mks

Hi all,

I did what most of you would probably discourage any inexperienced rotary-newbie from doing; I bought an RX-7 with an engine problem.

I was told it had no idle, that it didn't pull like it should, and was running less than smoothly.

yes, I got a good deal.

I now know that it won't start at all. I've read 30 or so "help, car won't start"-threads, most of which tell people that their engines are flooded, and that they should get some new plugs and some ATF.. well, I did that, but I still can't get it to start =(

Tonight I actually had a few puffs of smoke coming out the tailpipes, but it just won't start.

Since I have no experience whatsoever with troubleshooting rotary engines, I'd like some help with compiling a list of things to try or check.

Let's assume it's not just plain flooded, it should've been running by now if it was (I've been unflooding it for three full night-shifts in the garage).

I've read about MAP-sensors, Intake air thermosensors, throttle position sensors, O2 sensors, etc. Do any of these gadgets have the ability to make my car unstartable?

I also got hold of a compression tester tonight, so I tried to get a printout of the pressure pattern... let's just say I hope the info about rotarys not making compression without an oil-film inside the housings, and that compression can't be tested on a cold engine is true. My printout read roughly 2 bar on all surfaces of the front rotor, and a solid 0 (zero, zip, nada, nothing) on all surfaces of the rear rotor (if it was infact turning, who could tell?).

I noticed significant gas smell under the hood today, and something is dripping from the engine bay when I've been cranking it. This "something" doesn't seem to be pure gasoline, since the puddle on the garage floor isn't as flammable as I was expecting , but it certainly smells of gas.

So I'm going to check for spark on all leads, I've just checked the trailing so far, and I'm going to lift the UIM and see if there's a gas leak at or around the injectors/rails I'll check the coils, the TPS (to make sure the ECU understands I'm flooring it while cranking to prevent flooding), and fuel delivery/pressure.

If all this fails, I'll rip the motor out of there and send it off for an anabolics dose (port and rebuild).

What am I missing?

Any suggestions would be greatly appreciated.

spurvo

Note that I have NO real experience bringing an unstarting rotary back to life..

I go back to what a guy who was teaching me autos said. There are systems in a car that effect the basic starting/initial run of the car, then there's everything else.

So to start (hee hee), you need spark at the right time. Check the spark at all plugs. Put them back in, get out a timing light, put the connector around the leads and make sure your timing is correct as per the manual. It should be, but you HAVE to be sure to eliminate this sytem as the culprit.

Next, put a little oil into the combustion chambers when you are trying to check compression. This will help seal things, Note that the rear rotor more or less can't NOT turn, so if you still get no compression, this is where you stop and fix the problem.

Last, the fuel. My suggestion is what I would do, but I've done it before, so I trust me. YOU MUST ASSESS YOUR ABILITY TO WORK WITH FUEL HERE!!! (/disclaimer ) I pull the fuel line closest to the engine after the fuel pump. In this case, this is the forward most hose on the driver's side of the engine bay that comes up from under the car. I would SLOWLY pull that hose from where it is shoved onto the metal tube that runs to the injectors WITH A RAG AROUND THE HOSE. As you pull, wiggle the hose back and forth. You SHOULD get a little spray of fuel as you move the hose back if the system is holding pressure and the fuel pump is working correctly. Keep wiggling the hose, but don't pull it. You can drain the pressure of the system this way. I would then put the hose back on, short the diagnostic connector leads to cause the pump to turn on, and turn the key but DON'T crank the engine. This should fill the fuel system again. If no fuel sprayed out (just a little bit at a time, plenty of ventilation, replace rag as it gets wet, no fire), you have a fuel delivery problem. Diagnosing this is a PITA. If there WAS fuel in the line, you have compression and full spark, then clogged injectors and/or no electrical signal telling them to spray would be my next stop.

that's all I got for now.. really hope you get some compression

GsrSol

You can check compression on a cold motor, it won't be exact but it will read. Oil in plug holes will help compression but I've only done that on a piston motor.

When these motors detonate, it's usually the rear rotor that goes. If it had a little compression it should turn over after a while. I was able to drive mine about 60 miles with 2 blown apex seals.

You can test the plugs by grounding the tip to something to see if they spark. I would assume your rear rotor is completly gone.

mks

Thanks for your suggestions. I'll try the compression test once more with a little oil in there. If it still flatlines, I'll sigh and bring out the big toolbox.

Isn't it funny how similar the compression pattern from a rotary is to a heartbeat pattern from human beings? If it flatlines, it's dead (My garage feels like one of those hospital TV shows now)

mks

One more thing; will ATF qualify as "a little oil"? Since I've already put some of the red stuff in there, maybe I don't need to start filling the chambers with motor oil aswell?

GoodfellaFD3S

iTrader: (213)

You are correct, sir.

When you crank it with the plugs out, what does the compression sound like? Are the "psshh's" regularly spaced?

Rated R1

I'm going to go out on a limb here and say that the motor is toast. Chcek your compression once more if you get nothing get yourself a nice streetport rebuild from pineapple. I hope you got a real good deal on this car and everything else is in good shape.

mks

From pineapple you say, who pays for shipping? (I'm in sweden) =)

Seriously, I don't think that's a limb, you're on a friggin freeway ramp.

Rated R1

Whoa! I just noticed that you were in sweden. That's a long drive from oregon.

mks

I've never heard another 13B cranked without plugs, so it's hard for me to tell.. I think it sounds kinda limpy though, but it might just be the slow rotation in a rotary vs an otto.

mks

Indeed it is.. considering the amount of rotary engine builders around here though, I might start looking into cheap airfare to the U.S., with some overweight luggage =)

mks

You didn't cross your fingers now, did ya? =)

Last night ended with me taking off the hood, jacking up the car, draining oil and coolant, removing the airbox and battery.. you get the picture.

I tried it with a brand new mech compression tester for piston engines as well, just to rule out that the rotary tool was faulty. I had to face it, compression is zero on the rear rotor.

Time to read all the threads on engine removal.