Motronic 1.3 upgrade question (edited)

Garrett

Garrett

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Has anyone done a Motronic 1.3 upgrade? This is stretching my normal range, but with the best will and perhaps a little direction from this community, I'm hopeful for a happy ending.

I'm converting from Motronic 1.0 on a 1989 E24 motor with L-Jet intake. This weekend I stripped the ECU, harness and associated bits from a 1989 535i.

My specific questions are:

1) Is the harness long enough. The 535 ecu was in the engine bay. Mine's in the glove box. Looked like it would reach
2) Do I need anything past the driver side diagnostic port/engine harness connectors? Post connections, the harness looked like it went into the driver side fuse/relay box and forward toward the ABS module, and ultimately into the radiator. I'm assuming this is all for modern paraphanelia that doesn't apply to an E9.
3) There were two connectors under the intake, next to the starter, that I couldn't ID. One may be for the evaporative purge valve (per Bentley). The other was a collar type connector that led to another harness, possibly heading off to the trans. Will I be using these, and do I need to go back and get what they were attached to?
4) Wondering if I missed anything. I grabbed the 179 ECU, harness, ICV, TPS, coil, temp sensors, rpm/crank reference sensor & harness, toothed timing wheel, cylinder 6 firing sensor. I already have airbox, 027 AFM, throttle body, correct injectors, relays, etc. in my Motronic 1.0 setup.

I need to head back to the junk yard and grab anything else I need this Sunday, hopefully from the same car.

I would be grateful for any advice.

Garrett
 
Garrett,

Currently I am in the process of doing the same and I think I can answer some of your questions.
1) I pulled the harness from a 90 735i where the ECU was located in the engine compartment as well; right hand side against the firewall which I assume is the same location for the 535i. The harness is long enough but just. How are you running the connector through the firewall? I spent about three hours de-pinning the connector (major PIA) to run the wires through and now have to re-assemble it. I drilled a 1 7/8 hole in the fire wall and installed a rubber grommet. I’m gong to slip some over-braiding over the harness before I re-pin the connector. I should get that done this weekend.

2) Do I need anything past the driver side diagnostic port/engine harness connectors?
Pin 38 goes to the ABS Antitheft input and you don’t need it.
I kept several wires in the harness that I might use: Engine speed output (pin 6), Diagnostic line TXD (pin 55), Diagnostic line RXD (pin 13), Compressor on input (pin 40), A/C input (pin 41), Programming voltage (pin 37), Programming voltage (pin 39), Fuel pump relay control (pin 3), Main relay control (pin 36), Fuel rate output (pin 32) and check engine light (pin 15).

3) There were two connectors under the intake, next to the starter, that I couldn't ID.
Pin 5 is for the evaporative purge solenoid and you don’t need it. The other should be Pin 42 which is for the Park/Neutral input and you shouldn’t need it either.

4) Wondering if I missed anything. I grabbed the 179 ECU, harness, ICV, TPS, coil, temp sensors, rpm/crank reference sensor & harness, toothed timing wheel, cylinder 6 firing sensor. I already have airbox, 027 AFM, throttle body, correct injectors, relays, etc. in my Motronic 1.0 setup.
Sounds like you got everything; what injectors are you using and what fuel rail/pressure regulator are you using? Are you using an in-tank fuel pump as well, if so out of what vehicle?

HTH

Scott
 
Scott,

Thanks for the input.

1) Harness terminates in the same location on the 535 donor, so it's reassuring to know it will reach. I already have a big enough whole to get the 1.0 harness connector through the firewall, so the 1.3 should fit. Re-pinning under the dash must be incredibly tedious. What are you using for over-braiding? Same for the loose injector wires?

2) I assume some of these wires carry past the diagnostic port/engine harness connector and therefore I should grab these as well. I should be able to ID them by color.

3) My harness came out of a manual, so there's no Park/Neutral input to be gotten. I'll be on the car again on Sunday and I'll trace the connector a bit further.

4) I'm using the Bosche 19# Mustang injectors, adapted with Carl Nelson's clips to fit the L-Jet fuel rail. The FPR is 3 bar. The in-tank pump was also from Carl, I believe a modified 325i pump.

Garrett
 
Thanks Garrett,

The over braid material is PEEK that I can get from work but I might abandon that idea in lieu of just wrapping the harness with self vulcanizing rubber tape. Re-pinning the connector wasn’t that difficult; the passenger seat was out of the car so I could kneel on the ground from outside the car and reach in. I ohmed out each pin as I installed them and I put together a excel spread sheet with wire colors/gages for the 1.3.

No issues with the injectors and the L-jet manifold? I have installed injectors and I think they will work fine but the fit just doesn’t seem correct. I’ve looked for an L-jet style injector with the impedance to match the 1.3 but haven’t come up with one yet…

Scott
 
Scott,

Thanks for your input.

I can't say whether the injector fit is or isn't the cause of the weak power and slight surge since the installation of Motronic 1.0. I didn't look carefully enough when I installed the injectors regarding fit, but I have received input from the E9 community that supports your concern, and some advice on correcting it which I am in the process of implementing.

It was suggested that unmetered air is finding a way around the poor fit of the injectors. The L-Jet injectors use a fatter, square section o-ring, but they also have a long cap vs. the hat shapped one on the high impedence injectors.

I was advised to swap the L-Jet caps over to my new injectors, then use both the square section L-Jet O-Ring and the new injector's round O-ring to create a good seal.

I haven't worked up the courage yet to destroy the caps on my new injectors, so I'm trying this on some junk yard injectors first.

Hope that helps.

I went back to the pick a part to get the crank/rpm sensor and toothed harmonic balance, but found the head and sensor stripped from the donor car I got my Motronic 1.3 bits from. I don't have anything to lock the crank while I apply torque to remove the crank nut (which I found to be a 36mm, not 32mm as I expected), so I need to find an intact motor. Unfortunately there were no other suitable donors this past weekend.

Is it possible that the collar type connector I was refering to is for the O2 sensor?

Garrett
 
Pictures of Motronic 1.3 ECU mounting in CS?

I'm working on the installation of a M30B35 engine (89 735iL) into my 71 2800CS and I wondered if anyone had any pictures showing their mounting of the ECU and also just where/how they went through the firewall with the wiring harness. Lots of stuff to do and it's really nice to see how others have solved some of the problems.

Thanks,
Sparky
 
Thanks for the ECU under the seat picture. However, I'm using a standard length Motronic 1.3 harness so I think my ECU will have to be in the glove box.

Does anyone have any pictures of their ECU mounted in or around the glovebox. A picture of the engine side of the firewall to show the sealing method would also be great.

Thanks all.
Sparky
 
I few comments to you guys-

Home depot sells a great friction tape to re-do your harness.

Measure your ecu connector and then cut a hole with a dremel to the right of the firewall drain. There is no need to pull pins. Make sure you know where your ac lines are 1st.

The e32 uses a rubber piece for the wiring harness to the ecu box. Re-use it for the firewall on your e9.

The collar style connector is for the 02 sensor.

The harmonic balancer is held on by 8 8mm bolts with about 20lbs of torque each. You are mistaking the crank flange that is held on by that 36mm nut. Take a 3/8" ratchit and a 3" extension with your 13mm socket and pull the toothed dampener and pulley. You may find it easier if you smack the ratchit handle with the flat of your hand to get it started.

The Bosch 206 injectors are 300 bucks new for a set with hose and caps and rubber bushes ready to install. Why bother with used or adapters?

Good luck!
 
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