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preRS Clio Williams Clio XR25

kgavey

New Member
Hi, I have running issues on my long term 1995 Clio Williams project and need to diagnose if it is ECU or sensor related. Does anyone have a compatible XR25 cable to run on the PC based XR25 program that I can purchase? Or a known working ECU?
The issue is the car starts poorly eventually then runs for a few seconds on all four cylinders then cuts out again. Any throttle kills it. Immobilizer is bypassed.
It has had a recent engine rebuild, the cam timing is spot on using correct marks, most of the engine sensors are new, the loom has been inspected, the fuel pump and pressure is to spec, all cylinders are sparking. New plugs, cap, rotor leads etc.. Picoscope test shows poor spark though so I suspect internal ECU fault but I would like to rule out any dodgy sensor readings using XR25 first. I suspect water has got into the ECU but it looks dry now. Are there any Renix ECU experts out there that can test them?
Any suggestions welcomed.
Thanks
Kent

IMG_8532.webp
 
Hi, are you using fresh fuel as you say it’s a longer term project? Aged/poor fuel can create strange symptoms.
When it does not start are the plugs wet indicating again a poor/weak spark like you suspect?
Are you happy with the earth points for the ECU etc.
 
Hi, are you using fresh fuel as you say it’s a longer term project? Aged/poor fuel can create strange symptoms.
When it does not start are the plugs wet indicating again a poor/weak spark like you suspect?
Are you happy with the earth points for the ECU etc.
Hi Renaldo, the fuel is fresh, the plugs do foul easily which points me towards the spark, the injectors are new and pulsing ok with an LED tester on them, ignition timing seems accurate, all the earths are good, and checked wiring back to the ECU and run a separate ECU earth.
 
You said many sensors are new, but you could check if they're being fed the right voltage and their internal resistance. NT1651 has all the specs to check in these components with a multimeter. The group N manual has them too.
It's been many years since I sold my mk1, but I remember having trouble with the TPS, idle valve, water temp sensor and the intake temp sensor. MAP sensor and its tube might be worth inspecting for leaks. Check TDC sensor wiring too. I've never had any spark problem in 330.000km. Good luck!
 
Hi, Thanks for the reply, I have checked and validated the sensors using information from the Williams supplement and swapped the Idle valve with a known good one too, the MAP and throttle sensor is new (set up too) and the vacuum tube is clear, it would be easier if I can read what the ECU is seeing really.
Where would I find a copy of NT1651?
 
Where would I find a copy of NT1651?

or

 

or

Thank you :)
 
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