I have been having this problem since November of 2004. My problem is I recently put my new motor in 385ci 1985 MAF TPI with a 12:1 compresion running on 100 octane. Ran fine for the 1st 1000 miles then my problem started. It started running like crap like a few cylinders weren't firing. Did a compression check all checked out good, check the injectors all check out good, checked if all the injectors were pulsing and all checked out good, fuel pump works and the fuel presure checked out good. Also installed new distributor (coil in cap) with a new 50,000 volt coil so that is all good. After the car was running like crap I turned it off to try to start again wouln't start at all, when cranking the motor over every 5-15 rotations the car would want to fire but as soon as it wants to it stops. Also as I am trying to crank it over seems as if the battery wants to die loose power fast, like something is pulling alot of power off it. Went through entire wire harness under the hood looking for shorts or cut wires and nothing. I let the car set for a few weeks didn't have time to mes with it went out 1 day fired right up, ran for 3 days started running like crap, then it wouldnt start again. The ECM is good. I did check 1 more thing the power going into the coil the pink wire seems to be loosing power some how when cranking.

I am getting park at all cylinders but maybe its not enough to fire the 100 octane and high compression I have. So the only other thing I can think of is something is causing low power at the pink coil wire, causing low spark and varible spark. can anyone help or have any suggestions would be greatly appreciated.

Thanks in advance.

 

You can't tell if that ECM is good unless you test every parameter.

What areas are you having problems with?

 

xxx

 

Well I tried 2 ecm's my orginal then 1 from a car that was running
with that ecm and does the same thing with both so I know its no the ecm. I also installed brand new distributor and a ESCM, fuel pressure is good, all injectors are pulsing. Problem is the power going into the coil keeps dropping and draining my batter when I crank the motr over. What would be causing low voltage to my coil? Thanks

 

I am curious to know if you are also experiencing charging problems.. *correct me if i'm wrong* but I believe the pink wire in question is source fed from the alternator. If the internal ground in the alternator is broke or corroded badly this could cause intermittent power to the coil..

 

Well the pink wire going to the coil is coming from the Fuse block inside the car, or the ignition switch not sure witch one but I know for sure the coil power wire is coming from the inside of the car. As far as the Alternator there is only 2 wires a small gauge brown wire that goes to the voltage gauge inside the car and then the heavy gauge either a 8-10 gauge that goes to the battery to charge the battery. Well any way I installed MSD which helped my spark problem and got my car started but now the battery is being drained so when I get the car started and let it run shut it off the battery doesn't have enough to crank the car over. So now I am thinking something in the alternator is bad so I gonna change that and see if that helps. But I did have the alternator tested at Murray's and checked out good but I am still gonna change it and see what happens.