I asked this q in another thread, but y'all probably lost interest before you got that far.
Is it possible to upgrade an early Motronic car (82-84 533) to the post '84 ECU, or even to 1.1, without swapping the complete harness? For example, can I swap the ECU and injectors from an 85 car? And is 1.1 better, worse or not significantly different than 1.0?
Why? Looking to open up performance options. My car has early Motronic from a 533 with low resistance injectors. I have a remapped ECU from Jet, but I can't chip at will -- the ECU has to be sent in for programming. I also am limited in that I can't just throw in high resistance injectors, so upping fuel delivery is tough and the costs are higher.
Used 535 ECU's are cheap. If I have to swap the harness I can, it's not that much work. That would require swapping to a 3 wire ICV and the later ICM I assume.
Tony
Motronic meandering
I don't know too much about the early e28 fuel system, just that the injectors are like the L-Jet injectors (and M5 & eta injectors) and the idle is controlled by a separate box. I don't think the ECU plug on the harness is the same either, but I could be wrong. The pin count is lower on the ECU plug on the earlier system if I recall correctly.
That alone would tell me that the answer to your overall question is no.
If I were doing this swap; I'd go for the complete late e28 wiring harness and equipment. That solves several issues and makes servicing the entire system easier should you sell the car to another enthusiast, or for those times you want to ask a question without going through the full description of a bastardized system and why it's that way, everytime.
That alone would tell me that the answer to your overall question is no.
If I were doing this swap; I'd go for the complete late e28 wiring harness and equipment. That solves several issues and makes servicing the entire system easier should you sell the car to another enthusiast, or for those times you want to ask a question without going through the full description of a bastardized system and why it's that way, everytime.
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Velocewest
- Posts: 1558
- Joined: Feb 12, 2006 12:00 PM
- Location: UK
[QUOTE="fastpat"]If I were doing this swap; I'd go for the complete late e28 wiring harness and equipment. That solves several issues and makes servicing the entire system easier should you sell the car to another enthusiast, or for those times you want to ask a question without going through the full description of a bastardized system and why it's that way, everytime.[/QUOTE]
Oh sure, be sensible... :p I think you're right. There's an '86 harness at the U-Pull-It, think I'll grab it. There's enough bastardization all ready in the merged e12/Motronic wiring.
[Edit by Velocewest on [TIME]1108496578[/TIME]]
Oh sure, be sensible... :p I think you're right. There's an '86 harness at the U-Pull-It, think I'll grab it. There's enough bastardization all ready in the merged e12/Motronic wiring.
[Edit by Velocewest on [TIME]1108496578[/TIME]]
[QUOTE="Velocewest"]Is it possible to upgrade an early Motronic car (82-84 533) to the post '84 ECU, or even to 1.1, without swapping the complete harness? For example, can I swap the ECU and injectors from an 85 car? And is 1.1 better, worse or not significantly different than 1.0?
Tony[/QUOTE]
Tony,
I know on the M20 version of those harnesses and ECUS, there is a little bit of a difference.
The pre-85 ECU can be swapped directly with the post-84 one. No problem. I know this is a 528e-only, thing, though.
The Motronic 1.0 on all pre-88 528e's runs low impedance injectors similar to the 533i and M5. It also has an ICM (Idle control module located next to the ECU in the glove box, usually either green or black), an ICV, and a cold start valve.
The Motronic 1.1 on the '88 528e Super Eta runs high impedance injectors similar to pretty much every BMW after that year: E30 325i, E28/E34 535i, etc. It also has no cold start valve, IIRC, and it has no ICM. I'm reasonably sure it has an ICV but the ECU controls it, but I could be wrong on that, too.
Therefore, on the eta, at least, you have to get the plug for the CSV location, get different injectors, and all kinds of different stuff. It seems like it wouldn't be a problem if you had the engine out, but if you were just gonna convert over for the heck of it, it's going to be a little bit more of a pain than just a standard harness swap.
The main thing, IMO, is the injectors. The 533i harness runs low impedance injectors. You'll need to get high impedance injectors (535i, Mustang, etc) if you swap harnesses and ECUs.
HTH,
Tony[/QUOTE]
Tony,
I know on the M20 version of those harnesses and ECUS, there is a little bit of a difference.
The pre-85 ECU can be swapped directly with the post-84 one. No problem. I know this is a 528e-only, thing, though.
The Motronic 1.0 on all pre-88 528e's runs low impedance injectors similar to the 533i and M5. It also has an ICM (Idle control module located next to the ECU in the glove box, usually either green or black), an ICV, and a cold start valve.
The Motronic 1.1 on the '88 528e Super Eta runs high impedance injectors similar to pretty much every BMW after that year: E30 325i, E28/E34 535i, etc. It also has no cold start valve, IIRC, and it has no ICM. I'm reasonably sure it has an ICV but the ECU controls it, but I could be wrong on that, too.
Therefore, on the eta, at least, you have to get the plug for the CSV location, get different injectors, and all kinds of different stuff. It seems like it wouldn't be a problem if you had the engine out, but if you were just gonna convert over for the heck of it, it's going to be a little bit more of a pain than just a standard harness swap.
The main thing, IMO, is the injectors. The 533i harness runs low impedance injectors. You'll need to get high impedance injectors (535i, Mustang, etc) if you swap harnesses and ECUs.
HTH,