non starting 172

[hughesclio]

i recently bought a phase 1 172 which was a non runner, i got the car delivered only to find it had no ecu i got a ecu from paul at rs tuning and he unlocked it and brought it round to try, the imob light goes out as its meant to but you cannot here the fuel pump priming and there is no spark. paul bypassed one of the relays and the fuel pump worked so its like the relays are not getting the signal to power up.
has anyone got any ideas as to what it could be?
im starting to think its the uch unit any help or pointers would be great

 

[OEM Battery Nonce]

The engine control relays are prone to playing up on the 172's, I've just had some problems, have you checked;

Relays
Earth for the ECU
The wires beneath the fusebox (again prone for rotting)
The wiring going into the ECU

Check for them being green and corroded

Also if you decide you need a new relay, let me know, I have a spare one

 

[hughesclio]

i had a check the wiring doesnt look great but i have seen much worse it just seems strange that its fuel and spark that are doing nothing

 

[OEM Battery Nonce]

Just noticed you're in Leeds pal, so am i, if you wanna meet sometime and can try swapping a few things let me know, ie relays, compare wiring etc etc, cos I have just had this problem, but mine is PH2

 

[hughesclio]

cheers mate sounds like a plan to me, i think paul (rs tuning) is gonner bob round and do some diagnostics for me at some point ( bonus of being good mates with him and working for him for a year lol ) i will spend som time cleaning connections and things tomorrow and see how i get on.

 

[OEM Battery Nonce]

No worries, I have ODBII but it's only the basic KTEC one that requires the codes to be looked up, I know what situation you're in though, when mine was playing up I would have loved a working Clio to swap parts with to identify the faulty part lol

 

[hughesclio]

right i have a phase 2 172 aswell and have swapped all the relays and checked all the fuses but still no joy, anyone got any more ideas before i torch it lol
just an idea but i hear alot of people saying tdc sensors are a pest on these would that stop fuel and spark

 

[Tunst]

yeah that would stop spark and fuel because the Tdc tells the ECU the timing etc

 

[hughesclio]

nice one i will give it a clean and try that if not i will swap it for the one off my other clio and give it a go

 

[hughesclio]

tried changing the tdc sensor and still no joy

 

[hughesclio]

anyone got any more ideas its driving me crazy i have never had a car this difficult to get going

 

[cliocc]

I had this problem two weeks ago and the day before its MOT. I tried everything I could think of, checked TDC (230 or 330ohms it metered at, can’t remember which,) that was fine. I checked all fuses and relays and connections. Took apart the whole engine bay wiring loom and checked for the usual broken wire above exhaust manifold, all ok. Metered all of the engine sensors to check for the correct impedance, all seemed fine. Did the same as above and bridged the fuel pump relay which got the pump working, but that doesn’t help the lack of spark which I tested using a sparkplug in one of the leads clamped to the engine body.

The interesting thing to note is that on the ordinary Clio's the immobiliser dash light is run off the passenger multi timer unit, it actually sends the signal to the ECU saying the key is right for the car so “run”. The ECU gets power from the fuses and relays regardless of whether the correct key is being used or not, it just doesn’t get the "ok to run" signal. The 172's and 182's are the same except for the fact that the immobiliser function is carried out by the UCH instead. The point of this paragraph is that the immobiliser light going out doesn't mean the ECU is doing anything!

The biggest give away for my car was the lack of communications with the ECU when I plugged in my FCR to read the error codes. So with much heart ache (and wallet ache,) a new ECU, timer unit and key was required.

If all else has failed and you have no communications with the ECU then, and with respect to RST who are top blokes by all accounts and know their stuff, the likely culprit is the ECU.

As a foot note ESDS’s (electro-static discharge sensitive) devices, which is all computer chips, can be affected by discharges as little as 20volts. Considering sliding your shoe once along a carpet can charge you with 3000volts or more, It’s really not hard to see how your ECU could have been damaged in transit or even fitment.

 

[DannyR]

Not read any contents of the thread but the problem I had was the earth that goes to the back of the block on the left hand side had corodded and also the lambda wires, one had melted on the exhaust!

 

[hughesclio]

happy days mr paul murray rs tuning is a bloody legend he came round with all his gear and 20 mins later she was running the live feed for the ecu from the fuse box under the bonnet was giving out 12v at the fuse and by the time it got to the ecu was only giving 1.2v he traced the wire back and under the air box he gave it a little tug and it came apart green on both ends so re joined the wires and bingo shes a runner, also whoever says you cant use an old uch unit on another car, paul got his old one took a chip off mine and put it on his board and thats what mine is running on . paul is one clever bloke i can tell you that for nothing and would highly recommend him and his services.

 

[franx]

Happy days indeed !!

How much did you get the RS for ? Now when fixed i hope it was a bargain >?

 

[hughesclio]

Happy days indeed !!

How much did you get the RS for ? Now when fixed i hope it was a bargain >?

for mr murrays services its mates rates and a few beers in the pub tonight
will repay the favour by helping him out in out in other ways

 

[franx]

for mr murrays services its mates rates and a few beers in the pub tonight
will repay the favour by helping him out in out in other ways

no mate ; the car ?

 

[RSTuning]

for mr murrays services its mates rates and a few beers in the pub tonight
will repay the favour by helping him out in out in other ways

Still ill?

Haha

 

[hughesclio]

Still ill?

Haha

yup im still feeling it 24hrs later and its all your fault

 

[RSTuning]

not this time it aint