MyE28.com DEV

I'm posting this query here for it's one of the only places where the m30 e34s can find info and show love due to the fact we share the same engine.

I figured I'd post this query for anyone running Megasquirt or those having extensive knowledge on the electrical systems in the e34 m30b35.

I've run through all the electrical schematics. I have a good idea of what the issue is. I'm just not clear if my remedy would have a adverse effect on the car.

I will try to explain as detailed as possible.

On the e34 179 ECU wiring harness we have pin 37 which is supposed to be a switched 12v line from the main relay. That power lead splits before it connects to the ecu and goes to the AEGS.

Now in my car I currently have a dinan chipped 179. I'm installing a 55 pin MS unit.

When I put the MS unit in it didn't turn on. Everything checked out fine with the Megasquirt unit via stim.

I checked the pins on the ecu harness and Pin 37 is dead.

Here's the punchline... the car runs fine with the chipped 179 ecu and dead 37pin.

I traced the power back to the relay and I'm getting juice from the relay (red/blue line off relay) but not on the ECU harness.

So I'm guessing that there is a splice issue as the line heads toward the AEGS.

So boys and girls here's my question.

Being my car is a 5 spd manual and not a auto. I'm guessing the AEGS is only for automatic applications.(of course this can be wrong)

Should I go ahead tap the red/blue line off the main relay and run another line to the pin 37 line bypassing the AEGS or just dig and find the junction where it seems to have failed.


Thanks in advance.

Should I go ahead tap the red/blue line off the main relay and run another line to the pin 37 line bypassing the AEGS

that's what I'd do, your gonna love megasquirt
marc

marc79euro645 wrote:

Should I go ahead tap the red/blue line off the main relay and run another line to the pin 37 line bypassing the AEGS

that's what I'd do, your gonna love megasquirt
marc

Thank you marc.

I did tap the line and the power's back to the pin. YESS!!!

But it must have been covering for something else for it's still not coming online.

So now I'm troubled. It's coming online while using the stim. But not in the car.

Some more background on the unit...

It is a goatthumper build. It has the 3.0v PCB.
It's MS1/extra (planning to upgrade to ms2 as soon as I can find this bug)

I have a Glens Garage 3 wire idle board

It's modded for boost

I changed out the serial for the DLR RXTX usb upgrade.

I did the coil transister swap for the upgraded one.

Again it fires right up on the stim. No problem.

The car... another story.

I want to get the car up, running and boosted for my trip down to GA on 5/5.

So any and all help is appreciated.

Hands on help can be paid in Beer, BBQ, and gas money next saturday

so when you power on the key the first led should blink indicating power on, as you crank this led should flicker indicating pulse from the vr sender, then mega squirt should pulse injectors (a noid light helps here).
you getting any of these?
also check power to coil & injectors
marc

marc79euro645 wrote:so when you power on the key the first led should blink indicating power on, as you crank this led should flicker indicating pulse from the vr sender, then mega squirt should pulse injectors (a noid light helps here).
you getting any of these?
also check power to coil & injectors
marc

Negative. None of the LEDs are lit. As well when in start position it's not connecting to tunerstudio. Gas is going to the injectors as if in default mode. So when MS is removed and the stock ecu is reinstalled it takes a few cranks to get it back up and running (system is flooded gas fumes are present).

Now when powered via stim I get a one quick blinking led on the stim then it goes out. No LEDs on the MS unit. With this the MS will connect to tunerstudio and I am able to go through most of the functions except rpm (which iirc can't be done anyway)


I used a multimeter and check various points on the MS unit to see if it was getting juice while installed in the car. Power is flowing through it. Just no recognition via tunerstudio.

MonsterCntye34 wrote: I used a multimeter and check various points on the MS unit to see if it was getting juice while installed in the car. Power is flowing through it. Just no recognition via tunerstudio.

So you get 12v on the left leg of U5, 0v on the center, and 5v on the right leg?

So just to be clear, you're using the same computer with usb plugged into the same port,when switching from stim to car?
Try setting prime pulse to zero on stim to prevent flooding.
marc

Xenocide wrote:

MonsterCntye34 wrote: I used a multimeter and check various points on the MS unit to see if it was getting juice while installed in the car. Power is flowing through it. Just no recognition via tunerstudio.

So you get 12v on the left leg of U5, 0v on the center, and 5v on the right leg?

Yes.But I will double check.

marc79euro645 wrote:So just to be clear, you're using the same computer with usb plugged into the same port,when switching from stim to car?
Try setting prime pulse to zero on stim to prevent flooding.
marc

Correct. Same laptop. DLR-TXRX is reads as port 6. Port hasn't changed. On stim power it connects. On the car, MS doesn't connect and feeds fuel. Will take a second look and make sure prime is set to 0

You have verified 12v to the MS? Where do you have the grounds hooked up?

Now when powered via stim I get a one quick blinking led on the stim then it goes out. No LEDs on the MS unit.

This doesn't sound right to me. Did you build this unit? I think I would go back to the megamanual and trouble shoot the ms unit.
also, concerning flooding. I've read somewhere on ms forums about injector test mode not disengaging, just something to check.
marc

marc79euro645 wrote:

Now when powered via stim I get a one quick blinking led on the stim then it goes out. No LEDs on the MS unit.

This doesn't sound right to me. Did you build this unit? I think I would go back to the megamanual and trouble shoot the ms unit.
also, concerning flooding. I've read somewhere on ms forums about injector test mode not disengaging, just something to check.
marc

Here's what I got so far fellas.
I have the unit in front of me on the stim.

U5 has 12v on left leg (voltage is actually 15.6), 0 on center leg and 5v on right leg

I went back and checked the prime pulse here's what I have...
Prime pulse is as follows " Prime pulse>0"
Fire prime pulse is set on " Power up"
Standard Prime @ 0.4 (can't change the value)
Cranking pulse widths temps "CLT only"


pulse widths

-40 f @ 18.1
-20 f @ 12.1
0 f @ 8.1
20 f @ 6.1
40 f @ 5.6
60 f @ 5.1
80 f @ 4.6
100 f @ 4.1
130 f @ 3.6
160 f @ 3.1

Light on stim is the pump LED. It comes on then goes out.

LEDs for IG, I2, I1, and IDL are not lit.

No I didn't build it. Bought from a member here and had to rebuild it due to a failure with tps and not getting the full ADC current.
Once TPS problem was resolved. Other problems popped up which were the U5, U6, C16,C17, & D19.

once I replaced these pieces it fired up on the stim.

Reflashed code.

Reset the IAT and CLT sensors...

And I think I found the power culprit.

The relay circuit in the proto area.

Crossing my fingers and going in.

Will update tuesday.

fixed relay circuit.
Stim and MS still have no LEDS on.
Going to install wednesday to verify if relay circuit was the power up issue the car.

It's alive!!!!!"

Thanks guys.

Any idea what the problem was? I'm curious. 15 volts is a bit high for battery voltage. The LM regulator can take it, but some other parts may not. Your windows must roll up pretty damned quick

Xenocide wrote:Any idea what the problem was? I'm curious. 15 volts is a bit high for battery voltage. The LM regulator can take it, but some other parts may not. Your windows must roll up pretty damned quick

Lol no the ac plug which is connected to the stim was shooting out 15 volts which in turn shot 15v through the MS and Stim.

Turns out that the transistor for the relay switch in the proto area was bad. It was the only part which didn't receiving power through the stim and wouldn't receive power in the car.
(Which was why the MS worked on the stim and not in the car)
I'm not saying this was the correct solution. But it's working.

U5 was fine. All the wiring was correct via ryan's build and Brad's writeup.

The only difference I've seen in both write ups are the tach out pin. Ryan has pin 25 and brad wrote 31. I chaulked it up to being due to 2 different chassis. Hopefully that was a good guess.

I got it to fire up and it's communicating but I am holding off setting it up and tuning it till some minor maintenance is finished.

MonsterCntye34 wrote:U5 was fine. All the wiring was correct via ryan's build and Brad's writeup.

I was more concerned about the wiring to U5 than U5 itself (though it'll be pouring some heat into the heatsink at 15v). Not quite sure what relay in the proto area you're talking about, but whatever the case I'm glad you got it sorted. Also good call on getting the rest of the maintenance done before tuning. Good luck!

Xenocide wrote:

MonsterCntye34 wrote:U5 was fine. All the wiring was correct via ryan's build and Brad's writeup.

I was more concerned about the wiring to U5 than U5 itself (though it'll be pouring some heat into the heatsink at 15v). Not quite sure what relay in the proto area you're talking about, but whatever the case I'm glad you got it sorted. Also good call on getting the rest of the maintenance done before tuning. Good luck!

This was the culpritin ryan's setup:

When you combine the grounds from the 55 pin, place 2 more wires in the bundle. One is for Glens board and the other is for the Main relay circuit.

-Pin 18 and 36 also go to the relay control circuit. They will be loose from the rest. These three wire will connect to a 2n2222 transistor to activate the main relay.





-The emitter connects to the ground wire
-Th base connects to pin 27 with a 7.5k ohm resistor in line
-The Collector connects to pin 36
-Solder the 1n4001 (D1) diode from MS (that was not used because we didn't install the hall circuit) across Pin 18 and 36 with the banded end towards 18

The 2n2222 transistor was bad.

"I see," said the blind man. Good stuff, at least the quad 2s are cheap and available. Hell, they may even still stock em at radioshack

Xenocide wrote:"I see," said the blind man. Good stuff, at least the quad 2s are cheap and available. Hell, they may even still stock em at radioshack

Yep they are. I actually lucked out and got a couple bags of unused Megasquirt components from a friend for free. So my overhaul hasn't been too tramatic.Just frustrating. However I've learned a ton.

Now (hopefully) I just need to install the new center bearing, tune
and there shall be boost.