BMW M20 B25 initail startup

[panzertank]

Hey all... I have my harness made and am attempting first startup...however no catch... maybe some of you experienced dudes can look at my MSQ and datalog and give me any feedback... I have 1990 bmw m20b25 powered e34 with motronic 1.3 I crank and no ignition? any advice is welcomed .. thx ... it is a stock NA motor... using single coil with stock dizzy......I have TPS wired in and wideband oxy.... but I'm not really worried about the OXY untill i get that first startup.

James

[elutionsdesign]

Set your fixed advance to 10 and check that while cranking (have someone hold the accelerator to the floor so no fuel is injected) your timing is close to 10 BTDC. It's trying to start, you've got rpm and it is attempting to spray fuel. Also raise your cranking rpm to 300 or 400, that is the threshold where below it's "cranking" and the cranking settings are in play and above it's "running". You don't want to cross it while cranking.

Curious where in the world you are, the IAT and CLT values are from 95-105 F. Is that correct or close?

[panzertank]

Thx for the reply .... I'm in LA ... Those numbers are high. Usually it is around 70-80 deg f. Im surprised because I set the thermistor calibration In tunerstudio......I'll have to check why they are off.... However I don't think that's keeping me from startup....... So you're suggesting I set my MS3 to fixed timing of 10 degrees and check the engine with a timing light? The timing marks are really hard to check due to their location on the engine..... If it was pretty close don't you think I would hear some sort of catching? Thanks again for taking the time to scope out my MSQ. ......

~James

[jsmcortina]

Yes, you really DO need to confirm your timing. Guessing a great way to damage your engine!

It is covered in the "Setting Up" manual.

James

[panzertank]

Using settings from others with the exact same motor isn't good enough?
Also MAP only dropped about 2-3 Kpa on cranking.... I would think the canking vacuum would be higher....
Is this normal

~James

[grom_e30]

M20 engines only have a tdc mark so set the fixed timing to zero sorted.

[panzertank]

grome30 .. have you used a timing light on your m20? and advice on a good way to do it? I don't know how I'm going to see the "OT" mark with the radiator in....shy of pumping the coolant outside from some other pump and removing the radiator and fan shroud I don't see how I can get a timing light and my big dome in there.....that's why I didn't do that in the first place..

~James.

[elutionsdesign]

You have to verify timing, it's like the first critical step in tuning. Without that everything else you do will be worthless.

[grom_e30]

on an e30 its fairly easy to see, use white out (tipex) on the ot mark and the refrence mark on the timing cover, set fixed timing to zero and point the gun should be easy to see if they line up, maybe remove the fan for a bit more space. depending on how your sensor is wired and what edge you are using eg rising or falling your tooth1 will be either 84 or 88 iirc.

[panzertank]

I'm starting to get the vibe that I need to get a timing light.. harbor fright...you're my only friend. Will report back with more questions undoubtedly...
Thx Dudes

~James

[grom_e30]

You will be best off with the cheap non dial back type guns.

[panzertank]

got my hands on an old snap on light gun... it has advance settings .. I'll jut set it to 0 and set the megasquirt timing to fixed 0 .. it says cranking advance of 10 ... I guess I'll change that to zero too? right... off I go into the garage to try it out.. thanks for all your help everybody...especially Grom e30 ...
~James

[panzertank]

Tested timing with stock motronic 1.3 computer..which runs good.... I used the whiteout mark on the OT which worked great thx grom e30.... I had an adjustable timing light.. I had to adjust it to 45 degrees advance to see the OT marks on the lower timing cover and the toothed crank wheel align on the stock computer at 1/4 temp startup.. I do have a Jim Conforti chip which I believe advances spark across the whole table.. I don't know if this is too much it seems like a lot.. I did also notice when I was running MegaSquirt it was not firing the plugs and thus would not actuate the timing light....so I will check my coil wiring and settings and take it from there..my megasquirt wire 36 on the V3.57 board connector is wired to motronic 1.3 pin 1 which is coil ign timing neg according to a diagram I have ... I double checked this...... so now I need to figure out why I don't have spark.

also here are my current msq and datalog on startup. if anyone wants to hassle....

[grom_e30]

is the ecu set up internally for a spark out put?

[panzertank]

Yep JS10 ... I believe that fires the coil on pin 36 ..

[grom_e30]

do you get sparks in test mode?

[panzertank]

Haven't tried test mode... I'll try it after work today

~James

[panzertank]

Fuel and Spark won't work in test mode... I'll need to recheck wiring...

~james

[grom_e30]

how are you coil and injectors wired up?

[panzertank]

injector bank 1 is connected like this (inj 1,3,5)
motronic pin 16 to MS 32 and 33
injector bank 2 is connected like this (inj 2,4,6)
motronic pin 17 to MS 33 and 34

IGN coil is motronic pin 1 to megasquirt pin 36

however the motronic pinout says motronic 36 and 37 are the main relay power on key.. .
but I originaly wired it like that and those pins had plus 12 all the time

http://www.325ix.com/megasquirt/2007/07 ... squirt.png

I went by this pinout motronic to MS... I have seen it in many places.. but now i am doubting it..

~jamers