New Build Engine Fires but Doesn't Run and Dies

[LRGS2]

A friend of mine at work has just finished building a Caterham 7 Monaco special addition with the Sigma engine and is keen to get it registered next week. He is having a problem at the moment with the engine firing but then not running. Caterham have suggeted more fuel so now he is up to 4 gallons and this has not worked! He can here the fuel pump run when turned on so he assumes it is priming OK. I suggested taking a fuel pipe off to make sure that he getting fuel out, but the connectors are a make once connection. Also suggested checking vent for fuel tank which he is going to check tonight. Does anyone have any ideas, this is a brand new kit and my friend has been extremelly fastidious assembling it.

[Boss Hogg]

My sigma ran like a dog at first. Check all plugs and leads, some of mine were not fitted correctly. Try adjusting the throttle position sensor, I beleive the ECU is a learning type so you may need to disconnect the ECU/battery for a while so it 'relearns' after the TPS adjustment. Once you get it idling, it will take a good few miles of driving for the ECU to learn and settle down. I've heard some need the map adjusted at the post build check.

Mine is still quite rough when cold, fine when up to temperature.

[nigelpugh7]

Just a thought, have you checked the inertia switch on the bulkhead?

It might have popped, and just needs a quick press to allow the fuel pump to run!

Worth trying before changing extreme things like the maps etc?

[LRGS2]

Update: Car starts and runs but dies when throttle is released.

What is the setup procedure for the TPS on a Sigma engine?

Does the idling get better with the learning ECU.

[amk]

hi, i had this problem 2 years ago, sigma 125 new build, the butterfly was just shutting too much, there's an adjuster screw so you can set how open it is with no accelerator, I just tweaked that open a bit. hope this helps
adam

[downsman]

I think Adam is right, the adjusted screw on the throttle body is very tiny and easy to miss.

[LRGS2]

All sorted now - thanks guys. It was the simple procedure of setting the TPS and finding the very small adjustment screw.