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NO SPARK OR RPM WHILE CRANKING
Posted: Thu Jul 09, 2009 7:51 pm
by BILL C
I recently installed an MS2 on my Austin Healey kit car. The Motor is a 355 ci TPI motor. I have an MSD distributor HEI8, MSD plug wires and MSD HEI coil. I had it running and drove the car for about an hour and after returning home, the car would not re-start. I checked the battery and found it was low (70%), so while it was charging I removed the altenator, had it tested and found it was bad. I replaced it along with the HEI control module (since the distributor was given to me I didn't really trust it's condition). While I am cranking the engine over I noticed that no engine rpm signal is being displayed and after a few seconds, communication is lost with the computer. Now, before I drove the vehicle I wired the HEI8 using the HEI7 wiring diagram with the relay. It started and ran fine.
Could someone explain to me why the commincation suddenly drops off and there isn't any spark? It operates the same if i disconnect the "B" (VRef signal) wire.
Re: NO SPARK OR RPM WHILE CRANKING
Posted: Fri Jul 10, 2009 4:44 am
by Matt Cramer
It could be a faulty HEI module is shorting the VREF to ground. Maybe try putting a 1K resistor in line with the B pin? At least that way it won't be able to kill power to the MS.
Re: NO SPARK OR RPM WHILE CRANKING
Posted: Fri Jul 10, 2009 6:17 am
by BILL C
I replaced the HEI module. It is acting the same with the old and new one.
Re: NO SPARK OR RPM WHILE CRANKING
Posted: Fri Jul 10, 2009 7:22 am
by Matt Cramer
Could you post a data log of the communication loss?
Re: NO SPARK OR RPM WHILE CRANKING
Posted: Sat Jul 11, 2009 7:48 pm
by BILL C
Matt Cramer wrote:Could you post a data log of the communication loss?
I am new to the forum. How do I post a data log?
Re: NO SPARK OR RPM WHILE CRANKING
Posted: Mon Jul 13, 2009 6:16 am
by Matt Cramer
Below the Save - Preview - Submit buttons, you will find a pair of tabs marked "Options" and "Upload Attachment." Click the Upload Attachment tab. Then click the "Browse" button that appears. A file open dialog box will pop up. Select the file, then click Open. Then fill in the description in the field below the file name. Once you have all that, click Add the File. Repeat this, starting with "Browse," to add more files. Once you have these all attached, you can enter your post and the files will be attached.
Re: NO SPARK OR RPM WHILE CRANKING
Posted: Mon Jul 13, 2009 6:50 am
by BILL C
I first attempted to crank the engine over with the module connected, and then attemmpted without it connected. Is there a way to reduce the size of a logging file? I would like for you to check out the one prior to me parking the vehicle. Everthing appeared to go haywire at the end. The file is too large to send to you as is. Thanks, Bill