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logdog
logdog Reader
10/20/12 4:00 p.m.

Well, the RX7 I dragged home has compression issues. Like the gauge doesnt even bounce once compression issues. Cross your fingers and maybe we can get enough mojo going that the ATF routine I read about will help.

Curmudgeon
Curmudgeon MegaDork
10/20/12 4:27 p.m.

Take heart; when it's that dead the ATF thing will usually bring it back. It's when 2 lobes are 'missing', so to speak, that there's a strong indication of a problem.

SyntheticBlinkerFluid
SyntheticBlinkerFluid UltraDork
10/20/12 4:58 p.m.

The ATF trick worked on mine. Gave it 24 hours. Then proceeded to fog out the neighborhood the next day.

MrJoshua
MrJoshua PowerDork
10/20/12 5:00 p.m.

No bounces at all? You don't have all the plugs out do you?

logdog
logdog Reader
10/20/12 5:13 p.m.
MrJoshua wrote: No bounces at all? You don't have all the plugs out do you?

Just removed the trailing side per the service manual.

It makes me feel more optimistic hearing success stories.

JtspellS
JtspellS HalfDork
10/20/12 5:31 p.m.

Good luck Sir!!!

Snrub
Snrub New Reader
10/20/12 8:59 p.m.

Agree with above, pull the EGI fuse, pull the plugs crank. Inject some regular oil if it's really bad.

Hungary Bill
Hungary Bill HalfDork
10/21/12 2:30 a.m.

Fingers crossed!

logdog
logdog Reader
10/21/12 12:41 p.m.

Good news. I now have compression. I dont know how much because I managed to drop and break my gauge. It sounds healthy though.

Bad news. It doesnt run. Has healthy spark and new plugs. I got a couple very loud backfires out of it. The carb is bleeding fuel out of several places (I have a rebuild kit to install). But shouldnt I at least be able to get it to cough a bit, even with a junk carb? I shut off the fuel pump and tried to get it to run on carb cleaner ( thats when I got the backfires) and tried to get it to run with some gas dumped in the carb but neither worked. I figured I should step back and think about it for a bit.

Hungary Bill
Hungary Bill HalfDork
10/21/12 12:59 p.m.

think she's flooded? Fingers still crossed. On the injected versions we pull the injector fuse and crank her for about 5 seconds three times with the gas pedal to the floor. any chance of doing a similar thing with the carb? Pull fuse to fuel pump maybe? I've gotta be honest, I'm not real familiar with the carb-unflood...

logdog
logdog Reader
10/21/12 6:05 p.m.
Hungary Bill wrote: think she's flooded? Fingers still crossed. On the injected versions we pull the injector fuse and crank her for about 5 seconds three times with the gas pedal to the floor. any chance of doing a similar thing with the carb? Pull fuse to fuel pump maybe? I've gotta be honest, I'm not real familiar with the carb-unflood...

I pulled the fuel pump power and spark plugs and cranked it a bit to dry it out. Reinstalled plugs, left the fuel pump disconnected and still couldnt get it to cough with carb cleaner or a little gass down the carb.

Curmudgeon
Curmudgeon MegaDork
10/21/12 7:08 p.m.

Time to get out the big guns. Get a friend with a pickup and a tow strap, kill the fuel pump, then spin the engine over with the plugs out and of course kill the coil. Do this till it quits spitting crap out of the plug holes. Now put the plugs back in (be sure they are clean!), reenable the ignition system but leave the fuel pump dead. Now drag it behind your bud's truck with the gas to the mat. It's gonna make some nasty ass noises, you will probably see all kinds of stuff fly out of the exhaust, then at some point it will probably go 'pop', then start and run like nothing was ever wrong. Once that happens, reenable the fuel pump and start it back up again. It needs to run till the thermostat opens, so be sure you have coolant etc in it.

Forgot to mention: before doing all this, tap on the carburetor where the fuel lines connect. Use a plastic screwdriver handle or a plastic hammer, that should shock the flat needle free. A wood hammer handle will work too. I assume you have good gas in it, also? If not, drain the old stuff then put 4-5 gallons of fresh in it, then run the fuel pump with the fuel line disconnected at the carb till you get nice fresh gas.

Hungary Bill
Hungary Bill HalfDork
10/22/12 3:03 a.m.

Holy smokes, you aren't kidding around!

fidelity101
fidelity101 Reader
10/22/12 7:20 a.m.

Something easy too is to remove the exhaust manifold and turn the engine over spraying deep creep on each of the apex seal slots while pressing on them, also after cleaning plugs I like to spray them with starter fluid and put them back in.

logdog
logdog Reader
10/22/12 12:55 p.m.

Is there anything unique about a Dorito motor that would keep it from coughing with starting fluid/carb cleaner/ gas dumped in the carb? I really dont want to try and rebuild the carb until I can get it to run off a can. This is my first non-boinger but I dont see why it wouldnt. Does dragging it behind a truck do something cranking on the starter wont do?

cutter67
cutter67 Reader
10/22/12 1:18 p.m.

are you sure you are getting a strong spark from the leading coil and the plugs are new and they are giving a strong spark.... have you checked the timing i know some people overlook this on a rotary

DrBoost
DrBoost PowerDork
10/22/12 1:39 p.m.

You should give that engine to a guy that lives in Rural Fenton. He has plans for it. Drop in a 5.0 and giddyup!

fidelity101
fidelity101 Reader
10/22/12 1:47 p.m.
logdog wrote: Is there anything unique about a Dorito motor that would keep it from coughing with starting fluid/carb cleaner/ gas dumped in the carb? I really dont want to try and rebuild the carb until I can get it to run off a can. This is my first non-boinger but I dont see why it wouldnt. Does dragging it behind a truck do something cranking on the starter wont do?

The truck pull seems a bit unnecessary. I've been a rotard for about a decade now and this is just some of my witchcraft.

  1. remove all spark plugs, disable fuel and igntion hold foot on the go pedal all the way to the floor and turn the key to start for 20 seconds at time, once or twice.

you will likely see a cloud of fuel and gunk come out of the plugs, if you have unequal compression you will hear it because normally it will just go psst. psst. psst. psst. psst. psst. psst. like an early machine gun (you know the hand operated crank gattling gun, just without the bangs) Listen for unevenness in the air pulses.

as far as running, a cap and rotor from autozone is 20 dollars. couldn't hurt.

You can also pick up a spark tester while your there (fake spark plug basically) and you can test each lead. If it has been sitting for some time it is likely that the cap and rotor are bad and from the sounds of it sitting carbon builds up causing seals to stick.

MrJoshua
MrJoshua PowerDork
10/22/12 1:54 p.m.

Starting an old rotary is notoriously hard. If they had a weak battery they would often end up at the mechanic dead with a "bad engine". In the past I have bought many a "Dead" example that I brought back to life with the truck drag and then drove it home. Jumper cables were even less likely to start it than a weak stock battery. Dragging it spins it faster than the starter can spin it and for waay longer.

fidelity101
fidelity101 Reader
10/22/12 2:00 p.m.
MrJoshua wrote: Starting an old rotary is notoriously hard. If they had a weak battery they would often end up at the mechanic dead with a "bad engine". In the past I have bought many a "Dead" example that I brought back to life with the truck drag and then drove it home. Jumper cables were even less likely to start it than a weak stock battery. Dragging it spins it faster than the starter can spin it and for waay longer.

Yeah that makes sense, I guess I take for granted my properly working and frequently used electrical system. Slow start speeds are usually peoples false diagnosis for bad engine.

Curmudgeon
Curmudgeon MegaDork
10/22/12 2:23 p.m.

A badly flooded rotary has a hard time getting rid of all the liquid fuel. Liquid fuel won't ignite easily so it sort of 'blows out' what little flame there might be. Combine that with fuel soaked carbon in the combustion chambers and they can be a bitch to start. When it gets that bad, it's pretty much a 'drag it at 2000 RPM for a while' thing.

That's how I got my last flooded carbed 12A running; ~4 oz of ATF and dragging it around the parking lot. All kinds of nasty reddish stuff came out of the exhaust, along with white and blue smoke, we dragged it around for probably 10 minutes like that. It suddenly went 'POP', blew a big smoke ring and then ran like nothing was ever wrong. I wailed on that motor for 3 years after that, when I sold the car it ran perfectly, didn't smoke and would light the V710's up in 2nd gear.

SyntheticBlinkerFluid
SyntheticBlinkerFluid UltraDork
10/22/12 3:02 p.m.

FWIW, I had to pull my 7 around the block a couple times before it would fire after the ATF treatment.

93gsxturbo
93gsxturbo Dork
10/22/12 5:53 p.m.

I got an RX-7 running with the ATF treatment.

89 GXL. Parked for winter, wouldnt start in spring. Bought it for $300.

Pulled all the plugs.
Sprayed copious amounts of ATF in the motor, barred it over, more ATF, more barring, more ATF, more barring.
Left to Mexico for 10 days.
Came back, fresh and relaxed.
Installed new, clean plugs. Put in a fresh "big boy" battery from one of my trucks. It didnt fit in the battery box, and I didnt care. It came from a recently driven vehicle and had a lot of juice. Put the booster on it for good measure.
Car started on first crank.
Drove for 10k miles in 8 months.
Sold.
????
Profit.

I agree with the drag behind bigger vehicle statements, After an injector pump or some heavy diesel service at work we would have to drag the tractors behind another tractor until it popped off. All the bleeding/priming in the world did little compared to some higher RPM spinning.

logdog
logdog Reader
10/22/12 9:44 p.m.

I had a few minutes tonight to stare at it and scratch myself while going "yup". I am not getting anything out of the plug holes when I crank it over. I put the plugs back in and got another backfire. Hopefully in the next day or so I can drag it along and see if that helps per yall'uns recommendations. Is there a speed I need to reach? I was thinking for simplicity I would just drag it around the yard behind the tractor rather than take it out on the road. I'll just leave it in first gear and drag with connected spark and disconnected fuel until it pops

Hungary Bill
Hungary Bill HalfDork
10/23/12 3:32 a.m.

Don't worry so much about the speed. Maybe shoot for the 2k-3k RPM mark? Honestly, the only time I had to go for a drag the car lit off so fast I never really got a chance to give the tach a glance (fingers still crossed)

I thought it might be worth it to do another compression check, is there someone you can borrow another compression tester from?

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