Bizzar Situation: Battery shows 8-9V but all is running well
Discussion
Hi All,
Some help from the Collective please.
I've just got in from my 90 mile commute with me fretting I wouldn't make the last 10 miles.
I noticed the battery was showing 8.8 to 9.2V. I had the thoughts of a phone call for recovery, but no, she got me home without hesitation.
Got home, parked up, turned off, checked oil (a ritual I always do) and thought, well, she won’t start now. But she did. Starter span with normal gusto and engine fired like normal.
Strange, as the last couple of times I’ve seen the battery low on volts was when the alternator fuse blew. Even then the fuel pumps were cutting out and it wouldn’t spin the starter at 11V never mind 9V!
I’ve not had chance to put the Volt meter on yet so I can’t say what the battery really has but I guess it is fully charged and the ECU is lying!
Any thoughts?
Cheers,
Paul
Some help from the Collective please.
I've just got in from my 90 mile commute with me fretting I wouldn't make the last 10 miles.
I noticed the battery was showing 8.8 to 9.2V. I had the thoughts of a phone call for recovery, but no, she got me home without hesitation.
Got home, parked up, turned off, checked oil (a ritual I always do) and thought, well, she won’t start now. But she did. Starter span with normal gusto and engine fired like normal.
Strange, as the last couple of times I’ve seen the battery low on volts was when the alternator fuse blew. Even then the fuel pumps were cutting out and it wouldn’t spin the starter at 11V never mind 9V!
I’ve not had chance to put the Volt meter on yet so I can’t say what the battery really has but I guess it is fully charged and the ECU is lying!
Any thoughts?
Cheers,
Paul
Faircp, I had that error code once, was a partial short circuit/excessive load current being drawn intermittently, door/window passenger side not working properly, so disconnected door/window ecu which had water ingress, power came back up, also could be 100a fuse, this was a bad connection on mine, and finally blew (killing ALL electrical power) in the fast lane of the M25 at Heathrow in pitch black mid winter with a 3 ft central reservation to get on, and shut the motorway down for 30 mins, traffic police had to push it across 4 lanes of long tailbacked traffic to hard shoulder, luckily had a spare fuse to fit.
Tamster. said:
Faircp, I had that error code once, was a partial short circuit/excessive load current being drawn intermittently, door/window passenger side not working properly, so disconnected door/window ecu which had water ingress, power came back up, also could be 100a fuse, this was a bad connection on mine, and finally blew (killing ALL electrical power) in the fast lane of the M25 at Heathrow in pitch black mid winter with a 3 ft central reservation to get on, and shut the motorway down for 30 mins, traffic police had to push it across 4 lanes of long tailbacked traffic to hard shoulder, luckily had a spare fuse to fit.
Hi Tamster,
Which fuse was that? The one in the passenger footwell?
Spoke to Power who suggested it might be bad earthing and to check all the earth connections from the battery to the body and to the inside.
It is getting slightly worse, the dash ECU will occasionally shutdown and startup again when driving.
They also said the chance of getting fixed if the dash ecu is faulty is... ZERO!!!!
Edited by fairclp on Tuesday 3rd April 18:25
Try this link www.pistonheads.com/gassing/topic.asp?t=367576&f=7&h=0
it may help
it may help
I had a look at thread when it was posted and gave food for thought.
The ecu's were made inhouse; My passenger door ECU proudly states it was made by Tracey!
The other option if all else fails and it is a faulty ECU is to get one from a breakers. Except: it needs to be the right one as they are coded for model and certain years i.e. a Saggy one wont work a T350.
I'm off to check/pull fuses, pull a few cables and disconnect an ecu here and there...
The ecu's were made inhouse; My passenger door ECU proudly states it was made by Tracey!
The other option if all else fails and it is a faulty ECU is to get one from a breakers. Except: it needs to be the right one as they are coded for model and certain years i.e. a Saggy one wont work a T350.
I'm off to check/pull fuses, pull a few cables and disconnect an ecu here and there...
Does anybody have a pic of one of these door control units? Especially the electronics.
Do they control the door release and the window? Is there on per door, or one for both doors?
As a T350T owner and an electronics engineer I'd like to try and help find a solution to all these electronic issues people are reporting.
Do they control the door release and the window? Is there on per door, or one for both doors?
As a T350T owner and an electronics engineer I'd like to try and help find a solution to all these electronic issues people are reporting.
I can tell you where to find them if that helps?
On a tamora there is one below the glove box behind a pull back section that goes into the footwell. On the drivers side there is one on the right of the pedal box below the emergency door release.
I am up for helping but its been 22 years since I last designed a circuit board in earnest!
On a tamora there is one below the glove box behind a pull back section that goes into the footwell. On the drivers side there is one on the right of the pedal box below the emergency door release.
I am up for helping but its been 22 years since I last designed a circuit board in earnest!
maddog-uk said:
I can tell you where to find them if that helps?
On a tamora there is one below the glove box behind a pull back section that goes into the footwell. On the drivers side there is one on the right of the pedal box below the emergency door release.
I am up for helping but its been 22 years since I last designed a circuit board in earnest!
On a tamora there is one below the glove box behind a pull back section that goes into the footwell. On the drivers side there is one on the right of the pedal box below the emergency door release.
I am up for helping but its been 22 years since I last designed a circuit board in earnest!
Alas, my car is laid up awaiting a radiator
so cant take a look! OK, I kind of killed it off!
Well, it was on its way. At least it kind of works so I've still got a analogue Speedo, Tacho and all the interior controls but the dash lights up blank with usual beeps, but nobody's home.
Also, I found the interior 80A fuse was about to break with the battery side bolt loose and a bit scorched. Took it out, cleaned it and then it snapped just below the bolt cut out. Luckily I had a spare 100A (trip to Power tomorrow to get spares).
Rang Bell Hill Gararge and they've just sold their last dash ecu yesterday.
Well, it was on its way. At least it kind of works so I've still got a analogue Speedo, Tacho and all the interior controls but the dash lights up blank with usual beeps, but nobody's home.
Also, I found the interior 80A fuse was about to break with the battery side bolt loose and a bit scorched. Took it out, cleaned it and then it snapped just below the bolt cut out. Luckily I had a spare 100A (trip to Power tomorrow to get spares).
Rang Bell Hill Gararge and they've just sold their last dash ecu yesterday.
Are these guys involved www.mbesystems.com/automotive.html i seam to recall they made something for tvr.
May be we can find out the designs from someone!
May be we can find out the designs from someone!
Edited by maddog-uk on Tuesday 3rd April 17:47
Anyone else spot the watch battery in there. .. presumably to save the settings if the power fails.
Test the battery for voltage - you mention odd voltage readings..
Also - MBE did the engine mapping .. and other stuff ?
Doubtful as TVR were supposed to have their own electronics man ...
Test the battery for voltage - you mention odd voltage readings..
Also - MBE did the engine mapping .. and other stuff ?
Doubtful as TVR were supposed to have their own electronics man ...
A few thoughts and questions -
I'm guessing the battery is there for a real time clock (RTC). The device to the lower left of the battery looks like a crystal used with RTC's. From what i can gather from other forum posts there is some FRAM memory on the board which would normally be used for storing settings.
The two large devices will be the PIC17C766 microcontrollers - got that from the silkscreen label on the PCB. Looks like they have removed the other IC identifications though which could make any repairs difficult without schematic and part references.
Are the two D-type connectors at the bottom of the picture connected to the LCD, dash lights and revs & speedo? Again, a guess for the large connector to the top of the picture would be for connecting to the rest of the system in the car?
It would be interesting to see pics of the board below and see whether there are components on the other side of the PCB's.
How many electronic units are there in the tamora/t350/sagaris? Is there 1 unit in each door, 1 dash unit and one engine management unit? Does the dash ecu control the heater? Do the various sensors around the engine feed both the engine management and the dash ecu?
Finally, and im pretty sure the answer is no, but are there any wiring diagrams for these cars?
I'm guessing the battery is there for a real time clock (RTC). The device to the lower left of the battery looks like a crystal used with RTC's. From what i can gather from other forum posts there is some FRAM memory on the board which would normally be used for storing settings.
The two large devices will be the PIC17C766 microcontrollers - got that from the silkscreen label on the PCB. Looks like they have removed the other IC identifications though which could make any repairs difficult without schematic and part references.
Are the two D-type connectors at the bottom of the picture connected to the LCD, dash lights and revs & speedo? Again, a guess for the large connector to the top of the picture would be for connecting to the rest of the system in the car?
It would be interesting to see pics of the board below and see whether there are components on the other side of the PCB's.
How many electronic units are there in the tamora/t350/sagaris? Is there 1 unit in each door, 1 dash unit and one engine management unit? Does the dash ecu control the heater? Do the various sensors around the engine feed both the engine management and the dash ecu?
Finally, and im pretty sure the answer is no, but are there any wiring diagrams for these cars?
Hi Fairclp, the fuse that gradually went on mine was in the passenger footwell, are the rest of your electrics working ok? The earthing points are worth checking as on some cars the chassis paint wasnt removed prior to bolting down the earth lugs and acts as a poor conductor. My dash/ecu also failed and blanked out completely due to an internal problem,the factory repaired it, but afterwards would still blank out in extreme hot/cold temperatures.To isolate the problem to the dash/ecu or a power supply problem, a drawing would be needed to pinpoint and measure the 12v supply, would Tvr power have an electrical diagram they could make available to you?
Gassing Station | Tamora, T350 & Sagaris | Top of Page | What's New | My Stuff