Microdynamics PIC anyone got one?

[taz turbo]

Looks like the fuel enrichment module on my TVR has turned its toes up 😢




Does anyone on here have one they would be willing to sell?

Cheers,

Chris.

[stevieturbo]

Doesn't look like too many wires on it ?

Do you know exactly what it claims to do, and what is it wired into ? Or what's actually wrong with it ?

A little googling suggests it's a 5th injector driver of sorts, perhaps like an old Aquamist unit.

Very old school....but perhaps possible to repair ? less easy to replace.

Edited by stevieturbo on Saturday 16th April 17:15

[taz turbo]

Hi Stevie,

4 wires to it, +ve supply, -ve pulse from coil for engine speed, -ve control signal from boost switch and WOT switch and -ve pulse to 7th (on a 2.8V6 Ford) fuel injector.

All fairly simple, when on boost or WOT it fires the extra fuel injector to enrich when in boost, pulse length in relation to engine speed and injector pulse time is adjustable on the control box.

I’ve had the multimeter and oscilloscope on it checking all signals and all is good, injector resistance is good, injector fires fine by applying -ve onto it (+ve is permanently on with ignition) seems supply and two control signals are good but no output.

Really need to replace with like for like as it’s all original on a pre production prototype that never hit production, would just be wrong to bastardise it with a modern management system.

Could see about getting something made to replicate the original and get it mounted in the original case. But that’s a bit of a last resort.

Turbo Techinics used to put a profile block in the air metering unit (Bosch K Jet) to just make it pull a bit more fuel, crude but works. This was AVJ the engine builder for TVR solution back in 1982, certainly more controllable than the profile block.

Chris.

[taz turbo]

Should of said it’s been ‘potted’ in epoxy so although the back can be removed all you can see is a bath of epoxy, so repair isn’t really an option!

Chris.

[GreenV8S]

Some potting compounds can be removed with heat and/or acetone.

If you know what algorithm you want to implement, it would be possible to DIY one with a microcontroller and make it look superficially similar. I feel that would be in the spirit of TVR even if it wasn't strictly OEM.

[stevieturbo]

Have you tried contacting Micro Dynamics directly ?

Anything of that nature will be very old school...and almost non existent these days.

Although at a pinch and a few skills, you could entertain the likes of say an arduino based controller to perform the same task. Although I doubt it would fit into the same MD box.

Yes it's modern, but it would be very cheap and it would allow you more adjustability over fueling ( and of course require tuned ), and would be cheaper and easier than going full efi.

Or try contacting Aquamist, as they used to make similar controllers.

Or it may be possible that some of the modern water injection controllers might be able to be used.

Typically most now want a variable 0-5v input, but there might be some that accept an rpm/coil trigger. They usually PWM a motor/pump as an output, but I guess it could equally be an injector.

[stevieturbo]

eg...this one is perhaps overkill, but it does accept an rpm input.

https://www.methanol-injection.co.uk/index.php?rou...

https://torqbyte.com/products/cm5-lts-water-methan...

Speeduino will be cheaper though

https://diy-efi.co.uk/product/speeduino_0-4-4_asse...


https://zzperformance.com/products/lnf5m-fifth-inj...

Edited by stevieturbo on Saturday 16th April 21:30

[stevieturbo]

GreenV8S said:

Some potting compounds can be removed with heat and/or acetone.

If you know what algorithm you want to implement, it would be possible to DIY one with a microcontroller and make it look superficially similar. I feel that would be in the spirit of TVR even if it wasn't strictly OEM.

Even something similar, in a black box like that...with a new MD sticker on it to appear similar would pass.

If it really is buggered...then can't do much harm trying to remove any potting ?

Or are there any k-jet wizards that could re-calibrate the metering head to not need an additional controller at all ?

[twibs]

kmi injection can redo ke metetering heads for more fuel flow, worth an ask.
A mf2 aquamist fifth injector driver set up came up for sale on FB this week

Motorsport developments used to do a kit to drive the cold start valve as a 5th injector.

[GreenV8S]

stevieturbo said:

you could entertain the likes of say an arduino based controller to perform the same task. Although I doubt it would fit into the same MD box.

It would definitely be possible to fit it into the box. There are Arduino compatible boards off the shelf with integral motor drivers and buck converters that are only a couple of inches long, and the circuit is simple enough that you could DIY a board much smaller. You could even lose an Arduino compatible microcontroller inside a wiring loom if you wanted to. Of course it doesn't need to be Arduino based. It is nuts how capable and cheap modern microcontrollers are.

[stevieturbo]

GreenV8S said:

It would definitely be possible to fit it into the box. There are Arduino compatible boards off the shelf with integral motor drivers and buck converters that are only a couple of inches long, and the circuit is simple enough that you could DIY a board much smaller. You could even lose an Arduino compatible microcontroller inside a wiring loom if you wanted to. Of course it doesn't need to be Arduino based. It is nuts how capable and cheap modern microcontrollers are.

Or even just hide a new controller somewhere, leaving the broken MD PIC in place for visuals, if it can be seen ?

[taz turbo]

Thank you all, for your time and contributions of assistance.

I’ll be giving Autocar Electrical (owners of Micro Dynamics) a call on Tuesday.

Depending on the outcome of that I’ll give Motorsport Developments a call. Seems he’s done many enrichment injector control installs…

I’ve also been looking at some of the links posted on other solutions, which have also in turn opened up some other possibilities.

Also been looking (mainly YouTube) at removing epoxy type potting compounds, that doesn’t look so hopeful.

But if all else fails, it looks as if it will either come down to a home made controller, or an off the shelf item, and as you said Peter, leaving the original unit in place in the engine bay for aesthetics.

I’ll keep the thread updated with any developments.

Many thanks,

Chris.

Edited by taz turbo on Sunday 17th April 22:07

[taz turbo]

Thank you all, for your time and contributions of assistance.

I’ll be giving Autocar Electrical (owners of Micro Dynamics) a call on Tuesday.

Depending on the outcome of that I’ll give Motorsport Developments a call. Seems he’s done many enrichment injector control installs…

I’ve also been looking at some of the links posted on other solutions, which have also in turn opened up some other possibilities.

Also been looking (mainly YouTube) at removing epoxy type potting compounds, that doesn’t look so hopeful.

But if all else fails, it looks as if it will either come down to a home made controller, or an off the shelf item, and as you said Peter, leaving the original unit in place in the engine bay for aesthetics.

I’ll keep the thread updated with any developments.

Many thanks,

Chris.

Edited by taz turbo on Wednesday 20th April 14:33

[taz turbo]

Sorry for the long delay in getting back to this one!

I made some calls and didn’t get anywhere with an off the shelf like for like replacement, however I then did come across a new old stock one on eBay, I had to pay well over the odds but still probably less than a later retrofit system, anyway it’s all fitted all working, and you can’t believe how happy/relieved I am.

Thanks for everyone’s inputs.

All the best,

Chris.

[stevieturbo]

Good result then. But could still consider upgrades for the future.

Or maybe look into ripping the old apart to try and repair. Nothing to lose now