mak297

Hey guys, I'm sure somebody out there can help me with this. I have a first gen rx7 with the 12A motor and I've done everything I can think of and it just won't start, it tries and tries to fire up and gets really close but just won't fully start. I've replaced the distributor cap, distributor rotor, checked the fuel pump and lines and plug wires and I don't see any reason it shouldn't start. Any ideas?

diabolical1

iTrader: (3)

when was the last time it ran?
are both coils firing?
have you verified wire placement?

check the compression.

cab91089

iTrader: (3)

Could be a bunch of things. Check for spark, if spark try deflooding the engine and making sure the battery is fully 100% charged. Carb could need a good cleaning/tuning.

mak297

Thanks for the input guys I appreciate it. Just ordered new spark plugs and wires last night. Might need new coils also. One of the coils was arcing when I turned the engine over. But it looked like it was being caused by a bad wire. So I guess I'll try that and go from there

nofussgus

Rebuild Carb.

photoman

Check all the basics... spark, fuel, etc. Make sure it's not flooded. Confirm the timing. etc.

mak297

What would cause one of the coil packs to arc?

gerald m

when the coil releases it's charge if the plugs are fowled or wires are poor most often the spark jumps at the coil because there is no where for it to go . possibly the coil is dirty or oily . The spark follows the path of least resistance . make sure there is no corrosion inside the coil and wires are pushed all the way on

ghost1000

iTrader: (1)

Spot on. Consider a waste fire system. Fc3s coil is nice. If u eliminate ur trailing u won't need to buy another coil. It's a clean setup.

mak297

Thanks for the input guys. I just pulled my dizzy cap off and found a broken rotor button due to the cap not being seated on there correctly. I think that may have been causing it to spark at the coil. Could you explain a waste fire system? AMD the fc3s coils?

Cookboy

iTrader: (10)

The fc coil direct fire (2gdfis) search it. It's a cheap and easy ignition upgrade. I'd love to drive up and see what you've got. What are your days off normally? I'm 45 minutes south of you, I think.

kmad86

Came in for this

Cpeters

check all grounds, arcing at the coil can indicate pore ground contact at the motor leading to the arc aat the coil to the body. fouled plugs is possibly but unlikly since the arc distance to the housing is shorter than the coil to the body. likewise bad coils that have just been cooked can lose their shielding integrity and short straight through the pack more likely on an RX8 that a 7 the OEM coils are rather hearty.

ghost1000

iTrader: (1)

Fc3s coil is a stock coil from an fc3s/second gen rx7. The leading coil is a waste fire configuration.

Waste fire means firing two or more plugs at the same time. One spark ignites fuel while the other spark is wasted. This can only be done with the leading spark plugs. If u try it on the trailing u will blow ur motor. The benefit to a waste setup is u bypass the distributer cap which has resistance do to spark arching from cap to rotor.

FYI always keep the factory coil boots from your old wires. Taylor yourself some msd 8mm and reuse the old boots to fit ur factory coils.

mak297

Thanks for all your input guys! We tried a few more things and she fired up! Now I just have to drain the fuel tank and clean it out..and rebuild/clean the carb up

Cookboy

iTrader: (10)

Good show!

ghost1000

iTrader: (1)

If u ever want to try a Holley carb I can walk u through the setup. Forget about the drivability problems if u build it how I tell u it will run great.

gerald m

I would be interested in what you have to say about the Holley for the rotary . Good to know others thoughts on the subject .

GSL-SE-S5

+1 for waste fire....i did MSD 6a instead of FC coil but FC works and is cheaper

ghost1000

iTrader: (1)

A 12a with miles I wouldn't go bigger then the 450cfm.
The secondary venturies can be bored out and I have the tool to install annular boosters. The pump cams need to be custom made and the idle slots modified. I also make idle air bleeds that press in. 5/32" brass cut and drilled on a drill press. U can buy parts all day but its the parts u make thy make the difference.

gerald m

seeing as things are slow in this thread . I have played with holleys for some time and just like to know what others are thinking . So what in your opinion would a 500 2 barrel need for mods to work on a 13b na not ported but well cleaned and opened up a tad . single fire direct fire , maybe buy a msd in the winter to play with . not in a car on my drag bike . be honest but don't cut to deep .

ghost1000

iTrader: (1)

The biggest problem with the Holley is low idle and low rpm drivability. A 600 Holley is basically a 300cfm 2 barrel under normal driving conditions, so using a 500 Cfm 2 barrel would be harder to work with.