Thread: Puma 110 won't start after transfer case overhaul

I have checked and rechecked all the earth points on the transfer case and battery, they are all connected and have good contact, problem remains. I have jiggled all the wiring to the relays under the seat, when time permits I will pull the main fusebox out so I can get to the back of all the relays and check contacts.
The fuse that blows when the ignition is turned on is all by itself on the end of a pair of wires taped to the loom under the driver's seat, a brown / orange wire that has 12v with ignition on and a plain brown wire that has zero ohms to earth; I'll check this on my own car but it does not seem right that the brown wire should be direct to earth when there is 12v fed to the other side of the fuse. Will get back when I have compared on my own car.

In previous LR wiring looms, brown/orange stripe was a power wire that stayed on for a few seconds after the ignition was switched off, controlled by the ECU. Used for things like idle steppers, injectors, EGR valves and the like. I'm guessing that in your zeal to connect all earths that you've earthed the other end of the plain brown wire which used to power something like an EGR valve.

It seems that if there is a 'worst possible' scenario, that will always be the reality- I have discovered that the ECU is fried. After several hours of checking everything else, I took the ECU out of the problem car and fitted it to my car- the problem came with it. So it seems that I have fried the ECU by welding the puller onto the adapter shaft. Can't believe my stupidity- I have always made sure to disconnect the ECU before doing any welding, but I was so focused on the damn adapter shaft that I completely overlooked it when doing this job. Unbelievable.
I will post a new thread with questions about ECU repair / replacement. Thanks to those who have offered helpful advice on this one.

POD
I feel your pain would be the sort of thing I would do!
At least there is a lesson for all. Even if you earth adjacent to the weld whacking a few hundred amps down the vehicles common earth isn't pretty in a puma ;(
S

Originally Posted by roverrescue

POD
I feel your pain would be the sort of thing I would do!
At least there is a lesson for all. Even if you earth adjacent to the weld whacking a few hundred amps down the vehicles common earth isn't pretty in a puma ;(
S

Yeah I was being very careful not to pass the welding current through any bearings etc but completely forgot about the ECU. Sucks that it is a mates car rather than mine. I think I've put in around 50 hours over the last 3 weeks getting his transfer case overhauled, intermediate shaft bushed etc- this is how it ends up due to a stupid oversight

Did you unlock it before trying to start your vehicle? The ecu needs to learn the security code from your 10as system in order to start. Or does it blow fuses too?

POD when you welded on the car, is there any chance even small that a terminal has been in contact with the body (Even the Earth)? A welder, stick, MIG and TIG make massive amounts of frequencies through out any metal connected to it. If your earths or positive leads were in contact with the car metalicly, even slightly, you have fried your ECU.

At all costs do not ever weld on your car, if you do, remove the ECU unit and put it away no where near the car, then once finished, earth the car to the ground (Dirt) to get rid of any residual currents, then reinstall your ECU unit. When they build these processors (ECU) they use special gloves to stop static electricity from a human which is at most in en extreme case 2 Volts, most times 0.2v. 0.2V is enough electricity to fry some section of an ECU depending on how advanced they are. (My brother builds Processors).

Id say if you haven't fully insulated your battery leads or disconnected all the earths your looking at an ECU, or if they can repair the one youve got.

Im a fitter and Turner by trade, and we never weld near bearings or anything as the way electricity earths, if its near a bearing it can make like tiny little fuse marks on the bearing race and then ultimately kill your bearing in as little as seconds to months depending on what it is. If we have to we make 100% sure the peice if fully insulated from the bearing, and the weld area is as isolated as possable with a nice shiny earthing area for the welders earth.

Hope this answers some questions

As far as security codes and stuff, it wont blow fuses, it just wouldn't start. To blow a fuse your getting wayy to many amps through that circuit. so like a diode or a regulator is stuffed in your ECU. Or if your very lucky they will have an external diode/ regulators, but, thats very lucky!!

Get someone with a proper scan tool and get a professional diagnosis at least.