MegaJolt only firing on two cylinders

OJKD · Post by **OJKD** » Sun May 25, 2014 9:23 pm

OK, this might be a very weird problem. When I am running MJ, or EDIS for that sake, it only runs on cyl 1 and 2. 3 and 4 are completely dead, not even vacuum in carb throats when running.

When I went back to points, it ran on all 4, or I had vacuum on all 4 at least. The engine is a M10 from a 320/4, in a BMW 1602.

Post by **brentp** » Sun May 25, 2014 10:14 pm

You want to check your spark plug firing sequence for the coil packs to make sure they are firing in the right order for your engine. Remember that wasted spark fires A/B/A/B, where one of the sparks fires in the exhaust stroke.

OJKD · Post by **OJKD** » Sun May 25, 2014 11:02 pm

I've tried several configurations to firing order. 1 and 4 on right and 2 and 3 left. Clockwise 1342 from upper right ans some others. Same outcome on all. Only vacuum on 1 and 2, 3 and 4 are dead. Can you explain how it is supposed to be? My coil pack in unmarked, so don't use numbers please

Post by **brentp** » Tue May 27, 2014 3:32 pm

Hi OJDK,

If you look down at the top of the coil pack, with the connector facing you, coil pack pair #1 is the top-left & bottom left, and coil pack pair #2 is top-right and bottom-right.

These pairs fire in an alternating way, so the cylinders you connect to the coil pack should match up to the firing order.

If you have rough running or severe engine bucking, then the left and right pairs should be swapped.

-Brent

OJKD · Post by **OJKD** » Tue May 27, 2014 3:40 pm

Hi, I am just doing this the simple way; here is a video of it running. Do you think I´ve got the firing order right? It runs on Limp Home at the moment, I have another thread in Q&A because I have timeout issues. I am very grateful for the answers provided here. You do a splendid job brentp. Just because I/we come of as crass or rude at times, we are generally just tired of having troubles with our systems, this forum is really good. Although I would like some more activity in general.

Post by **brentp** » Tue May 27, 2014 3:43 pm

Hi,

I saw the video. To me, it sounds like the plugs are connected correctly, but the advance seems wrong.

With the megajolt disconnected, can you put a timing light on the engine and verify the EDIS module is controlling the ignition at 10 degrees BTDC?