Fed up with my 172 being broken

Stu Lane · Jul 4, 2015

Hi guys
OK so I'm now under the impression French wiring is a load of crap and they make it impossible to find a wiring diagram.
I've read so many posts now with people with electrical problems and problems starting.
My 172 sometimes starts and most of the time just cranks.
I took my clio to a mates workshop the other day and they replaced the fuel pump and it was working. Today it's not again. I'm trying to find the source if the problem but without tracing every wire it's impossible.
Can someone point me in the direction of a proper wiring diagram because I'm going to break the car soon as I've had enough.

Many thanks

cliosscott · Jul 4, 2015

Crank positioning sensor?

Stu Lane · Jul 4, 2015

Well unless it chooses when it wants to work I doubt it.

There's a wiring fault but without a proper diagram I'm wasting my time.

I've not voltage to the coil pack and that should be powered from the ignition relay. pin 85 on the ignition relay comes from the ecu but it's on 0v not 12v.
No idea why.
If I bridge the relay it works.

m&l172ph1 · Jul 5, 2015

@Stu Lane Try the 3 black relays in the fuse box, had a similar situation on my wife's clio sometimes it wouldn't fire within 10 mins of the last time I started it! After I'd play with the relays it would tend to fire up.
I replaced the relays at a cost of £60 from Renault but I think it was more down to the connections needed cleaning up.
Since then it's been spot on!
Hope this helps.

Stu Lane · Jul 5, 2015

Yeah this morning I was thinking I'm going to replace the fuse box as it's old and chances are that's the cause of the problem.
I've tried swapping out relays etc but it's not helped.
I installed on of these in my kitcar and it's pretty good and at least everthing will be new.
http://polevolt.co.uk/acatalog/Modular_Fuse_and_Relay_System.html

m&l172ph1 · Jul 5, 2015

I just cleaned the connections into the relay terminals with brake cleaner to clean all the green cr*p away! Been fine since!

Stu Lane · Jul 5, 2015

thanks, yeah I've cleaned everything and even replaced the engine wiring loom. it's either a damaged cable or poor connection.

m&l172ph1 · Jul 5, 2015

Apparently the wiring from the crank sensor can be an issue, if you got a new crank sensor from a motor factors sometimes you can get with a new plug and a short piece of cable. Something I was advised it could've been.
But if you've changed the loom???

Stu Lane · Jul 5, 2015

yeah no harm in buying a new one and running a new cable. I just want it to be reliable. It's so frustrating. It's a track only car so going to a track day and spending the day with a multimeter isn't a lot of fun.

clioben182 · Jul 5, 2015

You say you have repalced the engine loom but did it include the fuse box wiring plugs? I have come across a couple where the pins are corroded and cause a poor connection.

Stu Lane · Jul 5, 2015

yeah the engine loom includes the fuse box but there's that white multi plug it connects to the car loom with which is pretty crap. I've cleaned it up but could also be causing problems.

DannyR · Jul 5, 2015

Have you changed the battery? If not I bet it's that. This problem happens so much you could of found that with a search

clioben182 · Jul 5, 2015

Stu Lane said:
yeah the engine loom includes the fuse box but there's that white multi plug it connects to the car loom with which is pretty crap. I've cleaned it up but could also be causing problems.

If the pins are green inside the plug then it may well be causing a problem. If thats the case what i would do is break out the soldering iron and cut out the white block, it would rule out one more problem and it wouldn't cost much either

Stu Lane · Jul 5, 2015

Yeah I'll do that this afternoon

I'll charge the battery too.

DannyR · Jul 5, 2015

No no no, charging won't work. You need to try a different battery

Stu Lane · Jul 5, 2015

I've got a drycell battery atm and I've also got a clio battery. Could you explain why charging it wouldn't work?

DannyR · Jul 5, 2015

It's a mystery to me but I've had the problem and countless others have. I used to have a 172 that would not start for some reason, then after 20 tries was fine. Changed battery and has been fine now for 3 years as I know the current owner well.

Bluebeard · Jul 5, 2015

Clios are really REALLY battery sensitive.

I've cured lots of faults over the years by fitting a new battery.

DannyR · Jul 5, 2015

The only thing I've ever been able to put it down to is that when the starter motor is cranked there then isn't enough power for the ECU/Injectors/Spark plugs or something like that. Especially because if testing the battery at this stage it'll usually read 12v still

Stu Lane · Jul 5, 2015

OK so update: I removed the white multi pin connector and soldered all of the wires. I also sanded down the terminals on the relays and used a load of contact cleaner on the fusebox terminals. It fired up straight away - didn't touch the battery.
It's misfiring a bit but I need to change the pre cat lambda sensor over as i've hooked up a spare which is in the fresh air. I think the original one is not working.

Going to keep testing this afternoon and see what happens!

Stu Lane · Jul 5, 2015

Ok so it still has the same fault. Tried other batteries. Tested continuity between the ecu and crank sensor. Tested the Relays. No power to the coil.

Also sometimes when cranking it cranks a few times and stops and sometimes it just keeps cranking

clioben182 · Jul 5, 2015

Immobiliser? Cant think of why it would crank then stop! Can you get it plugged in?

DannyR · Jul 5, 2015

What's the immobiliser light doing?

Have you tried a different crank sensor?

Stu Lane · Jul 6, 2015

OK So after doing some more troubleshooting with a helper last night I found that moving the relay holder unit around made the engine keep cranking and at one point the fuel pump primed and it started.
I've ordered a new fusebox with all new fuses and relays so I'll fit that tomorrow.

Yes I did try another crank sensor

Stu Lane · Jul 6, 2015

Is there any way to obtain a wiring diagram for these cars?

Joe-s · Jul 6, 2015

Had a similar issue with a 172 turned to be the ignition switch car would turnover a little slow sometimes it would start sometimes it wouldn't also when turning it over it would stop cranking while the key was still in start position there's a little spring in there with little contact plates it wasn't making a good connection fixed this it sorted mine hope this helps @Stu Lane

Stu Lane · Jul 6, 2015

Thanks Joe

STEVE.M · Jul 6, 2015

Stu Lane said:
Hi guys
OK so I'm now under the impression French wiring is a load of crap and they make it impossible to find a wiring diagram.
I've read so many posts now with people with electrical problems and problems starting.
My 172 sometimes starts and most of the time just cranks.
I took my clio to a mates workshop the other day and they replaced the fuel pump and it was working. Today it's not again. I'm trying to find the source if the problem but without tracing every wire it's impossible.
Can someone point me in the direction of a proper wiring diagram because I'm going to break the car soon as I've had enough.

Many thanks :smile:

Point you in the right direction,easy.
Trailer it to Long Eaton.Self confessed electronics geek Mick Pitmann at Diamond Motors 0115 9721501 has the wiring diagram hard wired to his brain.

clioben182 · Jul 6, 2015

I bet £20 the new fusebox fixes it, based on what you said happens when you wiggle the relays.

Stu Lane · Jul 6, 2015

Lets hope it does!!

m&l172ph1 · Jul 6, 2015

Exactly what I was saying with my wife's, played with the relays and it would start.

Hope this sorts it for you!

Stu Lane · Jul 8, 2015

Hi guys,

bad news. didn't fix anything. I've narrowed the problem down to the switched earth not working from the ECU. I've checked all the earth pins going to the ecu and made sure the ecu is earthed. I've also tested the wire that goes from pin 9 to the fuel pump relay and it's fine. I've wiggled everything and no change.

I've also tried another ECU, UCH and barrel to double check it's not the ECU.

When will this end!

Joe-s · Jul 9, 2015

The bit I was talking about is the wiring at the back of the barrel I couldn't put an image up but this link is the part I was talking about
http://pages.ebay.com/link/?nav=item.view&id=121454159638&alt=web
I stripped the bit with like the little y and stretched the spring and cleaned the contacts and It sorted mine bud bit fiddly but worked

Stu Lane · Jul 9, 2015

I replaced that wire when swapping the barrel over. I was going to test running a switched earth to the relay later to see if it starts.
I tested all the grey, black, red and white wires from the ecu to the relay area last night and they are all ok. Also tested the twisted purple and white wires.

Addicted · Jul 9, 2015

Get it up to Diamond Motors - for the amount of money you are chucking at it, I bet Mick will fix it in no time - probably not what you want to hear but may save a huge ballache.

STEVE.M · Jul 9, 2015

Addicted said:
Get it up to Diamond Motors - for the amount of money you are chucking at it, I bet Mick will fix it in no time - probably not what you want to hear but may save a huge ballache.

Thanks for seconding my opinion.Trouble is,folk from Eastbourne regard East Grinstead as up North!
I know this as I was born there.

Joe-s · Jul 20, 2015

Did u ever get to the bottom of this @Stu Lane

Ander3670 · Jul 21, 2015

Was this ever sorted

Fed up with my 172 being broken

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