Help me understand the MBE in my Tuscan
Discussion
Had a Tuscan 2S for about 6 weeks now and I’ve noticed some odd behaviour (odd to me, might just be a speed 6 thing).
The response of the throttle at low rpm and smoothness of the engine at low rpm has been quite variable.
Yesterday on the way back from work i stalled it twice trying to set off. Low down torque appeared almost non-existent.
I got ECU waring 4 when I started it but it went away quite quickly.
This morning I decided to hook up the diag software so got the car out of the garage and left it running whilst I farted about with the laptop for about 5 minutes.
All of a sudden the rather lumpy idle suddenly became very smooth. I wasn’t particularly monitoring the engine as I was focusing on the bloody laptop but it was very obvious change.
Drove into work and it was like a different beast.
Really smooth, instant throttle response, pulled away like a train!
Mine is a 2005 model so I think it has the later MBE installed. Engine loom had fittings for the knock sensors.
Does this ecu ‘learn’ when the car sits at idle?
I remember one post about leaving the car to idle for a while so that the ecu can learn the engine without having to try to actually run it whilst you’re driving.
Hopefully it’ll be a monster again on the way home !
The response of the throttle at low rpm and smoothness of the engine at low rpm has been quite variable.
Yesterday on the way back from work i stalled it twice trying to set off. Low down torque appeared almost non-existent.
I got ECU waring 4 when I started it but it went away quite quickly.
This morning I decided to hook up the diag software so got the car out of the garage and left it running whilst I farted about with the laptop for about 5 minutes.
All of a sudden the rather lumpy idle suddenly became very smooth. I wasn’t particularly monitoring the engine as I was focusing on the bloody laptop but it was very obvious change.
Drove into work and it was like a different beast.
Really smooth, instant throttle response, pulled away like a train!
Mine is a 2005 model so I think it has the later MBE installed. Engine loom had fittings for the knock sensors.
Does this ecu ‘learn’ when the car sits at idle?
I remember one post about leaving the car to idle for a while so that the ecu can learn the engine without having to try to actually run it whilst you’re driving.
Hopefully it’ll be a monster again on the way home !
First thing is to look at the diagnostics, any sensor faults showing? The ECU is pretty good at picking up such problems.
If not, suggests to me a problem on the HT side of the ignition where not all cylinders are firing sometimes. That could be one or more faulty, or not properly connected, HT leads or one of the coil packs working intermittently.
If not, suggests to me a problem on the HT side of the ignition where not all cylinders are firing sometimes. That could be one or more faulty, or not properly connected, HT leads or one of the coil packs working intermittently.
glow worm said:
The factory fitted ECU will be the old MBE one unless it's been modified . TVR made provision for anti knock sensors but weren't fitted or supported by the ECU at the time . Bear in mind the ECU was already 10 years old when TVR fitted it 
.
Yes, it’s defo the original MBE that’s in there. Just trying to get a handle on how it learns to car, if it does. .It was a very significant change whilst idling and very sudden
I think your fixation on the ECU is leading you down a blind alley here. I agree with Englishman. It's much more likely to be ignition, or fuel related, or a sensor failing.
Fixing itself is what TVR's are famous for. It much more likely that the failing ignition or fuel component or sensor started working properly again, probably temporarily, rather than any adaptive or learning function of a very basic ECU.
The sensor 4 fault on start up isn't relevant. It's just not receiving the expected information as the car starts and it shows a fault, once it is running, and it receives it's expected information it, is happy and it clears. It's just how TVR's always were, right from new. Not developed properly. Had it been a Toyota, that kind of thing would have been ironed out at the prototype stage by Toyota's development engineers who would have had a budget of £1 million for that issue. At TVR, they had a budget of 10p, and they called those people customers!
Even if it was an adaptive or learning ECU, it wouldn't allow the car to run roughly, before adjusting to suddenly run smoothly at idle.
Fixing itself is what TVR's are famous for. It much more likely that the failing ignition or fuel component or sensor started working properly again, probably temporarily, rather than any adaptive or learning function of a very basic ECU.
The sensor 4 fault on start up isn't relevant. It's just not receiving the expected information as the car starts and it shows a fault, once it is running, and it receives it's expected information it, is happy and it clears. It's just how TVR's always were, right from new. Not developed properly. Had it been a Toyota, that kind of thing would have been ironed out at the prototype stage by Toyota's development engineers who would have had a budget of £1 million for that issue. At TVR, they had a budget of 10p, and they called those people customers!
Even if it was an adaptive or learning ECU, it wouldn't allow the car to run roughly, before adjusting to suddenly run smoothly at idle.
Well the fun was short lived.
It ran like a dream this morning but was not so good on the way home.
Parked up for an hour and then went out again and it ran like a bag of sh!t.
It kept stalling when trying to pull away. When I finally did get going it was no where near as powerful as the morning drive and was popping and banging on the over run so obviously running very rich.
Got home and plugged in the diag software. Both EFR 'BAD'. Adaptive maps where both a lot +ve.
So either both lambda sensors have just gone bad or it's something else that packed up.
I reset the adaptive maps for both banks and then restarted the car and both banks slowly started to creep up. Both got to about 9 before I shut down as had to cook dinner...
downloaded the new MBEtool from EvoOlli and took it out for a drive about 20 mins ago so I'll review the log file from that.
It ran like a dream this morning but was not so good on the way home.
Parked up for an hour and then went out again and it ran like a bag of sh!t.
It kept stalling when trying to pull away. When I finally did get going it was no where near as powerful as the morning drive and was popping and banging on the over run so obviously running very rich.
Got home and plugged in the diag software. Both EFR 'BAD'. Adaptive maps where both a lot +ve.
So either both lambda sensors have just gone bad or it's something else that packed up.
I reset the adaptive maps for both banks and then restarted the car and both banks slowly started to creep up. Both got to about 9 before I shut down as had to cook dinner...
downloaded the new MBEtool from EvoOlli and took it out for a drive about 20 mins ago so I'll review the log file from that.
As has already been mentioned, ignition related components are usually #1 suspect so if your ht leads and coil haven't been changed in a while it might be wise to change those. Don't pay the tvr tax though, the coil is a vauxhall item - about 80 pounds on ebay the last one I bought. HT leads you will have to buy through a tvr parts supplier, or get someone like mr retro leads to make you a set.
Popping and banging on overrun is not a rich mixture though, it's a weak one. The fact your adaptive tables are populated with lots of positive trim values tells us that the base fuelling is too weak, and the ecu is having to richen it up. Investigation required to get to the root of that.
Popping and banging on overrun is not a rich mixture though, it's a weak one. The fact your adaptive tables are populated with lots of positive trim values tells us that the base fuelling is too weak, and the ecu is having to richen it up. Investigation required to get to the root of that.
Spitfire4v8,
Thanks. I guess it makes sense. I’d always thought that the pops and bangs was unburnt fuel hitting a hot exhaust, rather then an un ignited fuel/air mixture going bang.
It also ties up with it being low on power if running lean.
Hmm don’t like this at all. Lean engines tend to not last long…
Could be something to do with the ecu / sensors or fuel pressure (pump, filter etc).
Oh crap
Thanks. I guess it makes sense. I’d always thought that the pops and bangs was unburnt fuel hitting a hot exhaust, rather then an un ignited fuel/air mixture going bang.
It also ties up with it being low on power if running lean.
Hmm don’t like this at all. Lean engines tend to not last long…
Could be something to do with the ecu / sensors or fuel pressure (pump, filter etc).
Oh crap
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