A simple as possible 4 cylinder ODB-II ECU?
 

G'day Folks,

Very general question for those who are used to using Obi wan kenobi stuff.

I'm looking (in principle) for a very basic - silly simple - ECU that has been fitted by a manufacturer to four cylinder petrol engines. Could be Volvo could be for other makes - doesn't really matter.


I don't want to play about with an ECU that freaks out about things such as brake pad wear, headlamps, air conditioning, abs, etc etc

Ideally I want an ECU that just needs things such as a water temperature sensor, a crank position sensor, perhaps manifold pressure if it is so inclined, an O2 sensor and a throttle position sensor - simple engine management stuff but nothing else.


Does anyone here know of such a simple ECU?


I don't want programmable after market options that the boy racers use - they are too expensive for what I have in mind.

You don't say whether you're running carbs or injection, how many cylinders or what else but have a look here,http://www.haltech.com/ecu-selector/ It might give you some idea of what you're looking for.
I don't think any old ecu will work given ignition advance differences and injector timing, a programmable aftermarket unit is probably your only choice.

When it comes to things like Haltech / derivatives of Megasquirt etc I'm looking at hundreds and hundreds of pounds / euros on electronics and software that I'm not especially interested in.

I'm not going to pay the best part of 1000 euros for a stupid computer - it doesn't make sense to me when in three years time we'll all be driving electric cars and parking them on Mars (ha ha).

Anyway if I were, for example, to take the fuel injection and ignition system from another more modern car say a Volvo V40 then I could fit that system of electrickery to an old B20.

Whilst I don't consider fabrication to be such a great problem, I'm sure there are many other problems with doing this.

The first step is to try and make sure I pick a system that doesn't have any over the top silliness such as alarms and lights and wifi connectivity and this and that.

My problem is that for petrol fuel injection systems I've only ever dabbled with Bosch CIS systems - all old school stuff. The modern day Obi Wan Kenobi experience I have not =>



So I'm looking for a silly simple fuel injection system with ignition.

I'm guessing it will have to be a wasted spark ignition system - It will have to be some form indirect spray it in the intake manifold injection. It has to be cheap - sort of 250 quid for the whole car cheap. I'll strip out what I want and chuck the rest.

Here's a potentially crazy thought but I'm going to throw it out there.

Can you not go for a fully diy solution based on some combination of raspberry Pi and Arduino?

It probably won't be long before a smart phone can do what an ECU does as well as downloading films etc!

I'm guessing it would be perfectly possible to do what you suggest - problem is I don't really have the time or the energy for such things: I see little point in reinventing the wheel - I just want to see if I can fool an ECU into thinking it is still driving around in a modern car when it is in fact fitted to an old one.

Your average smart phone is already more than powerful enough in computing terms. It just won't interface to anything useful.


I bet you could. But I reckon you'd probably need to do some basic electronics to manipulate some of the signals a bit.

I think your biggest challenge will be to find an ecu that's intended for an engine with a sufficiently similar profile in terms of things like air flow and torque at different revs and load. By that I mean, if you take an ecu that's meant to go on a modern 1.2 litre turbo, just for example, it's going to be programmed to have entirely different injector intervals at different revs than an ecu for an older 2 litre normally aspirated engine. The former is going to scream for max fuel flow at around 6000 romantic while the latter is most thirsty around 4000 rpm, higher than that the air flow is going to be restricted by the mere 4 inlet valves instead of 8 inlet valves under pressure from a turbo. Of course that affects injector intervals because you want to keep the mix right. The air flow sensor should correctly regulate all that if course, unless the signal goes out of range (according to the ecu) in which case it will want to fall back to mappings.

So I reckon, if you can either find an ecu for an engine with similar graphs, and you can do some basic electronics to make your sensors give the right feedback,I reckon you'd get it working. I personally wouldn't have the confidence to try though. I wish you the best of luck.

Just in case some one stumbles on this and wonders the same as me, I've gotten somewhere with the basic concept of silly simple EFI ECUs here =>

https://www.volvoforums.org.uk/showthread.php?t=277641

Started with a different subject of course but ended up finding out about this problem

Raspberry Pi wouldn't be much good realtime, but I am going to convert my Jumbuck Pickup to standalone ECU using the Arduino based Speeduino, nice and cheap and you can rewrite the code for the bits you don't like, as it is open source.

Only one, issue with the Speeduino, I am not sure you can make it ODBII compliant, so may not be allowed in certain countries, it's OK in the UK as we don't have police doing roadside emissions tests via the ODB socket, yet(!)

How come?