View Full Version : Running really rough

11-22-2005, 04:43 PM
Hey guyz, havn't been on here in a while....but here's the situation....i have an 89 SC with a 90 motor that has just shy of 10k miles on it. after about 3k miles it started cutting out under a load randomly, not bad but just enough to be annoying, felt like spark blowout or something, then over the past few weeks, it felt like i lost quite a bit of power and it was breaking down at about 4k and just feeling like it wuz pulling at 6200, when it runs out of steam....well then one of the pistons stopped firing.....sooo i pulled the wires one by one till i pulled one that didn't make a difference, pulled that plug and found that the electrode had been COMPLETELY melted off.....so i took it to car quest, then told me that whoever built the motor put in the wrong plugs..they were for the NA v6.....sooooo i replaced it with the NA plug again as a temporary fix, i ordered up some taylor wires and autolite double platinum plugs and put them in a day later.....well to my dismay the car still idles real rough, like i have a real aggressive cam, and still has a loss of power........i wuz thinking about it the other day and i wuz wondering if the injector went bad that wuz in the cylender with the melted plug....maybe i leaned out and melted the plug.....that's my only thought but i could be wrong...HELP!!!

11-22-2005, 11:13 PM
:( no one?

Kevin Varnes
11-22-2005, 11:39 PM
Run KOEO, KOER, and a cylinder balance test. Do you have the injector harness plugged in correctly?

RBH Racing
11-23-2005, 10:42 AM
The seriously increased gap no doubt put a huge load on that coil. I'd check it with an ohm meter to see it it still has sufficient resistance.

resistance should be 7,700-10,000 ohms on the secondary side

0.8-0.6 on the primary

11-23-2005, 02:28 PM
what's the gap on the autolites? i used a digital micrometer on the double plats and they all came out between 0.054 and .056, so those are all set, i have no idea how the old plugs were gapped....and i'm praying to god i didn't lean out enough to melt a hole in the piston

11-25-2005, 01:16 AM
I just recently went through this on my 92. I pulled wires and the piece that clips onto the plug had roke. It was better but not the same. I had replaced the fuel pump as I had a new walbro 255lph laying around. It didnt help and now I had a fuel smell. It progressivly ran worse until 1 day I decided to pull the tank to find out why it was leaking gas if I put more than 3/4 tank in it. After dropping the tank, I found that the fuel was leaking from the fuel pump o-ring. I pulled the whole assembly out just to look at it and found that the 2inch piece of hose had a rip at the top nd had allowed the hose to slip just enough to prived some fuel, but whn it needed to supply more psi, it just ran out everywhere in the tank. A new piece of hose and it ran like new again. I would check your fuel pressure to make sure thats all up to par.