Bosch Motronic 1.7 ECU Remap/Flashing Guide (WinOLS)

The motronic ECU’s are used in a lot of cars. This document may cover information that is the same for other motronic series. The motronic 1.7 has one 27C256 UV EPROM inside. It has a DIL28 package and is mounted in a socket, so removing it is easy.So this article show a guide on how to remap/flashing Bosch Motronic 1.7 ECU,hope it helps!

WinOLS Video+PDF Tutorial Download

001

Note:

All information and values given in this document may be used at own risk. I do not stand in for

any problems. Thanks to the members from www.ecuconnections.com I hope you enjoy it.

 

The rev limiter:

The rev limiter works by cutting the fuel off. When the rpm has dropped below the rev limit there will be applied fuel again to the engine. How much fuel is injected after a cut-off is regulated by the “deceleration injection after cut-off” map.

So we want to change rev limiter to 7100RPM. Open WinOLS and search for value 01 01 54.

When you found it deselect it. Skip one value and select next two and create map.

Bosch Motronic 1.7 ECU RemapFlashing Guide (1)
Pic1. Rev limit in WinOLS

Calculation steps:

1) 90 03

2) 03 90

3) Convert to DEC = 912

4) 52200 – (912*50) = 6600

5) 52200-7100=45100

6) 45100/50=902

7) Convert to HEX = 03 86

8) 86 03

 

Injection maps

Injection at Part Throttle

In M1.7 are two tipes of maps: High part and low part throttle.

High part throttle is 7×12 map and looks like this

Bosch Motronic 1.7 ECU RemapFlashing Guide (2)
Pic. 2 Injection at high part throttle

 

Low part throttle is 6×12 and looks like this

Bosch Motronic 1.7 ECU RemapFlashing Guide (3)
Pic. 3 Injection at low part throttle

 

The factor for RPM is 40, and the offset 0. The injection map does not have absolute values in it. The values are the correction-values for the, by the ECU, calculated injection pulse length.

Injection at Wide Open Throttle

The Injection at WOT is a 1×16 map which looks like this

Bosch Motronic 1.7 ECU RemapFlashing Guide (4)
Pic. 4 Injection at wide open throttle

 

The factor for RPM is 40, and the offset 0. The injection map does not have absolute values in it. The values are the correction-values for the, by the ECU, calculated injection pulse length. Just like the closed and part throttle maps. To change this map in a good way you need a wideband lambda sensor (or a dyno) to achieve the proper Air Fuel Ratio (AFR).

 

Ignition at part throttle

Ignition at part throttle just like in injection at part throttle, is two maps: high part and low part throttle.

High part throttle is 7×12 and looks like this

Bosch Motronic 1.7 ECU RemapFlashing Guide (5)
Pic. 5 Ignition at high part throttle

 

Low part throttle map is 6×12 and looks like this

Bosch Motronic 1.7 ECU RemapFlashing Guide (6)
Pic. 6 Ignition at low part throttle

 

The factor for RPM is 40, and the offset 0. If you change this map I suggest adding not more than 10%

ignition advantage. Also in that case using fuel with the highest possible octane number is

recommended (95-101). When you “over tune” this map it will result in damage to the engine.

For proper tuning knock-detection equipment is needed.

Ignition at wide open throttle

The Ignition at WOT is 1×16 and looks like this

Bosch Motronic 1.7 ECU RemapFlashing Guide (7)
Pic. 7 Ignition at WOT

 

The factor for RPM is 40, and the offset 0. If you change this map I suggest adding not more than 10% ignition advantage. Also in that case using fuel with the highest possible octane number is

recommended (95-101). When you “over tune” this map it will result in damage to the engine.

For proper tuning knock-detection equipment is needed.

 

Goodies for the 175 computer owner

Bosch Motronic 1.7 ECU RemapFlashing Guide (8)

Since I wrote this file using the 175 computer from a BMW e30 318is with software

214 I found almost all usefull maps. Here they are:

Bosch Motronic 1.7 ECU RemapFlashing Guide (9)

Checksum correction

Before writing the bin file into the chip you need to correct the checksum. For this procedure you need

hex editor. You can download one from http://mh-nexus.de/en/hxd/

Open HxD and load your original bin file.

Now press Analysis> Checksums…

Bosch Motronic 1.7 ECU RemapFlashing Guide (10)
Pic. 10 Hxd menu

 

Choose Checksum-16 and press OK

Bosch Motronic 1.7 ECU RemapFlashing Guide (11)
Pic. 11 HxD checksum menu

 

Check out the result

Bosch Motronic 1.7 ECU RemapFlashing Guide (12)
Pic. 12 HxD checksum result

 

 

Now load your tuned file and do the same

Bosch Motronic 1.7 ECU RemapFlashing Guide (13)
Pic. 13 HxD checksum result

 

My original file has 71A4 checksum and my tuned file has 898C checksum. Tuned file’s checksum must mach to original file’s checksum. So we need correct it. Open your calculator and set on scientific and on hex

Bosch Motronic 1.7 ECU RemapFlashing Guide (14)
Pic. 14Win calculator

 

You need to calculate the difernce between those two checksums. 898C-71A4=17E8

Go in WinOLS. Correction must be done in darker places with FF’s

Bosch Motronic 1.7 ECU RemapFlashing Guide (15)
Pic. 15 WinOLS hexdump

 

Now when you know where correction must be done, go into HxD. Highlight FF’s and do the checksum till you get right value 17E8

How to Make Checksums for ECU Files with WinOLS

Bosch Motronic 1.7 ECU RemapFlashing Guide (16)
Pic. 16 Checksum in HxD

 

Now write 00’s instead of FF’s in the highlighted place.

Bosch Motronic 1.7 ECU RemapFlashing Guide (17)
Pic. 17 Checksum correction in Hxd

 

Now do the checksum again

Bosch Motronic 1.7 ECU RemapFlashing Guide (18)
Pic. 18Checksum in HxD

 

If it is a match to original the you are done! You can write the file into the chip now.

 

Chip installing

When you wrote the bin into the chip you can install it know.

Unscrew the marked screws and bend the marked metal.

Bosch Motronic 1.7 ECU RemapFlashing Guide (19)
Pic. 19 ECU top

 

Bosch Motronic 1.7 ECU RemapFlashing Guide (20)
Pic. 20CU bottom

 

Open the case. You will see the black (not always black) plastic cover. Remove it and you will see the chip

Bosch Motronic 1.7 ECU RemapFlashing Guide (21)
Pic21 Ecu inside

 

Carefully remove it and install yours.

Bosch Motronic 1.7 ECU RemapFlashing Guide (22)
Pic. 22 Chip and socket

Done!