My check engine light was going on and off for awhile, and the car was hesitating in 2nd under full throttle maybe about 25% of the time, so I thought simple and bought 4 NGK 9's for her. Well that night I took it out and she ran better than she ever did in the 3 months that I've owned it. So I thought everything was all fixed and that it was just bad plugs, but within 48 hours of new plugs the light went back on and the same problem occured. What are the possibilties of the problem, I know they are probably endless, but a few common ones? I figured that the problem was most likely spark or fuel assosciated, so the order I planned on checking the problem was plugs, wires, vacuum hoses, and maybe the grounds, as I have heard they can cause the most random problems. Then if that all fails, I will spring for the laptop, pfc, datalogit, and wideband a little sooner than expected...

 

O.k.. I had some secondary problems.. but since I have PFC, my engine light do not come on.. besides that, my car ran like crap.. especially above 4500 RPM.. If you are also experiencing problems at high RPM.. check your one way valves, then your grounds.. usually your coils are ok... Can you also be discriptive on your 2nd gear?? is it primary turbo or secondary turbo, also what RPM or all RPM range..

 

Well...if your check engine light came on, check the engine codes! That's the first step to diagnosing the problem.

Dale

 

It's definitely the 2nd turbo range, but I really can't analyze the problem fully, because like I said, my car never ran as well as it did that day. I was only in second a short time, so I don't know how quickly it tackles the low RPM's, but the sputter is very obvious about 4500

 

I am pretty sure I can fix the problem without wasting money on checking the code. I figure if I replace the part and it doesn't fix the problem, then it's one less part to worry about, especially cuz I don't know the time frames of the previous part changes.

 

Sputters... Hmm.. That sounds exactly like my problem.. Let me address my problem that I had and see if it sounds like yours..

It all started off by my secondary turbo "sputtering".. almost like its misfiring or hesitating.. especially above 4000.. but at lower RPM.. ran fine.. primary turbo was fine..

So, i did exactly what you did.. check my plugs, wires, replaced the plugs, wires.. and it was very tempermental.. some times it was fine, other times same problem..

Then condition worsened.. and sounded like my second turbo was kick in then didn't..

So, i did the simplification seq. turbo.. Same problem.. except, now I heard more weird sucking or vacuum sound..

So, I checked all my vac lines, solenoids, turbines, almost everything.. until, i realized about the one way valves.. There is 4 or 5 one way valves in the vacuum/pressure system (the rats nest).. It helps hold vaccum in vacuum chamber or pressure in pressure chamber.. Those controls the acturators.. with out pressure or vacuum forming, non of the acturators will work.. so one way valves are very important..
How it works is as vacuum is created in UIM, it sucks air and the OWV will flow air out and do not let the air back in.. creating vacuum in the chamber.. And same with the OWV on the y-pipe nipple..As pressure builds from primary turbo, it pushes air and doesn't let air back out.. and pressure builds in pressure chamber.. I check all the OWV and only 2 flow the way it should.. others were either completely blocked or very very poor flow..

One of the two in the line were bad.. so I replaced it.. and now my car runs fine..

Also, check your vacuum chamber.. as when its filled with oil, you loose vacuum.. Because the space in the chamber is now taken up by oil and only hold specific about of vacuum.... in turn all your transition is messed up..

Hope this helps.. I wanted to explain things.. I should be mostly right about this.. If I'm wrong, someone please correct me.. good luck..

PHIL

 

It doesn't cost ANY money to check the engine codes:

http://www.scuderiaciriani.com/rx7/engine_codes.html

Takes about 2 minutes and a small piece of wire. VERY easy.

Dale

 

Checking the codes is as simple as jumping a connection under the hood and turning on the key. Go to the newbie's thread at the top of this forum and check out those links. The procedure is in there.

Checking the codes should *always* be the first step in trouble shooting nearly any problem, especially if the light is coming on. It's amazing how many people overlook this step.

 

Wow... thanks paw! A-Spec charges $80 for that ****? It's amazing what people can get away with these days. A shop in my area would have done it for $60 but they aren't rotary specialists so they couldn't touch her.

 

Sounds like it may be the same problem as herblenny. I got 4 codes, Intake Air thermostat, Feedback system for o2 Sensor, Solenoid Valve turbo pre-control, and Solenoid valve wastegate control. Any sugestions on where to start? Be very specific if you can please, I want to make sure I do it right.

 

I would start off by checking all the harness.. Intake temp is located under the UIM..

The pre control solenoid and waste gate control solenoids are located left/ front or UIM.. its the two solenoids next to the pressure chamber..

If you don't have a manual, search the forum.. there is a link to it somewhere.. also, if you need a diagram, search the forum also..

After checking the harness, check the one way valves.. and vacuum lines.. If you have not done vacuum line replacement, this might be a great time to do so..

You have to take the UIM to do this..

 

hmmm... i have the same error code: the "feedback system for the O2 sensor", what does this mean?? do i need a new O2 sensor?

 

hmm.. what I heard is that O2 sensor do not do anything.. the details to why, I have no clue.. But what i heard is that O2 sensor only works during idle.. but after that, its not essential.. i know lot of people who have taken the O2 unplugged and ran fine.. except idle..

But again.. i could be wrong and if someone could correct me, i would greatly appreciated..

 

hmm... where did you hear that??

runing wivout any O2 is bad isnt it?? how does the ECU know how much fuel to inject when it has no sensor that measures the A/F ratio? I think im running rich and it has something to do wiv my O2... i feel as though my rx7 drinks more fuel now!?!

Any1 has anythought?? sori to go off line a bit... but since DeepInTheGame has the same problem, i might as well ask.

 

O2 sensor operates during closed loop driving, also known as part throttle cruising. During acceleration, the ECU uses rpm, throttle position, intake temperature, and mass air pressure to determine timing and fuel rates. During deceleration, timing and fuel flow are also run by the above factors, wherein things like fuel is shut off to the rear rotor and other fun stuff. During idle, the injectors are at a fixed duty cycle, and rpm anf throttle position are the major determinants of timing. Note further that idle speed is primarily controled by the idle speed control valve on the side of the throttle body.

 

spurvo: tanx
nevermind... i did the search!! must replace o2 sensor..

 

Spurvo, Thanks for that info.. Things are clearing up..

 

so where do I find the feedback system for the o2 sensor, what about the intake air thermostat?

 

i think the feedback system for the o2 is telling you that the Oxygen sensor is bad/toast! so changing the Oxygen sensor will clear the code, rite?