What are my Spark Options? VB921 not working...

GodSquadMandrake · Post by **GodSquadMandrake** » Tue Jul 25, 2006 8:29 am

I have Megasquirt 1 with a version 3.0 PCB. I'm trying to run Megasquirt and Spark for ignition control with the VB921 hooked up to a distributor. I'm not getting any spark and i've been troubleshooting this for about 6 months now. I've searched high and low for answers and I haven't found anything. I guess i'll go thru it once more so you guys know i'm not an "misinformed person":

Here's my settings:

The coil is a standard MSD Blaster TCI coil, I also tried my stock coil with no luck. I've tested the board on the stimulator and it all checks out. I'm getting continuity from the processor to the VB921 and from the VB921 to the coil. VB921 is switching between high resistance and low resistance so that shows me it's sending a spark signal but for some reason the coil is not sending a spark. The coil is powered off of the fuel pump relay and I have verified it is getting power. The distributor cap has continuity. The ignition wires have continuity. I've tried holding the main coil wire against the head and there are no sparks. I've tried using an LED test light but I don't get any light on it when I hook it up to the VB921. I've heard that the signal is too fast to see on an LED light though. Literally i've tried everything and i've been troubleshooting this for 6 months. Nobody seems to know what is wrong or how to help me.

Can someone suggest a better ignition option? Should I do EDIS or MSD? I just want it to run. I don't care anymore if I get to control spark thru Megasquirt. My car has been down for almost a year and I just want to drive.

jsmcortina · Post by **jsmcortina** » Tue Jul 25, 2006 8:45 am

How is the your VB921 wired? Where do all three pins go.
I ask this because using FIDLE with the VB921 is not documented (well not by me anyway.)

What is your Spark->Dwell set to?

If you fit an LED tester in place of the coil primary you ought to see short flashes during cranking. (Set the cranking dwell to the 6ms for this test.)

James

GodSquadMandrake · Post by **GodSquadMandrake** » Tue Jul 25, 2006 9:33 am

I think you tried to help me with the VB921 once before and I had it wired wrong. I don't remember exactly what I did with the wiring but it is wired off of LED17 now with the 330 ohm resistor and then I just used one of the extra output wires on the DB37. I did test it with a multimeter and I verified that there was continuity.

Cranking Dwell: 8.0
Running Dwell: 3.3

I have an LED tester that I hooked up in place of the coil. The LED test light has a small resistor on it. Will that block the light? The test light works otherwise with 5v or 12v. But I don't see any flashes on it. So that basically means that VB921 isn't sending the spark?

GodSquadMandrake · Post by **GodSquadMandrake** » Fri Jul 28, 2006 1:51 pm

Can someone take a look at my board and tell me if you think that I did something wrong? I can get better pics if needed. I know these are kind of blurry.

http://www.god-squad.net/images/jetta/a ... _1_big.jpg

http://www.god-squad.net/images/jetta/a ... _2_big.jpg

jsmcortina · Post by **jsmcortina** » Fri Jul 28, 2006 2:55 pm

What is the 5v going to SPR1 for?

The wiring of the VB921 and tach input appears to be ok. You are getting rpm displayed during cranking aren't you?

Have you changed the VB921 since it was miswired? Maybe it got broken somehow?

James

GodSquadMandrake · Post by **GodSquadMandrake** » Sun Jul 30, 2006 12:51 pm

jsmcortina wrote:What is the 5v going to SPR1 for?

The wiring of the VB921 and tach input appears to be ok. You are getting rpm displayed during cranking aren't you?

Have you changed the VB921 since it was miswired? Maybe it got broken somehow?

James

The 5v is actually power to the hall sender. The VW hall sender does good when you give it +5v from MS, it's a more stable signal. Yes I do get an rpm signal while cranking.

Actually I have changed the VB921. The first one fried when I didn't invert my spark. How can I test the VB921 to know if it's wired up right?

GodSquadMandrake · Post by **GodSquadMandrake** » Wed Aug 02, 2006 11:08 am

I just figured something out. I can test the coil by grounding it manually and seeing if a spark comes out of the spark plug. I guess this will tell me if megasquirt is broken or if it's my coil.

mops · Post by **mops** » Wed Aug 02, 2006 12:48 pm

GodSquadMandrake wrote:I just figured something out. I can test the coil by grounding it manually and seeing if a spark comes out of the spark plug. I guess this will tell me if megasquirt is broken or if it's my coil.

aswell you can hook up test light to ms, i.e. +12V to one side of test light, and - to the coil driver. set dwell to something large, like 8ms, apply low rpm's on stim and the test light should be flashing....

GodSquadMandrake · Post by **GodSquadMandrake** » Sun Aug 13, 2006 10:13 am

The coil fires if you ground it manually. It seems that megasquirt is not sending a spark. How can I test the VB921?