Megasquirt ON BMW m52 Engine

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billr
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Re: Megasquirt ON BMW m52 Engine

Post by billr »

It's been a while now, have you figured out how to get a good trigger log; do you have sync?
maxo-tt1
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Re: Megasquirt ON BMW m52 Engine

Post by maxo-tt1 »

billr wrote:It's been a while now, have you figured out how to get a good trigger log; do you have sync?
i tried many times, but nothing shows trigger log... empty black window... only compsite logger works(log on previous page)...

when i try to start engine, it writes synced,cranked and something else in green(p.s no errors in red), but engine not starts...

i think i've done wiring wrong, because its siemens one...

i gonna try on bosch 3.3.1 tomorrow

only thing i worry about is ms3 37 pin... :RTFM:
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Re: Megasquirt ON BMW m52 Engine

Post by jsmcortina »

maxo-tt1 wrote:thats all i got from diagnostics today....
There's no cam signal in that log and the crank signal is very sporadic.

James
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protomor
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Re: Megasquirt ON BMW m52 Engine

Post by protomor »

They both go to pin 85 on the same relay... I don't see why not. I'd trace the wires to be sure though.
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maxo-tt1
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Re: Megasquirt ON BMW m52 Engine

Post by maxo-tt1 »

so, today i've tried installing ms on my friends car. m50b25TU with bosch 3.3.1(aka 413) wiring... (works perfect with stock ecu)

but i got problems with start circuit. the transistor gets too hot and about 2Volt comes on motronic pin 54 (ms3 power)

at first we've connected the ecu, there was 12V on 54 pin, then when we tried starting the engine, suddenly power has lost

then i've replaced the transistor with new one, but the same again...

start circuit done exactly like this http://www.msextra.com/forums/download/ ... p?id=21430

any idea? :(


after all that, i've connected ms3 28 pin directly to ignition 12V. no power lost, but engine not starts again...

there is all logs i;ve got today


please look at it people :(((
protomor
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Re: Megasquirt ON BMW m52 Engine

Post by protomor »

I'm going to prefix this with "I don't get what you are trying to do"

I don't get why you have a all that jumbo stuff on the ground side of the main relay. Aren't you just trying to power stuff?
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maxo-tt1
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Re: Megasquirt ON BMW m52 Engine

Post by maxo-tt1 »

protomor wrote:I'm going to prefix this with "I don't get what you are trying to do"
wiring diagram is done for 3.3.1... so i'm trying on 3.3.1, if everything goes ok, i'll change harness on my car as well
protomor wrote: I don't get why you have a all that jumbo stuff on the ground side of the main relay. Aren't you just trying to power stuff?
sry, what do you mean?
billr
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Re: Megasquirt ON BMW m52 Engine

Post by billr »

That's to "invert" the +12V signal from the ignition switch; make it into a ground for the main relay. Is it the 2N2222 tha is getting hot? Lower the 7.5K in the base circuit, the 2N2222 may not be turning all the way on.
protomor
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Re: Megasquirt ON BMW m52 Engine

Post by protomor »

billr wrote:That's to "invert" the +12V signal from the ignition switch; make it into a ground for the main relay. Is it the 2N2222 tha is getting hot? Lower the 7.5K in the base circuit, the 2N2222 may not be turning all the way on.
But why....

I apologize for n00bnews
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billr
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Re: Megasquirt ON BMW m52 Engine

Post by billr »

Are you asking why the 2N2222 may not be turning full-on, or why the signal needs to be inverted?
protomor
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Re: Megasquirt ON BMW m52 Engine

Post by protomor »

No I'm being more primitive than that. What's the point of the circuit?
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hoveringuy
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Re: Megasquirt ON BMW m52 Engine

Post by hoveringuy »

protomor wrote:No I'm being more primitive than that. What's the point of the circuit?
Point of the circuit is that the main BMW relay needs a ground to close, providing the amps to power the MS. The key IGN circuit is not meant to power anything. Circuit takes power from the IGN and converts it to the ground necessary to trip the main relay, which can source the necessary amps.

What's happening on this circuit is that when you engage the starter voltage is dropping which brings the resistor out of saturation. Lower the resistance as suggested.
protomor
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Re: Megasquirt ON BMW m52 Engine

Post by protomor »

My experience was that the stock ign signal was the power side and the ground side simply went to the ground. I should double check my wiring schematics on my spare harness.
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billr
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Re: Megasquirt ON BMW m52 Engine

Post by billr »

In the pre-electronics days almost everything was wired like you say. It was pretty handy, just one wire out to a device and use the chassis for return "wire". Now, most cars (like this apparently) are opposite.
protomor
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Re: Megasquirt ON BMW m52 Engine

Post by protomor »

soooo why not mod the stock harness to do it the easy old way? :)
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billr
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Re: Megasquirt ON BMW m52 Engine

Post by billr »

The relay shown being used is "pre-wired" internally the new way, so that would have to change as well as harnessing. One big advantage to the "new way" is that expensive driver devices, like ECMs, are connecting the driven device to ground. So, if you are fiddling with something that is powered on, and accidently short wiring to chassis ground, you won't fry the (expensive) driver...that is also handy! It wasn't important before the electronics were involved, as you would generally just blow a fuse, at worst.
maxo-tt1
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Re: Megasquirt ON BMW m52 Engine

Post by maxo-tt1 »

billr wrote:That's to "invert" the +12V signal from the ignition switch; make it into a ground for the main relay. Is it the 2N2222 tha is getting hot? Lower the 7.5K in the base circuit, the 2N2222 may not be turning all the way on.
yes, its 2n2222
billr wrote:Lower the 7.5K
can you please tell me exactly which one i need(ohms and watts)? i'm not good at electronics
billr
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Re: Megasquirt ON BMW m52 Engine

Post by billr »

Try 2.7K, 1/10W or more. I would need to know the relay coil resistance to be sure.
maxo-tt1
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Re: Megasquirt ON BMW m52 Engine

Post by maxo-tt1 »

billr wrote:Try 2.7K, 1/10W or more. I would need to know the relay coil resistance to be sure.
i've tried today 3K 1/8W but the same :( as i try to start engine, ecu losts power. on pin 54 comes ~2V



seems today the transistor was hotter then 2 days ago...

:cry:
billr
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Re: Megasquirt ON BMW m52 Engine

Post by billr »

Referring to the schematic you linked to recently, showing the 2N2222...

Voltage at 54 drops to 2V, right? Measure voltages on 30, 85, 86, and 87A of the ECU relay, and voltage on the 2N2222 collector. Also measure resistance of the ECM relay coil. It would help to verify the current in the collector circuit, to make sure it is only handling the coil current. It really sounds like a wiring problem, not the triggering of that ECM relay.

Edit: You could also try by-passing that 2N2222, just short the collector to ground. However, if there is some kind of a wiring problem that may fry a wire instead of just heating the transistor. Be careful, observant, and quick.
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