Expert HELP Needed - My Car STILL won't Start!

[bmh.01]

A twisted pair is exactly what it sound like it will be a twisted pair of cores.

Shorts/leakage, basically make sure that those two wires aren't shorting to any others or to ground (the body of the car in our case). UCH lives under the dash passenger side, has several plugs on it (5 or so I can't remember exactly) you want the first of the pair of 20 long pin plugs. They should be marked in some way but it might be marked on the UCH so you'll have to work out which pins are the right ones on the plug.

Continuity is the first thing to ensure then the others.

 

[J@Y]

Do you have an email address mate I can sen you this wiring diagram I have to you on? Then I can point at what I think I need to check?

It's hard to decifer what's what on here.

 

[bmh.01]

Pm'd

 

[J@Y]

Sent it over pal

 

[johncote69]

Hi all - i've joined as i have the exact same problem - have tried all sorts of things - i'm based in BEDWORTH - so BMH.01 - please feel free to contact me as i'm just down the road - its a mare of a problem and i've been told a grand at renault mate.... by some firm that sell immobolier overide modules for the older clio or flahing light prob. The car is a beauty too.
If anybody wants to contact me - feel free - it's John by the way - and i'm a brand new member, i have poor sight in one eye - no technical knowledge and cannot afford to be ripped off.
HELP!

 

[bmh.01]

PM'd you back

 

[johncote69]

Well... what can i say? bmh.01 - Ben - a legend. Sorted my problem out for the cost of a fse at Halfords.
This guy has all the kit, is super polite, a credit to you young uns - I cannot thank him enough - and will make sure he gets rewarded for his kindness.
Thanks to everybody on the forum who have taken the time to write on this thread - not direct to me - just to help people - its a breath of fresh air.

 

[J@Y]

Well... what can i say? bmh.01 - Ben - a legend. Sorted my problem out for the cost of a fse at Halfords.
This guy has all the kit, is super polite, a credit to you young uns - I cannot thank him enough - and will make sure he gets rewarded for his kindness.
Thanks to everybody on the forum who have taken the time to write on this thread - not direct to me - just to help people - its a breath of fresh air.

Glad you got your problem sorted! Out of interest, what fuse was it that you had an issue with? Which fuse box, what number and what rating? Unfortunately I don't think my problem is that simple but it's definitely worth a try!!

I'm going back to the car tomorrow to run the final tests before I give in and buy a new ECU. I've established with Ben that I need to check the connections from the ECU to the UCH but the only thing I am unsure of is where I find the UCH?

 

[bmh.01]

Passenger side under dash by the bonnet release.

 

[J@Y]

Just had a look on my Mrs 1.2 in that area. Is it the Sagem unit under there? I think I've found the wires I'm looking for... Theres a white plug towards the back houseing several wires, on the end of which there are two grey twisted wires... That's them right?

 

[J@Y]

Thanks guys!

Went to the car last night with Jonny 1.2 (legend btw!), we went over it with a fine tooth comb. Changed the ECU and UCH with key chip but nothing changed, the immobiliser light remained on constantly solid.

We checked the live feeds to the ECU which are fine and checked the connecting wires from ECU to UCH which both showed continuity and no leakage..

The car now won't crank over as it was. The battery has been flat so we had it hooked up to another car but it still showed no signs of cranking, just a distant clonk from the engine bay and a few relay clicks when the IGN was switched on. The started motor shows no signs of engaging. This is possibly somewhere to check now.

What is the best way to check this? Check the voltage going to the Starter? Also, where does the starter get it's signal from to crank the engine? I don't think this is controlled by immobilser is it as it was cranking before even when the immobilser light remained on solid.

 

[J@Y]

At long last- ITS FIXED!!

After admitting defeat and deciding it needed specialist diagnostics, I embarked on a two hour trip to Nottingham to take the car to Mick @ Diamond Motors [MickPM].

After speaking to him at length over the phone he assured me he'd find the problem and have it running again. He also came highly recommended by other C/S members so I decided it was worth the trip!

So Saturday morning off I went, car on a trailer and arrived late morning to great Mick, who was full of cold, but still managed to get up to help me out. We set to work on it, going over all the basics again just to rule anything simple out. Come 6 o'clock we threw in the towel and I decided to leave it with Mick on the basis that he'd take a look whenever he had a spare hour or two, leaving us both to ponder in the mean time over Schematic's.

Come midday Monday morning, I had a missed call from Mick. when I called him back up, he expressed his apologies and said he'd nailed it! I broken wire in the Engine bay loom to the ECU. One of the lives was getting intermitant signals with fluctuating voltage, preventing her from starting up. Although I'd already checked live feeds to the ECU, my multimetre wouldn't have picked this up. Mick tested it using his Osciloscope over miliseconds and found that voltage was jumping from 3V to 12V. Anyway, after replacing that short length of wire she now runs like a goodun'!

And the best bit - When I asked Mick how much I owed him for his services? "Just an hours labour as I should have found this sooner". Had he not been dieing of flu on Saturday, I'm sure we would nailed it then.

So thanks Mick! Top guy, really knows his stuff on these cars and he can't come reccommended highly enough!!