Arrgh Dicky oil/water readings now flat battery- Earth falt?

[fredd1e]

Yesterday my oil pressure and oil/water temp readings on the dash started to jump around, from previous info on here it seems to be an engine earth prob that causes it? I left it for the weekend to investigate as it was running well but today got up to a flat as a fart battery . Are the two likely to be related or just the fickle hand of the TVR faults god! (tempting fate there I suspect). I've had the battery out to replace engine mounts (its run fine for a week since) but they cables disturbed seem pretty secure as does the earth cable to chassis engine mount on drivers side. Any other areas I should be looking at for suspected earth issue?
PPS I meant fault... (spelkchk err)

Edited by fredd1e on Thursday 22 July 11:27

[Targarama]

Well the magic 100A fuse needs checking, it could have broken in the last few miles of driving, resulting in varying/no charge from the alternator to the battery, leaving no juice in the battery for when you turned off.

[fredd1e]

Hmmm the mystery continues, the magic fuse was found to be intact and showed continuity for Resistance and Volts. Nipped up the nuts for justin as they weren't much more than finger tight. All the earths points to engine mount, and passenger foot well also seem to be good/tight and corrosion free. Just took it for a test drive and whilst it was better ie some stable readings its still getting the odd jumpy water/oil temps lots of randon ecu faults flicking up and displayed voltage jumping up to 15.5 then settling back to 13.5~14.odd. I suspect it may be the main earth cable from battery to chassis is going intermittent as thats the only one that appears to have flakey feel (has a significant 90deg kink as it approaches battery post and seems more flexible than usual for a battery cable. Plan is to pull it and replace fingers crossed.

[SwampySi]

Your not having much luck mate

[fredd1e]

Lol its certainly feels like its got a few items on the snagging list.

[fredd1e]

Ps famous last words Si? anyways just to share my misery (literal exageration) with yours, my battery is flat again too, but I had suspected that it would be... oh electrical faults... don't you just love them. Not.

[RicSpeedSix]

fredd1e said:

Hmmm the mystery continues, the magic fuse was found to be intact and sh owed continuity for Resistance and Volts. Nipped up the nuts for justin as they weren't much more than finger tight. All the earths points to engine mount, and passenger foot well also seem to be good/tight and corrosion free. Just took it for a test drive and whilst it was better ie some stable readings its still getting the odd jumpy water/oil temps lots of randon ecu faults flicking up and displayed voltage jumping up to 15.5 then settling back to 13.5~14.odd. I suspect it may be the main earth cable from battery to chassis is going intermittent as thats the only one that appears to have flakey feel (has a significant 90deg kink as it approaches battery post and seems more flexible than usual for a battery cable. Plan is to pull it and replace fingers crossed.

My money is on your cable. That sounds exactly the same problem I had and earth lead was like that too.

[fredd1e]

Main earth cable Cable found to be good, remade the end as it shrouded the bolt/nut when fitted so difficult to tighten. Re-checked cleaned the main earth mounts battery/chassis and engine/chassis. Found the main 12v lead into car was pulling a bit of current when the car was off , wasnt sure if this was normal with the alarm but this was the same with alarm off . Visual fault finding in the car found the Heater amplifier in passenger foot well resting on the main foot well fuse holder which was also slightly open and the heatsink seems to capable of touching the fuse terminals . Moved the amp to a less perilous location and it seems to have been the mail culprit for the current drain /flattening battery, no idea where the amp is supposed to be originally located as it was hanging free on its cable.
Starts ok and readings of oil/water temps a bit more stable (only a couple of degs variance as opposed to 10s) but voltage o/p of alternater now seems to be unregulated ie exceeds 16Volts when engine revved so that looks like its spat the dummy too .
marvellous.
As mine is an air con car is this a TVR parts special or can I get one from any regular alternator supplier?

Edited by fredd1e on Saturday 24th July 18:36

[SP6 Animal]

I think theres another fuse in the passenger foot area could still be that but you should be able to get your alternator tested for faults.

[fredd1e]

I've measured the voltage off the back of the alternator and its same as shown on the dash give or take a point so deffo looks likes the alternator regulator pack has failed /not keeping the voltage within expected limits (I would expect less than 15V on full O/P)
Ps did you mean they are two fuses in the passenger footwell? or just the main in line fuse in the 12v feed from battery to dash area?

[FactoryPilot]

Not wishing to state the obvious, but watch that over-voltage. It really won't take very much to fry things like the dashboard LCD display etc....

[fredd1e]

Yes it did worry me when the voltage went that high , its off now until I get the alternator out (task for this afternoon)
As an aside the battery was flat again this morning leading me to think its also not holding a charge after it had been on a long charge yesterday . Just in case I checked if I was getting excessive current drain into the car and measuring current draw across the interior passenger footwell 80amp fuse/holder with the car off it was showing 0.4 amp. I suspect this seems about right for the alarm unit, though it would be usefull if anyone else has a view on that .

[fredd1e]

Alternator now off and it seems to be a bit dodgy as the serpentine spindle was fairly hot to touch ! this was with the car connected to the CTEK trickle charger and not having run since yesterday, so seems to be pointing at something fubar inside it to generate that much heat when all the charger current should be going into the battery. <SNIP>

PS it looks like a Range Rover alternator AMR4247 will fit but will need the pulley swapped as the T350/S6 one is 10rib and the LR one seems to be 7 Rib. There also appears to be two price ranges, those in 120ish bracket and those in the 240ish.. Clever Trevor also lists the alternator in these prices ranges. So its stick with the TVR parts suppliers to avoid the faff of pulley swaps.

Edited by fredd1e on Sunday 25th July 16:01

[fredd1e]

Well have much faff and tooing /froeing I've got the fault sorted (caused by duff parts and lack of pulleys). Fault was definitley due to a dying alternator rectifier/regulator pack causing voltage to vary affecting the dash readings as well discharging the battery.
A new (recon) alternator eventually fitted and works a treat (1st alternator ordered turned up DOA).
I found I had enougth length on the starter /100amp fuse holder /Alternator cables to move it to the offside inner wing making it accessible without removing airbox, also replaced it with a 125amp midi fuse. Oil and water temp readings now very stable and voltage is a nice 13.7volts .

One thing to note for would be alternator swappers is that the 10rib Sepentine alternator pulley is now low longer available so most replacements will come without one fitted as the stock drys up. It can be a bit tricky getting the old nut and pulley off and tightening it back up on the new one so plan accordingly.

[Targarama]

fredd1e said:

sorted

Great news! Now enjoy!