M30B35 - What's this connector/cable?

[grr]

Jeff:

3. Seems like an automatic engine harness.
4. It's only the oil level plug thats been cut off. Three blue cables.
5. Correct.
6. Yes, it's a E28 535i manual gear box on it. There's been done some work either to shorten or lengthen the axle. This was done before I bought "the project".

I've already got an E34 engine laying around, with a complete drivetrain and front and back axle.. it's the backup plan. But i'd prefer to get this E28 engine running, because the E34 engine was originally bought to convert the 520i to a 535ia.

Why would the E28-engined E34 end up underpowered?

[genphreak]

6. Yes, it's a E28 535i manual gear box on it. There's been done some work either to shorten or lengthen the axle. This was done before I bought "the project".

> Don't you mean drive shaft? Be sure to check its length with an expert- they do not have any room for mistakes, if it was not calculated perfectly you might hit a bump and lose everything including your rear passengers

I've already got an E34 engine laying around, with a complete drivetrain and front and back axle.. it's the backup plan. But I'd prefer to get this E28 engine running, because the E34 engine was originally bought to convert the 520i to a 535ia. Why would the E28-engined E34 end up underpowered?

A: Different cam, injectors, chip and throttle body, AFM spring, exhaust- on the e34 a lot of this was changed to improve torque so it would shift the extra bulk of the e34. Injectors, cam and chip were upsized to maintain highway performance (ie ensure it still managed the same 220kph speed) and as close as possible 0-100 times without destroying economy (which did increase a bit).

You might check to make sure the compression may have changed a tad too, perhaps the pistons and head were a little different. I know some e28 535s (M30B35) were fitted with slightly smaller valves (on one side), though this makes practically no difference- it was probably due to a parts/supplier tweak or change. The main thing is pistons and head- I suspect the chambers in the M30B34 head are the same as the M30B35 let alone there be any differences in the M30B35 production.

With your e28 motor you will find that your economy may well be marginally better in some cases, but probably not in stop-start driving. I doubt the performance will be as well rounded as a real e34 setup. Should I be wrong and the engine be essentially the same, dumping the AFM (or changing its spring), an e34 cam and ECU might fix things somewhat. Is your ECU Motronic 1.3? Check its part number online to find out if you are unsure. I don't know if you can run 1.1 with a e34 cam or vice versa, even if you are using the correct eeprom chip for the cam. I suspect 1.1 chips mean e28 cam and 1.3 require an e34 cam. Perhaps you would be better off changing out the ECU to a MegaSquirt since you already have the wiring headaches happening over there. Best of luck Nick

[Jeff N.]

... which I'm familiar with, the M30B35 engine (E34) vs. the M30B34 engine (E28) had a significant power difference. The B35 motor is rated at like 205HP , 215 ft/lbs torque. The B34 motor was about 180HP and 180 torque. (all from memory). Physical diffs include compression ratios, intake port size, intake valve size, cam, and ECU.

You mentioned you had a M535 engine and seem to be non-US. Is it a eurospec engine? If so, I believe the power will be similiar to the US spec B35.

Jeff:

3. Seems like an automatic engine harness.
4. It's only the oil level plug thats been cut off. Three blue cables.
5. Correct.
6. Yes, it's a E28 535i manual gear box on it. There's been done some work either to shorten or lengthen the axle. This was done before I bought "the project".

I've already got an E34 engine laying around, with a complete drivetrain and front and back axle.. it's the backup plan. But i'd prefer to get this E28 engine running, because the E34 engine was originally bought to convert the 520i to a 535ia.

Why would the E28-engined E34 end up underpowered?

[Paul in NZ]

He is in Noeway according to his profile so Euro engine.Dont know if he means M535 which the e28 did come in or just a cooking manual 535

[Scott H]

but I guess my point was that on an untouched wiring harness, there is no way that should hook up to the TPS.......each connector is unique.

It's definitely a three pin. And the picture is NOT from the E28 engine. It's from a working '89 E34 535i engine. If you don't have a three pin there, there might be differences from year to year, or differences between EU and US models.

[grr]

... which I'm familiar with, the M30B35 engine (E34) vs. the M30B34 engine (E28) had a significant power difference. The B35 motor is rated at like 205HP , 215 ft/lbs torque. The B34 motor was about 180HP and 180 torque. (all from memory). Physical diffs include compression ratios, intake port size, intake valve size, cam, and ECU.

You mentioned you had a M535 engine and seem to be non-US. Is it a eurospec engine? If so, I believe the power will be similiar to the US spec B35.

It's all euro over here.

The E28 M535i(A) has 218hp, and the E34 535i has 211hp, both with 300-320Nm. I'm guessing the 7hp difference is mostly because of the catalyzer on the E34, so the engines are probably pretty much the same allthough I think the E28 engine has somewhat higher compression than the one from the E34. They're both 3430ccms. The E28 also had an older version of Motronic, but with the E34 sensors and the E34 wiring harness I'm hoping it's all good..

[grr]

Woohoo! It's alive!

It dies on idle and the timing is "a bit" off, but it starts and runs fine otherwise. Looks good!

[genphreak]

Woohoo! It's alive! It dies on idle and the timing is "a bit" off, but it starts and runs fine otherwise. Looks good!

Great news dude, check your o2 sensor is working properly, I think more or less any e32/e28/e34 sensor will do. After that, its simply a matter of making sure your Fuel pressure is regulated properly and the ECU is getting the temp feed right. I had a problem with my old euro e28 with conking out- BMW changed the brake bomb (accumulator) and that fixed it. The vacuum was being loist through it... so be sure to check all the vitals before doing too much, its easier to work back from something solid. keep us updated now... Nick

[grr]

I got the idle sorted out when I got the sensor on the pulley in the correct position, but the rough idle is still a problem. There's a new thread about it. Thanks for good advices!