If I had any hair left, I'd tear it out

[big2bird]

That doesn't leave much
1)HEI module bad again
2)Miswired
3)Carbon tracking/spark scatter

Your black soot described maybe excessive carbon brush residue that is making your HV output spark all over inside the cap.
It's not a good condition anyhow. I would change the cap and rotor first. Use a good unit like Delco or NAPA. Do not use Niehoff crap from the Zone. It's trash.

#1-I'm on the third module?
#2-Nothing in the wiring changed
#3-third new cap and rotor from Nappa
CR is 9.8:1 and have both AC Delco 6 and AC Delco 5 plugs. Both sets almost new
wires are MSD 8MM and are reading about 55 ohms per foot? Same wires that were on the motor before the cam change.
My wife just told me to go ahead and order the new Accel Thruster DFI engine management system. As I said, it is sequential fire and fully diagnostic and programmable. I'm sick of messing with this one. I know it's not mechanical or fuel related. Only other thing I can come up with is maybe when they burned me a new chip for the cam change, they f*cked up the program??

What is the plug gap you are using? I wonder how compatable that coil really is with HEI. Do you have the stock GM coil?

 

[mrvette]

That doesn't leave much
1)HEI module bad again
2)Miswired
3)Carbon tracking/spark scatter

Your black soot described maybe excessive carbon brush residue that is making your HV output spark all over inside the cap.
It's not a good condition anyhow. I would change the cap and rotor first. Use a good unit like Delco or NAPA. Do not use Niehoff crap from the Zone. It's trash.

#1-I'm on the third module?
#2-Nothing in the wiring changed
#3-third new cap and rotor from Nappa
CR is 9.8:1 and have both AC Delco 6 and AC Delco 5 plugs. Both sets almost new
wires are MSD 8MM and are reading about 55 ohms per foot? Same wires that were on the motor before the cam change.
My wife just told me to go ahead and order the new Accel Thruster DFI engine management system. As I said, it is sequential fire and fully diagnostic and programmable. I'm sick of messing with this one. I know it's not mechanical or fuel related. Only other thing I can come up with is maybe when they burned me a new chip for the cam change, they f*cked up the program??

What is the plug gap you are using? I wonder how compatable that coil really is with HEI. Do you have the stock GM coil?

Yeh, stock coil '91 F body TPI.....change it bet it works fine....

 

[AJ77]

Plug gap ia .042" and hasn't changed since I first got the car on the road in July 2007, 14000 miles ago. Same with the coil. Why would it change after just removing the engine and changing the cam. Anyway I have a E type MSD coil coming from Jegs tomorrow. It is the one recommended by one of the guys that built the TPI system. We'll see if that makes a difference. Can't really see why it would though. Going to call them and ask about the program in the new chip today to see if it couod possibly have something to do here. If they say no, I'm putting in an order for the new Accel Thruster engine management system. It's only another $2000.00. With what I've got in this car now it just doesn't matter anymore how much it costs if it will make it run right.

 

[AJ77]

Still beating my head against the wall! I think I've narrowed it down to the IAC circuit. I've checked the wiring and all is intact. With the TPS set @ .54VDC @ idle and the car running 850 RPM, all is good for a while. It might take 30 min. or 1 min. but the car will ramp up to anywhere between 1200 and 1700 RPM. I had a meter in the back of the computer measuring the TPS voltage the whole time and it never changed. This tells me that the IAC was just opening up for some strange reason. As soon as the RPMs come up, the check engine light comes on with a code for low voltage @ TPS. I know why--the computer is seeing the engine RPM increase but not the TPS voltage like it would if the throttle plate was opening. I can shut the engine off and about half the time when I restart it all is normal for a while and then the same thing happens. I took the IAC motor out and cleaned it and the port in the throttle body. No change. The IAC seems to be working properly @ startup. The engine starts and goes to about 1100 or so RPM and then comes down to 850. That tells me the IAC is working at least at startup. I guess I'll get another IAC motor and see what happens. That's about my last ditch effort before dumping the whole management system. I can't see it being a problem in the programming with the problem being intermittent.

 

[AJ77]

A update on this issue. Every time I would move the computer it seemed like there were wires falling out of the plugs on the back. The last time I actually got it to start, the injectors on the pass side weren't even working. I finally had enough and ripped out the entire system. Computer, wiring and all sensors. I went with the Accel Thruster system with a wideband O2. It's on the dyno getting tuned as I write. He was almost done yesterday when I stopped in so I told him just take his time and I would pick it up on Friday. It's going to be a rush to actually drive the car with the new setup when it's running properly. I haven't been able to successfully drive it since Eureka Springs in Oct.

 

[mrvette]

A update on this issue. Every time I would move the computer it seemed like there were wires falling out of the plugs on the back. The last time I actually got it to start, the injectors on the pass side weren't even working. I finally had enough and ripped out the entire system. Computer, wiring and all sensors. I went with the Accel Thruster system with a wideband O2. It's on the dyno getting tuned as I write. He was almost done yesterday when I stopped in so I told him just take his time and I would pick it up on Friday. It's going to be a rush to actually drive the car with the new setup when it's running properly. I haven't been able to successfully drive it since Eureka Springs in Oct.

Tell you what, I go apeshit over wiring and connections, and even then I mess it up sometimes....:clobbered::banned: and I"m a old ET from before transistors yet.....

 

[AJ77]

Got the car back from the tuner and OH MY GOD!! The difference is unbelievable. Only problem now is when I left work yesterday, the return spring on the throttle blade shaft snapped as soon as I put it in drive and started to take off. The car immediately went to full throttle, went straight sideways and then threw itself right into the curb. It took out both pass side wheels and knocked the front end out of line. It also bent the back, bottom control arm support slightly and cracked the weld. WTF!!! I haven't even had it back on the road for a week and this. I think I'm cursed.

 

[MYBAD79]

that hurts....