Ok so we had a zed in Saturday for a simple brake pad change, however prior to traveling to us he had a flat battery and had a jump start from a mates van. He noticed on the way to us the abs light was on, the interior light was not working and the radio was acting up as in lighting up when the door was open but not switching on and the power light going out when the door was closed? also the central locking was not working.

 

So after a quick brake pad change we turned our attention to the fuses in the drivers foot well, it was quickly found that the fuse supplying the radio, central locking and interior light was blown replacing this cured the radio, locking and interior light.

 

Sadly the abs light was stiil on, we connected our Nissan ABS diagnostic tester, this is the oringinal one Nissan had when the Z32 was a new car and has a dedicated connector to suit.

 

The system tests failed on two points, low voltage and a missing earth on pin 32 of the ecu, under the bonnet a brand new battery was obvious but when a volt tester was connected it confirmed the low voltage at 11.4 volts, after checking the alternator exciter circuit was functioning the alternator was deemed dead. The owner agreed for us to fit a replacement alternator whilst he waited, once done we started the engine and again performed a volt test and all was good with a healthy 14.4 volts at idle.

 

However the abs light was still glowing strong, the abs diagnostic was again done this time the low volt fault was gone but the missing earth to pin 32 was still there. I checked through the wring diagram and identified pin 32 on the connector and made a temporary connection to earth rather than spend time looking through the loom, however the fault still was present, knowing there was no missing earth it left only one possible fault and that was the ecu, you can see what we found in the pictures below, there is a blown copper track that although not directly connected to pin 32 it was part of a circuit fed from it, a repair to the track could of been made but with some overheat marks elsewhere it seemed better to raid our stores for a good used item, surfice to say a new unit cleared the fault and the abs light.

 

So looking back to the faults, blown fuses, blown alternator, blown abs ecu, the only possible cause was the earlier jump start, polarity mistakes can cause issues like this but the owner was adamant he got the leads the correct way around, but he did mention a big spark when they were connected. Then when we spoke more he revealed the van engine was running when the connection was made! this is a definate no, no, the leads should never be connected whilst the engine is running as the alternator can be in high charge state as it was most likely was in this case, also diesel vans often have much higher output alternator than a car and should be used with the engine switched off.

 

So an expensive mistake, be carefull when using jump leads it can lead to sever wallet damage.

 

Jeff TT

 

 

ABS ECU BLOWN

 

 

 

 

Thank's for the head's up Jeff as I always jump start a car with the engine running when connecting the leads:oops: I wont be doing that again.

wow did well to spot that jeff :cool3:

Great info as always, thanks Jeff

A very interesting & usefull piece of info.

Thank's for the head's up Jeff as I always jump start a car with the engine running when connecting the leads:oops: I wont be doing that again.

 

 

Yeh me too Gaz, I wont be doing that again!! ......Top advise from the best, cheerZ Jeff

That's unlucky I was chatting that guy on sat when I dropped mine down he was a nice guy, he's never had a problem with that car in 5 years of ownership, all that aggro just from a simple jump start mistake, at least it's sorted now nice find jeff

I was always told to leave the leads on for ten minutes after you have jumped it off to allow the alternater to settle, the damage is usually done to the diode pack on the rear of the alternator when the leads are removed.

I blew up a turbo timer on my zed jump starting it befote as well .

Another great piece of advice - thanks Jeff; have some forum rep for that!!

 

This is of particular benefit to those of us for whom the ZX is a weekend toy, as our batteries are most likely to go flat if the car is not used for weeks at a time....

 

Richard:cool3:

good advice jeff

one of the thing my granda taught me

allways connect the earth first then the live AND always with both engines off

Another great tip from Jeff,

 

Another thing I've found is to not directly jump the battery but to connect the negative to a ground point further reducing chance of battery explosion or so I've been told!

great detective work there Jeff! :thumbup:

My 300ZX TT and Holden Barina [Opel Cora 1.4] I have fitted spike & surge protecters fitted across the battery terminals to protect the ECU.

ZHoody...........Other way round dude!

Was told from somebody that modern day technology can tell the healthy car that it is being drained on power and can compensate its own protection ??

 

Only if the ignition is switched on, and not running ?

 

No help to the sick car in question tho ?

 

Jump leads on, ignition on the donor car, then start the donor car seems to be the way to go then ?

 

Alan.........