Well, I know this has probably been covered before, but I only found one thread with a similar problem to mine, and he never got an answer. So, anyway we finally got the engine rebuilt and back in the car, and got everything hooked up, but unfortunately the car just won't fire up. It appears that it might be flooding because the spark plugs are covered with fuel. All of the plugs seemed to be firing alright though. We did run a compression test and were seeing about 75 in the rear rotor, but only like 40 in the front. :( I'm not sure if this is cause for concern on a new rebuild, but it seems to me like it should be. :( This is a full rebuild with all new hard parts, gaskets, and bearings.



I've eliminated all emissions equipment per the guide over at rx7club(Am I allowed to say that here?). It appears that all vacuum lines are connected, as well as all electrical connections. We pulled the spark plugs and decided to just let it sit over night and dry out. The only other thing we could think of was the battery. It's the battery that was in the car, and the car was sitting for several years. We let it charge all day, and it appeared to be holding a charge. I guess it's worth a shot to try another battery anyway though eh? Does anyone know what could be the problem? Thanks for your help.

make sure you set your cas/timing, then do it again to make sure it is right, then, yea check it one more time...after that push start that bitch down a hill or somethin. keep it running and see if it idles, if it doesn't u prolly got some vacuum leaks as i did... also keep your eye on your coolant temp gauge just in case. good luck

Alright, well we checked the timing 2 or 3 times. It looks right on. I'll check it again tomorrow. Prolly try a new battery, then maybe try push starting it I guess. I really wanted to avoid that because if it doesn't work I'll be even more screwed than I am now with my dead car down the road instead of in the garage.



I can't figure out how you're supposed to fill the damn coolant. we got about half a gallon in there, and it takes 2 but the thermostat is blocking it on the one side and the low spot in the hose is blocking it on the other. I'll definately be keeping an eye on it though for that reason.

try putting a lil ATF on the engine, it will help build some compression, or someting like that. thats how i got mines to start, we had the same problem, thought it was bad timing, then my friend comes over and poured some ATF and after a few cranks it started. and definately get a good battery.

timing is a very important



go to Lighting in a World of Thunder for INFO and tips

then comeback here if you have problems.

check all your grounds..... if everything is fine. roll it down a big hill and pop the clutch

yea wat treceb is sayin is tru try puttin some atf on in the engine because most likely its the compression that wont let it turn on and also check ur coils and how much spark ur getting .. check if there is any spots or places where air is escaping like on the intake if u torque it too much that might cause it to let air come out and things like that

PUT MARVALS MYSTERY OIL IN BOTTOM TWO SPARK PLUG HOLES(MAKE SURE YOU FLUSH ALL EXESS GAS BEORE DOING THIS). ADJUST TIMING ON CAS WITH PULLY. GET A GOOD BATTERY(VERY IMPORTANT WHEN TRYING TO START A REBUILD-MUST BE SPINNING FAST).mAY HAVE TO DO THE OIL PROCEDURE A FEW TIMES BUT IT SHOULD START. MAY WANT TO HAVE A FRIEND WIH YOU WHEN YOU DO THIS BECAUSE YOU MAY NEED TO ADJUST THE HARD IDLE SCREW TO KEEP IT IDLE.(DO NOT LET IT DIE WHEN YOU GET IT STARTED, STAY IN CAR AND GIVE IT GAS WHILE YOUR FRIEND ADJUSTS SCREW. THIS IS ONLY MY EXPERIENCE WITH REBUILDS( ABOUT 12). IF YOU HAVE ANY MORE QUESTIONS PM ME

don't give up man, **** is very very very frustrating but i once u get it all good, everything will be gravy

What is the hard idle screw? Isn't that something on the N/A's?



I might try the ATF thing tomorrow I guess. I really wanted to avoid push starting the thing because my road is kinda curvy and I don't want hte car at the bottom of it if it doesn't start, but if that's what it comes to then that's what I'll do I guess. Thanks for the help everyone.



We've had some trouble timing it. When we connect the timing light to the trailing wire, it shows the exact same timing as the leading wire which is not right. That seems to mean to me that they're all firing at the same time. When we pulled the plugs out though, they're firing at different times. I donno what the deal is with it.



Also, all the idiot lights and gauge cluster lights are on whenever I turn the key on, but I don't think it was like that last night. I messed with the EGI fuses today, but that was it. Anyone know if that problem could be related? Or if it is even a problem after the car is started?

Well, we tried pull starting it today. It coughed a lot of smoke, but that was about it. Still never fired up. We had the intercooler off because we put some starting fluid in the throttle body before that, which is probably a no-no. I donno if that would have anything to do with it. I'm quickly running out of ideas though. :(

did you have it soaking in oil? when i pushed started mine i had to do it many many times but every push it became easier to start. keep trying!

This may sound stupid.. but are you sure the wires on the plugs are hooked up right.. the vert I bought would not start because of this.. once I fixed that it never gave me a problem again..

What do you mean, did I have it soaking in oil? We oiled the engine per the Haynes manual when we put it back together. The engine is getting oil pressure when try to start her up.



Maybe I should doouble check all the wiring. Is there a good wiring harness diagram somewhere online? The Haynes manual didn't really have crap, so we pretty much has to guess by the memory of the wires and the connectors. All I really need is something that shows the wiring harness and the connectors in order from one end to the other and says what they all go to.

this wiring is probably your problem. check fc3s.org for the factory service manual, good way to double check everything else to troubleshoot too.

Sorry but 40psi is way to low if using all new parts.



I just finished rebuilding a 12a with all used parts except for new apex seals and soft parts, all of the reused parts were checked properly specially side seals and corner seals.



I have been testing compression everyday this week and it started up pull started with a compression of 80 and 75 psi cold (no oil added), now after 4 hours of idling is up too 83 psi and 80psi when hot. It's still difficult to start but it starts up with a few drops of oil since it floods easily due to having a weber carb and no fuel cut off for it since the carb holds gas in the bowl.



Your engine should start pull started even at 65 psi but 40psi is too low and might be a bit difficult but it's doable, you should check internal specs again if everything else fails.



sorry for the bad news.

how where u measuring compression?

Using a compression tester in the spark plug hole, while cranking the engine.

Well we got her running finally. https://www.nopistons.com/forums/pub...#>/biggrin.png We pull started it in reverse of all gears. We noticed it seemed to like reverse when we pushed it down the driveway to start off with so that's what we used. The idle was real rough to begin with but it seems to have smoothed out, though it still bounces a little bit. At first it wasn't wanting to idle at all. Then it would idle at like 500rpm, but we noticed that we forgot to hook the BAC back up so after that it's up to about 750rpm, and it will hold the idle better. We drove it around the neighborhood for about an hour, and it seems alright. There's a pretty big jump in power around 1500rpm though, which I'm not sure is normal. Below that it doesn't really feel like it wants to go, but above that it accelerates a lot quicker. Now our problem is getting it to start on it's own. It will push start relatively easily, but it won't start by itself. Any ideas as to why? I killed it at a stop sign a couple times(my first manual car), and we had to roll it back to get it to fire up again. If we just drive it more will it start on it's own, or is there something else we need to check?



Thanks for all your help thus far, by the way. I really appreciate it.

try to get it to idle as well as possible, then get out and spray starting fluid on all of the parts that connect to each other,(injectors, manifolds, ect.) see if the idle revs up,

Isn't it supposed to idle at 750? The Haynes manual said 750+/-25rpm. I assumed it was the same for all models, but maybe not?

Sounds like low compression due to apex seals or side/corner seal clearance being too great.



My first ever rebuild was the same- pull started really easily but couldn't start on the key. Mind you, I was using second hand seals that I had scrounged out of a couple of dead motors and didn't have a clue what I was doing back then (and some would argue I still don't... https://www.nopistons.com/forums/pub...IR )



It could be a huge vacuum leak somewhere, I guess that would be the first place to look. If it's still no good, there is a fairly radical measure you can take, which is to put some bon-ami (Ajax or Jif?) powder down the inlets which forms an abrasive paste and beds the seals in very quickly. This used to be a Mazda recommended procedure and bon-ami actually had a Mazda part number!



You know the powder I mean? Household cleaner used for cleaning sinks etc.



It might well be this that's the problem but if it's too great clearance on corner to side seals, you'll have to rip the engine apart and re-clearance them. They always have to be clearanced when new. Did you do this?



Also, what condition were the rotor housings in? If they're not perfect it can take some time for the apex seals to bed in.



750 idle is about right. It will hold idle ok even if the compression is too low to start on the key...

Well my dad went out there and started it this morning, and he said it started by key but didn't want to idle. Strange it starts when cold, but not hot eh?



Hmmm I don't guess we clearanced the seals that well. I used all new seals in the engine. We ground the seals down to make them fit in the rotor, as the manual said. We tried to get them as close to perfect as possible, but I think we went over a bit too far on one or two of them. I also had to use one old seal, because I broke one of the new ones sanding it down. The front rotor was kind of screwed up though, because it was carbon locked in the housing and no matter what we couldn't get it out. So we had to take the front half of the engine apart backwards(front housing first), and then once we got it apart, we had to beat the rotor out of the housing because we couldn't push it out. The engine had been sitting for something like 7 years I figure, though it only had 60k miles on it. I was amazed by the amount of carbon in it. Anyway I think that the seals might be sticking where we hit the rotor because those were kinda tough to get in. We had to sand down the bit where corner seal goes in to get it in, and it still didn't feel as smooth as the other rotor.



I suppose the next thing would be to check for vacuum leaks. I need a gauge or something I guess.



Why did Mazda stop recommending the bon-ami thing?

try to get it to idle as well as possible, then get out and spray starting fluid on all of the parts that connect to each other,(injectors, manifolds, ect.) see if the idle revs up



do this to check vacuum leaks,, very easy. hold engine at about 2k, it will work better

If you build the motor with used parts you have a chance of it coming in after at least 1000mi. of driving. You said you used all new parts, well 45 psi. with new parts means to me it was not put together right at all. All your symptons are classical low compression.

Ya man not to be a bummer, but you need to check your compression again. Do one spark-plug hole at a time. Unplug the connector to the destributor so it wouldn't spark on you and then check each camber for compression. You should get at least 85 psi out of each camber and they should also be closely matched to each other too. In other words 87 for the front rotor 90 for the rear. If not or if either one comes in below 85 psi your going to probably have to go back in their and correct the sealing problems. Just for an example a fresh rebuild with all new seals, clearenced and installed correctly should give you over 100psi compression at each camber. Do this first before you spend anymore time or money and get back to us with some hard figures after.



PK797 NYC

You really need to do another compression test. Get back to us with some hard numbers. Check one plug at a time and disconnect the plug going to the distributor before you start cranking so you don't get spark. Let us know what you get. P.S. what year/model is it?

PK 797 NYC