Nibbles wrote:
3 - The throttle position sensor is acting as a full potential divider rather than a variable resistor, The value of the resistance of the whole track is therefore second order, what matters is the ratio of resistance from wiper to gnd vs wiper to supply. If the 165 is a different resistance potentiomer then the above readings are meaningless. I doubt this would affect idle anyway, only throttle response.
So, having driven the car etc this evening i can safely say the car can still be revved to around 2300rpm with the pfc thinking its still on IDL!?
maybe this is down the the st165 TPS? i will try and swap this out still i think..
The car drives fine other than this.
Nibbles wrote:
5 - The voltage at the engine bay end is mainly going to be driven by the alternator. At idle with a heavy load, the alternator won't cope so the voltage will drop to what the battery can supply, minus the drop along the cable. At higher RPM, you will probably see over 14 at the ECU. Not ideal to have this much swing as you're relying on the dead time settings for the injectors vs voltage being accurate otherwise fuelling alters - one of the biggest hurdles to smooth / predictable idling. This MAY be your problem.
Measuring the voltage at the battery with the engine off shows around 11.90-12.10v and again similar figures with all electrical systems on, this is echoed as the same in the PFC 'Batt voltage' monitor.
same can be said for testing voltages at the ecu connectors.
There is a big fuse holder under the bonnet where the original battery cables attach to one side and the other side and runs back to the battery.
I swapped out two relays, Main & EFI relay to ensure these weren't causing any issues, dirty contacts inside (Read clutching at straws here) no difference.
Nibbles wrote:
What size cable are you running from your battery, and how long is it ?
Where is the battery Earth connected, and have you removed paint to ensure a good Earth to the body ?
What have you done about earthing engine to body ? Ideally use the large cable that used to go from engine to battery and link instead to a good earth point on the body.
The cable running from engine bay to the boot is around 5M long and is 20mm2, thick enough?
There is two earth's for the battery both terminated in the boot area, one goes to a rear suspension top mount stud...as i type this i realise that is a terrible earth point as the top mount is mounted in rubber, no paint has been scratched off from the turret area..
The other from memory is using the same earth point as used by the ABS unit just behind the rear seats..
I think this is an area that needs further attention!
Engine earth points.
one from the inlet manifold to bulk head.
one from alternator bracket to suspension front turret, fairly small being held in by a 10mm headed bolt.
There is a couple of others on the N/S of the engine bay but can't remember exactly where? TBC
Again Thank you for your continued input and advice