Hey everyone i am a gm mechanic that has got into a stock rebuild of a 1986 mazda rx7 13b fuel injected. I am looking for help on a problem with a bad running car at times and others runs like it has been racing for years(good) it gets in these moods where it is hard to start and when it does start it wont rev up over 3000 no matter what. New wires, does not matter temp wet dry driving or sitting in a lot idling just does this randomly. Asuming a wiring problem but cant find it any help on this please let me know its driving me crazy!! lol

Also looking to find parts for it body parts, engine parts, interior parts anything, im from eastern canada and no junk yards got any avalible.

Any help and ideas welcome!!
Daniel Desroches

 

Hey Daniel,

You are going to need to do a little more troubleshooting. Your problem is not a common one at all.

Try and find out when it is acting up, if there are any other electrical circuits not functioning and if it is at all temperature related.

 

Could it be a pressure leak?

 

its not at all tempeture related. its not just on startup. its could be runing at 100km an hour down the road and then i would do it just out of the blue no check engine light no hickup or nothing first just blah and its reves at 3000 and wont go anyplace wont take any load on the engine you gotta stop and pull over and shut it off and hope that its out of it and if not you gotta wait for a bit or get it towed. I have changed wires new coolant tempeture sensor. exahust leaks but i was told that was not a big deal with these engines.(is that true) There are no other electrial problems on this vehical at all. when the engine is running without this problem it runs perfect lots of power!
Also its not turbo its n/a
daniel

 

im having some-what of the same problem im replacing plugs, wires, and fuel filter.

 

Could this be possibly cause by a sticking air flow sensor?

 

Could it be something in your fuel system/bad gas? Was it sitting for a long time ?

Maybe wierd TPS problems ?

 

Hey nope not the fuel unless its injector related new fuel pump and filter and fresh fuel 2nd full tank. Not a air flow sensor reads good during these problems steady on a scope graph... Thinkin it may be a ground issue anyone ever have ground problems causing things like that?
Daniel

 

i'll try the plugs replaced wires already.

 

could it be going into limp home mode? Just a guess. My freinds 89 vert goes into limp mode randomly. He has to turn it off then on again and it will act normal.

 

the same thing happens to me, except i didn't know it was limp mode. i have to turn it off and back on for the Service Check Engine Light to turn off, and then it drives normal, but it sucks. how do you get rid of it.. im not even sure its limp mode... what is it? help!?!?!?!?!

 

have you tried checking/changing the oxygen sensor? perhaps the tale of a dying cat?

 

it ive had a simmilar problem with my 86 fc. try looking at the fuel injector resistor. it is located under the air box on the passenger side. chrome in color. look and see if its corroded or get a multimeter and test the resistors.