1991 E34 M20 - 4HP22 won't work after some changes

[marko84]

This car was previously 535i m30, but now I installed the engine m20 2.0 with the 4hp22 automatic transmission. While it was m30 it had the ASC along with the ABS, but now when I installed the engine I tried to replace the ECU of the ABS but the connectors didn't match, then I replaced the connectors but then I got some extra wires because I replaced the connectors by matching the colors of the wires, but now I got some extra wires and my ABS doesn't work. Does the ABS affect the ECU of the transmission? My kickdown knob is still under the accelarator pedal. The ECU of the transmission receives power but it may not receives the input data of the engine which is vital for functioning. How can I revive the transmission and what I need to do make it work? Do i need the return the old ECU of the ABS even if it didn't work because this engine has no ASC?Do I need to connect some other thing which isn't in the M20 electric system?

Thank you in advance!

[shogun]

there someone with expert electronic knowledge has to answer, I only can give you the links to the wiring diagrams, which might help you
E34 (1988 to 1995 5 Series) Wiring Diagrams

[marko84]

On these pictures you can see that I'm putting back the other connector for ABS and the whole ABS module. As you can see on the small white connector the wires are cut and they give the signal to the ECU of the transmission. ABS won't function but it may give the necessary data to the ECU of the transmission to make him work. Is this a possible solution? Any other suggestions?

[whiskychaser]

You dont say so, but what I think you have is a '93 535i auto shell into which you have transplanted a '91 M20 and 4HP22 auto box. On the '93, ASC talks to the EGS but from what I can see, on the 91 does not. You dont say it either but I understand your wiring loom socket has 8 pins whereas your transmission only has 7. I'd suggest you start with the EGS and wiring loom from the M20 donor. Even better would be to get them from a '91 M20 which had ABS/ASC though I do not know if such a beast existed Best of luck with it

[marko84]

First, this wiring loom socket has 8 pins but it has seven wires in it which are rearranged for 7 pin transmission. So, the connector is OK and it matches the wire colors, everything's properly done according to the wiring diagram. Unfortunately, there's no M20 with the ASC and this M20 is '89. I have no donor car and I have bought this transmission because the previous one had a mechanical failure. I just want to know if there's a point in connecting these 4 wires with the ABS which was previously connected, but I'm pretty sure that it won't work on this engine?

[whiskychaser]

Your original post says it is a '91, you have posted elsewhere it is a '93 and now you are saying it is an '89? It sounds like Johnny Cash's '56 Chevrolet
If your M20 and 4hp22 are out of an '89 you need the TCM and loom out of an '89 to stop you getting transprog and going into limp mode. AFIK your ABS will still work though you may well get the ASC light on. Maybe do a search on ASC delete

[marko84]

Today I quite coincidentally noticed two little connectors, one with two pins and one with three pins. Then I remembered that the car had cruise control, but the module or whatever was there, was dismounted. I think that the couple of wires from these connectors also go the module of the transmission. Does this affect something? If it does can I somehow fool the ECU of the transmission that I still have cruise control. So, my point is that I discovered a couple of connectors which were on the cruise control, and now on M20 I don't have that. It seems to me that the transmission was receieving some data from it. What can I add to the transmission and what are the key input data to make it work?

[marko84]

So far I haven't been able to move my car or should I say to activate the transmission. By analyzing the TCU connector I noticed some anomalies during the speed sensor test on the transmission itself on the brown and white wires. The brown wire (pin 8) with ground should display 500 kohms but I get nothing. The white wire (pin 27) which is connected on the connector with the brown wire (pin 8) should display 800 ohms to 1.6 Kohms and I get nothing. When I raised the rear end of the car and accelarated to 70 km/h I should have received a voltage of more than 3.5V on the brown (pin 8) and white (pin 27) wire but I got nothing. I suspect on the speed sensor on the transmission. How and in what way can I fool the TCM that my speed sensor is working? Can I do that by adding a resistor or by adding some power? I must state that it's impossible to change that sensor in my country and my car is immovable.

[whiskychaser]

You normally test speed sensors by simply disconnecting the wiring and connecting a DMM on ohms range between the pins. You would have to find what the reading should be but my guess is 300-500ohms. Not sure where you got the voltage info but the speed sensors normally produce an analogue AC signal. That may be why you are not seeing it. Hopefully you are using the correct '89 TCM as I think without it you will continue to struggle. I believe it is part no 24611216849 and is unique to the 520i.