Re: Help!! Engine Miss
 

Get some 10 and 12 gauge wire and wire just the ignition up straight to the battery with jumper wires. Eliminate ALL wiring and ALL switches from the system. Have the battery, or batteries, fully tested. With just new wires straight to the battery for the ignition system, you eliminate everything outside the engine and the ignition system.

Re: Help!! Engine Miss
 

The problem you describe sounds familiar. I assume your combo is a quadrajet. You don't mention if you have tried a different carb. I have seen where a piece of something gets lodged in a jet and basically causes the engine to run extremely lean. It almost sounds like is running on 1/2 the cylinders. Just another idea. When reving the engine up what does the timing do? Does it stay steady?

Re: Help!! Engine Miss
 

Do like Alan said and eliminate everything and use jumper wires straight to the battery. I would bet that your issue is somewhere with the new ground wires for the switches either at the switch or at the terminal block. Hope you find it soon.

Re: Help!! Engine Miss
 

Hans - When the problem started, I was using my old battery. I replaced it last month with a brand new one.

Larry - Good thoughts. I wouldn't have considered that. If I can pinpoint the problem to the wiring, I plan to just replace it all.

Alan - I'm leaning towards doing what your saying. If I can find one, I may just wire in an HEI as someone had previously suggested, and eliminate the ignition system this way.

Bob - At this point, I'm pretty confident that it's not the carb or fuel system. Fuel pressure is steady as a rock, and the plugs definitely do no show a lean condition. I'm actually seeing some unburned fuel, pointing me towards the ignition system.

TWRS2006 - The distributor was just out, and looks great. I tried another distributor this past weekend, and the problem persists. The distributor connector from the MSD is the same one that I used before with no problems, so I know that the wires aren't crossed.

Thank you again to everyone for your responses. You're ideas keep me thinking and I find them very encouraging. We'll get this figured out eventually.

-Ben

Re: Help!! Engine Miss
 

My first thought was the wires from the msd box to distributor, do not let them go anywhere near the coil, I know this has been suggested already. So I would look at the wiring/ switches you changed then I would throw a different carb on and see.
I have had two quadrajets over the years that went bad all of the sudden. They would not rev over 4500 rpm. Rebuilt them several times with the same results. Finally gave up and they are in the trash now. Don't assume the carb is ok, the only way to know for sure is by trying a different carb.
If a different carb doesn't work, I think I would rewire the entire car with a nice new switch panel.

Re: Help!! Engine Miss
 

Hey Ben! just my 2 cents but you dont have solid core sparkplug wires do you ? because i learned this one the hard way years ago before MSD posted a warning about the RF interference from them screwing up the operation of the MSD box. Good luck and hope you find it soon. Kevin

Re: Help!! Engine Miss
 

Had the same thing happen to us. Had a fresh motor right off of the dyno (ran great on the dyno) put it in the car and it picked up a miss. The cause was a leaking header gasket. Put new gaskets on..... problem gone. Just a thought.

Re: Help!! Engine Miss
 

Ben, have you checked fuel pump flow and your fuel filter? For an engine like yours, the pump should flow a gallon in 15 to 20 seconds to keep up with the QJet demand. Anything more than 20 seconds is suspect. The filter could be clogged inhibiting flow. If you have a return style pump, where is it plumbed back into the cell? Good luck.

Re: Help!! Engine Miss
 

Dumb question but was the cam changed and is a 4-7 swap?

Re: Help!! Engine Miss
 

Monte,

Thanks for the thoughts.

Kevin,

I'm running MSD 8.5mm plug wires. No solid core.

Arnold,

I checked the fuel filter when I drained the fuel system, and all is well. I can fill a gallon in about 23 seconds. I had previously been told that anything under 25 seconds was ok. Regardless, my problem is occuring when I'm barely tipping the throttle. I would think that even if fuel flow was insufficient for racing, I'd still be able to drive it around the block.

Bob,

Not a dumb question, and yes I did install a new 4-7 cam, and yes I've checked and rechecked the wires about 2 dozen times. I always assume the possibility that I've done something foolish.

-Ben