1641CC VW Frustrations

General Topics for configuring, operating and tuning the Megajolt. Also see the <a href="http://www.autosportlabs.net/MJLJ_V4_Operation_Guide">Operation Guide</a>

Moderators: JeffC, rdoherty, stieg, brentp

Post Reply
manx3094
Posts: 15
Joined: Fri Apr 06, 2012 10:45 pm

1641CC VW Frustrations

Post by manx3094 »

Just got my dunebuggy runnuing on the MegaJolt however, it does not run well. It seems to miss at idle. As the RPM increases the motor smooths out. Also the software shows that it is idling at about 1000 RPM and 12 degrees of advance. My timing light shows that it is at about 20 degrees of advance. When i add more advance in at the lower RPMs it smooths out some, however i have not added anymore than 5 degrees. I am using the enclosed spark map.
I don't understand why the degrees of advance do not match what i am seeing with my timing light. And is this a good map for my motor?
Attachments
MegaJolt Map 1.mjlj
(815 Bytes) Downloaded 642 times

toenee
Posts: 75
Joined: Mon Aug 31, 2009 6:46 pm

Post by toenee »

Have you tried without the megajolt plugged in ? ie. just run it on the ford parts, you should see steady 10 degrees just running it like this.
It may just be your timing light, it may be picking up the second (wasted) spark. More modern timing lights can do this.

brentp
Site Admin
Posts: 6282
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Agree, you should first check what the EDIS default advance is. It should show 10 degrees- if not, you can adjust the trigger wheel to sensor alignment. Or, you can use the trigger offset feature in the Megajolt firmware (see the operation guide in the How-To link above)

Let us know what you find out!
Brent Picasso
CEO and Founder, Autosport Labs
Facebook | Twitter

WhatDidIDoWrong
Posts: 8
Joined: Fri Mar 09, 2012 6:15 pm
Location: United States

Post by WhatDidIDoWrong »

Try a little more advance around a 1000, I idle at 14.

What rockers do you have?

manx3094
Posts: 15
Joined: Fri Apr 06, 2012 10:45 pm

Post by manx3094 »

I have the stock rockers.

Long story short.... what i found out was my coil had a bad #1 tower. I replaced it with another used coil and it now is running on all 4 cylinders again.

Does anyone have a recommended spark map for a 1641cc VW?

manx3094
Posts: 15
Joined: Fri Apr 06, 2012 10:45 pm

Post by manx3094 »

Almost forgot.... I had it running on just the EDIS and checked the timing. It was at about 11 1/2 or 12 degrees rather than 10 degrees. I will make the needed adjustment within the MegaJolt software.

manx3094
Posts: 15
Joined: Fri Apr 06, 2012 10:45 pm

Post by manx3094 »

it's nearing time to get the buggy out again. this year i went to an electric fuel pump and duel carbs. i also have replaced the Ford coil with a coil from Pantera EFI that he sent me because he wanted the defective Ford coil i found last year. everything seems to be wired properly however, the motor is only running on 2 cylinders. when i start it only the exhaust pipes on the 3,4 side of the motor get hot and it runs rough. the carb on the 1,2 side is getting gas. i have checked the spark on #2, it's there, just seems weak.
Any ideas, suggestions?

Post Reply