treewojima

I just got an 87 NA, and everything seemed to be working fine for the first month. Recently however, it has been experiencing a drastic loss of power while driving, and then will idle very roughly. When this happens, I can floor the accelerator and barely reach 3000 RPM. Power will sometimes kick back in after a bit, but not frequently enough for it to be reliable. I've not much experience with cars, much less a rotary engine... do I have a case of the dreaded blown apex seal?

anthonywe

check this link (https://www.rx7club.com/new-member-rx-7-technical-256/no-oil-pressure-857169/) it might help you.

treewojima

Ack, I just had the engine rebuilt about a month and a half ago... I don't want to go through that again >_<

calpatriot

1st two things to check:

1. Trouble codes
2. Closed loop operation

You can make your own code checker from two 12v LEDs and three wires, three spade lugs.

The closed loop check can be done with the same assy.

The check connector is left of the battery, in front of the leading coil. Green, 6 pin female. See the FAQs on how to make and use your own (cheap) code checker.

calpatriot

Before you presume drastic internal damage (blown apex seal, etc) I would make darn sure the O2 sensor is working, that the signal is getting to the ECU, and that the ECU is going into closed loop operation (seeing crossings on the 'green lamp' check per the FSM.

Kerberos_8

iTrader: (2)

well the simplest thing to do would be do a compression test on the motor if it has compression in both rotors you can rule that out and have piece of mind then do all the troubleshooting.

anthonywe

dd compressor test 1 of the was around90 and the other one was around 60??? So i guess that is really bad? How much is it supposed to be? And when you rebuild a motor how much schould the compressure be?

Rotech7

iTrader: (10)

Heres a link to a previous post

https://www.rx7club.com/showpost.php...87&postcount=2

anthonywe

Ok that helped.. But everytime you rebuild it does it have to have the same amount of compressor after rebuild? If yes what is the amount supposed to be after? So that i can check after i have it rebuild to see if it was done good and with new and not old parts.. Thanks

Kerberos_8

iTrader: (2)

90+ in an s4 na motor is fine 60 is really low. If you rebuild then they both should be 90+ and they dont both have to have the exact same compression. so if one rotor is 92 and the other is like 89 that would still be fine.

anthonywe

Oh ok cool.. But 1 of the rotor reads like 90 now.. After rebuild it should be more right? Just want to make sure that if i pay this guy to rebuild the whole engine he does not just do the rotor that id 60 and leaves the other one like it is and keep the parts that i payed for it.
Thanks

White94

your cars ecu is in limp mode.. check ur MAF sensor .. i bet you this fixes it

anthonywe

limp mode.. it goes to that mode by itself? and that can fix a compressor of the motor? don't understand

Kerberos_8

iTrader: (2)

he is saying that your car is running in a safe mode that makes it run slow and not accerlerate right. to check your maf sensor first. also just have the guy show you the old parts if he rebuilds its then you know he would have replaced them because you have the old ones on hand.

anthonywe

oohhh ok ok nice to know.. yeah I guess but you never know he might allready have old parts from an older rebuild and he can show me that:p.. you know here where I live at people do bad things allot. it is most people that fix car here does bad thing to people and your car. But I guess I will see what happens. thanks

Mizuki

this is exactly what is happening to my car right now -_-" were you able to fix it??

anthonywe

Well I have had 2 people looking at it. And was told by both that It needs a rebuild. But also people told me that there can be something wrong in the connection in some wires or the secondary fuel injector. That maybe it is not working and cause the secondary one is being used after 4 rpm. But it is good to take a compression test which I did and the guy told me one of the rotor was around 90 which supposed is good enough and not yet needs a rebuild but the second one was around 60 which is pretty low and does need a rebuild. I will have the motor rebuild next week and prob will take a week so I hope in 3 weeks it is done. and If you want I can give you any details about it (anthony_wever@yahoo.com
Good luck with your problem and keep me updated what you do with it.
thank you

treewojima

Thanks for all the responses guys, I now have a good starting point for troubleshooting. But how would I go about checking a potentially faulty MAF sensor? Is it something I just have to swap out, or is there a tool I can use? I'm determined to fix this myself now.

siCk FC

iTrader: (1)

Did the MAF fix your problem? I bought my rx7 a week ago and had to take it home a 2 hr. drive home. halfway home on 5th gear my car was not accelerating. I was giving it gas and i was just gradually slowing down. Tripped me the **** out. As i hit 50 to 40 i threw it on 4th gear and got up t 60 then shot back in 5th and everything is cool. Everything has been cool since then. It just tripped me out because it acted up on the freeway like that. Scared the **** out of me. Anyone have an idea of what was going on? i'm sure it's a common problem too.

treewojima

UPDATE:

MAF sensor is working properly. I suspect the problem lies somewhere in the fuel line, whether it be a bad spark plug or a dirty injector. Once I get the engine above 4k RPM, the secondaries kick in and seem to work properly, so that narrows it down to the primaries.

treewojima

UPDATE:

I checked the TPS with a homemade LED assembly, and only one light turns on (as it should). I then yanked the spark plugs to see what condition they were in; the tips were 100% black. Carbon buildup, I'm guessing (good or bad)? Next up, the fuel filter and injectors.