Clio 172 no spark/fuel - UCH fault?

[cliokid95]

Hi guys, went to start the 172 yesterday and its not starting; the dash lights up and the battery is giving the correct voltage, but the car isn't getting spark and the fuel pump isn't priming, the car turns over 3 or 4 times and then the starter cuts with the immobilizer light solid on. What's really odd is sometimes after disconnecting the battery and reconnecting it the light goes off after a few seconds as it should. In the latter case the car turns over as much as you'd like on the starter but still no spark or fuel.

I'm getting nothing to the coils and I've checked the yellow relay under the bonnet and am getting about 80 ohms so this doesn't seem to be the issue.

At this point I'm thinking it's either a dodgy ground or a UCH fault (don't want this!). Should mention that currently the car is being converted to full track spec so a lot of the interior loom isn't connected, things like the rear lights, airbag ecus and rear boot sensor etc. It doesn't feel likely but could it be the case that all of these open connections are throwing the UCH and immobilizer into not starting the car?

Any advice would be greatly appreciated before I go down the road of getting a specialist to look at it, feels like it could really do with someone with CLIP having a look at it but I know this is rare in terms of people having that software. Cheers all

 

[MicKPM]

There's loads of people around with access to clone CLIP but it's not a magical silver bullet.

What you need to do is understand the actual cause for the solid red ADAC. Firstly, when you turn the key to IGN ON, do all the warning lights come on and then go out? Pay particular attention to the EML... I'm guessing this light won't illuminate.

Mick

 

[cliokid95]

Thanks Mick, agree that finding the cause of the solid light is key, however having as mentioned it's an intermittent solid red light, sometimes it's on sometimes it's off.

The EML light is on when the key is on IGN ON but still no power to the coils and no pump prime, thinking dodgy earth at this point?

 

[Mr Underhill]

It doesn't feel likely but could it be the case that all of these open connections are throwing the UCH and immobilizer into not starting the car?

Mine was a completely stripped out race car with original loom but no connections to headlights, airbags, boot sensors, air-con etc....Other than the usual airbag warning lights, everything behaved as it should and started without issue. Hopefully you'll get it fixed soon.

 

[cliokid95]

Also worth saying that when above photo was taken the immob light went out after in position 2 as it should.

 

[cliokid95]

Thanks Jon, thought as much but just wanted to rule it out!

 

[Mr Underhill]

Just thinking about the times my Clio Sports have never started and what the issues were.

Once when i removed the coil and forgot to stick that black plug back in. Another time when the TDC sensor was faulty. I put a new gearbox in and hadn't tightened the earth strap from the loom to the box. Probably neither of these but worth checking.

 

[cliokid95]

Fallen victim to the coil plug forgetfulness before so made sure to check that as a first instance, also not getting 12v to it when the ignition is on so confident it's not the coils plus the fact the pump isn't priming. Haven't checked the TDC sensor or earth strap so those will be the next ports of call!

 

[MicKPM]

Thanks Mick, agree that finding the cause of the solid light is key, however having as mentioned it's an intermittent solid red light, sometimes it's on sometimes it's off.

The EML light is on when the key is on IGN ON but still no power to the coils and no pump prime, thinking dodgy earth at this point?

The EML light being on is a good thing! It shows the issue isn’t the usual bag of worms.

The most likely issue here is the injection latching relay function. You’ll either have 0-3v on the output or the control side of the circuit, which powers the Injectors common +12v and IGN Coil +12v. In either case the most likely cause is a naughty wiring fault resulting in high resistance or an open circuit to Gnd/Pos.

 

[cliokid95]

Fantastic, thanks for that, so i take it that it's most likely to be a wiring fault back from the relay board? good to be able to narrow it down.

 

[MicKPM]

I had it on a 182 Trophy recently and it turned out to be the relay battery supply, where some kind soul had historically pierced the wire to probe it. They're usually easy fixes on cars of this age, once you understand the circuits and how they function. The later stuff is all CAN/LIN and needs fire!

 

[cliokid95]

lets hope it's that simple, thanks for the help Mick! One last question from me, my engine relay board looks like this - any idea which relay is the fuel pump/ ignition, I was told it was the yellow block (1) that's shared between both but I'm not 100% on that.

 

[MicKPM]

It'll be one of the GMV's so 4 or 5... can't remember exactly which one I'm afraid, it's been a while.

 

[cliokid95]

You're a star mate - thank you

 

[cliokid95]

Thought I'd update as I don't like to leave threads hanging - put the car back together this weekend and once everything was plugged back in it fired right up, so it looks like there was a dodgy earth somewhere that had to be reattached. On closer inspection of the loom it looks like the fuel pump ground goes off to the rear light cluster so once this was wired up there was good voltage all round and all back to normal - happy days!