Poindexter10thae

iTrader: (2)

Ok, I recently acquired a 88 10th ae. w/ blown motor. I swapped in my 91 jspec(swapped the front coverer w/ a s4 motor) removed all emissions just like Kevin Landers told me to(followed your instructions exactly. I am still running the BAC valve. here is my current setup

91 jspec motor w/ 120psi compression on each rotor
60-1 HiFi hybrid turbo
s5 manifolds
s4 throttlebody(w/TB mod and s4 tps
no smog pump
no acv, egr, or rats nest, running vaccum to boost sensor, FPR, and Oil Injectors(oil injectors are connect to stock port, this was left untouched)
s5 CAS
Walbro fuel pump(getting steady fuel, good fuel pressure)
Using S4 T2 Harness w/ all S4 sensors

I have fresh gaskets on all manifolds and the throttle body, all vaccum ports that are not in use are plugged, I have good engine ground.

one of my major concerns is that I may have the cas stabed in 180 degrees. I dissassembled and reassembled the main pulley assembley, mazdatrix told me that they will only bolt up one way (asymmetrical, idiot proof) so I set it at TDC and stabbed in the cas(with the cas aligned to mark on gear)

I have swapped several N/A engines, done 1 n/a to turbo conversion, and 2 turbo motor replacements(stock stuff) , this has got me completely boggled, please help.

The engine will crank over all day, but will not fire, rotates great.

I do have 1 stray connector coming off of the charging harness, there is the lead that goes to the oil level sender, and another lead that I forgot where to connect it and cant find a stray lead similar to this(been drinkin a lot) this lead is a single red wire with a male spade type of connecter shrouded in a plastic housing that holds the locking tab for the other end of the connector. where the hell does that go??

Please help me out , i gotta get this car under its own power by tuesday.

BlackRx7

well just as test you might want to check

1: Spark
2: Fuel
3: Throttle linkage..

if anything else this will provide a bump

AreExSeven

Well, I'm none of those guys, but I'll try to help anyway
To me it sounds like you are lacking spark or fuel. Have you checked the plugs removed form the engine to make sure they are sparking? Are you sure you are getting fuel?

You can only align the pulley 1 way, it has notches that will only allow one way. So I doubt your CAS is set up wrong.

Do some tests for fuel and spark and then come back with the results.

Sounds like the Oil Pressure Sender, but I can't be sure w/o a pic.

Poindexter10thae

iTrader: (2)

Yeah forgot to mention that I am getting spark, but I am getting fuel and compression as well. the oil pressure sender is connected, so is the oil level sender, this wire comes out of the harness in very close proximity to the lead that connects to the oil level sender.

AreExSeven

You have to not be getting one of those vital components. If you had them all, the car would at least rev up quickly, rather than just cranking.

How did you test for fuel?

HAILERS

Darn. Should start. But.......I'd go pull the cas. Align the pulley with the pointer. Take the top off the cas, two phillips screws. Lay the top cover to the side.

Align the marks on the bottom of the cas, and hold that position with your fingers. Now look in the top. Mentaly select a tooth, any tooth, and look at what is exactly opposite that tooth on the body of the cas. A part that does not move. Now reinsert the cas. You can see the tooth that you had selected has moved away from the fixed point on the cas. Now rotate the body of the cas til the tooth once again aligns with the fixed place on the cas. Lock the cas down. Now try to start the engine.

Now that the above has been done......if it still does not start, try pouring some motor oil into the intake. One fellow on this site used the bac's hole to do that. Maybe a full cup of motor oil. Pull the lower plugs and rotate the engine so the oil will relube the apex seal to give you more compression. Just a five to ten second spin should do the job. Reinsert the plugs and fire the engine up.

When you pull the plugs out in the above procedure, see if they seem to be heavily saturated with fuel. That might give us a clue if it's flooding. If that is the case, you might disable the fuel pump and spray starter fluid into the intake before the air filter. A blast of five seconds should do. Then try again.

Personally I've never had to pour oil into the intake on a series four, but I had to do it on my first gen. It had a handy carb that was easy to pour into. I abused that poor car sooooooo bad its compression was an amusing figure. Needed help on occasion to start up .

So I figure the timing was off due to the cas turning as you put it in the engine . And the compression is way low because the fuel has washed off the oil around the apex seals giving you low compression which in turn makes the engine hard to start.

BlackRx7

But it is possible to drop an S5 TII engine in an S4 TII without changing the ecus and or wiring harness? just the front cover correct?.......cause I maybe getting a new engine for my 88 also...

Rotorific

iTrader: (1)

you cant use an s5 engine and run it on s4 brains. If he didnt swap it then thats a big part of the problem.

dr0x

Rotorific sure you can.

hypntyz7

Order of troubleshooting a rotary, for those who dont know:

1) compression, cause it's the easiest to overlook and the more common problem...part of regaining compression on an engine that is flooded or has sat a while is to inject oil into the chambers, either through the lower plugholes, or pumped slowly into a vacuum hose/nipple that feeds both front and rear rotors/intake runners. Even if you dont believe flooding to be an issue, its worthwhile to inject some oil, this will eliminate any possibility that flooding is a problem, and its a quick fix.

2) spark, cause it's quick and easy to check. insert a plug in each wire and lay it by a ground to observe each wire's spark...

3) fuel. start by being sure fuel lines are on properly; supply (from fuelfilter) goes to the forwardmost line on the engine rail, which goes to the primary (lower) fuelrail. Next, pull off this supply hose, crank for a second, and see what comes out. This can diagnose fuelpump issues. Finally, if fuel delivery is still in doubt, after having checked all fuses inside and out, remove the upper intake and the lower fuel rail. Tie both injectors to the rail, put them over a pan, and crank the engine over, while a friend observes. Youre looking for alternating pulses of fuel. THis is a good method to troubleshoot wiring harness/ecu problems, but is also a bit hard for the newcomer to do, and should be regarded as a last resort.

After all this I begin to wonder about something like a CAS setting etc. By now, there isnt much that can hold the car back from running, or at least trying to. Hailers gives an excellent description of how to set the CAS. Even if you get it a tooth off, the car should start and run, though maybe not idle, or run realy smooth...

NZConvertible

Dunno where you got that idea, but it's wrong. In terms of control, S4 and S5 motors are practically identical, with only the front cover (for the MOP) and the TB (for the TPS) needed to be swapped. The ECU will have no problems with the slight increase in compression ratio.

Poindexter10thae

iTrader: (2)

Thanks guys! ok heres the deal, about to go to work. but
1. Already checked the deadhead, and inline fuel pressure from the fileter to the primary rail. installed test gauge in series on fuel line and turned key to on position, I have a walbro so it did exceed the factory specs slightly(in pressure and volume tests)

2. I'm gonna double check spark.
3. Thanks for the tip on the cas hailers, reminds me of stabbing in a HEI distributor on a SB Chevy.

4. I already installed a LED on the wires of the primary fuel injector leads(1 for each inj) had a buddy watch the led and both led's activate when cranking the motor. Still gonna pull primary fuel rail to verify injector output.

I'll keep yall updated, this motor will come alive today

HAILERS

I forgot. While your cas is out of the hole, take the wires out of your LEAD coil assy and just lay them within a half inch of the coil bore. Now turn the key to ON. Now rotate the gear on the cas. Sparks should crackle and pop at the wires, showing that you have output from the cas/ECU. Then stab the cas as described in the other post.

hypntyz7

still good thinking but that only diagnoses wiring problems and verifies the signal, not that the injectors themselves are truly opening...

Good idea. Most likely not the problem, but there are a limited number of things available to stop you from running...

Poindexter10thae

iTrader: (2)

Ok, here are my findings for today. I have no spark, and my injectors are not firing.

I am not getting any spark from the coil to the wires, I dont even have 12v at the leading coil harness connector(should be 12v with key in on position).

Also, I am no longer getting signal from the ecu to the primary injectors, I have plenty of fuel, fuel pump test results have not changed.

I am beginning to think my ECU is bad

3 days ago I had spark, but my injectors were not connected properly(connectors hooked up to wrong injectors), I fixed this and now I am not getting any spark. I am hesitant to say ECU, because I just had spark the other day, and signal to the injectors. What could possibly affect the ecu from firing the injectors and not putting any power to the coils?

hypntyz7

I will bet it is not your ecu, they dont just die. I assume youve checked all your fuses? Also check your main relay if you get no power to the coil. I am betting you have a wiring problem at this point, or a fuse/relay.

Cheers!

i would say give it another go with a fresh battery that you know for sure its good...

Poindexter10thae

iTrader: (2)

All fuses are good, you should know im not that dumb

The main relay was my next concern, spent the better part of the evening scouring the wiring diagram in the FSM, and everything goes through the main relay, im assuming the test procedure for the relay is in the FSM, but im too exhausted to look.

again, thanks for the help.

86OrangeRx-7

I know this is stupid to say and you probably already have this checked.. but on j-spec engines aren't the fuel lines switched ?

scathcart

Are you using a complete Jspec assembly, or just the shortblock?

Poindexter10thae

iTrader: (2)

Yes they are on the J-specs. BUT I have removed the rats nest, and I am running the fuel line directly to the primary fuel rail.

Poindexter10thae

iTrader: (2)

I am essentially using the J-spec engine(all manifolds) a S4 throttlebody (american), s4 wiring harness and sensors (american) and the s4 t2 ecu(american)

Poindexter10thae

iTrader: (2)

I have a brand new Optima Red top, that I know is good

HAILERS

Good! No spark. Now we can fix it. Check the 40 amp fuse in the engine bay first then the ENGINE fuse inside the car.

If both are good (one's gonna be bad I''ll bet) then go to the Main Relay and see if there is 12v on the Black/green wire.

It's not the ECU if you don't have 12v on the little white connector (key on) at the Lead coil assy (the black/yellow wire).

HAILERS

The ENGINE fuse is the one in the schematic that is 15amp and called x-07 here https://www.rx7club.com/forum/showth...hreadid=154593

Nah, forget that, I meant here:

I see where you said you check all fuses. Hmm. When you take the plugS off the main relay, and check for 12v at the black/green wire, also check for 12v at the black white wire. It should be there when the key is to ON. That power passes thru the ENGINE fuse and the ignition switch. That plug on the main relay is the four socket one.