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Non start and no dash lights issue
https://forums.tipec.net/viewtopic.php?f=25&t=24333		 Page 1 of 1
Author:  infrasilver [ Wed Mar 18, 2020 11:07 pm ]
Post subject:  Non start and no dash lights issue
The other day I was about to drive my 944S for its MOT and the car wouldn't start, ie doesn't turn over, if I try a few times it does a single click of the starter motor but nothing else and no or dim dash lights.

I originally thought it was a flat battery so put a jump pack on it but still nothing, I used jump leads from another car and still nothing. I removed the battery and fully charged it, still nothing, I even used another fully charged battery.

I then started to wonder if the starter motor wasn't letting power to the front of the car, so I removed all the terminals on that, cleaned them up and put it back together, I had 12v at the starter motor before and after cleaning the terminals.

I then moved onto the ignition switch, I removed the dash etc and when I removed the plug at the rear of it the whole unit fell apart, this led me to believe I had found the problem.

Image

So the new switch arrived today from OPC and guess what, I still have no dash lights and the car doesn't turn over.

I've had a look at the fuse box and there are two relays assigned to IGNITION, G2 Relay 15 and G14 Relay X, does anyone know if either of these could be the culprits, I ran out of time tonight to investigate any further but I'm desperate to get the MOT sorted before places start closing for you know what!!!
Author:  Waylander [ Thu Mar 19, 2020 1:16 pm ]
Post subject:  Re: Non start and no dash lights issue
you can find wiring diagrams at www.pdlibrary.co.uk

in the manuals section
Author:  infrasilver [ Mon Mar 23, 2020 10:04 pm ]
Post subject:  Re: Non start and no dash lights issue
I had a bit of a play with the two relays, I removed the cover off G14 and refitted it to see if anything happened, when I turned the ignition i had the dash lights back and it started up first time.


Image


I have left it over the last few days and each time it has started up first time each time, I refitted the relay cover and all seems to work fine again. I'm still not sure what the problem was as the inside of the relay looked clean and didn't have any burn marks in it?

I have ordered a used spare relay in case the problem reoccurs but in reality I'm not even 100% sure this relay was causing the problem?
Author:  Waylander [ Mon Mar 23, 2020 10:17 pm ]
Post subject:  Re: Non start and no dash lights issue
Might have been more a connection or earth issue in the relay socket rather than the relay itself, just plugging it in and out a couple of times might have sorted it out
Author:  infrasilver [ Mon Mar 23, 2020 10:28 pm ]
Post subject:  Re: Non start and no dash lights issue
I had previously taken it off to clean the terminals but when I put back in there was no difference but removing its lid seemed to get it going again, like you say it could have been just remove/refitting that did the trick?
Author:  infrasilver [ Sun Apr 19, 2020 11:37 am ]
Post subject:  Re: Non start and no dash lights issue
This problem reared it head again yesterday while I was starting the cars to charge batteries as they aren't moving at the moment, it turned over but didn't quite fire, so on the second try it clicked once and the dash went dark again, I have 11v at the battery and used another fully charged battery but the car was still dead. I had ordered a spare relay for a spare after the first time this happened so immediately tried that but still nothing and this time it doesn't seem to be intermittent, which could be a good thing in helping trace why?

I'm guessing its going to be within the fuse box or a wire going to the ignition so will have a dig around, I'm not very good with following wiring diagrams so this could be a bit of a headache trying to trace what should or shouldn't have power?
Author:  infrasilver [ Thu Apr 23, 2020 5:29 pm ]
Post subject:  Re: Non start and no dash lights issue
Had the fusebox out today and have been checking voltage at various areas for the incoming power cables and cleaning them all up along with all the earths.

I was also looking at the battery cable running through the N/S footwell and the 5 cables spliced from it going to the fusebox, they seemed to fluctuate their voltage from 5v to 7v depending how the fusebox is moved, I still have 11v at the battery cables so something isn't right.

I then decided to check the connection in the footwell and cut the heat shrink off and this looks slightly corroded internally. I want to cut it off to renew the connection but I can't find anything suitable or heavy duty enough to replace this, any ideas what to use to replace this without the need for a heavy duty crimp tool? The footwell did have water in it when I had it parked up for a few months over Winter on a slope facing down as the hatch seal was leaking, so I'm hoping this connector is the culprit?

Image
Author:  Waylander [ Thu Apr 23, 2020 6:52 pm ]
Post subject:  Re: Non start and no dash lights issue
50amp connection block from an electrical wholesales, like CEF or Medlocks
Author:  Crank Case [ Thu Apr 23, 2020 9:13 pm ]
Post subject:  Re: Non start and no dash lights issue
Water in the footwell? Passenger footwell? Eeek.

I see the ECU mounting plate, so I presume the above.
Not a nice thought, but is your ECU got some damp in say, the DME connector block? ...and have a look at the white connector block too.
Has the damp caused any other corrosion in that area?
If you get it started, measure the current across the battery?
Author:  infrasilver [ Thu Apr 23, 2020 9:24 pm ]
Post subject:  Re: Non start and no dash lights issue
It had only soaked the carpet and didn't go further up, the connector pictured is under the carpet so would have likely been submerged, moving these cables around changes the voltage I get at the fusebox so I am swaying towards this connection, especially as the bottom 2 red sheathed cables look green and corroded.

Just struggling to find something suitable that is slim enough and is rated at 50amp. I can't even find the size of the cable to get the correct connectors at the moment.
Author:  Crank Case [ Thu Apr 23, 2020 9:52 pm ]
Post subject:  Re: Non start and no dash lights issue
As a simple stop gap, you could use a terminal block like Waylander suggested:

https://www.ebay.co.uk/itm/Chocolate-Bl ... tspzrK-5pA

Or: Have you got a soldering iron and some heat shrink?
Spliced connection.
Author:  infrasilver [ Thu Apr 23, 2020 10:04 pm ]
Post subject:  Re: Non start and no dash lights issue
I have both a soldering iron and heat shrink but I'm not sure if the battery to starter cable is in one piece or not until I get the crimp off, it could be beyond repair if it is totally corroded in there and I may have to cut a sections out, I'm not sure a soldering joint is up to the size of cable.

My preferred repair would be two crimp connectors bolted together then tap the 5 fuse box connectors from that, then heat shrink over the whole lot. I just need a couple of the correct size crimp connectors, I have a large crimp tool but unsure if it'll be big enough for this size wire crimps, I think it goes up to 25mm2.
Author:  Waylander [ Thu Apr 23, 2020 10:20 pm ]
Post subject:  Re: Non start and no dash lights issue
You only have small voltages all over the place, you should have at least 12.3 with a full charged battery

Think you should go round the whole car and redo every earth connection 4 under the dash, engine, boot, get the diagrams out and clean them all

Just as a temp solution you could use a bolt up battery terminal to connect them all, they can handle 700 amps
Author:  infrasilver [ Thu Apr 23, 2020 10:47 pm ]
Post subject:  Re: Non start and no dash lights issue
I had a go at some earths today, 4 under the fuse box, 3 in the inner wings and the main bulkhead one, easy wins but didn't make a difference. I did do them all when I first bought the car so most should be fine, the ones I did today were all ok.
Author:  infrasilver [ Tue Apr 28, 2020 2:15 pm ]
Post subject:  Re: Non start and no dash lights issue
I feel I have sorted this problem out now, I cut the 5 red fusebox cables from the large crimp with a hacksaw and gave them their own 16mm2 crimps in the same groups as before and then drilled through the brass crimp to take a bolt and bolted these either side of the crimp. I'm happy that this is a good permanent fix. I'm getting battery voltage at the fusebox again now.

Image

The battery to starter cable is split in this large crimp so I couldn't get heat shrink over it so I used self amalgamating tape over the whole thing.

Hopefully I can find somewhere to get an MOT on it now?
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