My nephew (16 and first car...sigh) bought this 87 RX7, even though I recommended he not. I love my sister dearly so, well you know the rest. Problem is 1) I have to hold to the floor to start and when it does start it idles erratically. 2) It has no power , to me it seems to be running on 1 1/2 rotors. If you try to put in drive and go it won't ( no power ) and just dies out. It will then restart. I have checked the compression on the lower or trailing plugs. Results 90 psi on the front and about 60 on the rear. This being done with a standard compression gauge after removing the schrader valve. Another thing I noticed is the car doesnt change when you remove injector terminal on either the primary or secondary injector. Matter of fact the car will stay running even with both injectors unplugged? What this tells me is the injectors are open all the time???? Correct me if I'm wrong. What I dearly would like to know is do I need an engine or is thier something else wrong ? I scanned for computer codes and got none. I am also pleased with the spark ( it didn't feel so good though )Another thing the TPS connector is melted sort of as though it got hot and there are no working indicator lights in the dash , no oil light ,no check engine light, and so on. Thank you in advance for your responses.

 

Sounds like a lot of problems....Hope he/she didn't pay much.

For the idle/power problem, it sounds like one or more injectors are stuck. However, with the other electrical problems, it may be that the ECU has been fried, or something else is screwed up somewhere. I could keep guessing forever, but if the engine has 60 PSI compression on one rotor you need to rebuild the engine anyway. It will not run very well at all with a 30PSI difference between rotors. What happens when you disconnect all the injectors and try to start the car?

If the TPS is melted, it will NEED to be replaced as the car will not run properly with a bad TPS (could be causing the fuel symptom you are describing). Any indication as to why it melted?

Your broken indicator lights sound like the standard cold solder problem. A search of this forum should provide more info.

 

I am a novice when it comes to Rotary. In other words I am dumbfounded. How many injectors are there anyway, I can only see two. And if I unplug them the car still runs the same

 

the injectors you can see are the secondary injectors, those should only come online (work) when are driving and the rpms climb past 3800 rpm.

the Primary injectors are the ones that work all the time, from idle up to 8000 rpm, or more. thats why unplugging the injectors you saw makes no change.

an erratic or surging idle usually means a faulty Throttle Position Sensor. it sends voltage signals depending on how far the throttle is opend. when the TPS goes bad, it sends erratic signals (rapidly fluctuating) to the computer and it thinks that the throttle is being modulated, thus, it modulates the fuel. but if you really ARENT moving the throttle, and the computer thinks it is moving, that will create an erattic idle.

try to change the TPS sensor. this will be made easier by purchasing a Hayne's Repair Manual from autozone. its not very hard once you look it over. this fix should allow the car to at least be driveable. it wont have Nearly the performance it should have.

as far as having the engine rebuilt, i would go w/ a motor from Mazdatrix.com. you can have them built to different power levels and reliability levels. remember, this isnt something you want to skimp on. these are, in essence, race engineered cars, not honda civics. these cars REQUIRE preventative maintanence and attention to detail.

other than that, just read anything that you can get your hands on relating to RX7's and rotary motors. themore you learn, the better. two years ago, i knew nothing about them, look at me know!

chris

 

before you go rebuilding that engine and spending heaps of money.. try the atf trick to increase compression on the rear rotor.. may as well, u got nothin to lose!

(atf trick: put very small amount of auto tranny fluid in lower spark holes, let sit overnight. warning: will foul out spark plugs and maybe o2 sensor)

 

good suggestion. it cant hurt to do this trick. a little more elaboration:

remove the lower spark plugs, get a funnel and a tube and put the tube just inside the spark plug hole, not more than 1/2". then dump down maybe 2 tbsp. in each hole. then bump the starter, very quickly. then a little more ATF. and try to get it on all 3 sides of each rotor. put the plugs back in, and crank it over a few revolutions and then let it sit over night.

if you dont already know, automatic tranny fluid is PURE detergent oil. it will dissolve your carbon deposits. there is a slight chance that the rear rotor has low compression because one or more of the Apex seals (similar to a piston ring) is stuck and wont follow the rotor housing surface (similar to a cylinder bore). if so, the ATF will break down the carbon deposits and also lube up the seals restoring compression untill it is burned off.

if you do this trick, watch out. as soon as you start the car the next day (After letting the ATF sit in the engine) it will smoke like an old muscle car w/ a cracked head: A LOT OF WHITE SMOKE will pour out for about 15 min. you will have to keep your foot in the throttle to keep the engine from dying out. just keep revving it till it stops sputtering and starts to smooth out. dont be afraid to redline it. rotaries like to be redlined. (if the previous owner had redlined it once-per-commute, it would have never been carbonized in the first place) good luck,and let us know how it goes

chris

 

No catz also, careful with the atf fluid if you live in a residential neighborhood. 5 speed or auto???

 

Auto ?

 

I have a 91 auto. basicly at a dead stop, with the gas all the way down the car would verly move but once it move it was ok but rotarie power pull
here what help me
new catz, check the acc, smog pump, new exaust gaskets
make sure you have original muffler and no exaust leaks

the automatic works with the engine vacuum so check the lines.

how is the mpg??

my tranny broke a few days a go, so your tranny can be going

try a filter and oil change, can buy some time

 

When checking compression, did you hold the valve OPENED so it lets the pressure leak out, Then watching the needle, check for 3 even bounces on EACH rotor... 60 is pretty low, and the rear is usually the first to blow.. If both rotors have 3 even bounces that's good..
if one has 2 even bounces and one low,,, That means a side seal is most likey blown or stuck due to carbon, if it has 1 high bounce and 2 low's , probably means apex seal is blown or stuck due to carbon, Either way try the ATF like they said for sure.. Been known to restore compression nicely =)

has the car sat long? or did he buy it from a user that drove it recently ?

 

Green, I will do another compression test and get back. I pulled the schrader valve but did not hold the pressure release valve . The car has been sitting for about a year after it broke down . My nephew got the car for cheap ( $300 ). He was to infatuated ( 1st car ) with the car to realize the possible expense involved in getting the car road worthy