Hi guys, Is there a flow chart that clearly explains the operation of the engine (ECU 2.5)? I imagine a diagram where are represented, ignition, injection and all sensors. The goal is to understand what are the elements involved and especially what are their states for: - Cold start - Warm start - Normal running I think this kind of flow chart would help everyone understand and solve problems.
The Service Manual has a good write up on general theory of operation, sensor diagnostics, etc. No flow chart, but there is solid explanation of what happens when, and there are graphs for relevant elements.
You may be able to find more information through other cars that used the same system. I believe there were at least one or two other cars fitted with 2.5 Motronics.
Hello A 80's or begin 90's ECU doesn't work like that. I uses a lot of database ( graphs) stored in an Eprom. Most of them use 2 analogue inputs ( like rpm and temperature), that are converted to digital value (4 or 8 bits), to give an output value . This value is digital (4 or 8 bits) and converted back to analogue to give for example a injector opening time. You can not put this in flow charts. A very well known chart (database) is the fuel table. This is the fuel output for the injectors (in mSec) in relation to rpm and throttle opening. ( vacuum) Here is a fuel table that i programmed myself for my ford cosworth engine some years ago.This one has vacuum and pressure value's (psi) because it was a turbo engine. Image Unavailable, Please Login
Inside of that Coswort ecu ( Magneti Marelli). The empty socket top left is for the eprom. On the bottom right you can see four transistor drivers for the four injectors. Image Unavailable, Please Login
This is how the data is stored in the eprom. Hexadecimal value's at a certain address. MAP is the signal from the pressure sensor. Turbo engine !. I an normal aspirated engine like our 348 the TPS signal is used. Image Unavailable, Please Login .
Patrick, I suspect Marc is looking for a block diagram of the engine management system, showing the various sensors and perhaps containing some basic information about their interaction. Done correctly, it'd be a useful quick reference. For example, it'd be great to know at what temperature the Motronic starts referencing the O2 sensor input. Marc, it occurs to me that you may be able to find helpful information in some of the Bosch publications on the subject. I need to check my copy, but I think general information on the early Motronics systems was available in the old "Bosch Fuel Injection Handbook". It's long out of print now, but I'm sure you could find a copy somewhere. From what I found on Amazon, it seems as though it's been superseded by "Bosch Gasoline Engine Management". No idea if it covers the early Motronics systems, but worth looking into if you want to know more about how those systems work.
This is a great site to learn. In the part "program" you find some diagrams but for the marelli ECU of course. But as they are also 90's ecu's maybe the difference with Bosch is not that big. Certainly the "sensors" part. http://www.bigturbo.co.uk/
I attach documents on Motronic 2.5 and 2.7 (from other cars) that I have plus a long list of all Bosch and some other ECU-s providing basic data.
Thank you so much guys ! There is so much to study... It is a good opportunity for me to learn it, it is very important to me to underdstand how it works.
Mike said : Cool site/ Yes Think so to. Was my starting point to learn ( and have done ) to install and program an universal ECU for my cosworth 2.0l turbo engine. Was a big learning cycle of many, many months but worth it. Sometimes very scary, certainly with a turbo engine. Lol
Couple few years on those documents with some real time programming you may be ready to attempt the early ferrari motronic thats pretty simple once you define the tables and addresses.
Correct that's how it works. The first part is to extract the data from a eprom (if it's not locked !!) but then to find out where the correct address is for a given table. Here is how such an address table looks like. The code is in hex. This is not my work. L1-P8 are the ecu models.(more memory) Image Unavailable, Please Login
And more strange a fuel table in hex code. Each code is a digital value for injector opening time in relation to rpm and manifold pressure. The top two rows are the RPM headers, the next two rows are the MAP headers and the following 13 rows are the actual fuel map itself. This gives as result the graph from a few posts ago. Image Unavailable, Please Login
This was the independent ECU i used. It is from Poland (the have a great drifting community !) and served me very well. But there are more brands. So to cut it very short you can extract the data from a 348 eprom and put it in an ecu and put it in your Ferrari . This way you can program your Ferrari wired with a laptop while you're driving. This is how i programmed my Sierra Cosworth. Here is the ecu+ perifics i used. Image Unavailable, Please Login
And finally my engine. +- 300Hp at 1.6 bar pressure for a 2.0 liter from 1986.Look on youtube and you will see what these cars where all about. Image Unavailable, Please Login
Here some info on the marelli ECU. I think very similar to the Bosch. And remember, they used 2 of these for the Ferrari F40. Good to learn how these work. Just forget the part for a knock sensor ( 348 don't have) and the manifold air pressure sensor (MAP) that the 348 don't have. You shall have to use a bit of Google Translator.
Here a picture from me driving with the laptop and programming online the ECU. (dangerous i know but it was on a deserted road.) This is live streaming recording of the mixture. You see a bit lean at 16.4/1 so had to "rich" it by changing the value's in the fuel table. Image Unavailable, Please Login
