clio 172 wont start after gearbox change!

[olly188]

hi there, i recently had a gearbox diff break on a 2002 clio 172 sport, but the differential planet wheel came through the gearbox into the clutch bell housing area,the engine was still running when it broke,but quickly shut it off when i heard the noise from it,i have recently changed the gearbox from a clio of the same year, but when i went to start the car, it would keep popping flames and not start up, i was told this could be the timing, so i had the cambelt changed and the timing seemed all ok, i was then told it could be crank sensor,so i have also changed that too, but it hasnt seemed to help as it still wont start.

Any ideas as i cannot think what it could be :S

Thanks for help in advance, Olly

 

[Carlv8415]

Reconnected all earth straps ?

 

[olly188]

yeah all the earth straps are all connected,it wouldnt turn over attal would it otherwise?

 

[Fred@BTM]

yup, if you miss the one on the back of the box above the driveshaft

 

[olly188]

there was one near the diff housing,would that be it?

 

[Fred@BTM]

aye above the driveshaft, and the big braided one at the front

 

[Carlv8415]

Can't miss the big braided one on the box, it's on the far N/S of the box

 

[olly188]

yeh those are all connected,the engine spins over,and its getting fuel and a spark,i was told the timing could be out,so i had the cambelt changed as it needed doing anyway and i had the timing checked at the same time too,so all the timing is fine,but it still sounds as if the timing is out,even though it isnt?

 

[Dan@SJM]

Who did the timing belt? If they didn't have the right tools the timing will still be out.

 

[Carlv8415]

Serious question: How many teeth can you be out on timing before the car won't even run ? Surely if it out too much you would smash valves and if just a little out it would run like a dog ?

 

[olly188]

well the timing was checked,and it was completely fine and wasnt out attal,but the cambelt needed doing anyway so had it checked then,and it all lined up so didnt need re timing

 

[1uk3m4n]

To me sounds like during everything happening it has damaged the teeth on the flywheel that the crank sensor picks up from did you check that?

 

[olly188]

hmm thats already been checked from where you can see thru where the crank sensor goes, havnt got a clue as to why it wont start :/

 

[1uk3m4n]

How well tho have you counted how many teeth between the air gap? And compared to a working Clio? The slightest bent tooth can throw the signal out you best off getting a garage check it with a oscilloscope tool that tells you how many teeth and shows you how good of signal your getting.

We haves zafira wouldn't start one of the teeth had moved but you couldn't see it by eye

 

[olly188]

ahh ill have to have a garage check that then,didnt realise they were quite that sensitive

 

[1uk3m4n]

Yeah slight difference in air gap fools the engine to think that's the tdc Mark then it don't no what's going on

 

[1uk3m4n]

Just make sure it's checked with a oscilloscope not by eye :thumbup:

 

[olly188]

ok mate thanks