2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Okay you 7 experts, is my engine dead?

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Old May 13, 2002 | 11:39 AM
  #26  
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1) Pull the plugs out and inspect. If really fouled and the electrodes are worn down, replace and try starting it again.

2) When you do a compression check, you'll need to check all faces (3 per rotor). You can have an assistant start the car and you can watch the needle bounce on the compression gauge (remember to hold the Schraeder valve open). Mazda dealership may charge around $65 last I checked (a few years ago).

3) You can try pouring some ATF into the rotor housing via sparkplug hole. Use a good amount (a few tablespoons) of ATF. Remember to unplug the EGI fuse, pull out plugs from the rear and front rotor (1 per rotor housing), push the accelerator down all the way to fully open the throttle plates, crank the engine over for a few seconds. Wait a little bit and repeat the cranking under the same conditions. It should help de-flood the excess fuel in the rotor housing. It'll burn out and create a little more compression due to the attributes of ATF. It's not the solution, but it'll get it started and provide some compression for an interim time.

4) If you see white billows of smoke, most likely you're burning the excess amount of fluids (ATF or pre-mix, etc) out of the engine. If it continues to smoke or if it smokes before pre-mix a white or blue-white smoke, then it could mean your oil seals are going or the oil seal wear on the intermediate housing is excessive.

Good luck!

See if it's the engine before you freak out about an engine rebuild. An engine rebuild is not that bad.

If you're close to Austin, I could rebuild an engine for you provided that we re-use what we can salvage from your core.
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Old May 13, 2002 | 12:23 PM
  #27  
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Do you consider houston close to Austin???

Hopefully it won't come to that...

Cardio
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Old May 13, 2002 | 01:00 PM
  #28  
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Originally posted by 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.
Exactly, starting small cost me $300 last time.....always compression check first, then go over the small stuff.
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Old May 13, 2002 | 01:53 PM
  #29  
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To do a compression test using a normal compression tester, You do 2 things on each rotor (or at least I do).. pop it in the trailing plug and pull the spark and fuel fuses... Turn the engine over for about 4 seconds.. and see how high it managed go to up to... Ok.. Now hold down the valve that release the air (schrader valve) and have a friend turn the car over for about 4 seconds... you are looking for the needle to bounce.. What you are looking for is 3 EVEN bounces... if you see it go high high low... Then that indicates that a side seal may be broken/STUCK.. if you see High Low Low, then you have a problem with an apex seal usually.. Either broken/gone/Stuck... A rotary can run missing an apex seal.. I have done it and I have driven it on the interstate ..., it would lose speed in 5th and I had to constantly downshift into 4th to regain speed.. But it drove rough...

if you read the manual (not sure if it was my haynes or the acualy FSM) it says that the compression should be within 30psi....

as for the smoke.. Sounds like oil to me.,.. One time I put an oil control ring upside down (it was early in the morning give me break..) and it just burned white smoke bigtime... That was acually my first rebuild, so I wasn't sure if that much smoke was normal or not.. everyone says it smokes a lot also your fuel injector is a good idea.. Check make sure they are plugged in securely, and check make sure they are not WIDE open..
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Old May 14, 2002 | 04:37 AM
  #30  
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GOOD NEWS!!! MY COMPRESSION IS BACK!!

However...eh-hem...I did not do the ATF trick.

Don't ask me what happened, when i checked it yesterday, it bounced at 65-80, then earlier today it bounced at 90 consistently, and amazingly this evening it bounced straight 115's.

WTF is going on?!?!?

I stripped the intake components off to check the primary injectors (I also checked the secondary). The only thing I noticed was that one of my secondaries was missing the plastic insulation ring and someone had replaced it with an o-ring. I found the original insulation piece wedged in the engine compartment (dumb luck) and replaced the o-ring with it.

After re-assembly, I decided to check the compression one more time. Straight 115's, nothing lower. I freaked, I even had a friend read it when I cranked the engine, he confirmed.

My plugs still look like they have not fired, so I guess I am gonna go grab some coils from the junkyard tommorow and see if that helps.

Any ideas on why my rear plugs won't fire? or even better, anyone know how the hell I got my compression back!??!

Cardio
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Old May 14, 2002 | 04:52 AM
  #31  
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Don't spend money on coils. They run the top and bottom plugs on both rotors, not each rotor seperately.

Pull one plug at a time, hook its corresponding plug wire to it, and lay it across the nuts that hold the struts on. Turn the key and watch for spark.
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Old May 14, 2002 | 05:49 AM
  #32  
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Originally posted by 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.
Maybe I didnt phrase my answer correctly: I meant that after you've done the compression check AND this shows decent numbers, THEN start doing all the inexpensive stuff
We all know that very low compression could mean only a couple of things, all of them bad I didnt mean that if you get low CR numbers, then start small.
Sorry for the mixup, but as I see, no harm no foul for Cardiovoid
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Old May 14, 2002 | 02:27 PM
  #33  
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Okay, so I have compression, and I checked the plugs the way Felix Wankel Described and they are working.

So I try to start it, it struggles firever, then starts. This time I still have no power, but now just tons of raw fuel pouring out my exhaust pipes!!

What gives? Throw some ideas at me please.

Thanks,

Cardio
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Old May 14, 2002 | 06:47 PM
  #34  
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Now it won't even start, it just reaks of fuel, both rotors are flooded...ARRRRGH!

Cardio
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Old May 15, 2002 | 01:48 AM
  #35  
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The plugs are firing ? Are you sure ? If the car struggles to fire up, and you have fuel coming out your exhaust, then obviously there is something wrong along your ECU-Alternator/Distributor-Wires-Plugs line.... The car struggles because not all plugs are firing, and thus almost all fuel is left unburned...If you did see spark when you tried to start the engine with the plug near a metalic surface, then how come they wont fire when inserted into their place in the housing ? Double ...

Do you get any error codes from the ECU ? Well, you should be getting a couple, so check which ones they are
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Old May 15, 2002 | 03:27 AM
  #36  
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The only code I was getting was a code 12 (throttle position sensor) I assume that is because it is way out of tune with my frantic adjustments .

Since I know it is sparking, and I know it has compression, I am going to concentrate on getting my injectors cleaned, replacing vacuum hoses and intake manifold gaskets. (and some better plug wires than the P.O.S.'s Hi-Lo sold me)

There is a junkyard in my area that has a few 7's with plenty of parts, they do not charge much. While my injectors are being cleaned I am gonna pick up another TPS, Injectors, coils (trailing and leading), and ECU. By the time the injectors are back, I hope to have the vacuum lines replaced.

Does that sound like a decent plan? or does anyone have other/ additional recommendations?

Cardio
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Old May 21, 2002 | 01:37 PM
  #37  
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I'm baaack....

Hi Again,
I finally made it to the fuel pressure test to see if my injectors were leaking. Problem is I could not get the car to fire...SOOO...I had someone crank the engine for me.

When the engine was cranked the pressure went up to about 35 psi, my assistant stopped cranking and I quickly clamped the fuel return line, within about a minute it dropped from 35 to 22 psi, then stayed at 22.

When we first did it, my assistant stopped cranking, but left the ignition on and the pressure dropped to zero almost imediately. That seems wierd, right?!?

Why would I have no fuel pressure with the key in the on position? After cranking stops, I can hear the fuel pump working, and the needle on the tester moves to about 30 psi. Then as soon as the fuel pump shuts off, the pressure goes to zero. (and I have the return line clamped)

SOOO....either it is going back into the tank, or into my engine. If you have followed my numerous posts, I am guessing it might be the engine. Can anyone verify that this is, or is not supposed to happen? Would this be an ecu thing?

Onc again, thanks for all your help.

Cardio
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Old May 21, 2002 | 01:41 PM
  #38  
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Re: I'm baaack....

Originally posted by Cardiovoid
If you have followed my numerous posts, I am guessing it might be the engine.
Guessing that the fuel is going INTO the engine that is....

Cardio
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Old May 21, 2002 | 02:09 PM
  #39  
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Thats weird. I have never heard anything like that before. Is your feul pump going haywire maybe? The one on the TII I'm getting is all messed up so it throws max feul ALL the time flooding the engine. I geuss it could go the other way too right? See I had low compression in my rear rotor too until I changed plugs and wires. Your ecu could be messed up too. How is your TPS doing? Did you get that fixed? oh yeah. I almost forgot. My trailing plugs fired well when they weren't in the engine like Felix's test but when I put them in they misfired or didn't fire at all. I would think ignighters but I'm not an expert on that.
Charles
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Old May 21, 2002 | 02:39 PM
  #40  
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Well, the only things I have yet to try are a new ecu and TPS. I got some different coils for cheap at a local Junkyard.

When I get a chance I will go and pull an ECU and TPS. I know of a yard that has them in stock.

Anyone else hav any opinions on this situation?

Cardio
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Old May 22, 2002 | 12:15 AM
  #41  
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anyone? (think my ECU is the prob?)
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Old May 22, 2002 | 12:45 AM
  #42  
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Injectors are probably leaking and flooding it out.
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Old May 22, 2002 | 12:48 AM
  #43  
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but why does it maintain fuel pressure when the key is off?

Cardio
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Old May 22, 2002 | 01:01 AM
  #44  
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Got me. I guess swapping the ECU wouldn't hurt.
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Old May 22, 2002 | 01:05 AM
  #45  
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Thanks,
It should not cost much. won't hurt to try

Cardio
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Old Jul 18, 2002 | 10:27 PM
  #46  
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wow

Well,
My automotively inclined Uncle came in town this week. He was only here for a day before he brought my 7 back to life. Apparently my Metering Oil Pump Wiring Harness was bad. I happened to have a spare laying around (not perfect, but still a substitute), and after placing the new harness on, the car fired right up. NO SMOKE, NO FUEL COMING OUT THE EXHUAST. However it was severley out of tune from my frantic adjustments. An hour later, it was idling perfectly.

So, the good new is my engine is not blown. The bad news is, that I am still getting a code 27 after it idles for a while. I have trouble believing that the three MOP's I have used are all bad. They all pass the continuity tests, etc. So, I fear I have a long road of wiring tests in front of me.

If any one has had this happen to them (perfect idle, then a code 27), let me know your solution. I will be ordering a new Wiring harness for my MOP to eliminate that possibility.

MY CAR IS ALIVE!!!!------YAY!!!!
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Old Jul 19, 2002 | 12:24 AM
  #47  
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Sigh....

I thought your mass airflow sensor was not working or is disconnected.

Disconnect your battery and reconnect it.
drive for 5 minutes

check it again.
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Old Jul 19, 2002 | 12:45 AM
  #48  
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I've done that several times. The code keeps coming back..

Cardio
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