Hfmotorsports

2004 GT 6 speed. This problem and noise are directly related...or at least it seems.
Some time the car runs fine others not so much. problem arises around 4k-5k rpm and follows to red line. I noticed that the exhaust tone is different from start up to driving. Also Yesterday it had a new symptom parked the car on the lift, turned it off, went outside to fish for abit, came back 1 hr later started the car, to line it up on the lift and cranked over/started just fine...cold idle, it died as it reached it. (1000rpm)
All sensor according to my scanner are functioning properly during closed loop. however i did notice that b1s1 o2s flatlined once...but only once. (between shifts)

NO CEL!!


Put new plugs in about a month ago, just Cleaned maf. I check the cat with my pyro meter and its 1600-1800 Fahrenheit. The plug wires may need to be changed. i also noticed that the throttle body was to hot to touch. and the % when i mashed the peddle down to the floor it only said 78%. on my scanners ( snap on)........

Hfmotorsports

It's crossed my mind, I got the car on the lift, took the cat out and visibly inspected it....it check out ok. But I do not have a back pressure gauge. Took the throttlebody off to check it out and remove the coolant line from it. Next is the fuel pump.... Luckily I already have the walbro in stock in my shop. Thanks for the +1 on the fp

Hfmotorsports

Lol fore sure. Well the car has 68k on it... Nothing is ever pass suspection... Even new parts

roflcopter

iTrader: (2)

Our issues seem like they might be connected... I've been watching for someone else to have them but every time the symptoms look close, something I've already tried ends up fixing their problems.

But if you have the ability to pull more data you can compare it to my logs and see if it's looking similar or not.

Check out my thread here

Hfmotorsports

Well I pulled the throttle body and tested it. According to my shop manual the ohm ranges .3 to 100 and mine closed 4.2 to 4.2 open....so I'm suspecting that the tb is bad....but why is there no code? I had a Subaru in the shop last month with the same problem and the same conclusion ( bad tb)

Hfmotorsports

I just ordered some more software and found out my tactrix cable doesn't work with it. Only a elm327... I need to order Charles ignition kit and a Cobb ap but this throttle body crap is going to set my plans on hold. Guess I have to sell my ar now

Hfmotorsports

"It's nice to own land"--Stewie griffin....I have a 3 acre pond and a 5 acre ponds full of bass 30 feet east and south of me so when a car gets the best of me I just set the tools down pick up a gloomis and Calcutta

roflcopter

iTrader: (2)

Hmmmm, I hadn't thought to look at my throttle body because it should be fine.

I'll ohm it out this evening and see what mine comes up as.

Hfmotorsports

I went ahead bought a new one anyways. tonight i'm going to check the vdi and ssv too. I talked to the Mazda tech in this area about the numbers and he said that it was abnormal.

with out pushing on the butterfly at closed position i had a reading of 4.2 ohms
pushing it closed read 4.4 ohms

all the way open was 4.2 ohms.....

according to the shop manual closed was .3 ohms and open was 100 ohms

How ever i for got to put the negative lead on the tb and check each pin with the positive lead....if there is any continuity then there is a short. thats another test to check too!

The crazy thing is The pcm should throw a code due to unstable voltage (out of range). i would think so anyways.

roflcopter

iTrader: (2)

Which pins are you supposed to test resistance across?

Hfmotorsports

http://www.rotaryheads.com/PDF/RX8/3EngineDetails.pdf


Page 84

roflcopter

iTrader: (2)

Well... mine isn't showing the correct resistances either.

3.2 all the way closed, 3.4 sitting where it wants to, then 3.4 all the way open.

Hfmotorsports

Which meter are you using? I'm using a fluke 88? I know it doesn't really matter i'm just curious.

here's the thing. I checked out another throttle body that was drive by wire i got a completely different type of reading. The throttle bodies are the from the same company, not that that means ****, but i ordered a new throttle body so wait for me to re install the throttle body find the issue. If it's not the throttle body then, i'm back to square one...

Anyone else with a known good throttle body want to check their throttle body to determine the Ohms?

Since i had the throttle body off the car i went ahead and did the coolant re-route. I noticed that the throttle really hot, too hot to touch. so..... heat/servo isn't that great of a combo

Hfmotorsports

Ok so i got my old automotive tech book out...the one that i bought while i was in school to do some reading. I'm very unfamiliar with this system. What i learned is the d-b-w system, utilizes 2 or 3 tp sensors when one goes bad it my not throw a code but it will have a diminished power and fuel economy....so i'll get my new throttle body and install and see what happens.

I wish someone with more knowledge than i could chime in....it would not be to hard to out think or smart me, maybe i read it wrong.

The fact that "roflcopter" got the same-ish numbers as i, makes me wonder if its bad or good. since we have similar problems i don't know if my conclusion is right or wrong.

roflcopter

iTrader: (2)

The way I read the shop manual didnt make me think that the resistance should change when open, but we will see. I'm using a Fluke 88 as well actually.

My friends 8 will get tested this evening and I'll let you know what his numbers are.

Hfmotorsports

The only reason im thinking throttle body is: i noticed how similar our pcm is to a Subaru....as far as reading that is. so even though we are Mazda i tested a Subaru d-b-w throttle body which the inner eds are the same it test out different. and its a known good one...its the only one that i had in close proximity to me.

Like i said its unknown

roflcopter

iTrader: (2)

What did that one test like?

After looking into it a bit more, the test that you linked in your other post is to test the actuator itself, not any of the sensors, so basically you are just checking resistance in the coils of the motor(which is why you have such a large range 0.3-100 ohms because you are just making sure that the motor doesn't have an internal short or an open circuit).

The other pins in that connector are for the position sensors, which the shop manual does not have a procedure for testing. But I'm willing to bet that if you test resistance over pins C and D or E and F, you will find a varying reading as the butterfly moves.

I was also doing some digging in my datalogger and came across PIDs for AbsThrottle, CommThrottle, ThrottlePosi, and AbsPedalA, AbsPedalB, and a few others, so I'm going to guess that there are two position sensors in the throttle body and I think 3 on the pedal itself.

Hfmotorsports

Wow interesting. Thank you for clarification. To be honest that manual is kinda a joke... Well my skill could be the one on the stand though

The Subaru on the same two pins tested out at 1ohm to 85ohms and the pins were the same.. Also on a side note I tested my buddies tb on his rx8 and his came out to 1.3 closed but I didn't want to take his intake off his car to test the open value.

roflcopter

iTrader: (2)

I didn't take mine off, I just pulled the accordion tube out and actuated it with my hand.

Hfmotorsports

I know I just felt odd taking someone's car apart

roflcopter

iTrader: (2)

So after doing more research I think the throttle body is not the issue.

By any chance does your car have an aftermarket exhaust on it?

Hfmotorsports

Negative.

Let me explain further why i thought throttle body. Even though i tested the servo/ stepper motor, i tested that bad throttle body on the Subaru and it gave the same reading, but when i tested the good throttle body i had completely different numbers...of course im comparing apples to orange. All i'm saying is the bad Subaru throttle body tested with the same response and readings as mine...but when i tested the good throttle body on the subbie it read completely different. similar to the ranges that the Mazda service manual stated. (found that to be weird)

This is my 1st Rx-8 but the principles are similar.

Hfmotorsports

I was sayn negative to the exhuast question

roflcopter

iTrader: (2)

Hmmmmm, well I tested my friends known good one and it came up with similar numbers(2.3ohms at about every position.)

I ran through all the different PIDs on his car at idle and the only one that wasnt nearly identical to mine was one for 'Cmd Prge', but I'm not exactly sure what that number even means... Anyone want to chime in?

Hfmotorsports

CMD is to access command prompt . So.....I really don't know... But I got my new throttle body however I'm still waiting on the gaskets. I'm debating on removing the vdi and ssv to clean them before I reassemble the intake. I'm also waiting on Goodwin racings order of Samco hose kit. I really want to do it all at the same time. Thinking of pulling the injectors out too. Clean all that up and put new gaskets and o-rings in. But at that point if the problem is fixed I won't know what did it.