flooding out FC3S4 N/A
 

Im working with the guy selling me an 86 FC3S4 to get it running before i have him paid off. initially this is what he said:

I secured a used CAS and he swapped them but

He's got a T-II FC for his own and is a competent mechanic. I just picked up some known good injectors to send to him, but does anyone have any additional thoughts on what might be causing it to flood that fast?

Low compression is a likely culprit. If gas blows past the seals much it'll wash out the oil needed to seal the chambers, and then it'll just crank and crank because it can't build compression. This is a very common problem with low compression rotaries. A temporary fix sometimes works, you can install a fuel cut switch so it doesn't just POUR fuel into the chambers on startup. You probably will have to rebuild a motor with that low of compression before soon though. I would keep that in mind. My TII came to me with probably 80psi compression and had the same trouble starting and I used a fuel cut switch to help it start. I was probably lucky to get ~8,000 miles out of it before it let go. I knew it was coming though and I had stocked up on all the parts I needed for a rebuild, so when it died I was prepared to build myself a new, better motor.

i thought 80-90 psi compression was good....(HIS T-II has the 50-60psi, not the N/A he's selling me)

does the FC have a flood threshold for the throttle? floor it on crank and it cuts fuel?

any way to temporarily re-oil the seals? put a bit of oil in through the intake or spark plug holes and crank it over?

injector problems CAN be the cause of the issue. I had a string of rx-7s come through once that all had serious running issues from constant flooding, stalling and bucking. They all turned out to have bad injectors.

you know, that might have just been the gauge.

I tested my car with two gauges that both got 90psi, and then with this other one that only displayed 50psi, and I was like WTF?

So it might just be the gauge.

90 is rebuild time. My NA rotors pump out 110-115 on both faces with pulses up to 60PSI on any single compression.

well, i can't afford a rebuild ATM, (student, i.e. broke as hell) provided the engine is in good shape, can a rebuild be just the apex, side seals and a small list of other parts? the master rebuild kit on Atkins was like $900...

Im hoping that its the injectors and she'll run with better ones. im guessing an oil change is in order after all the flooding.

I know I will need to rebuild the engine, but a 100k one is better than a 140k one, so for now it will do. (old one had a coolant seal pop in 3 places on the front iron)

50-60 psi is really low, even for a TII. And you can't compare compression numbers between an NA and a TII. TII's come with lower compression rotors and NA's are higher compression. So if you had an NA and a TII that both got 80psi, the NA is probably a lot weaker than the TII.

So back on topic, the motor probably has lower compression than he's telling you. If the injectors you sent him weren't professionally serviced then they will still probably leak and cause more flooding. The injectors and low compression are what cause flooding.

any particular reason you think the compression numbers are lower than he says? (hes a long-time member of a forum im on and a standup guy by general consensus) FWIW the injectors i sent came out of a running N/A so...*shrug*

on the subject of rebuilds, is there a quick and dirty rebuild to get the compression up to where it should be? im not liking the $900 pricetag for a master kit... aside from seals etc, can you do just the seals and such and have a refreshed motor?

The only way to save money on a rebuild would be to see which seals are still in spec (IE Apex seals). If your Apex seals are still in spec you can probably find a kit that doesn't have them included which can save you some money. Also, find out if your oil rings are in good condition as well as your side seals, then you might not have to get those seals either (though it is a good idea). After that you will just need a gasket and seal kit for taking it apart. Honestly if you're getting low compression and you're flooding out it very well could be leaky injectors in which case your compression numbers are lower than what they should be. If the injectors are not faulty and are in good condition you're still low on the compression side which can mean a few things. Your apex seals are out of spec, your side seals are toast, etc. It just all depends.

ok, ill see what happens with the new injectors. ive had experience with gunked injectors on my Duster, so i know how much of a PITA a stuck open injector is.

Atkins had a rotor kit or something like that which was apex, side seals and some other parts. is there another supplier for rebuild parts other than atkins?

There are, but their prices are more expensive from the ones i've been able to see. Not sure though. Check their vendor section for a deal they're doing with re-build kits. It's not a bad deal all things considering.

Well like its been said already, the causes for a flooded motor are leaky injectors and or low compression. Just because you got injectors from a running car doesn't mean that they wont leak either.

The S5 cuts fuel if you put the pedal all the way down, but the S4 does not.

http://www.rotaryresurrection.com/2n...nflooding.html