rotornoob

iTrader: (2)

Ok so I started repairing/building my car not too long ago and decided to tackle an issue that has plagued me since I bought the car. When the car idles ( hot or cold ) it has a miss. I never hear/feel it miss during driving, only at idle and it never backfires.

I'm thinking ignition since i would suspect a bad seal to miss even during driving. but I'm not sure where to start. It fires right up every time, whether its a cold start or a hot start. Carb was rebuilt about 4 years ago and it recieved fresh floats so I don't think the carb is the problem as it doesn't run rich. It currently has new plugs/wires and the ignitors tested good.

Coils are good, but old. Ignitors too. Question is which parts tonstart replacing first. It will pass smog this way, but I'd rather have it run right, not just smogable. Vac lines are relatively new and as far as I know all emissions components are working properly.

markmazda

When it starts missing, put a timing light on each of the plug wires to see if they are all firing normally and not missing...point gun at hood/etc and watch for missing flash.

rotornoob

iTrader: (2)

^will do. Ill let you know the results.

project7s

iTrader: (5)

What year is your car? If its an 80 model they have an igniter box which has a cross triggering problem. Mine is an 80 and it does the same thing your describing and I'm beliving that's my problem.

rotornoob

iTrader: (2)

Mine is an 85 gs. Had to postpone the testing as I'm dealing with cleanup issues after I made a dumb mistake..I let the battery sit connected to the car for too long and the corrosion around the terminals was horrible not to mention the battery is dead as **** now...so for the moment I'm cleaning up that whole mess and saving for a new battery. You can check my build thread to see the condition of the battery...its not the worst I have SEEN, but its the worst I've ever had in one of my cars.

NCross

iTrader: (18)

Check the distributor gear shaft for end play.

rotornoob

iTrader: (2)

Will do. Should be easy enough with it parked in the garage right now

rotornoob

iTrader: (2)

Lol ok so I'm suprised I didn't find this sooner, but I may have found the issue.. there is a body ground from my negative battery cable that wasn't making a very good contact, so I think that may be a part of the problem. Also, upon inspection during cleaning, I noticed the ground on my leading ignitor was not properly tightened all the way. When I attempted to loosen it the whole post rotated inside the coil. I'm able to turn the nut the other way and the post inside the coil feels like it tightens in to some kind of threading. Still can't get the nut off. I'm thinking that both of these could cause my problem. I checked the dizzy shaft for play and found nothing to be concerned with.

That having been said, I think I'm going to replace my coils with blaster coils, fix the body ground, and when I come up with a battery I will see if that fixes the issue.

NCross

iTrader: (18)

Blasters are expensive! Hope it helps.

rotornoob

iTrader: (2)

Yeah they aren't the cheapest, but I'm of the frame of mind that when smething needs to be replaced, upgrade it

rotornoob

iTrader: (2)

Besides its only 20 $ more than the stock coils...

Smokeyfb33

iTrader: (8)

I have the same mindset and I was thinking of upgrading my coils in the near future as well.

What are your plans? I was looking at the 8203 coils, I could find them on ebay from $30-50.

Do you plan on getting two and running them in the stock location?

rotornoob

iTrader: (2)

^ yeah I was looking at the 8203. I'm planning to run both as stock replacements with a 6a box later on down the road.

Eventual engine swap will probably force me to upgrade again later, but it should be fine until then.