kurtoli2

Second attempt at rebuild. First build had water seal o-ring issues so I was never gonna start it up. Like trying to ignite water.
This time around and after learning a lot, I have a beautifully renovated block that I air pressure tested before installing to car. It holds coolant nicely and has good compression.
Confirmed spark is strong at the plugs.
Confirmed e-shaft angle when I installed the pulley and have perfect line up with the distributor cam, leading and trailing. At least good enough for initial start and can do timing light later.
Had to really work at the fuel injection rail because every time I cranked the motor, the fuel pressure blew out the seals and I had gas everywhere. I ended up using brand new seals from my Dodge Caravan that I had on hand and it seals the entire injection system much better. Holds pressure, not a drop leaking. I also tested the injectors for resistance and continuity before installing, and the leads/clips are brand new and receiving voltage from the harness.
Cranks well....doesn't start. I figured this time around I'd be able to start it right away, but no..nothing. No indication anything is firing.
wtf. I've done plenty of piston rebuilds and they always start up, even if things aren't perfect. Not feeling too good about rotary engines at this point. Seems way too sensitive to everything, and if I can't even get it to fire up after a good rebuild, I wonder how reliable a working one is gonna be.
Anyone with some tricks to firing up first time?

diabolical1

iTrader: (3)

Do you hear it trying to start at times or not at all? Also, a few key questions ... are the cap and rotor new or at least in good condition? What about the plugs? Are you getting all six pulses?

There are also a few things you could try.
- reinstall the distributor, it's fairly easy for it to be a tooth off and it costs nothing but a few minutes of your time. Maybe use another method to locate TDC? Doesn't hurt.
- sometimes you can install the distributor correctly and the engine is still unhappy with it for that first fire, so (for lack of a better or technical term) you can look for the sweet spot. Oftentimes it's not where the timing needs to be set, so keep that in mind.
- maybe try a thicker oil to coat the chamber walls (some rebuilds can be particularly stubborn in building initial compression
- put a little Seafoam in the chambers
- crack the throttle a little
- pull start it

I'm out of ideas for now.

Don't be discouraged. They can make you question your sanity, but once you're driving one, all the despair pretty much melts away. Also, they can be very reliable. I will stand by that statement all day.

kurtoli2

There's no indication it's going to fire up, no. It cranks well though. lol. I alternate between cranking for a bit, then removing the plugs and cranking to blow out everything in case I'm flooding it.
As I mentioned, before I installed the motor I set the e-shaft keyway to 9:00 and then mounted the pulley accordingly, because this is one of those 13b's where the pulley can be positioned any of 4 ways. In fact, to be sure I didn't mess that up, I spent about 45mins yesterday, unbolting the pulley and moving to the next of 4 screw holes, mesh the distributor with the new location, try cranking, then do that all over again until I was back to my original position. There was no indication of firing at any of the alternate locations.
The cap and rotor are brand new, and I rebuilt the distributor when I rebuilt the motor, and the L and T plates in the distributor are set to be in optimal positions for Trailing and Leading initial timing. What I am wondering after taking the plugs out tonight after a lot of cranking is why it doesn't smell like fuel. All of that should be working, but it could be that there's no fuel getting sprayed in to the chambers...again. That was the case the first rebuild and so I bought new injectors, but it seems like they only worked for a little while (i.e. I could tell when they're working when if the plugs were out and I cranked the motor there was a fine mist of fuel coming out the plug holes - I usually disconnect the terminal on the coil to turn off the fuel pump and spark, but now it doesn't seem to matter....there may be no fuel going in either way). I'll look at this latest development and update. Thanks for all of the suggestions. Yeah, I drove this car a lot before the rebuild, and it's my 2nd RX7. But this is the first time I've attempted to refresh one of these. Not having the best of luck. Love rotaries, but would be nice to hear it run again.

diabolical1

iTrader: (3)

Somehow I thought fuel was confirmed already. No worries. That's where we are now, so okay, possibly no fuel at the chambers. You said you confirmed positive voltage at the injector, so I guess the next step is to confirm whether the ECU is grounding it or not. If that checks out, then the next step would be rig up a way to check the injectors or try known working injectors in the car.

Not sure why I missed that in your original post. Sorry.

diabolical1

iTrader: (3)

Something I completely forgot about the SE ... check out post #8 in this thread: https://www.rx7club.com/1st-generati...o-gas-1059716/
Worth a shot. right?

kurtoli2

That's an excellent read. Thanks for that. It's the most sensible direction I've considered so far. There has to be something very simple going on that isn't obvious but completely shuts down the entire works til it's fixed. Good spark, good compression, good injectors, reasonably confident timing is correct. Something isn't allowing the system to function as a whole and maybe it's a simple as that fusible link box. I have messed with those links and they seem old and fragile. I just ordered an entire new set from Atkins. I'll give it a try and update. Including some pics of the newly rebuilt patient.

diabolical1

iTrader: (3)

That's because they are. You never really think of them until one of them goes bad. It's a pity you bought new ones though. It would be better to just replace them with fuses like the Bussman FLF-type. You just need to figure what ratings equate to each of the fusible links you're replacing.

kurtoli2

I am considering getting a new fuse block of more modern type and upgrade this thing. But the links are only $6/ea so it's a quick way to see if that's been the problem all along. I'll still upgrade.

diabolical1

iTrader: (3)

Your engine bay looks nice. Is that Tender Blue?

kurtoli2

That is the original color, blue, which was very common for the 1985 RX7. It needs a new paint job after I'm done with the mechanical restoration and I'm sticking with the original factory Blue.
Still no start up, but I found that the wiring to the control solenoid (and the solenoid itself) at the transmission is damaged so I'll replace that before further troubleshooting. Other things like turn signals and emergency flashers are also not working, so I need to get the electrical in order before figuring out why the injectors aren't working. I have good spark at all plugs, but neither the fuel pump nor the injectors seem to be doing anything. All fuses and fusible links are good.

tim.

iTrader: (1)

I would try taking off the rubber air intake and have someone spray carb cleaner or throttle body cleaner in the intake while you crank the engine. It will fire on that if the ignition is correct.