Non starting 1.6 sigma
Discussion
We are in the final stages of a caterham 1.6 Sigma 270SV but it will not start!
We tried to start it when the engine went in and all the ancillaries were connected but got a slow, lethargic turnover, the positive cable got very hot and having checked all earths, put it on the back burner and finished the rest.
With the car very nearly complete we have attempted to start it again, but get nothing from the starter motor at all, doesn't even attempt to turnover.
What we do know:
The immobiliser activates and appears to deactivate with the fob
The fuel pump primes with the ignition key turned and the car has around 22 litres in it
The battery is fully charged and giving a healthy output
The earths that are in the engine bay on the bulkhead and the bell house are checked.
The car just doesn't attempt to turnover, the red cable to the solenoid was getting hot when it was turning over very slowly, but now it doesn't but the starter isn't doing anything right now.
Any advice going forward? As you can imagine, at the end of a relaxing build, for it not to start is quite frustrating!
Thanks in advance.
We tried to start it when the engine went in and all the ancillaries were connected but got a slow, lethargic turnover, the positive cable got very hot and having checked all earths, put it on the back burner and finished the rest.
With the car very nearly complete we have attempted to start it again, but get nothing from the starter motor at all, doesn't even attempt to turnover.
What we do know:
The immobiliser activates and appears to deactivate with the fob
The fuel pump primes with the ignition key turned and the car has around 22 litres in it
The battery is fully charged and giving a healthy output
The earths that are in the engine bay on the bulkhead and the bell house are checked.
The car just doesn't attempt to turnover, the red cable to the solenoid was getting hot when it was turning over very slowly, but now it doesn't but the starter isn't doing anything right now.
Any advice going forward? As you can imagine, at the end of a relaxing build, for it not to start is quite frustrating!
Thanks in advance.
Bit belt & braces this but have you put a bar on the crankshaft pulley and checked that the engine will physically turn over without excessive force?
If the solenoid is throwing out and the pinion trying to turn it suggests that your connections are correct however if the live cable is getting hot you must somehow be getting massive impedance somewhere.
As well as the one on the bell housing there should also be an earth strap from the engine block to the chassis on the nearside engine mount? Are your other earths on the bulkhead tight?
The next thing to try I suppose would be a different battery, you can also use a jump lead as an additional earth to rule that out, and finally you can use a length of wire to short the battery positive directly to the starter motor terminals to rule out everything upstream of the starter motor itself.
If the solenoid is throwing out and the pinion trying to turn it suggests that your connections are correct however if the live cable is getting hot you must somehow be getting massive impedance somewhere.
As well as the one on the bell housing there should also be an earth strap from the engine block to the chassis on the nearside engine mount? Are your other earths on the bulkhead tight?
The next thing to try I suppose would be a different battery, you can also use a jump lead as an additional earth to rule that out, and finally you can use a length of wire to short the battery positive directly to the starter motor terminals to rule out everything upstream of the starter motor itself.
No joy, the engine earth seem ok, it's strange that we have gone to a hot red cable and slow turnover to having nothing now, it was all supposed to be brand new!
One thing I have noticed is, having read that someone had a loose connection to his rev counter that prevented it from starting is this thing photo' above which is plugged in to something in the dashboard. It is extremely hot when the ignition is on
Edited by Mattygooner on Tuesday 22 August 17:22
Sadly not, but having another crack this afternoon with some beers of contemplation, anything to take our minds of the bloody IVA bits!
The engine cranks freely.
The inertia switch doesn't make a satisfying click but have tried it many times having pressed it. My understanding is that the inertia switch would still allow it to turnover but not have spark in order to fire. We are sadly not getting it to turn over at all.
The earths were our initial thoughts, but we have checked them all many times.
We have an earth going from the battery to the bellhousing and an earth from the battery to the bulkhead. Tried it with one form the bellhousing to the engine mount as well.
We think it might have burnt out a sensor somewhere which is subesequently telling the ECU not to turnover.
It's bloody frustrating.
The engine cranks freely.
The inertia switch doesn't make a satisfying click but have tried it many times having pressed it. My understanding is that the inertia switch would still allow it to turnover but not have spark in order to fire. We are sadly not getting it to turn over at all.
The earths were our initial thoughts, but we have checked them all many times.
We have an earth going from the battery to the bellhousing and an earth from the battery to the bulkhead. Tried it with one form the bellhousing to the engine mount as well.
We think it might have burnt out a sensor somewhere which is subesequently telling the ECU not to turnover.
It's bloody frustrating.
Mattygooner said:
The inertia switch doesn't make a satisfying click but have tried it many times having pressed it. My understanding is that the inertia switch would still allow it to turnover but not have spark in order to fire.
Mattygooner said:
We think it might have burnt out a sensor somewhere which is subesequently telling the ECU not to turnover.
Are you getting any starter motor noise at all?
Do not assume that because the battery shows 12v it is healthy. Batteries can fail internally and deliver hardly any cranking power while still displaying a normal surface charge.
Have you checked your battery electrolyte level? I wonder what’d happen if the battery had been shipped dry and you attempted to star the car with it when it had no electrolyte in it?
So difficult to comment on these threads as you assume it's all connected correctly. But if the red battery cable is getting hot then you have a massive current draw. It is possible that there's a fault but with that amount of current, I would guess that a fairly fundamental error has been made when connecting up the starter or alternator cables (are they touching something?). If it has a FIA cut-off switch then this will have probably failed by now. My advice would be to go back and check the basics.
[Edit to add] Looking at it again, I would double check you've got the starter solenoid wired correctly. There should be the starter supply and alternator feed both on one heavy connection and the starter 'button' on one small connection. The other large connector in not used (it is connected internally to the starter motor).
[Edit to add] Looking at it again, I would double check you've got the starter solenoid wired correctly. There should be the starter supply and alternator feed both on one heavy connection and the starter 'button' on one small connection. The other large connector in not used (it is connected internally to the starter motor).
Edited by DCL on Thursday 24th August 19:33
I'm sure you've checked this loads of times but I also had problems figuring out what the build manual was getting at re the starter motor connections. I used photos from various build blogs to confirm I'd got it right. The clearest explanation was here: https://csr175.wordpress.com/2013/09/18/water-elec...
The page is for a CSR175 but it's the same on my Sigma 310.
The page is for a CSR175 but it's the same on my Sigma 310.
See if this works (no laughing) 
https://www.flickr.com/photos/61984578@N03/3664305...
Was from 2008 as I agree, the build manual was really unclear. Very easy to short the connections also and blow the fuse, you should hear a loud pop if you do that though.
https://www.flickr.com/photos/61984578@N03/3664305...
Was from 2008 as I agree, the build manual was really unclear. Very easy to short the connections also and blow the fuse, you should hear a loud pop if you do that though.
Edited by griggsy2 on Thursday 24th August 21:07
Why do you think this? With a poor earth, little current will flow and the wire will not get hot.
Sounds to me like a dodgy starter. Presumably this can be checked with a fly lead from the battery to the solenoid very easily.
That's where I would start.
Bert
Sounds to me like a dodgy starter. Presumably this can be checked with a fly lead from the battery to the solenoid very easily.
That's where I would start.
Bert
pilotprice said:
Have you got the earth strap from the block to chassis? On the engine mount
It has to be an earth fault if the live is getting hot.
It has to be an earth fault if the live is getting hot.
I still don't understand that! Did you manage to short the battery to earth through the main feed to the starter?
pilotprice said:
Probably my poor explaination
There is a sigma wiring diagram flying round, when I rebuilt my car I incorrectly earthed the starter which caused the main 25mm2 cable to burn up.
There is a sigma wiring diagram flying round, when I rebuilt my car I incorrectly earthed the starter which caused the main 25mm2 cable to burn up.
We actually used that high def image of the starter and solenoid when checking everything, we also emailed it off to Caterham to double check.
Tried another healthy battery that was fully charged to rule that out.
Tried to get the starter out, but one of the top bolts was just to hard to get to with where we are with the build.
Will concentrate on trying to test out as much as possible with the starter and solenoid in the next session, but sadly it may need to be resolved by Caterham prior to testing.
Tried another healthy battery that was fully charged to rule that out.
Tried to get the starter out, but one of the top bolts was just to hard to get to with where we are with the build.
Will concentrate on trying to test out as much as possible with the starter and solenoid in the next session, but sadly it may need to be resolved by Caterham prior to testing.
Mattygooner said:
The earths were our initial thoughts, but we have checked them all many times.
We have an earth going from the battery to the bellhousing and an earth from the battery to the bulkhead. Tried it with one form the bellhousing to the engine mount as well.
As above, pretty sure there should be a chunky earth from the starter to the engine mount. We have an earth going from the battery to the bellhousing and an earth from the battery to the bulkhead. Tried it with one form the bellhousing to the engine mount as well.
Have you been able to test the starter in isolation? (edited to add... sorry... note to self... read whole thread before commenting!)
As you say, bloody frustrating!
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