mprete

iTrader: (2)

carb ls1. so sometimes when im driving at a steady speed at a lower rpm, I lose the whole driver side of the motor. all 4 cylinders stop firing. when this first started happening it happened while I was playing with it in my driveway and was able to pull all 4 plug wires and they did not have spark and the pass side did. I found 2 terminals in the coil pack wiring harness to the msd harness were a little messed up so I replaced the harness with another and it was fine for awhile until I was on a longer trip and it happened again while driving. I cannot confirm its the same side because it only happens while driving now. my ground for the box is to a stud on my firewall that is also grounded to the engine block. also I can usually get it to come back if I floor the car and get the rpms up it comes back to life or sometimes I wont change a thing and it just comes back on its own. any ideas before I hassle with calling msd?

also brand new gm crank, cam, and map sensors.

EastTn6.0

Hmmm. The first thing I would do is ground it directly to the motor or the frame. I personally like to ground to something soild. I'm not big on depending on sheetmetal for good grounds. Seems like it would do it all the time if it was the box.

onefast84

I would just call MSD. They have good customer service, and can tell you if there is a common problem.

fast89stang

iTrader: (2)

I had to dielectric grease my terminals for my harness to coil packs. I have a 6012, but same thing. I lost a race because you cant really run your dial on 7 cylinders.

mprete

iTrader: (2)

ok so it was raining all day today so I didnt take the car out but I am going to dielectric grease the connectors and make a jumper wire to ground the box straight to the batt. if that doesnt fix it then im going to go with its the box and call msd. I just know they are going to tell me to do these things first so there is no point in calling until its done... thanks for the help guys. ill let you know if it helps.

niscur29

Have you checked to see if each side is getting 12v to the pack harnesses? If one side does and not the other it may be a problem with the Msd harness as I believe the coil pack 12v lead is spliced inside the harness to both sides. If they are getting power pull the plugs (fuel pump fuse etc) with wires still connected ground them and crank it over to see if they are lighting off. If not then they aren't getting the signal to fire from the box and could be a bad new sensor or the Msd box. The Msd harness is easy enough to rip the sleeving off and check the wires for any damage too.

mprete

iTrader: (2)

I found it! haha so because the old coil harness had a messed up terminal it screwed up the female side in the msd connector. At a first look you cant see it was messed up but I pulled the connector apart and the terminal came out of the connector pack without even trying. it just fell out. So I had to bend it all back into place and made sure it was a tight connection and all good! it was the ground wire for all the coils so it was losing ground to all the coils and I would lose the while bank. thanks for the help guys.

ZONES89RS

iTrader: (25)

Just found a local to me member here had a poor ground on his. Was breaking up and RPM would drop to 0. Voltage would dip to 5v. Was grounded to the coil pack, number 7....

Now she is tuned with my input and pulls damn hard for being a small efi grind cam in a full size truck.

jwang203

When the voltage was dropping, was his battery light coming on? I've been having what I thought was charging issues. Mabey I have a bad connection in my coil harness.

ZONES89RS

iTrader: (25)

Was watching the laptop when he was driving so I could monitor everything possible. Voltage was great at idle but when he went to accelerate it would rise and fall from 5 v to 13.

Ground was poor. Check all your connections and clean any grounds for good contacts and make sure you have battery to body and battery to engine grounds and a ground from the engine to the chassis.