Hello everybody, I have been floating around here for a lil' while now, but recently I got a wierd issue going on.

Iam not a newb, I've been wrenching for a lotta years now, but this is actually my first third gen project, and your site has been really nice.

Several months back, I traded a 75' firechicken esprit for an 85' T-Top Trans-Am, a sweet deal I know. All the TA needed was a fuel pump. After $90 and a carter pump she purred like a kitten.

The TA'S a 305 TPI, a/c, 4 wheel disk, ws6 package,and power everything, and I mean everything except a rear hatch pop. I cant leave anything stock so I decided I needed to upgrade the ignition system.

I installed an MSD #8401 hei coil bypass cap, Ecoil 50,000 external coil, MSD 8.5mm super conductor wires and Bosch +2 plugs. The old plugs were pretty old autolite 26's but looked really good, perfect burn color, no oil or deposits. At first she ran great with the new coil, but now that I changed the plugs and wires, she started acting real wierd.

On cold starts, she don't wanna stay fired. After a couple starts, she picks up to 2,000 rpm and then drops to 900 rpm. Only now shes got a rougher idle, then without warning the idle will drop to 500 rpm and barely stay alive rolling on the cam. It'll stay there for a minute or two then go back up to 900rpm, after which it repeats itself all over again.

I double checked the firing order, connections and timing, even advancing the timing doesn't phase it ?. Funny thing is, it does it when the knock sensor is unplugged as well. As long as I am on the throttle it runs alright, but it did lose a lot of acceleration though.

Any help would be appreciated. Thanks guys

 

Sounds like the IAC is relearning the idle speed. It might smooth itself out.

And although you don't want to hear this because of your $ investment, stock replacement ignition parts are plenty good enough for a stock engine.

 

Are the spark plug boots making good contact with the spark plugs?

Also I've had SO much trouble with aftermarket ignition stuff I stick with stock as much as possible.

If nothing else start swapping the old stuff back in one piece at a time to see what happens.

 

Did you burn a plug wire against the exhaust?

 

Thanks guy's, I got some good sleep last night, went to church this morning and had time to think about my issue. I popped the hood and pulled off the MSD hei coil bypass cap, plugged in the stock coil back in and turned the key.

She fired right off, I unplugged the knock sensor and set the timing to 6' btdc, plugged in the knock sensor and stood back. The sensor did its thing, and she started cacklin' on the cam and rumblin through the catback exhaust system. Damn she sounds purty'.

The msd wires and Bosch +2 plugs made a hella difference once the timing was set right. I thought that msd hei bypass cap looked like a pretty cheesy design. Now that I know what the problem is, I'll try to correct the issue and run the external coil. If it wont work, I'll toss in an aftermarket hi voltage hei replacement coil and be done with it.

Thanks guys !!!

 

dont u mean unplugged the est? you dont have to unplug the knock sensor.

 

i would just use a stock coil.