Electrical trouble? 1992 2.9 V6
Discussion
Driving yesterday afternoon I noticed a brief loss of power when I went over some pretty rough surfaces. About ten mins later, on a very smooth bit of new tarmac, all power was lost. I coasted into a side road and tried to restart but nothing happened. While cooling down I checked for obvious loose connections under the bonnet and in the footwellbut none found.
When the AA fellow arrived we checked the fuel pump and coil, both fine but the ECU didn't appear to be 'switching the coil'.
This morning I disconnected the multiplugs on the distributor, ISCV and throttle pot, sprayed with contact cleaner and refitted. Also disconnected the ECU and sprayed there too. Still not starting.
I saw a couple of older threads mention an 8k resistor bestwwen the ECU and coil but I can't see one and the wiring diagram only shows the could connected to the distributor(green) and tacho(white/yellow).
Any advice on what I can check or re-check would be gratefully received.
Thanks,
Steve
When the AA fellow arrived we checked the fuel pump and coil, both fine but the ECU didn't appear to be 'switching the coil'.
This morning I disconnected the multiplugs on the distributor, ISCV and throttle pot, sprayed with contact cleaner and refitted. Also disconnected the ECU and sprayed there too. Still not starting.
I saw a couple of older threads mention an 8k resistor bestwwen the ECU and coil but I can't see one and the wiring diagram only shows the could connected to the distributor(green) and tacho(white/yellow).
Any advice on what I can check or re-check would be gratefully received.
Thanks,
Steve
Wasn't there a similar post quite recently, turned out to be a badly soldered spliced connection taped up "somewhere" in the loom?
Do you have an alarm/immobilizer, could that be playing up?
Or the "old favourite", the big yellow connector?
[i] New Search is rubbish! "TVR S Series yellow connector" should bring up loads, it's bringing up bugger all of an relevance
Check that you have a HT voltage at the spark plugs to check the function of coil/dist. Also, check the voltages of ALL of the various sensors which input to the ECU.
Details can be found in the Steve Heath manual/book, where there is also a troubleshooting checklist on "when engine does not start".
"When the AA fellow arrived we checked the fuel pump and coil, both fine" - do you hear the fuel pump priming when you switch on the ignition ?
Details can be found in the Steve Heath manual/book, where there is also a troubleshooting checklist on "when engine does not start".
"When the AA fellow arrived we checked the fuel pump and coil, both fine" - do you hear the fuel pump priming when you switch on the ignition ?
Fuel tank is half full. Fuel pressure good when AA tested it.
Just spent an hour poring over it and the situation at the moment is that the coil is not generating a supply down the HT lead to the distributor. Spun the engine and no spark when we tried to earth it.
Tried a different coil, no different.
Disconnected, cleaned and reconnected the multi-plug to the distributor, no different.
Disconnected, cleaned and reconnected all multi-plugs in the footwell and the ecu, no different.
Fuses all ok.
Lights, horn, fan all ok.
Dropped the steering column shroud but couldn't see a melted yellow connector anywhere.....
Gin and tonic and a good read of the Steve Heath troubleshooting guide coming up.
Thanks for the help so far.
Steve
Just spent an hour poring over it and the situation at the moment is that the coil is not generating a supply down the HT lead to the distributor. Spun the engine and no spark when we tried to earth it.
Tried a different coil, no different.
Disconnected, cleaned and reconnected the multi-plug to the distributor, no different.
Disconnected, cleaned and reconnected all multi-plugs in the footwell and the ecu, no different.
Fuses all ok.
Lights, horn, fan all ok.
Dropped the steering column shroud but couldn't see a melted yellow connector anywhere.....
Gin and tonic and a good read of the Steve Heath troubleshooting guide coming up.
Thanks for the help so far.
Steve
Remember what
phillpot said:
Do you have an alarm/immobilizer, could that be playing up?
You didn't specifically mention that you'd checked this. The immobiliser can also be set up to intercept the low-voltage ignition circuit, and if your immobiliser is not OK, the engine will not start. Superb schematic, many thanks.
Before the immobiliser key is used the speedo is at 40mph and the tacho at about 2000rpm. Both reset to zero when the key is used.
Last night I noticed that the tacho needle is in the zero position before and after the immobiliser key is used.
Not sure if this means the immobiliser is faulty or that there is no feed to the tacho. There is definitely no power form the tacho to the coil.
Steve
Before the immobiliser key is used the speedo is at 40mph and the tacho at about 2000rpm. Both reset to zero when the key is used.
Last night I noticed that the tacho needle is in the zero position before and after the immobiliser key is used.
Not sure if this means the immobiliser is faulty or that there is no feed to the tacho. There is definitely no power form the tacho to the coil.
Steve
Thanks for the help and tips gents. Had to leave it for a week but finally got to the bottom of it.
The heater blower/fuel injection fuse was blown. Only found it when I decided to right back to basics and check every fuse. Looking at the wiring diagram in the Steve Heath book I don't think it should be part of the supply to the coil but who knows..... just glad to have it back up and running.
Thanks again,
Steve
The heater blower/fuel injection fuse was blown. Only found it when I decided to right back to basics and check every fuse. Looking at the wiring diagram in the Steve Heath book I don't think it should be part of the supply to the coil but who knows..... just glad to have it back up and running.
Thanks again,
Steve
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