Reverse Battery Problem.

[Guest EVSS]

hi friend of the family bought a secondhand galaxy because he liked ours tdi ghia x 98 r reg. now at the weekend he took the battery off to charge it up as it had been standing. now his son thought he was helping and without realising picked up the smaller vauxhall battery and put it on the wrong way round. now not realising friend trys to start and of course nothing. he replaced the correct batteryand the vehicle restarted.now ive had a look at it for him because ever since when it starts it revs to about 1800 revs and then goes to tickover normally, there appears to be no power when you drive it ,and then other times it will be back to normal again. he changed the air flow meter about a month ago due to lack of power (236 from ford , he bought one from vw 80...) and today v/w swopped it again beleiving it to be faulty, (but no difference) any body had this surge in revs before, it may or may not be connected with the battery . thanks gary

[Ivor_E_Tower]

If you mean he connected the smaller battery the wrong way round on the Gal, there is probably some damage to the electronics. Maybe some diodes gone in the alternator, maybe worse :o

 

A few years ago my dad went to jump-start his old car and connected the leads the wrong way round from by brother's car. Fortunately brother's car was OK, but this was just before they went on holiday and whilst they were away, my job was to source a new alternator for dad's car. Diodes had blown and red "ignition" light was on all the time that the ignition was off, and the battery was draining rapidly - one battery lead had to be taken off every time the car was stopped until I fitted the replacement alternator.

[Guest EVSS]

weve checked the alternator and thats fine, it just seems like a total lack of power, (almost maf sensor failure, but after a rest is fine for about 15/20 mins then fails again). the other problem is common i believe in that he has had all his aircon pipes replaced and every thing was nice and cold , then about 1/2 later he noticed a humming from the drive belt area and now the diagnostics are telling us his compressor clutch has failed!!!!! (presumably due to it not working for so long). one other question , without giving the impression that the vehicle is jinxed, i am given to beleive the immobiliser codes are stored in the ecu , has anybody swopped an ecu on a tdi . the reason i ask is we have a spare one here and the dealer arnt sure if they have to code them. gary

[Guest fredt]

I was lead to believe that the codes were a stored in the PAT's systems ECU and not the main engines ECU, I would imagine that you wouldnt be able to start the vehicle after the swap if the main ECU does hold the codes? try it and see! :rolleyes:

[Guest EVSS]

yes i thought that, from what i remember its the siemen unit on the bottom of the fusebox, now all i have to do is get the old one out.