I recently fixed a BIG problem with my car, but in It's wake I now have a smaller problem I'd like to correct.

The big problem with my car was Upon cold start, it would not hold It's own idle properly. It would misfire and search/surge. After it warmed up, it usually ran OK, but it would still misfire and sometimes it would throw a code 44 and richen the fuel mixture to try and compensate for the low o2 reading. When it did this, it would always run like CRAP and misfire badly. This problem turned out to be a bad MAF and I have since fixed it.

Another problem was the spark plug wires. The exhaust headers cooked them so badly one wire was split right down to the core. A couple wires were jumping spark off onto the exhaust headers causing the engine to misfire. I have since replaced the wires and used spark plug wire heat shields to prevent the problem from happening again. I also used a dab of dielectric grease in both the spark plug boots and the distributor boots to both make installation easier and to primarily prevent corrosion.

Now I have one last problem I'm trying to get corrected. The engine still misfires. It only does this when cold. It is most pronounced when the engine is cold and idling. Once it warms up and has been driven around for a few minutes, the misfire diminishes greatly or disappears all together.

I know all my spark plug connections are good to go, and I highly doubt It's the grease since I have never had this sort of connection problem with it before. The metal to metal contact should displace the grease where it needs to be displaced.

I believe the problem may be the rough condition of the engine from the bad MAF may have fouled out the spark plugs.

It's F'n cold over here right now so I don't feel like tinkering with them. I just want to know what you guys think so I will have an idea to go on in the meantime.

Thanks.

 

my tpi runs rough when I start it in the morning and then stabalizes

not a big deal

you say it runs fine when warm

is there even a slight miss when its warm

 

I'm going to say yes sometimes.

Not nearly bad enough to make me want to pull over or dive under the hood the second I get home, but yes sometimes it is noticeable depending on It's temperment.

 

while it is running disconnect the injector harness one at a time

if the idle does not stumble then you have a misfire at that cly

take out the plug and take a pic and post

 

I don't think this will be informative as we'd like.

The misfire is not constant on every combustion stroke like a cylinder is totally dead. It's intermitent like a cyl is firing, misfiring then firing and misfiring again.

Unplugging an injector won't tell us much as now we have a constant misfire. And when the engine is constantly misfiring, I kinda doubt I'd be able to tell the difference from an intermitent misfire on a different cylinder.

 

Change your plugs sounds like a fouled spark plug. Let me know what u get?

 

OK, heres the skinny.

Today I replaced the ignition coil with an HEI incap Accel supercoil I picked up off ebay for $10.50 with 20k miles (Good deal).

As soon as I started the car (Off a cold start), the misfire was reduced by about 90%. Here is what I think happened:

Two owners ago, some idiot stripped the car off the MSD cap, rotor, coil and 6AL (Maybe for crack money?), and returned all the parts back to stock. Oh, except for the MSD superconductor wires, which were RUINED when I bought the car because for some odd reason idiot owner number 3 felt the need to remove the header heat guards owner number 2 had installed.

The coil I pulled out of the dizzy had red and yellow primary wires. But I heard that the correct coil for a TPI has red and white primary wires. Or maybe I was told wrong, and I just installed the wrong coil (Which I talked to Accel about and they said the car will still run fine but it changes the magnetic field which can cause backfiring upon starting (Something else that happened every now and then with old coil) and misfire). Either way, the misfire is almost totally gone now. I'm suspecting the every once in a while blue moon sorta misfire left is due to the plugs being fouled from a bad MAF dumping a crapload of fuel. The car also starts much better now, although upon trying to start right after shutdown, and starting the car when the engine is cold, the throttle still needs to be manipulated to get it to fire (Last problem remaining with my engine I'm still trying to figure out). But it does run so much smoother now.