EU2 VHPD K-series not starting - no spark

[mcerbm]

I originally modified my car with the external relay for the starter motor as per most k-series owners. Over the winter I tidied up the car  a bit by relocating the external relay to a spare spot on the main fuse block under the dash. I also did the MFRU deletion mod as described in low flying July 2013.

This suggests that two relays in the MFRU are redundant and the caterham application only uses the starter relay and the fuel pump relay. I externally wired in the fuel pump then insulated all other MFRU plug wires and tucked them into the loom.

The car turns over better than it ever has, the fuel pump primes and works fine I presume. But there are no sparks.

I removed a spark plug and cranked with it earthed on the block and nothing.

I can only presume that I have chopped something in the MFRU that gives power to the coil.

[Jonathan Kay]

With that good cranking it sounds unlikely to be the problem but what's the battery voltage while cranking?

What's your coil set-up?

Is there now any connection between the fuel pump and the ECU? Check ECU fuse and earth.

Jonathan

[mcerbm]

Jonathon, the battery is ok. Its always isolated and is currently on a ctek, the car is turning over better than its ever done. I'm pretty sure its related to me removing the MFRU.

The coil setup is normal EU2 with a distributor fed by a single coil.

The fuel pump is switched by the emerald ECU, all works fine there, it primes for a few seconds when you first turn the ignition on as normal

[revilla]

Certainly on the EU3 MFRU you are correct that only two relays are used and you can replace the MFRU with two discreet relays. The EU2 MFRU is wired differently inside so while I am fairly sure that you are still correct I'm not 100% sure. I do have a copy of the EU2 wiring diagram and will try to have a look when I get home. If you want me to send you a copy, BM me your email address.

[mcerbm]

I think this is my wiring diagram:

http://www.lotus7.club/sites/default/files/images/Docs/Guides/YSB104490%20Engine%20harness%20K-series%20EU2%20non%20VVC.pdf

It looks like the main relay has a brown/pink wire that goes to the coil and to the injectors. Thats currently chopped and tidied back into the loom.....

The oxygen sensor is also in this diagram, am I right in thinking that this also needs powered? Why is it obsolete in the EU3 configuration?

[revilla]

That's the same diagram I have. For sure the injectors and coil packs need powering, if you have cut the brown and pink switched supply wire it won't run. The oxygen sensor needs powering too - the power supply is to the internal heater to get it up to operating temperature. The EU3 MEMS3 ECU is able to drive this directly without needing a relay. There was an article I wrote on this for Low Flying a while back, although that was specifically for the EU3 engine.

[revilla]

Was the VHPD wired the same way as the VVC with sequential injection and wasted spark or did it have a distributor? That wiring diagram is for the VVC and it was wired very differently to the solid cam K standard K Series. I have the other diagram too if it is relevant.

[mcerbm]

The VHPD has a distributor. Revilla, yes that would be very helpful if you have the other diagram. Looks like I need to find a neat place for a further two relays or put the MFRU back in

[Mankee]

I assumed exactly the same as you and wired out some of the redundant relays in the MFRU of my previous EU2 (coil/distributor/leads) install. And then ended up with no feed for the coil and no spark! Revilla (Andrew) and I were messing around mapping out the EU2 and EU3 MFRUs one time at band camp, so he may still have the one I helped do for the EU2 MFRU. This may help you or you might just do what I did and reinstate the MFRU and leave the rewire for another job.

[revilla]

I'm back home now, will email you all the relevant stuff I have.

[mcerbm]

Thanks for the help I managed to get the MFRU connected back into the loom and the car running. However it's been a bit of a bodge and I would like to redo it properly but don't have the wire lengths.

does anyone know where I could order wires of the correct size and colour codes for the MFRU wires so I can solder in new lengths?

[revilla]

This is what you want: Thin Wall PVC Cable from Autosparks - they carry pretty much all the colours and sizes by the metre. Did I send you a copy of my version of the EU3 wiring diagram before? I know yours is EU2 but it has all the cable sizes marked on it and most should be the same for EU2 and EU3.

[mcerbm]

Yes thanks I received your comprehensive update and it's very useful. I'll use that website to tidy up the loom and get all the lengths correct for me newly situated MFRU.