Cardiovoid

I am having problem on my 1990 GTU. I had just fixed the MOP (at least i thought i did) and from out of nowhere when I was driving yesterday, I lost all power. I had put 2-cycle in the tank to be safe, but the guy who I just bought it from said he was driving it around in limp mode for a while. It started running like crap, would not idle on its own. I managed to get it home and do a compression test. 90-110 on the front, and 65-80 on the rear. After the Comp test I decided to start it up again..OH MY GOD!!! White smoke everywhere, and it did not go away, and it was burning my eyes the exhaust was so rich. Does this mean my engine is FUBAR'd?

Any advice would be great.

Thanks

Cardio

Samps

You MAY have just added too much 2 stroke oil in the tank.

Cardiovoid

so, those compression numbers sound about right? I put in 16.oz of 2-cycle for a full tank. But it was just generic multi-purpose 2-cycle (all I could get my hands on).

Any other thoughts?

CrackHeadMel

iTrader: (2)

16 oz? lol 1 oz to one gallon, was there 16 gallons of gas in your tank?

Cardiovoid

Okay, I drained the tank and put straight fuel, no pre-mix. It continued to produce white, fuel-rich, smoke and would not idle down. It idled through 5 gallons of gas in about 30 minutes.

I am guessing I have a stuck or broken fuel injector?

Any thoughts, guesses?

Thanks

CrackHeadMel

iTrader: (2)

5 gallongs of gas in 30 min??

Fingers

Good god!!!!!!
BTW, how many gallons are our gas tanks??

VetteKiller

65-80 on the rear

thats really low, 65 is barely enough to get the engine to start. I'd Try the ATF trick and see if you can maybe get back some compression.

Cardiovoid

Our tanks are 18 gallons big, i had less than one oz of oil per gallon.

K, my car is still idling high, but with no power, around 2k rpm. I pulled the plugs on the rear rotor, they are spotless, like they are not firing at all. But the front rotor's plugs look normal (firing stains).

Is that a sign of a bad Apex Seal? How can the ATF trick regain compression permanently?

IS MY MOTOR SHOT?!!?!?

arrrgh...thanks for your help on this...

Cardio

peacekeeper

dude settle down,
Don't worry about the damn apex seal right now. Get new NGK plug wires and new igniters. If the little things don't fix it (Which they should) then start thinking of bigger things. I had the same problems and these fixed them. If something goes wrong with the engine, EVERYONE thinks its and apex seal, or the motors shot. START SMALL!!! If it doesn't work, Get alittle bigger. A Fricking sensor will make a car do that. Throw some fuel injector cleaner in there and see what happens. These engines are stronger than everyone here thinks they are. They can rev past 20,000 rpm without feul cut, good rotors and strong housings. The University at Austin did a test. You can get a rotor to go almost mach 2 before the engine will blow if all you stuff is good. Try the LITTLE things guys. And try not to freak people out over little problems. If this doesn't work, then worry some but not much. We'll get it fixed dude.
Charles

Cardiovoid

K, I am Calm....

I have already put new plugs and wires on...nada, same problem.

Any ideas as to what sensor might cause this, where I should start testing?

I will get some fuel injector cleaner (should I spray it directly into the throttle body?)

I know I am asking tons of questions, but when this is over, I should be able to answer everyone elses!!

Cardio

RX7GT

I'm wondering how the compression test was performed. If done with a digital display like the dealerships and the rotary specific shops use, it would show the compression for each of the three sides of the rotors. If done with a standard dial gauge, there is no way to accurately tell if there is a bad seal or if there is some other problem. In assuming that it was done with a digital type tester, the value of one side would certainly be higher than the other two sides as it is unlikely that two seals just go bad at one time. This is usually the case if there is a bad seal which would be directly opposite the highest side. If you used a dial type tester, and the overall compression was that low, it would appear that you have another problem. I would almost guess that you have a bit of carbon built up in the rear housing. As suggested above, try the ATF trick to try to break any carbon loose that may be there. I'm not sure how familiar you are with the ATF trick, so I'll explain it for you. (If you know it already, then great. Maybe someone else can benefit from the explanation) First, remove your trailing plug from the rear rotor housing. (that is the top plug closest to the firewall) Get some kind of flexible tubing that is about the same size as the plug threads and insert it into the hole in the housing. Do not try to push it any further than about an inch into the hole. Get a quart of ATF (any brand will do - we used to use Dexron because we were also a GM dealer) and pour it into the tube allowing it to flow into the engine. (a funnel helps) Next, you want to rotate the engine so that you can fill each of the three rotor positions with the ATF. Reinstall the plug just finger tight as you will be removing it after the very next step. Allow the ATF to stay in the engine overnight. The next day, remove both plugs on the rear rotor. Clean any residual ATF from them and then rotate the engine so the ATF is not right against the plugs and then reinstall them. Make sure that your battery is strong because you will want a fast starting spin on the motor. Make sure the car is outside. After you have cleaned and reinstalled the plugs, crank the starter. It may take quite a few spins before you feel it start. You may need to remove and clean the plugs again. It will also be very rough (and SMOKE its @$$ off) to begin with,but it should smooth out after it runs for a few minutes. Make sure to keep the car at a high idle after it starts so that it does not cut off. You should actually be able to start it easily since you already have the front rotor running well. Allow the car to run for at least a half-hour to burn out any ATF from the engine or any that has collected in the exhaust system. That should remove most carbon deposits if that's the problem. If you still have low compression, it may be time to think about a new engine. I recommend 1 bottle of Techron added to the fuel at every oil change to help with future carbon problems.

Felix Wankel

Don't start small. Compression check comes first for a reason. To keep from wasting money blindly replacing parts on a blown engine.

I'd like to see you rev your car to 20k RPMs. Clutch explosions and stationary gears shattering is not pretty.

Cardiovoid

K, I will check the compression again.

Is it possible that the 65-80 reading I got on my rear rotor is to low to allow combustion of the fuel? Maybe that is why my plugs have no cumbustion marks?

Thanks,

Cardio

SonicRaT

iTrader: (6)

Well, I had the exact same problem on my 89 T2, it would start, but wouldn't idle below 2k, though this was caused by only 30psi on the front rotor Anyway, is there any kind of smell to the white smoke? Does it smell sweet? Do you have bubbles in your overflow tank? Mine smoked a little, but it went away shortly. Try some ATF, can't hurt.

Cardiovoid

Okay, I will try the ATF trick, but I want to be clear..pour the whole bottle of ATF in? in each face of the rotor?

And for the ultimate dumb question, how can I be sure I have rotated the rotor to the next face?

Thanks, you have no idea how much I appreciate your help.


Cardio

SonicRaT

iTrader: (6)

A whole bottle sounds a little excessive to me, when I did it, I put a nozzle top from some gear oil bottle I had or something and I just had someone sit in side and bump it over every once in while, squirt some in, bump it over, squirt some more, did until I was pretty sure I had covered each rotor, though I'm not sure if thats the best way to do it.

Cardiovoid

Okay.

I am reading on RX7.com about how they do the ATF trick.

Cardio

RX7GT

I have a feeling that your plugs look clean due to the fact that they are not causing proper combustion of the fuel/air mixture possibly due to low compression. The rear rotor should be the same compression as the front; at least 7bar (101.5psi) to maintain a smooth idle. If it is at all possible, get a Mazda compression tester or take it to a Mazda dealer service dept for the test. They will ususally charge about one hour of labor to do this. (around $65-85) It will tell you an absolute value with which to work from.
As for the ultimate dumb question, a wise man (my old boss) once told me: "The only dumb question is the one you don't ask".
You are going to be filling each rotor position up with ATF. Don't worry about pouring in too much, it will only hold so much. If I remember right (it has been a couple of years since I last performed this) you will actually use more than 1 quart. Just be sure to pour it very carefully and slowly to lessen the amount of spillage. (note:use of a drip pan under the engine is helpful to avoid spots on the floor or driveway) It may be good to study the internal shape of the rotor and housing in a cutaway drawing to get an idea of how the fluid will flow and where the positions of the rotor are. As you rotate the rotor with the plug out (note: remove the plug wire completely from the coil for the plug you have removed and also remove the EGI fuse from the engine fuse box located just in front of the LF strut tower under the hood) you will hear the compression release each time you open the next face of the rotor. Just remember that since you have the top plug out, when you hear the release, the rotor still needs to be rotated down so that it opens into the lower half of the housing. If you can get it exactly to the point where you hear the release, you should be able to move it down slightly, pour in ATF and rotate it back up so that the ATF stays in the top of the housing. Only do this for the third face though.
I hope this has been kinda helpful to you. I have tried to explain the best way I can in words. If you need to, PM me and I'll try to help you out more if I can. Also to answer your earlier question as to how it will permanently rebuild compression, remember that you have to have an established oil coating around the rotor housing to achieve compression. ATF is thicker than oil so it tends to stick better to the housings to build that coating. It also has the added benefit of breaking up carbon deposits if you let it soak for a while.
btw:Felix has a very good point, check the compression first, then try the ATF before you throw parts at it. You should be able to do the ATF trick for less than $20. Just take your time. ---Jeremy

RX7GT

I know that they recommend starting the car up immediately after putting the ATF in, but they are refering to deflooding not the loosening of carbon. The procedure is almost the same except for the waiting time. If you have SOME compression in the rear rotor, you do not have a flooded engine.

Cardiovoid

Yes, That definitely helps. I don't think my 7 will make it to the dealer for a comp test, so I will do the ATF treatment in the morning.

So if I rotate the engine from the bolt on the main pulley, I should be able to hear when the next rotor face is inline. That helps alot. i was wondering how I was gonna do that.

Okay Everybody, cross your fingers....

cardio

Cardiovoid

Yeah, I am gonna let it sit for a day. I'm getting used to having no ride, so no rush

Cardio

RX7GT

Fingers are crossed!

The Ace

*crosses finger too*

About the "start small first" remark...I also agree. If you cannt afford a good mechanic, start of course with the compression check (which is free ), and then take it from there. If you can definitely see that you have a serious problem AND you dont know how to fix it, start replacing all the small things first, making sure that everything that can be configured/adjusted has been configured/adjusted CORRECTLY. If, after changing all the "small" stuff (stuff that you can easily afford), only then start worrying....

RX7GT

I just can't think of any inexpensive parts that may cause low compression. Sure you could change the plugs and wires, air, oil and fuel filters, brake fluid, a couple solenoids, TPS and maybe the front floor mats. Are any of these actually addressing the problem at hand? The compression MUST be raised in order for the engine to run properly. Focus on this issue FIRST. Do you want to invest another $50-200 in an engine that is toast? I would rather try the $20 fix (ATF) and find out if the engine can be saved. If the compression can not be brought up, then worry about a new engine. You can throw $5000 worth of parts on it and if the compression remains low, you will still be in the same spot from which you started. (and out $5000)
Ace: you do have a good point about checking all the adjustable items. These can sometimes be way out of line and cause some serious driveability issues.