Parts Needed for Motronic 1.3 Upgrade?

[mpvibes]

Hey everybody, I have an 85' 735i motor with 83' 733i electronics and wiring I would like to find out what parts are needed for the Motronic 1.3 upgrade and how difficult is this project?



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[Jay535is]

Well, I've done the job, its no fun-mainly because of the harness.
But the rest of it is standard upgrade as listed on many sites like MyE28.com
Whatever you do, do NOT use the 733 harness/electronics with your current motor.
Also, if you have a US car with the 8:1 compression motor, there won't be much performance upgrade going to 1.3, since there aren't chips made for the low compression motor.
I did it for my Euro 10:1 motor.

[pennybond]

Wire harness was a pain. I used one from a 90 535i and had to extend it 2ft. to reach the glove box where I moved the ECU to. That was about 110 solder connections! Also have to deal with RFI shielding on certain wires like O2 signal, Cylinder Identification signal and Crank Sensor signal. Also the C101 connector for the E23 is pinned slightly differently than the E28.

[Hit Man X]

Also, if you have a US car with the 8:1 compression motor, there won't be much performance upgrade going to 1.3, since there aren't chips made for the low compression motor.

This.



Seems like a waste of time. Just toss an 059 on it, EAT chip. Motor on.

[mpvibes]

Thank you Jay535is, pennybond, and Hit Man X for chiming in and giving me some advice on the upgrade. So, I guess its not really worth it then considering if I have a US car with 8:1 compression (not sure, I will have to check my motor and see what it is). Alright, let me tell you all whats going on and the crossroads that I'm in between. I've owned the car since 2003 and with my current setup (1985 735i engine, w/ 1983 733i harness/ electronics, Automatic Transmission) the car feels slow/sluggish and not where I want it to be power and acceleration wise. Also, my current engine/setup has other issues that bother me, like when you are driving it in the summer with regular gas it diesels when you turn off the car (with premium it rarely does it and in the winter it doesn't diesel at all using regular gas). I plan on keeping the car long term and I want something with a little more power and accleration. I want to weigh my options and see whats the best route I should take. Maybe you all can give me some advice and point me in the right direction for my E23.

Option 1: Motronic 1.3 upgrade (may be waste of time like Jay535is and Hit Man X stated considering if I do have a US Car with a 8:1 compression motor)
Option 2: Put a 059 ECU, EAT CHIP (But then I will have to find a good 85 735i harness in addition to all the components like MAF, ICAV, etc...)
Option 3: Possibly retiring my M30 Engine and swapping it for a m60b40 motor (this has been something I've been researching and possibly considering. I know it has been swapped into an E23 before and it can be done) Or what other Engine swaps do you all recommend for the E23 that will work?

Thank you all for the advice!

[BONDOSPECIAL]

Pennybond, why did you move the ECU to the glove box? If you left it in the stock location, would the e34 harness have been long enough? I gathered an e34 harness and the trigger wheel and sensors in preparation for using an MS diyPnP setup that is for MS 1.3. I was hoping the e34 harness would be long enough

[Jay535is]

mpvibes, you have some serious issues.
One way or another you need to swap your harness, ECU, injectors, AFM, sensors etc.
The 733 system is far more primitive than the Motronic 1.0 that the 735 employed, which in turn is more primitive than the 1.3 employed by the later B35 motors.
What I am not sure if you understand is how fuel/air maps work for each engine.
The M30B32 in the 733 is an 8.8:1 compression motor, with a different cam, and uses very different fuel/air/timing maps than the later US M30 B34 which is 8.0:1, and has a different cam.
Since you HAVE TO swap out the harness anyway(seriously), you may as well do the 1.3 upgrade, just don't expect huge performance gains since the M30B35 is 9:1 compression with a similar cam to the B32, so the fuel/air/timing maps are not optimized for the US B34 motor.
You will need to change EVERYTHING though: harness, ECU, injectors, sensors, add front trigger wheel, AFM, ICV...
I've done a number of 1.3 conversions, and while its not rocket surgery, if you're not comfortable reading a schematic and soldering, its going to be a nightmare for you.
The harness from the E32 and E34 aren't long enough to reach the stock ECU location in the passenger kick panel, but they MAY be long enough to tuck the ECU up into the dash area...I cut the E32 harness, and added about 20" from a 1988 528e harness (55 pin motronic).
See the link in my signature for a wiring diagram, but the E23 C101 is different.

[pennybond]

Bondo, moved it there so that it was easier to get to like the e28. The e34 harness is still not long enough to reach the footwell location behind the speaker. Even though there is not much "apparent " benefit to going 1.3 on the US motor I have noticed better idle, smoother power delivery while accelerating and elimination of the cold start injector and the pesky reference and speed sensors. Also, I've heard that it is easier to do MS with 1.3. I do experience benefits however, like Hitman was alluding to, it was a ton of work to get them.

I have asked SSSquid Tuning if they make a chip for the US b34 motor running 1.3. (Interesting, they have a tuned chip for the e2i conversion I'm going to do on my 84 528e.) I'll let you know what they say.

[Jay535is]

I have asked SSSquid Tuning if they make a chip for the US b34 motor running 1.3. (Interesting, they have a tuned chip for the e2i conversion I'm going to do on my 84 528e.) I'll let you know what they say.

Now that would be cool, I'd forgotten about them.

[cfisher535is]

I'd be interested in one or more if they did.

[mpvibes]

mpvibes, you have some serious issues.
One way or another you need to swap your harness, ECU, injectors, AFM, sensors etc.
The 733 system is far more primitive than the Motronic 1.0 that the 735 employed, which in turn is more primitive than the 1.3 employed by the later B35 motors.
What I am not sure if you understand is how fuel/air maps work for each engine.
The M30B32 in the 733 is an 8.8:1 compression motor, with a different cam, and uses very different fuel/air/timing maps than the later US M30 B34 which is 8.0:1, and has a different cam.
Since you HAVE TO swap out the harness anyway(seriously), you may as well do the 1.3 upgrade, just don't expect huge performance gains since the M30B35 is 9:1 compression with a similar cam to the B32, so the fuel/air/timing maps are not optimized for the US B34 motor.
You will need to change EVERYTHING though: harness, ECU, injectors, sensors, add front trigger wheel, AFM, ICV...
I've done a number of 1.3 conversions, and while its not rocket surgery, if you're not comfortable reading a schematic and soldering, its going to be a nightmare for you.
The harness from the E32 and E34 aren't long enough to reach the stock ECU location in the passenger kick panel, but they MAY be long enough to tuck the ECU up into the dash area...I cut the E32 harness, and added about 20" from a 1988 528e harness (55 pin motronic).
See the link in my signature for a wiring diagram, but the E23 C101 is different.

Yes, I'm dealing with some serious issues with this car and I believe the main problem is that I have the wrong harness and computer for this engine which is causing these issues. Overall, I just want this car to run correctly and run like it should! Your link on your Signature wasn't working so that I can take a look at the wiring diagram for the motronic 1.3. I was doing some research on the motronic 1.3 upgrade and man it looks like its gonna be quite a bit of work involved and I don't know if "I'll be jumping from the frying pan and into the skillet" . However, I do like a challenge. I found a part list of what I would need to do the 1.3 upgrade if I were to do it and this is what I found (tell me if I'm missing anything):

M30B35 harness (from an e32 or e34)
1 M30B35 O2 sensor (NEW)
1 M30B35 coolant temp sensor (NEW)
1 M20B27 super eta temp sender (NEW)
2 M30B35 thermostat housing plugs (NEW)
1 M30B35 set of ignition wires with inductive pickup (BavAuto red wires)
1 M30B35 179 ECU (from an e32 or e34)
1.M30B35 harmonic balancer
1 M30B35 crank trigger bracket
1 M30B35 crank trigger bracket hardware set
1 M30B35 crank trigger sensor
1 M30B35 purge valve
1 M30B35 purge valve retainer
1 M30B35 purge valve retainer bracket
1 M30B35 oil level sensor (if using M30B35 harness)


Do you or anyone you know of have a motronic 1.3 upgrade kit up for sale?
Also, I know this may be a dumb question but, does this 1.3 upgrade involve dropping the transmission?

[Jay535is]

That's a pretty good list.
You also want the coil and TPS (the auto 6 pin TPS is just better and CAN be used with a manual trans)
I don't remember if you have an auto or manual...that can definitely complicate things.
You don't have to drop the transmission at all, just remove the sensors from the bellhousing.
The easiest way to do this is to strip an E32 yourself, and take EVERYTHING that is attached to the engine harness, sensors and brackets and all.
make sure to get some 'body side' wiring from the power distribution box, and the C101/diagnostic plug.
You should also get an 'A' thermostat housing and the ever so slightly smaller water pump pulley from the donor.
Be careful when you get the ECU, many E32 came with the 150, which is actually more like motronic 1.1, and not as desirable as the 179 1.3.
When you have all this in hand I can send pics of my harness and how I (and a good friend) solved some of the wiring challenges, mainly with getting battery power to the relays.

[pennybond]

Here is the response from SSSquid:

Hello Eric,

sure do! I assume you are running a 179 ECU from the M30B35?

The M30B34 chip is available here:
https://www.sssquid.com/v3/ssshop/m30b34-chip/

Thank you, and please feel free to ask any questions you may have, Jay

Hmmmmm.......more $'s to spend??

[Jay535is]

Well, was your question about a chip for a B35, or for a 10:1 motor running 1.3?
They are certainly not the same.

[mpvibes]

That's a pretty good list.
You also want the coil and TPS (the auto 6 pin TPS is just better and CAN be used with a manual trans)
I don't remember if you have an auto or manual...that can definitely complicate things.
You don't have to drop the transmission at all, just remove the sensors from the bellhousing.
The easiest way to do this is to strip an E32 yourself, and take EVERYTHING that is attached to the engine harness, sensors and brackets and all.
make sure to get some 'body side' wiring from the power distribution box, and the C101/diagnostic plug.
You should also get an 'A' thermostat housing and the ever so slightly smaller water pump pulley from the donor.
Be careful when you get the ECU, many E32 came with the 150, which is actually more like motronic 1.1, and not as desirable as the 179 1.3.
When you have all this in hand I can send pics of my harness and how I (and a good friend) solved some of the wiring challenges, mainly with getting battery power to the relays.

Ok, so now I'm gonna be on the hunt for an E32 Parts car/ Part out. I read where you said be careful of the ECU I get from an E32. What years E32's carry the 179 ECU's? Also, what if I have trouble finding an E32 Parts Car/Part Out, do you recommend me going with an E34?

I currently have an Automatic Transmission but, in the future I may "consider" doing a 5 speed swap if I can find an E23 parts car with a 5 speed manual . Thanks for your help!

[pennybond]

Jay my question to them was if they had a chip for an M30B34 running Motronic 1.3. If you follow their link it takes you to the B34 chips where you can customize the chip by inputting the ECU you are running, injector flow rate, fuel rating you plan to use and stage you want.

[Hit Man X]

I still say 059 it and get on with motoring. Hell, do this in the interim. Those harnesses are cheap, common, and drop right in.

Only way I would do the 1.3 is if I planned a B35 swap or 10:1 B34.

[mpvibes]

I still say 059 it and get on with motoring. Hell, do this in the interim. Those harnesses are cheap, common, and drop right in.

Only way I would do the 1.3 is if I planned a B35 swap or 10:1 B34.

Hey Hit Man X, I may consider this if I have trouble finding the parts for the motronic 1.3 upgrade.

Even if I 059 it I will still have to get a wire harness for an 85 735i along with all the components like IACV, AFM, Fuel Pressure Regulator, injectors, etc. Correct?

I saw on ebay complete E23 735i wire harnesses are going for $240. Can I use a wire harness from 84-87 for an E23 735i if I have an 85? I haven't checked any other places yet.

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[Jay535is]

You are correct, because you have the B32 system installed, you will have to replace just about everything EITHER WAY-Harness, AFM, ECU, ICV, Injectors, O2 sensor, etc.
If SSquid has a tune for the 8:1 motor on motronic 1.3 (179 ECU) I'd say long term the 1.3 upgrade is the only way to fly.
But here is where your lack of compression works in your favor even without the aftermarket chip: Since the 179 fuel maps are tuned for a 9:1 compression ratio, it will not introduce as much timing advance-which is where ping or pre-detonation comes from (A big problem that I have had to deal with on my 10:1 motor). So you won't have to struggle with ping as I do, but it may feel a little lazy since it won't be using as much timing advance as it could if the fuel/air tables in the ECU were optimized for your US 8:1 motor.
Hope that makes sense...

Hey Hit Man X, I may consider this if I have trouble finding the parts for the motronic 1.3 upgrade.

Even if I 059 it I will still have to get a wire harness for an 85 735i along with all the components like IACV, AFM, Fuel Pressure Regulator, injectors, etc. Correct?

I saw on ebay complete E23 735i wire harnesses are going for $240. Can I use a wire harness from 84-87 for an E23 735i if I have an 85? I haven't checked any other places yet.

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[mpvibes]

You are correct, because you have the B32 system installed, you will have to replace just about everything EITHER WAY-Harness, AFM, ECU, ICV, Injectors, O2 sensor, etc.
If SSquid has a tune for the 8:1 motor on motronic 1.3 (179 ECU) I'd say long term the 1.3 upgrade is the only way to fly.
But here is where your lack of compression works in your favor even without the aftermarket chip: Since the 179 fuel maps are tuned for a 9:1 compression ratio, it will not introduce as much timing advance-which is where ping or pre-detonation comes from (A big problem that I have had to deal with on my 10:1 motor). So you won't have to struggle with ping as I do, but it may feel a little lazy since it won't be using as much timing advance as it could if the fuel/air tables in the ECU were optimized for your US 8:1 motor.
Hope that makes sense...

Thank you for helping me understand better. Yes, that makes sense.

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