What triggers the injectors on the V8

andy-w · Post by **andy-w** » Mon Aug 15, 2011 7:41 am

Hi Guys,

I am a newbie to the forum so please bear with us.

I have a TVR Chimaera and am going down the megasquirt/edis route.
I have bought all the edis parts and have made a loom for it and have managed to test it on the car by removing the standard dizzy leads a plug in the edis and it all worked...so i went a step further and removed the coil and other bits a pieces and when i tried again it would not start. So obviously something coil/distributor is sending a signal to the ecu to fire the injectors.

Has anyone found a way of fitting just the edis kit for now to the v8 using the 14cux ecu?
Or do i just leave standard dizzy and coil on to fire the injectors....yes i know it is not ideal but i have not bought the edit kit yet and just wanted to run it at 15deg advance so i can test the edis kit.

Cheers for your help guys.

Andy

Ian Anderson · Post by **Ian Anderson** » Mon Aug 15, 2011 11:45 am

Probably you are missing the Black wire with white trace from coil to air flow meter.
This then goes to the Ecu hence telling the ecu that the engine is turning

How you get around this without using a triggr wheel etc I don't know
Ian

andy-w · Post by **andy-w** » Mon Aug 15, 2011 12:12 pm

sorry, yes i am using trigger wheel etc...i just wanted to get ignition working without using the megasquirt and keeping the standard coil on

I assumed it would be something like everytime the coil fired it would pulse the injectors...so i am going to have to leave the coil and dizzy on for now and then when i finish the ecu get that on asap....

DEVONMAN · Post by **DEVONMAN** » Mon Aug 15, 2011 3:03 pm

The EDIS-8 box will have a IDM output ( pin 2) which normally triggers the tach and the ecu when the coilpacks fire. You could try connecting the black/white normally connected to the negative side of the coil to pin 2 on the EDIS- 8.

If not you could use a tach adapter (£20 from Trigger Wheel). This connects to the four coil signal/input wires and also to the black/white wire.

You can then dispense with your single coil and dizzy but you will not have any ignition advance other than the limp home mode 10 degrees or what ever you set the trigger wheel to.

Cheers Denis

andy-w · Post by **andy-w** » Mon Aug 15, 2011 3:10 pm

This sounds like the kind of advice i am after.....!!!

Thanks for that....i am not thrashing the car at the moment and the 10 15 deg although not optimum for the car will be ok for a couple of weeks....the vacuum advance is goosed on my distributor so its not different to that...!

I shall have a play tonight and see how it goes...

DaveEFI · Post by **DaveEFI** » Mon Aug 15, 2011 3:25 pm

andy-w wrote:This sounds like the kind of advice i am after.....!!!

Thanks for that....i am not thrashing the car at the moment and the 10 15 deg although not optimum for the car will be ok for a couple of weeks....the vacuum advance is goosed on my distributor so its not different to that...!

I shall have a play tonight and see how it goes...

The vacuum advance makes little difference to the running of the engine - it's more to do with economy.

Running with a fixed ignition setting will result in a very 'flat' engine.

FWIW, I'd get a decent second-hand dizzy and get things running correctly.

First fit the MegaSquirt fuel only, then the EDIS. You can then flog off the dizzy.

andy-w · Post by **andy-w** » Mon Aug 15, 2011 3:30 pm

i thought the va changed the timing by quite a few degrees...i appreciate the timing weights in the dizzy change most things but i honestly thought the va made a difference as well....from what i can gather all the timing changes on a tvr are mechanical...not software as in the ecu....might be wrong ther eso dont quote us on that...

DaveEFI · Post by **DaveEFI** » Mon Aug 15, 2011 10:14 pm

andy-w wrote:i thought the va changed the timing by quite a few degrees...i appreciate the timing weights in the dizzy change most things but i honestly thought the va made a difference as well....from what i can gather all the timing changes on a tvr are mechanical...not software as in the ecu....might be wrong ther eso dont quote us on that...

I can give you the figures from the SD1 dizzy - the mechanical gives 30 degrees of advance. The vacuum adds 6.5 - 9.5 degrees to that, but mainly under high vacuum conditions, rather than full load.

If it has a dizzy, the advance is entirely mechanical. RV8s with ECU controlled advance don't have one, IIRC.

FWIW, I've not tried to trigger any of the standard injection set-ups off EDIS. Given it's not that easy to get a standard Rover rev-counter to work off EDIS 100%, the same may apply to triggering the ECU. Basically, the type of pulse you get from a single coil is rather different from the PIP and IDM ones - or indeed from the EDIS coils.

karlos01 · Post by **karlos01** » Fri Aug 26, 2011 1:14 pm

ive taken the -ve off the coil packs and wired them in as the megajolt website suggests and got it working lovely that way.

andy-w · Post by **andy-w** » Fri Aug 26, 2011 1:26 pm

so take the -ve off the coil....connect to the -ve on the coilpacks and away you go....sounds like a plan....!

I might give it a go this weekend...if the weather holds up...!