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172 won't start after engine swap



  Clio 172 sport
Recently bought a 172 for a track car project and had a new engine (172 engine) and gearbox (182 gearbox) put in (old ones were pretty far gone). When we bought the car it did have immobiliser problems where you sometimes needed to do a sequence to get the car to start. After the engine swap I noticed some of the electronics aren't working (that were previously working), which is fine for the project, but one of the problems is the starter motor. When you turn the key it doesn't engage the starter motor at all, just some clicking under the dash (from the UCH). Even weirder, I can get the car to start fine if a run a power cable from the starter signal terminal (blade type connector) to the battery and just touch it until the car starts (sometimes I still have to do the immobiliser sequence). I did some research and came to the conclusion that possibly the UCH is bad. I disconnected it and inspected it and when i reconnected it, it wouldn't start at all and most of the electronics didn't work (some that weren't working before came back as well). I then mounted it and reconnected it again and it was back to normal, but weirdly let me start the car once from the key (back to normal after that). If it is relevant, the service light is always on (although the airbags/ tensioners/ controllers are all removed which can cause that I've read) and the immobiliser light stays on solid for a few seconds when the ignition is switched on then turns off (unless the immobiliser plays up). Sounds like I need a new UCH, do they need to be re-coded or something (HG type)? Kind of a long question, thanks greatly for any help - I know nothing about these cars!
 

Mbeau

ClioSport Club Member
  Clio 172
This thread might help you.


Easiest way is to buy ECU/UCH and key from a known working vehicle that is being broken. Check all fuses, relays, connectors and Earth points first as they are prone to breaking down and being quite heavily corroded causing issues.

Hope that helps. I have just been through all this myself due to non starting.
 
  Clio 172 sport
Thanks, getting a set from a wrecking car might be the way to go. Can confirm that fuses are good, relays are good and did a continuity test on the wire so that shouldn’t be the problem
 
  Clio 172 sport
If you can plug into a CLIP thing (or whatever the system is called) can the immobiliser be turned off (i.e. so it doesn't operate at all)?
I really don't know, maybe it can be, but I don't know much about Renault's, so I'm not sure if it can be done or where i'd find that sort of equipment. That being said I don't think that the immobiliser is 100 percent the problem, I think there's other electrical root causes. Getting a new UCH might be the only solution (although as a track car it isn't really that big of a problem as of yet, I can just install a start switch to bypass the key, but other UCH problems will probably come up unexpected). Thanks though.
 
I really don't know, maybe it can be, but I don't know much about Renault's, so I'm not sure if it can be done or where i'd find that sort of equipment. That being said I don't think that the immobiliser is 100 percent the problem, I think there's other electrical root causes. Getting a new UCH might be the only solution (although as a track car it isn't really that big of a problem as of yet, I can just install a start switch to bypass the key, but other UCH problems will probably come up unexpected). Thanks though.
IIRC one of the Kangoo build threads on here has pictures of the system, where you can turn things off and on - I can't remember which thread it was!
 


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