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Need help with 89 mazda rx7 rotary engine.


j cam
09-25-2007, 08:06 PM
hi, any help with my problem will be much appreciated.
i have a 89 mazda rx7 rotary engine with 79k miles. loads up on fuel, will not idle but will run good at higher rpm's. take my foot off the gas the engine dies. it has no acceleration. takes longer than it should to get to the speed limit. smell gas on startup. mechanic says its dumping too much fuel. any suggestions?

additional info:
just replaced an 02 sensor because the mechanic said a code came back saying the fuel in the engine was staing lean instead of switching back and forth from lean to rich, have a new computer comming in the mail. no codes found for any defective sensors or anything else.

drftk1d
09-26-2007, 06:03 PM
check injectors and their wiring

jcsaleen
09-26-2007, 06:42 PM
Milage, condition, Turbo or non?

j cam
09-27-2007, 01:25 AM
79k miles, condition is iffy, it has been sitting for 3 years. non turbo. just replaced an o2 sensor. if it did any good you cant tell.

jcsaleen
09-27-2007, 07:41 AM
You might need a rebuild. It really sounds like you might have blown a seal OR your seals are dryed up. Your right at the predicted mileage for one even though your is N/a. From the sound of it, it is your seals since you operate fine at high-rpm this is usually the case sinc rotaries can blow seals AND continue to run hard as long they are above 6-7k rpm depending on the engine type/port. I'm assuming you since your is N/A you probably have the six portand not the 4. Now before I jump to conclusions do this...

1.Get some good non-sythetic tranny fluid (1 bottle at most).
2.Pour the tranny fluid in the engine (a good amount on both rotors)
3.Just crank the engine over for a good 10 minutes or more but don't try and start it... -> You might have to manually turn it over.
4.Let the fluid sit/soak in the engine for about a day or so.
5.After a day or so try and start that bastard up, this should work if you don't need a rebuild. It will also unleash a HUGE cloud of smoke if it works.
6.Let me know how it goes

Why do this? Tranny fluid moisturizes the seals and gets them to expand in a sence. My mechanic taught me to do this on an Fb (1978 Rx7) that sat for 5 or so years. And yes this does work.

j cam
09-27-2007, 09:11 PM
ok, ill try that, that may help the loss of acceleration, but what about the flooding? it will not start after its been running for a few mins, you have to really feather the gas. it will not stay at an idle, and the mechanic said thats for some reason its has too much gas going into the engine. he also said that the exhaust was turing beat red when they were trying to get it to stay at an idle, im assuming because of the exess gas thats being thrown into the exhaust and burning when it hits the hot exhaust. mechanic also says all the other sensors check out to be ok, but hes no mazda expert.

jcsaleen
09-28-2007, 01:36 AM
It is probably trying to compensate for loss of compression or something along those lines. I'm not sure why exactly your running rich but it definetly has to do with the rough idle and no low end power obviously.

j cam
09-28-2007, 07:26 PM
ok thx, this gives me a place to start, im not doin anything till the new ecu computer comes in, my dad says we should just wait till it comes in to see if that fixxes it. he is afraid we will mess something up when the computer will have fixed the problem.
one thing i dont understand is that the car started this problem when the girl was driving it. so how could the seals have dried out, when the car was in everyday use? i understand that the 4 year sit period could have done that but i dont know how that could have been the problem when it was in use.

jcsaleen
09-29-2007, 12:20 AM
The car sat for 4 years... Thats your problem right there.

mwolvin
09-29-2007, 05:36 PM
These cars tend to flood themselves out if they don't warm up-- that's not helping you any either. You may also have a stuck fuel injector.

j cam
10-03-2007, 01:51 AM
hey, im gettin ready to do the automatic tranmission fluid thing and i need to know how to access the rotars. someone toled me that i need to take the efi off and someone else told me that i need to take the engine out. what do i do?

jcsaleen
10-03-2007, 07:35 AM
Comeplete engine removal is the only way to access the rotors, Your N/a so it shouldn't be that hard.

Try www.teamfc3s.org or www.rx7club.com for pictorials on engine removal.

ahog
10-03-2007, 05:21 PM
If you haven't started your work yet, you might want to visit www.RX7.com/techarticles_unfloodFC.html (http://www.RX7.com/techarticles_unfloodFC.html) . I made the mistake of moving my '89 RX7 from one area of the driveway to the other. It didn't have time to heat up and it flooded. This article was a tremdous help. Pulling the engine out was unnecessary for me...it was a little tricky getting to the spark plugs but with the right tools (such as an elbow extension ratchet) you can do it. It worked like a charm. I used the "Complex Unflooding Procudure" but it really isn't that complex. Good Luck.

j cam
10-04-2007, 03:01 AM
jcsaleen, is engine removal the only way to get the automatic transmission fluid on the rotors, or do i put it in where the plugs are or into the engine oil? and this may but a dumb question, but whats a n/a? if its a model, under the hood it says model: fc.

jcsaleen
10-04-2007, 07:44 AM
Natrually Aspirated model isn't turbo...

A turbo II has a big top mount intercooler above the engine as well. I'm not sure but I think you can put inject it through the spark plug holes. How old are the plugs because if they are really old you might want to have a pro remove them.

WARNING! Rx7's are notorious for having spark plugs break in half on removal due to heat! Guess where the side that your not holding onto goes... In your engine! Then you have to remove your engine and get out the half a spark plug. Take your time and do it slowly.

Rx7 Turbo II
http://www.flashoptions.com/i_prod/Copy%20of%20DSC02276.JPG

N/a ~
http://www.johnr.com/rx7faq/dans-rx7-engine.gif

The N/a doesn't have a hood scoop either...

j cam
10-04-2007, 11:52 AM
the spark plugs were replaced in 2002 or 2003 just before the car was parked.

jcsaleen
10-04-2007, 10:39 PM
EEeesh... Hmmm be carefull and take it slow thats all I can say my friend.

j cam
10-18-2007, 10:03 PM
hey guys. took this car of mine to a dealership to have a professional to work on it. first thing they did was do a compression test on it. 3 out of the four chambers, cylinders or whatever read about 5.3 compression when the best possible is 7.9 or somthing like that. the 4th chamber read 0(zero) compression. will replacing the rotary seals repair my problem or am i screwed?

drftk1d
10-20-2007, 03:30 PM
hey guys. took this car of mine to a dealership to have a professional to work on it. first thing they did was do a compression test on it. 3 out of the four chambers, cylinders or whatever read about 5.3 compression when the best possible is 7.9 or somthing like that. the 4th chamber read 0(zero) compression. will replacing the rotary seals repair my problem or am i screwed?

1st rule of owning an rx7: never take the car to the dealership (unless its under warranty).

there aren't 4 chambers in a 2 rotor engine, there are 6 (3 per rotor). you want to take your car to a rotary specialist, let us know where you live so we can find you someone.

j cam
10-20-2007, 07:42 PM
Grangeville idaho zip 83530, gettin ready to move to missouri for 6 months car will be left here in idaho

rotorme21
11-26-2007, 06:18 AM
Sounds like it could be a few things actually. If the engine is not idling correctly and you are having to press the accelerator to have it run then it could be the BAC(Bypass Air Control)valve located right below the intake manifold next to the top fuel rail. Disconnect the harness from that and try to crank the car. Could also be bad TPS sensor or MAF(mass airflow) sensor giving bad readouts. Had that issue before.

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