Distributorless ignition using GEMS coils and Hotwire system

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GDCobra
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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by GDCobra »

DaveEFI wrote:
Thu Jan 07, 2021 9:36 am
Can you fit it in the same place as the 14CU? At least then you'll know it is a suitable environment.
The 14CUX is mounted in the car with trunking passing through firewall using the rubber "grommet" which is integral with the loom. I have considered doing similar with the Nodiz as it's a better environment however this would mean the cabels being longer than necassary and I'm particularly concerned about the VR-CPS cable as the advice is to keep this as short as possible and away from sources of EMI, not ideal to route alongside feeds to coil-pack.

Every solution has pro's but also con's. I'm currently leading towards the idea of mounting near but inside a project box, this seems to give best balance of wire runs and environment (due to the box)



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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by DaveEFI »

If you used a decent twin screen cable for the VR sensor, you should be OK. A decent source for that would be a good music shop etc - balanced mic cable. A decent spec of that should be strong, flexible and have excellent screening - a TV studio and stage etc has lights fed from dimmers that can produce a fair bit of RFI.
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GDCobra
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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by GDCobra »

DaveEFI wrote:
Thu Jan 07, 2021 12:48 pm
If you used a decent twin screen cable for the VR sensor, you should be OK. A decent source for that would be a good music shop etc - balanced mic cable. A decent spec of that should be strong, flexible and have excellent screening - a TV studio and stage etc has lights fed from dimmers that can produce a fair bit of RFI.
I suspect you are correct and I may go that way yet although I have other reasons for not wanting to go through the firewall (in fact I’d prefer to mount the unit to the chassis rather than body so it does not have to be disturb it when I separate body and chassis so that is also a factor, bit of time yet for making decisions.

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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by GDCobra »

DaveEFI wrote:
Wed Oct 14, 2020 12:40 pm
This the schematic of the pulse amplifier. The original circuit used a plain NPN transistor - something like a 2N2222 - but I found a Darlington pair worked better with my tach. That may of course just be a funny with it. It didn't read on start up - then kicked in when you revved it, and then stayed working. With the TIP, you can see it kicking when cranking. If space is an issue, you can remove the coil from the relay. If not, you may want to either remove the armature from the relay or glue it up to prevent it buzzing.

Image
Hi @DaveEFi

Just looking at this curcuit, I believe that the TACH signal from MS if 5V, from the document I have the signal from NODIZ is 12v, would this mean I'd need a different, higher value, resister to your 1K1 do you know?

Also what power rating should I look at?

Fortunately I live close to CPC (Farnell) so can pick these up for 'pennies' witout incurring postage charges.

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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by Bexam »

Hi, as the Nodiz is a wasted spark coil driver does this mean if all four coil negs are connected to the 14CUX it will see twice as many signals as required as does as timing light with advance/retard dial in ?

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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by GDCobra »

Bexam wrote:
Thu Jul 29, 2021 10:16 am
Hi, as the Nodiz is a wasted spark coil driver does this mean if all four coil negs are connected to the 14CUX it will see twice as many signals as required as does as timing light with advance/retard dial in ?
Shouldn’t do, each coil is fired one per revolution hence 4 ignition events per engine revolution which is exactly the same rate as the single coil. Obviously the coil outputs can’t be directly connected together or each coil will fire all others, must go through diodes.

My understanding with adv/ret timing lights is that they calculate RPM to allow them to shift the spark, on wasted systems any plug lead will fire twice per engine cycle (2 revolutions) give it the timing light the impression that the engine is going twice as fast as it is. Best to use a simple timing light and read the advance off the pulley. In fact with an ECU based system reading the timing position is of less interest (IMHO), if the zero position is set correctly any other position will be also. Unless system is broken!

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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by stevieturbo »

Base timing position is utterly critical with any ecu. It is the key to everything !

But dialback lights can have their issues on wasted spark type setups. If you set timing to zero and verify it is at TDC and at a few different rpms and all is well, you can't go wrong.

If it changes with rpm with what should be a fixed value in the ecu, then you know something is wrong, whether it's your light or the trigger setup.
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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by GDCobra »

stevieturbo wrote:
Thu Jul 29, 2021 3:19 pm
Base timing position is utterly critical with any ecu. It is the key to everything !
Absolutely, once you have one correct value, all others must be correct as long as settings in the box reflect the physical configuration and nothing is broken.

One think I like about the MS setup which I've eventually gone for is that it's a simpl setting to run the engine at a constand timing value, in my case I chose 10°BTDC as that's where I have a timing mark on the pulley (and the engine will start and idle no problem at that value). All I did after that (with constant timing turned off) was make sure I was geting something in the right area and timing variation was reacting to both RPM and vacuum (indpendently).

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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by Bexam »

Thanks, I've got my head round that one now. My engine fired up and ran nicely for the first time yesterday ( big relief after spending ages mucking about with it), now I need to start looking at the value of connecting the other inputs the nodiz can take.

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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by GDCobra »

Bexam wrote:
Fri Jul 30, 2021 8:41 am
Thanks, I've got my head round that one now. My engine fired up and ran nicely for the first time yesterday ( big relief after spending ages mucking about with it), now I need to start looking at the value of connecting the other inputs the nodiz can take.


Out of interest, what coils are you using?
Are you running EFi? If so how are you feeding the ignition pulse to it the Nodiz
Have you run the car under load and up to high(ish) RPM? That's where my problems occurred, it sounded/felt OK when only running the enging. I'd make sure of that before adding anything else.

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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by Bexam »

My project is a little different, it's an 18' speedboat which was converted from its original engine to a rover V8 (it looks like from range rover going by the timing cover).
It was using strombergs and a dizzy with luminition fitted.
At some point with the previous owner it had overheated and broken some rings so I've built a fresh engine but because I'm partial to big ideas that I don't have time for I decided to modernise the installation with old fashion 14CUX fuel injection, a trigger wheel + VR sensor from a Gems engine, coil packs from a Thor engine (Bosch) and a nodiz (which I think I've just managed to blow up) to run the ignition system.
As trying to do all this in the engine bay of the boat would be virtually impossible I've made an frame to run the engine in from the comfort of my garage. Unfortunately I lost one of the coil returns and soon after whilst fault finding the nodiz gave up altogether.
More head scratching now and maybe a call to Motorsport Electronics.

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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by GDCobra »

Bexam wrote:
Fri Jul 30, 2021 12:12 pm
My project is a little different, it's an 18' speedboat which was converted from its original engine to a rover V8 (it looks like from range rover going by the timing cover).
It was using strombergs and a dizzy with luminition fitted.
At some point with the previous owner it had overheated and broken some rings so I've built a fresh engine but because I'm partial to big ideas that I don't have time for I decided to modernise the installation with old fashion 14CUX fuel injection, a trigger wheel + VR sensor from a Gems engine, coil packs from a Thor engine (Bosch) and a nodiz (which I think I've just managed to blow up) to run the ignition system.
As trying to do all this in the engine bay of the boat would be virtually impossible I've made an frame to run the engine in from the comfort of my garage. Unfortunately I lost one of the coil returns and soon after whilst fault finding the nodiz gave up altogether.
More head scratching now and maybe a call to Motorsport Electronics.
That's an interesting sounding project, always good to hear of something a little different.

How are you feeding the ignition pulse to the 14CUX? I've ended up with a diode on each coil which seems to be the default way of doing this.

I'm running the GEMS coils, I think the Bosch/Thor were later but similar if I've understood correctly. They run fine now with the Megasquirt so there's not a problem with them but possibly Nodiz didn't like them

Strange that you could have popped the Nodiz as the coil connections only supply a ground, hard to imagine what you could have put in there which would overload it.

Good luck getting it sorted.

Are you hooking up to a computer or setting up just with the buttons?

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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by Bexam »

I'm using a diode pack from the coils supplied by 'Trigger wheels' to signal the 14CUX, I've seen mention of a resistor utilised inline but mine seems fine without (for now anyway).
The nodiz which will be heading back to ME for repairs/renewal (after speaking to a very helpful chap called Edwin) and when it's back I'll start with a set up using the buttons and maybe play with the software side once the boat is in the water and driving.

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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by DaveEFI »

The problem can be when playing is you can power up the coils full time. Bit like having the points closed, ignition on. And burn out a coil or driver.

I'm really quite surprised Nodiz doesn't provide a suitable signal to drive an injection only ECU. There are loads of cars around with distributor ignition and electronic injection.
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Re: Distributorless ignition using GEMS coils and Hotwire system

Post by GDCobra »

Bexam wrote:
Fri Jul 30, 2021 2:22 pm
I'm using a diode pack from the coils supplied by 'Trigger wheels' to signal the 14CUX, I've seen mention of a resistor utilised inline but mine seems fine without (for now anyway).
The nodiz which will be heading back to ME for repairs/renewal (after speaking to a very helpful chap called Edwin) and when it's back I'll start with a set up using the buttons and maybe play with the software side once the boat is in the water and driving.
Yeah, I've seen circuits which use resistors in parallel with the diodes but never really understood the point of them if I'm honest. I've also seen circuits with a Zener diode on the output (Think the Trigger Wheels circuit may have that but may be thinking of another) I used mine both with and without the Zener and the EFi worked fine either way. Now I know the 14CUX trigges at a voltage of around 70v I understand why.

I had the Zener for the tacho, that didn't work without it presumably as that triggers at a lower voltage.

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