Did my megasquirt2 die?!

[JehTehsus]

Thanks!! This is great diagnostic info. Will follow the steps you described. I checked for 12v at the post under the engine bay previously but will double check again tonight and cross any potential issues out there.

Take a look at this explanation of the wire route. Interested in this "two pin socket above the glovebox, fitted with a plug and a loop (where the immobiliser should have been connected)" as well. What is the immobiliser? The harness has been manipulated to adjust to the new ECU so maybe there's a break at this two pin socket as well.

*Edit - I'm not sure this site is very accurate. They had pin 26 listed instead of pin 27 and in this attachment pin 20 listed instead of pin 7, as you described.

I don't know a ton about the in-dash wiring. That said, it sounds like it is just talking about how the engine start (i.e. key in run 2, green wire, connects to pin 7 on C101 among other place) also gets routed through the On Board Computer/OBC. The OBC has 'immobilizer' functionality where you need to type in a code to start the engine. It does this by interrupting the ECU start wire (green wire we were just talking about) before it goes to the ECU (which really means routed through C101 and the entire engine harness). So technically if you have entered a code/locked the OBC it would prevent the ECU from ever seeing a start signal.

Here is a ghetto diagram of our items of interest:

(Ignition/Key in position 2) ---> (grn wire) ---> OBC ---> Fuse box (passes through, no connections) ---> C101 connector, pin 7 -----> engine wire harness ----> ECU connector pin 27

So a break/bad connection anywhere in there will prevent the signal from getting to the ECM. If you turn the key on and check at pin 7 on the C101 (car side) for 12V, you can potentially rule out the ignition switch, in dash wiring, OBC etc. all at once and focus on the engine harness and ECM connector. If you do *not* have 12V on pin 7, I would take a close look at whether or not the OBC is locking you out or if you possibly have a bad ignition switch.

[ForcedFirebird]

And just from my memory what is the mysterious "Fusible Link A", by the battery leading directly to the fuel pump relay? The reason I ask being that the fuel pump relay is also energized by main relay pin 87 (same pin which energizes motronic pin 37 as well) so maybe there's something happening there. Just some morning thoughts. I'll have to search for the fusible link A diagram later in the day. The instant death of my car mid-idle is explained (no voltage at pin 27), now must find the cause.

Fusible link goes directly to the main relay. It's function is to have a clean signal directly from 12v+. If that link goes bad, then the main relay will never energize. Easy test: the little 10mm nut with a ring terminal connected to it is the fusible link lead. If you jump that lug to the battery positive, you bypass the fusible link.

[ForcedFirebird]

Thanks!! This is great diagnostic info. Will follow the steps you described. I checked for 12v at the post under the engine bay previously but will double check again tonight and cross any potential issues out there.

Take a look at this explanation of the wire route. Interested in this "two pin socket above the glovebox, fitted with a plug and a loop (where the immobiliser should have been connected)" as well. What is the immobiliser? The harness has been manipulated to adjust to the new ECU so maybe there's a break at this two pin socket as well.

*Edit - I'm not sure this site is very accurate. They had pin 26 listed instead of pin 27 and in this attachment pin 20 listed instead of pin 7, as you described.

Immobilizer is the green lead that goes to the ignition coil. With car equipped with code protection (13 button OBC) then the coil wire get interrupted by the OBC when in protection mode. Leaned that a long time ago when building my first e30 race car. After ripping the dash out, the car wouldn't start and traced the green coil wire and had to reunite it after removing the OBC.

[McGyver]

I think you already covered it, but I figured that I'd recap how (I think) the stock ECU works:
- Always receives power on ECU Pin 18, per sheet 1360-6 (stores codes and such)
- When you turn the key to Start/Run, the ECU gets power in Pin 27, per sheet 1360-4
- Once Pin 27 gets power, the ecu grounds Pin 36
- Once Pin 37 is grounded, the Main Relay powers Pin 37, per sheet 1360-1

Start by checking that you have power at the junction block in the engine bay. Once that's good, move on.

You should have constant 12v going to pins 86 and 30 of the Main Relay. Verify you have power to those pins on the Main Relay as they both should always be powered. (Pull the relay and stick your voltmeter into the female connectors) If you don't have power here, start tracing to wires back to the battery looking for a short.

Once you know you have good power to the Main Relay plug it in and jumper relay pin 85 to ground and check for power at relay pin 87. If no power at 87, your relay is busted. If good, move on.

Go inside the car. Connect ECU Pin 36 to ground and then look for 12v on ECU Pin 37. There aren't any fusible links or loops or anything else between the Main Relay and the ECU plug. If you don't get power inside the car, figure out which wire (power or ground) is busted and fix it.

Once you have power at Pin 37, MegaSquirt should power on. Unless you have a bad ground. So check the grounds that MegaSquirt is using (Power Grounds: Pins 2, 14, 24 & Signal Grounds: Pins 10 & 26)

Good luck!

[E30Bastard]

Good Evening Gents,

I was able to perform the diagnostics suggested by everyone earlier this evening. Going to try and list these in logical order as multiple tests were recommended. Thanks to JT, McGyver, and ForcedFB for all the great info!! Here are my results:

1. 0 gauge and 8/10 gauge wire at battery junction box by the six-pack holder both have 12v. Fusible Link A is good.
2. Ignition key on, both green wires at steering column coupler get 12v with key on (there is a green wire and a purple/green wire coming from the ignition and both couple to separate, matching green wires at the steering column coupler/connecter). Ignition is good.
3. OBC functions normally, no code lock out seems to be in place. I disconnected battery just in case. Did some diagram and forum searching before i dismantled the glovebox a little further and yanked the panels in search of connecter C104. The picture in the ETM is terrible but I attached it to this post. Pictured is the C104 connector that E30 Wiki refers to as the "two pronged socket above the glovebox", the wiring junction for code lockout. I cannot find this connector. This would be a great place for me to test 12v from ignition without having to dismantle everything.
4. Pin 7 @ C101 does not get 12v with ignition on. As per JT's post I should have voltage at pin 7 before moving on. Just to test the rest of the circuit I did. More to continue on point 4 shortly.
5. 12v @ ECU Pin 18 confirmed
6. 12v @ main relay pins 86 and 30 confirmed
7. Main relay tested good
8. shorting ECU Pin 36 actuates the relay and delivers 12v to Pin 37

Cause for no ECU power & no power @ coil wire: No voltage to pin 7 from ignition/key on.

This is brings me back to point 4. Where is this mysterious c104 connector and what does it look like? Where does the immobilizer exist and what does it look like? Is the immobilizer the same thing as the "OBC Relay"? If this is the case I know what it looks like and just need to know where's mounted.

The wire exiting the steering column is of a much thicker gauge than the wire that terminates into the 13 button OBC harness. Checked the diagram and steering column green wire from ignition hits splice S213 first and is stepped down before splitting and going to both the "power distribution"/C101 pin 7 and the OBC relay. The arrows for obc and non-obc versions both point to power distrubution from S213, which means OBC is less likely a culprit as it functions properly. Would be great to test at this stepdown connector S213 if I can get any intel on it but would first like to test voltage at C104 to rule OBC out. Wondering what else S213 hits, I took a look at ETM. If I am reading the ETM correctly the ETM shows that S213 does power the cluster PCB and, eventually, the OBC (so it's ignition, s213 to pin 7 and cluster to obc?) while S212 and S319 power the SI board and the Tach/Econ Gauges on the two pages following ETM 6210-0.

If the issue is at OBC and voltage does stop at the relay in one form or another I can splice green to green or green/red to green depending on which relay box I have. It's an 88 so as a transition year could be either 88 or 89. I attached pics of both situations regarding the relay box.

Pretty sure running a clean, switched 12v to C101 pin 7 from custom fused source would safely kick everything back on but I would like to get this properly sorted out.

Please review the 5 attachments and let me know your thoughts. Little voice inside of me wondering what happens if I disconnect the cluster.

[JehTehsus]

I don't think (could be wrong though, haven't tried, but from what I recall looking at wiring diagrams) you need the cluster connected to get power on that green ignition on wire when the key is on.

Before disconnecting the IC though, do you get any lights turning on when the key is on? In position 2/run it should look vaguely like a Christmas tree. If it is lighting up then it sounds to me like the S213 junction is good... which leaves only more wire and the OBC relay between C101 pin 7 and that junction. While you are in there it may be worth simply bypassing the OBC relay entirely (assuming you don't want to keep the code lockout functionality).

[E30Bastard]

Yes. Christmas tree is on, all status lights and SI board check out.

Decided to follow your suggestion and start with the OBC. I tracked down the OBC relay, it is located directly behind the ABS module mounted against the firewall. Guess what? The C104 connector is right by it, not under the RH dash as pictured next to the ECU in the EMT. Green/rd gets 12v with ignition on and green has continuity to C101 pin 7 (late model has grn/red @ obc relay but, regardless, bypass fiddling with the OBC relay harnesses and just mess with the C104 connector). I disconnected the C104 connector and tested there - two green wires as per diagram. Since I had already tested everything else in the circuit over the past few days I jumped these two wires and of course ms2 turned on like a charm. Definitively OBC Relay failure.

See attached pics for C104 and OBC relay module location.

Progress!!! Stoked!!!!

Only problem is the car isn't starting even though it died mid-idle. Definitively the OBC relay died on me. Spontaneous cause of death - unknown. Hoping that something didn't fry it vs it just deciding to die a couple days after installing and idling with an MS2.

It has been over a month since I installed this MS2 unit so I don't remember little details like whether or not the ICV supposed to buzz with ignition on? I know it does buzz in stock config but not sure if it should with MS2 in KOEO. Anyone know?

[2mAn]

[JehTehsus]

Yes. Christmas tree is on, all status lights and SI board check out.

Decided to follow your suggestion and start with the OBC. I tracked down the OBC relay, it is located directly behind the ABS module mounted against the firewall. Guess what? The C104 connector is right by it, not under the RH dash as pictured next to the ECU in the EMT. Green/rd gets 12v with ignition on and green has continuity to C101 pin 7 (late model has grn/red @ obc relay but, regardless, bypass fiddling with the OBC relay harnesses and just mess with the C104 connector). I disconnected the C104 connector and tested there - two green wires as per diagram. Since I had already tested everything else in the circuit over the past few days I jumped these two wires and of course ms2 turned on like a charm. Definitively OBC Relay failure.

See attached pics for C104 and OBC relay module location.

Progress!!! Stoked!!!!

Only problem is the car isn't starting even though it died mid-idle. Definitively the OBC relay died on me. Spontaneous cause of death - unknown. Hoping that something didn't fry it vs it just deciding to die a couple days after installing and idling with an MS2.

It has been over a month since I installed this MS2 unit so I don't remember little details like whether or not the ICV supposed to buzz with ignition on? I know it does buzz in stock config but not sure if it should with MS2 in KOEO. Anyone know?

Glad you got the MS powered.

The idle valve should vibrate if the MS is powered up - the megasquirt sets it to the cranking position when powered on but the engine is not started.

Car not starting could be many things - what happens when you turn the key? Does the starter fire and the motor turn over? If so it may be fastest to get the computer hooked up to the MS and just see what the MS thinks is happening.

[E30Bastard]

Thanks! Good to know. It's definitely not turning on with ignition. I know Motronic pins 4 and 22 control it but not sure where the center wire gets its 12v from. Just guessing but probably main relay as this powers on with ignition. I spent a couple hours trying to find it in the EMT but had no luck.

Fuel pump primes, starter fires, motor turns.

I'll get logged into it this evening and see if anything is awry.

[ForcedFirebird]

Immobilizer is the green lead that goes to the ignition coil. With car equipped with code protection (13 button OBC) then the coil wire get interrupted by the OBC when in protection mode. Leaned that a long time ago when building my first e30 race car. After ripping the dash out, the car wouldn't start and traced the green coil wire and had to reunite it after removing the OBC.

So it was that pesky green wire to the OBC. Grrr. Glad you found it!

[E30Bastard]

ICV checks out with 12v at the harness's center pin. When I hit ignition it just locks into one direction, no buzz. Not sure that would prevent me from starting (or trying to start), though. Coil pack C also felt hot as hell. Going to double check all the quadspark connections. Update soon.

[E30Bastard]

Ok...

Spark Output C has something funky going on. At the coil I get 12v from the switched 12v and 2 volts on the other side of the coil (channel C, quadspark). The coil heats up like crazy, to the verge of being an electrical fire. I tried Spark Output C with the other two coils and the other two coils exhibit the same behavior with C connected to them. Keep in mind that the switched positive for the coils is a 12v pigtailed/common wire, so this is definitely not the culprit since the the same behavior would exhibit on all 3 coil packs if this were a short issue with the switched 12v. I still went ahead and unsoldered Spark Outputs A, B, & C to test my harness. All wires tested good.

Output A and B give out 12v solid on either side of the coil (switched voltage+quadspark). Output C is the only one creating this madness of 12v on one side and 2 volts on the other no matter which coil I use.

100% all wires in the wasted spark circuit are good, no short and 100% the quadspark is wired up correctly per MSPNP diagram - 1/6 - Spark Output A, 2/5 - Spark Output B, 3/6 - Spark Output C. I've double checked everything by unsoldering and testing the custom wires I ran for pins 15-17. There's zero reason why this should happen from a wiring perspective. Why is output C acting up? Looking more and more like the obc relay is the only point of failure in an unfused circuit...

*edit - Are my jumpers off?

[E30Bastard]

Update - My jumpers were indeed off. I am 100% sure I had them set to WS when I sent this unit back. So either they returned the jumpers to sequential for testing or they replaced the unit and did not tell me. Either way, I set the jumpers to WS and now all coils have 12v on both posts and they are not heating up.

The car still doesn't start. Here's how my jumpers look now:



And here is the diagram followed by the legend for the ms2 jumpers from DIYAutoTune:




Going to take a quick break then come back and compare settings.

[JehTehsus]

Can you run through output test mode on spark and injectors? May be easier to identify what else is wrong that way.