hi all, having real trouble with my 270s. Took for mot which it failed miserably on emissions, over 9 on co2. Very reluctant to star recently. Changed battery today because the old one was getting tired. Now it won't start, turns over fine, removed spark plug and it was wet. Turned over with plug still removed and there was no spark. Really at my wits end now don't know what else to do. The car is standard self built by me in 2015/16. Any help, suggestions would be greatly appreciated. John
What's the voltage across the battery at rest, and the minimum when cranking?
Check all of the relevant cables and connections: battery, starter, engine earths.
Try jump starting it from another vehicle, engine at 3,000 rpm, fat cables.
Jonathan
Hi Jonathan, battery is brand new, turns over fine
Hi John, I would look to see if the ECU ground is tight and gives close to zero ohms resistance to the engine block, if not go through all the major earthing points to see they are clean and tight. Next would be to check that the ECU is getting close to battery voltage in it's supply. The common grounds and 12V supplies to the coils should also be checked for integrity.
James
Hi James, silly question but where would I find the ecu ground cable
Hi James, silly question but where would I find the ecu ground cable
James found the ground. Reading 0.4 ohm to engine block
Hi John, I'm not sure which ECU that you have, but if it is an MBE ECU, the wiring diagram I'm looking at from a 2012 Sigma engined car has the ground lead 320mm from the ECU connector. It should be a black lead with a yellow stripe with a 6mm ring terminal on the end that is under an M6 nut on a stud attached to the body.
James
Hi John, I would say 0.4 ohm is reasonable, as long as it doesn't vary if the wires are flexed. If you have the MBE ECU, the ECU power should be on pin 10 and 13 (switched from ignition). The common ground on the coils is likely the white wire with yellow stripe that is chained between the coils, which could potentially have a break in it at a connector.
Also assuming that when you did the spark test, the plug threads were resting against the bare metal part of the block or cylinder head with the coil attached and non of the plugs showed a spark?
James
James, had the plug resting on the manifold. Where will I find 10 and 13?
Please let me know if you'd like the wiring diagrams.
Jonathan