Funky no spark issue...Now with Bosch Module oddities!

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SeStone
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Funky no spark issue...Now with Bosch Module oddities!

Post by SeStone »

MS1 chip
V3 board
IGBT wiring
029q

A few days ago I went out to my car in the morning and got zero spark out of it. Like, went from running fine the night before to zilch the next morning. I verified coil was good, ignition wires were good, replaced the VB921 (I was running it at the time), and verified everything on the wiring harness. Everything checks out. I then tried switching from LED17 as my ignition output (to the IGBT circuit), to LED19, then FIDLE. Then I clipped all connections from FIDLE to the IGBT circuit, and threw in a Bosch module. With every one of these combinations, I have an issue: There's no spark, and the respective LED for that item stays lit solid...even on the stim or so on. I've tried replacing with two known good chips, and checked the board for shorts all over. What on earth did I blow up?

Sam
Last edited by SeStone on Sat Jul 08, 2006 9:46 pm, edited 2 times in total.
1990 Audi 80 Quattro running Megaquirt'n'Spark-Extra
jsmcortina
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Post by jsmcortina »

Do you get any rpm displayed?

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

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SeStone
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Post by SeStone »

Yes, I get a great RPM signal, injectors fire/work, etc.

I'm going to try throwing the 029s code on my laptop and the ECU along with a fresh .msq. I tried it on my desktop briefly and I thought I saw some sensible blinking going on.

Sam
1990 Audi 80 Quattro running Megaquirt'n'Spark-Extra
SeStone
Helpful MS/Extra'er
Posts: 49
Joined: Tue Dec 21, 2004 11:29 pm

What on earth does it take to make a 124 module work!?

Post by SeStone »

MSnS-E 029S
MS1
V3 board
Bosch 124 out of a 1984 Audi 4000 Quattro

I've spent a good 8 hours today trying to get my car to run with the Bosch 124 module. I have a Good ground to pin two. Pin 1 goes to the negative side of the coil, out of the same 4000. Pin 4 is switched 12v off of the positive side of the coil. Pin 6 is connected to the FIDLE wire out of MS. Dwell control has been set to 75% duty cycle and then 6ms cranking when that didn't work.

I've tested and verified and retested two of these things now that came out of running cars. I can hook the input straight up to a dizzy on a hall sender, and no dice (using a pickup resistor...I can see the signal switching 12v-0-12v). I can see 12v switching when the FIDLE wire triggers the thing. But two of these now have not done a THING to the negative side of the coil...they aren't switching them to ground!

What am I missing!? Part number is 211 905 351 B on both. 7 pin connection.

Sam
1990 Audi 80 Quattro running Megaquirt'n'Spark-Extra
SeStone
Helpful MS/Extra'er
Posts: 49
Joined: Tue Dec 21, 2004 11:29 pm

Post by SeStone »

Edit: Moderator apparently took thread and spliced it in here, with heatshrink. Thanks!

Sam
1990 Audi 80 Quattro running Megaquirt'n'Spark-Extra
SeStone
Helpful MS/Extra'er
Posts: 49
Joined: Tue Dec 21, 2004 11:29 pm

Post by SeStone »

Had it running brieflyon the VB921, then it died. Suspected cause? Overheated VB921 since I'm running without a case on the box at the moment.

Am I right in saying I should be able to take an unmodified FIDLE signal and get that to fire a Bosch module? I tried a third module today and it still won't fire...I'm doubting that works so simply. I think what I'm going to try next is to short out the VB921 spot on the board and use LED17 and its accompanying circuitry straight to the Bosch thinger.

Any insight in to what kind of signal those Bosch things need is GREATLY appreciated, I need to get someplace with the car at 3pm cst.

Thanks,
Sam
1990 Audi 80 Quattro running Megaquirt'n'Spark-Extra
jsmcortina
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Post by jsmcortina »

You need a pullup resistor on the output that feeds the module. The led17 or fidle transistors only provide a ground, the module needs +5v? +12v? to work.

Have you tried the input manually? i.e touch to +5v then ground then +5v to see what gives a spark? (Or +!2v)

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
SeStone
Helpful MS/Extra'er
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Joined: Tue Dec 21, 2004 11:29 pm

Post by SeStone »

I just tried a 1k Ohm resistor between pin 4 (+12v) and pin 6 (FIDLE), no change. I also tried it between pin 4 and pin 1 (coil -). No dice!

So, I take it the module triggers (goes to ground on pin 1) when 5v or 12v goes to the input pin?

Thanks James, anything else?

Sam
1990 Audi 80 Quattro running Megaquirt'n'Spark-Extra
SeStone
Helpful MS/Extra'er
Posts: 49
Joined: Tue Dec 21, 2004 11:29 pm

Post by SeStone »

I tried the pickup resistor on my other Bosch module...works great :D . I'm throwing everything back together now and I'll make my appointment!...thanks James!

Sam
1990 Audi 80 Quattro running Megaquirt'n'Spark-Extra
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