Lambda and, can be giving this problem?
All help is gratefully received
Clive
Answer has already been posted above and at TVR forum
There is a 99% chance of a short to earth on the injector signal cable
A faulty injector somehow shorting to earth inside its body would also cause the same problem but the chances of that happening are very slim
You posted same to the TVR forum
Looks like you're working on a 14CUX system
There is a 99% chance of a short to earth on the injector signal cable
A faulty injector somehow shorting to earth inside its body would also cause the same problem but the chances of that happening are very slim
You posted same to the TVR forum
Looks like you're working on a 14CUX system
Edited by Polly Grigora on Friday 1st April 08:59
E-bmw said:
Max_Torque said:
Unplug the ecu and see if that stops the injectors being opened, if it does, then the ECU has failed, if not, the wiring has failed
Wot 'e said.This is where you should be diverting your time.
Unplugging the ECU will stop the injectors from opening even if there is a short on the injector wiring
Ignore the above advice
Unplugging the ECU will prevent the injection relay from energising and the injectors will be without a positive supply
Polly Grigora said:
No way, this is not the case
Unplugging the ECU will stop the injectors from opening even if there is a short on the injector wiring
Ignore the above advice
Unplugging the ECU will prevent the injection relay from energising and the injectors will be without a positive supply
Many thanks for the reply it just gets more confusingUnplugging the ECU will stop the injectors from opening even if there is a short on the injector wiring
Ignore the above advice
Unplugging the ECU will prevent the injection relay from energising and the injectors will be without a positive supply
I have just replaced the spare ECU its original car and it runs
I have then put my ECU in that car and it runs
But neither ECU allows my car to start
I have checked the injector cables and all are good, it looks like it something before the ECU but what ???
By any chance has an injector plug or injector cables been connected to a sensors wiring by mistake? (just a thought)
Below is a good test method
Be sure to disconnect the ECU and Injectors before testing for the short
Don't go bigger than a 5 watt bulb as a higher wattage bulb might burn the short off the loom due to its higher current consumption
The 5 watt bulb should be illuminated when the injector signal cable is shorting to negative
Move and waggle away at the engine loom and same again at the engine to ECU loom in the footwell
The 5 watt bulb will extinguish when the short is remove or disturbed
There could be a bolt or screw through the loom, there could be a short inside the loom close to where the injector cables are joined together
Below is a good test method
Be sure to disconnect the ECU and Injectors before testing for the short
Don't go bigger than a 5 watt bulb as a higher wattage bulb might burn the short off the loom due to its higher current consumption
The 5 watt bulb should be illuminated when the injector signal cable is shorting to negative
Move and waggle away at the engine loom and same again at the engine to ECU loom in the footwell
The 5 watt bulb will extinguish when the short is remove or disturbed
There could be a bolt or screw through the loom, there could be a short inside the loom close to where the injector cables are joined together
mgwanderer said:
E-bmw said:
Wot 'e said.
This is where you should be diverting your time.
As I said earlier in this threadThis is where you should be diverting your time.
when tracing back the signal to open them it is shown at the emu and is permanently present on the pins going to LH injectors. When I change the emu the new unit is the same!!! Any ideas where to go now??
What sensor is only for the LH bank injector signals apart from the Lambda and, can be giving this problem?
All help is gratefully received
Clive
The 12v signal is meant to be permanently on the injectors.
They are triggered by an earth/chassis being put onto the injector.
Thus if there is a short to earth on that bank they will always be triggered.
It will not be a sensor.
E-bmw said:
I am not sure (as are others) that you are doing what you think you are doing here, or maybe we aren't completely understanding what you are meaning.
The 12v signal is meant to be permanently on the injectors.
They are triggered by an earth/chassis being put onto the injector.
Thus if there is a short to earth on that bank they will always be triggered.
It will not be a sensor.
I am now beginning to worry myself that I am dreaming the whole thing and I will wake up and it will be gone (wishful thinking)The 12v signal is meant to be permanently on the injectors.
They are triggered by an earth/chassis being put onto the injector.
Thus if there is a short to earth on that bank they will always be triggered.
It will not be a sensor.
Ok lets summarize the situation
Problem
when I turn on the ignition the LH bank of injectors opens and stays open RH bank remains closed
after checking many things looked at the diagram and help messages from here I realised the 12 volts are permanently on and the earth is switched on and off by the ECU.
first check voltage is at both injector banks LH injectors open RH closed
is it a short or the ECU?
removed wire on ECU plug pin 11 to injectors
ignition on
LH injectors not activated
OK must be the ECU
swapped ECU from another engine that runs
Re-connected pin 11 to ECU plug
Ignition on
LH injectors open
Connected my ECU to other car (where I had removed the ECU from)
Engine runs
I shall sleep on it now and start again tomorrow
mgwanderer said:
I am just mystified and that is why I was thinking " what else could cause the ECU to switch the LH bank on?
Nothing can do this intentionally.The two scenarios have been given, a wiring problem, or an ecu driver problem. It would appear it is probably not the ecu
Max's advice is sound, albeit in this case the ancient ecu also seems to provide the injectors with their 12v supply, which is not common on anything half modern.
Simple test. Unplug the ecu. Give the injectors a 12v supply and see if either bank opens. If the LH does, clearly it is a wiring short.
if they stay closed, then somehow it may be an ecu driver problem
Although with talk of swapping ecu's, some running, some not....are they all absolutely identical, or could you be causing harm plugging things in that may not be identical ?
Should also add the drawing is poor, labelling an injector relay as injectors.
Or quite simply....
When you test, what are you getting at the injector trigger wire ? key on, engine off ? do it with injectors unplugged or fuel pump disabled so you don't drown the engine
Edited by stevieturbo on Thursday 31st March 21:21
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