Battery/Electrical/Ignition/Dunnowhat problems MR2

Story Bud?

I have this lovely little car that I love with all my heart and all my soul, but it's not behaving itself.

Before Christmas I had battery issues, car wouldn't start if laid up for a few days which turned into not starting the following morning having driven it the night before. Replaced the battery which seemed to fix the issue for a while.

Then the alternator went, replaced that.

Then the fan belt went, replaced that.

Didn't drive it last weekend from Saturday to Wednesday and it wouldn't turn over. Jumped it and all fine again. Drove it yesterday evening (as the weather was too good not to!), and this morning not a dicky bird out of it.

Any suggestions as to what could be draining it? Or how I can go about identifying what might be draining? I have a fairly hefty sound system in it (put in by previous owner) and I don't switch off the isolator switch when I'm not driving it, but I had the car 6 months without that being an issue. I'm considering getting that taken out because this is a bit of a pain in the arse!

Let me know if you need any more info.

Thanks

(1994 MR2 Non Turbo G-Limited model)

Cee-Jay-Cee

Most definitely sounds like it's a drain problem rather than a bad wiring problem.

If you don't use the sound system rip it out it at least disconnect it to eliminate it as the problem. If it persists then get the alternative tested, if it's a reconditioned unit then it may be faulty.

gctest50

don't rip out the sound system

Tiny fault, easy find and fix

What you really need ( just in case it ever happens again) :

A Low Voltage Disconnect

basically automatically disconnects the battery before it goes too low to start the car

What you need to do now :

Disconnect one cable from the battery

Put a meter ( set to current ) between the end of the cable and the pole of the battery

You should see it drawing power

Now go around disconnecting things in the car one by one

When you find the culprit the meter will read near zero

gctest50

this kinda craic

gctest50

May not be much use to you if it is the sound system but anyway :

You can also buy current draw testers like these :

MAXI FUSES :

http://www.maplin.co.uk/p/400mm-automotive-current-tester-maxi-blade-n48cy


MINI-FUSES :

http://www.maplin.co.uk/p/400mm-automotive-current-tester-mini-blade-n49cy

just pop out the fuses one-by-one and plug in that yoke - you'll see which one is drawing power

Wibbs

Might be your alarm install too. I and one years ago now that after a few years of faultless alarming decided to be a major draw on the battery. Still working perfectly on the surface but...

eringobragh

Was the factory alarm on mine - got stuffed full of water as its in the passenger side wheel arch

I ended up disconnecting the siren and replacing it - I put the new one in 2 think platic router bags - not sure if the 94 ones had a factory alarms


Heres what I did to resolve it:

Yeah definately I think I got that multimeter about 5 years ago in maplin for 4 euro!

Anyway an FYI for anyone looking to do this - move the positive probe to 10ADC unfused link

Remove the earth from the battery - stick the multimeter to 10a (like below) and put the probes between the battery and the earth lead..remove fuses until it drops to a reasonable level 0.02 = 20ma...average consumption should be 20 - 50ma!

Story Bud?

Sometimes I don't lock my cars

After I started this thread, I gave it a good run down the M50 and back and not a bother out of it again until the other day. I came out and noticed my driver door was open (not unlocked, but "open closed", if that makes any sense). Car wouldn't start. This happened a few weeks ago too and I'm trying to remember now if it was the same morning it wouldn't start having driven it the night before. Don't know why it didn't click with me at the time. This time my BMW's passenger door was also open in the same position, so looks like someone was messing with my cars. They also turned on the "door" light in the MR2 so that's what seems to have drained the battery overnight. Again, absolutely grand since, and jumped started a Nissan Pathfinder not a bother.

Lesson learned, I'll be making sure my doors are locked. Still potentially a drain issue (and a paranoia issue?!!!) but she's running well at the minute.

Beautifully valeted yesterday ready for summer

Thanks for your help lads, I'll revert back to it if there are any more issues.

Wibbs

Another one not immediately obvious and again an alarm issue can be the siren. Specifically the sirens with a built in battery backup. These are kept charged (via the alarm) from your car battery. If the siren's internal battery goes on the fritz(technical term) it can fail in such a way that the alarm brain keeps it in charge mode all the time. Thing is it's not a big obvious drain and might be missed but that can drain your battery over a few weeks and weaken it to the point where it won't hold a charge for very long.

From what I recall the 94 Mr Twos didn't come with much in the way of factory security at all. It's why Japanese cars of that period are pure scum magnets as even a dribbling moron could steal one. So if it does have any security it's gonna be third party.