1 Bank not firing.
Discussion
The drivers side cylinder bank on my 97 4.2 is misfiring badly.
When applying almost full throttle however it picks up and fires ok.
I have tried cleaning up plug leads, and various other connections as it had been raining heavily the last few days. The ECU is dry and there are no signs of water in that area.
The car is under warrenty still so I will take it back to the dealers on Monday.
Just wondering if any one had any advice as to what it could be. (it actualy feels like the drivers side bank is not firing at all unless applying a lot of throttle, when it then fires smoothly) Maybe throttle pot sensor on that bank, or coil??
Any advice apreciated.
Cheers
Mark.
When applying almost full throttle however it picks up and fires ok.
I have tried cleaning up plug leads, and various other connections as it had been raining heavily the last few days. The ECU is dry and there are no signs of water in that area.
The car is under warrenty still so I will take it back to the dealers on Monday.
Just wondering if any one had any advice as to what it could be. (it actualy feels like the drivers side bank is not firing at all unless applying a lot of throttle, when it then fires smoothly) Maybe throttle pot sensor on that bank, or coil??
Any advice apreciated.
Cheers
Mark.
Hi,
Sounds like you've either got a dodgy lamaba sensor or you've got water/moisture in your Lamba sensor connector (yellowish plug with three wires going into it). Had this happen to me once, as water/moisture can collect in the connector causing incorrect voltages to be sent back to the ecu. If this is correct then i would guess that under 4k the car runs badly missing and coughing, put past the 4k its fine. The reason being is that past 4k the fuel mapping isn't controlled by readings from the sensor but instead TVR's own pre-determined map.
If the car's still under warranty then best get them to do it - not a hard job but if left can cause damage to the engine and cat - over fueling.
Regards
cruty
Sounds like you've either got a dodgy lamaba sensor or you've got water/moisture in your Lamba sensor connector (yellowish plug with three wires going into it). Had this happen to me once, as water/moisture can collect in the connector causing incorrect voltages to be sent back to the ecu. If this is correct then i would guess that under 4k the car runs badly missing and coughing, put past the 4k its fine. The reason being is that past 4k the fuel mapping isn't controlled by readings from the sensor but instead TVR's own pre-determined map.
If the car's still under warranty then best get them to do it - not a hard job but if left can cause damage to the engine and cat - over fueling.
Regards
cruty
I think your dealer is wrong. It won't be the lambda sensor. The MBE ECU is clever enough to detect a lambda sensor failure and to copy the lambda values from the other side.
What this equates to is an engine which runs slightly unevenly but will run okay and tickover okay. One side will NOT shutdown.
What this equates to is an engine which runs slightly unevenly but will run okay and tickover okay. One side will NOT shutdown.
Julian64 said:
I think your dealer is wrong. It won't be the lambda sensor. The MBE ECU is clever enough to detect a lambda sensor failure and to copy the lambda values from the other side.
What this equates to is an engine which runs slightly unevenly but will run okay and tickover okay. One side will NOT shutdown.
and even if both lambda sensors totally fail, then the car will still run ok, just rich (or is it lean, I can never remember).
I'd put money on it being a coil problem if it's hardly firing at all, with a covering bet on the throttle pots
trooper1212 said:
I think your dealer is wrong. It won't be the lambda sensor. The MBE ECU is clever enough to detect a lambda sensor failure and to copy the lambda values from the other side.
What this equates to is an engine which runs slightly unevenly but will run okay and tickover okay. One side will NOT shutdown.
and even if both lambda sensors totally fail, then the car will still run ok, just rich (or is it lean, I can never remember).
I'd put money on it being a coil problem if it's hardly firing at all, with a covering bet on the throttle pots
Thats more along the lines I was thinking at first, leads, coil etc....
Its not firing at all on any of the drivers side cyl's during idle or part throttle, then fires fine on throttle.
Hope they get it sorted soon, the fiestas a nightmare
Julian64 said:
I think your dealer is wrong. It won't be the lambda sensor. The MBE ECU is clever enough to detect a lambda sensor failure and to copy the lambda values from the other side.
What this equates to is an engine which runs slightly unevenly but will run okay and tickover okay. One side will NOT shutdown.
No it wouldn't.
it will substitute throttle pot values, default coolant and air temp values or run on the base map but won't take a lambda reading from one bank to the other ...
Finally got cerb back today!
New lamda sensor fitted, throttle pots checked, ecu checked, eventually found problem to be the wiring loom itself so they fitted a new loom.
Only problem was new looms are different from the older 4.2 looms (said changed around 2001 so 4.2 and 4.5 were the same). Once the loom was replaced the throttle pots were reading backwards (due to the different loom type) so had to check with blackpool to see if they could swap the wires around.
All seams to be working fine now.
It scared the life out of me (in a good way!!)driving home, after getting used to pottering around in a 1.2 fiesta for over a week!!
New lamda sensor fitted, throttle pots checked, ecu checked, eventually found problem to be the wiring loom itself so they fitted a new loom.
Only problem was new looms are different from the older 4.2 looms (said changed around 2001 so 4.2 and 4.5 were the same). Once the loom was replaced the throttle pots were reading backwards (due to the different loom type) so had to check with blackpool to see if they could swap the wires around.
All seams to be working fine now.
It scared the life out of me (in a good way!!)driving home, after getting used to pottering around in a 1.2 fiesta for over a week!!
Got mine back today, lambda sensor changed under waranty,and various oil leaks and a diff mounting fixed, that the waranty dodged !!
Great to get the performance back, but pi##ed off that she came back with no screenwashers, speedo not operating, dirt on the passenger seat scratches/chips off the back valance and a scratched airbox.
Learnt my lesson the hard way, She`s going to an indy next time !!
Great to get the performance back, but pi##ed off that she came back with no screenwashers, speedo not operating, dirt on the passenger seat scratches/chips off the back valance and a scratched airbox.
Learnt my lesson the hard way, She`s going to an indy next time !!
mark.rowe said:
Finally got cerb back today!
New lamda sensor fitted, throttle pots checked, ecu checked, eventually found problem to be the wiring loom itself so they fitted a new loom.
Only problem was new looms are different from the older 4.2 looms (said changed around 2001 so 4.2 and 4.5 were the same). Once the loom was replaced the throttle pots were reading backwards (due to the different loom type) so had to check with blackpool to see if they could swap the wires around.
All seams to be working fine now.
It scared the life out of me (in a good way!!)driving home, after getting used to pottering around in a 1.2 fiesta for over a week!!
Hmmm, call me paranoid pete but whats the chance it was a wiring problem AND a lambda sensor?
.. but a persistent overfuelling fault could go on to make the lambda response dull down .. [sarc]sensible precaution to change it anyway[/sarc] .. though as they're so hard to get to I suspect they didn't have that in mind when they *left it on and charged you* .. why are we always so cynical hey? lmao ..
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