04 rx8 dyno problem/somethings wrong
 

hey all so i have an 04 rx8 manual trans and got the car dyno'd today. so i was expecting lower than reported numbers but i have a few other problems... here is the picture http://www.personal.psu.edu/ajm5291/docs/alandyno.jpg. o and it was one of my pulls in 4th gear.

first of all that pulling the abs/dsc fuse or pushing the dsc button for 10 sec is the same thing. did a dyno twice with both without difference. so of course props to Mazdamaniac of course on an old thread about dynos.

second, why in the world is my AFR at 10? thats beyond rich. is that all rx8's or just mine?

next and my biggest problem. why after 6000 rpm did my car take a dump? :suspect: look at the zig zag pattern that starts happening after 6000. when its zoomed in on the guy who did my dyno's computer its a very violent zig zag. this printout is the tame version of it since its the whole curve of course. and no i dont have the other printouts, the guy only gave me this one.

finally i had my plugs, wires, and catatyltic converter replaced at a mazda dealer and I replaced my ignition coils. all of that less than 2 months ago.

i dk if this is a pre-knock or what but it almost sounded like i got my misfire back once while it was running hard again. im lookin for help before i start with the expensive run around with the dealership yet again.

--Alan M

The dip at 6100 is the normal (ish) drop from the Aux ports opening . There is not much wrong with the shape of the dyno however :

It only goes to 7500 and peak power should be at 8500
Yes it gets overly rich from about 7000on . Who knows why ...
Whole curve is down on power

so why would my entire curve be low. i mean if that was the normal than a honda can kick me. :shocking: these cars are suppose to at least be half decent. it just doesnt seem right. 120 for torque and 150 for hp. no. lol.

also the guy at the dyno said around 6000 rpm the engine sounds like its just giving up.

and is that was other peoples dyno's look like? keep in mind the zig zag was worse after 6000 than is showed on my chart.

Here is what a good engine makes

https://www.rx8club.com/attachment.p...1&d=1236029552

get a compression test - if that is normal then it is a small possibility that the dyno itself is about 20whp out because that is about what you are down right across the whole rev range .

chances the dyno was off by 20??? he is well known up here in state college. but is there anything else that could cause my spikes. your dont look quite as rough as mine in the higher end....

not my dyno but yeah - low compression .....

hopefully going to the dealer this week to get my compression test. anything else i should have them look for/do?

also ive had a mifire issue that i had taken care of but i replaced it all with aftermarket parts and the dyno guy thinks i still have a misfire...is the misfire and such covered under like the lemon law? if this happens 2 more times or does it have to be mazda parts?

--alan

Same thing mine did on the Dyno https://www.rx8club.com/showpost.php...&postcount=231

No CEL, no issues with idle or normal operation.

I'll leave out the weeks of troubleshooting etc...
Solution for mine
Turned out to be a pin hole leak on the SSV actuator.

It's rich because the leak somewhat shuts the SSV and VDI @ WOT
On Cobb the log shows up as a low MAF reading... but only a bit low @ 197g/s max flow WOT vs. maybe 210+ normal.
Here's the airflow comparison from AP logs https://www.rx8club.com/showpost.php...&postcount=314

Test the SSV actuator for a vacuum leak with a vacuum pump/gauge. Mine took almost 60 seconds to bleed to half vacuum in a static room temp test. But looking at the comparison you can see the change across the entire rev range.

AFR change is in this post https://www.rx8club.com/showpost.php...&postcount=135

is that covered under warranty by any chance...read the TSB and it looks like somtn im not comfy with doing. lol.

No CEL = almost 0% chance of getting anything from Mazda

I don't know what you mean by TSB in this case

If you confirm the SSV issue...
You can buy the actuator and SSV from Mazda for about $250 plus labor. So figure $1K +
Or you can find a friend to help, buy a used vacuum actuator (tested) for ~$50 and do it yourself.
WCS and I replaced the actuator in a couple of hours. No need to touch the SSV or LIM

Honda's will always kick you, especially the automatics.

I got beat by a farm tractor pulling a hay wagon yesterday, and I was under the spray as well.

So just drink the cool aid like all the other torque haters on this forum and say it's a drivers car, made for the twisties.

Just to check, it is a manual, correct?

lol. out of cool aid...drank too much when i bought the car lol. maybe i should look into a mustang.

and yes its a manual with 48100 miles.

Just had to check. Besides compression, could it also be a coil/plug/combo thereof about go bad?

Please read the posts carefully :banghead:As I said above

Same issue on the dyno

Solved with SSV vacuum actuator

dark brew can u tell me how to go about this? the easy way?

Not saying it's the same cause but certainly worth checking first
Believe me, I'm well aware that correlation is not causation.

Easy way to what? verify a leak? Get/beg/borrow/steal a vacuum tester
Make sure your set-up doesn't leak
Test the SSV and VDI for a leak

ALternate 1
Do you have a datalogger? Test MAF flow
Wire the SSV open, block the vacuum line the retest the MAF flow.

Alternate 2
Wire the actuator, block the vacuum line and re-run the dyno

I know of at least one other car with similar symptoms

My bad, multi-tasking fail.... :(

Darkbrew......ALternate 1
Do you have a datalogger? Test MAF flow
Wire the SSV open, block the vacuum line the retest the MAF flow.

Yes i do have a datalogger. I have a cobb accessport. and i actually have a buddy that has a vaccum tester. so wheres this thing im lookin for at? and what am i actually looking for?

im a little mechanically dumb. ok so pretty much dumb.

We're all just trying to help :)

yes helping is amazing. without this site and these guys id be broke from all the trips to the dealership.

Start reading here https://www.rx8club.com/canada-forum-35/mazdamaniac-dyno-tuning-gta-spring-summer-2010-a-195294/page10/
You need to datalog MAF flow across RPM and compare it to the logs I posted in the GTA dyno day thread. You also need the logs to check against the post replacement log to confirm that that your repair worked.
You need to test for the vacuum leak to confirm that the actuator is bad. The other actuator in the pic is for the VDI. Test it too.
https://www.rx8club.com/attachment.p...0&d=1282570623
If all that checks out then I have more for you :)

https://www.rx8club.com/showpost.php...&postcount=314
that thread?

and so im correct.....test maf flow from 820rpm to 8500rpm. check numbers and compare them to thread above which if its incorrect sould look like your before's and if its not the ssv actuator than they will look like the after.....if it is the ssv actuator than what. i didnt understand your alternative 1.

Okay, look at the actuator in the pic.
You can reach in and move it by hand.
Normally it's run by vacuum. John316G has a lot of posts about the SSV and vacuum control system.
You can plug the hose that runs to it to hold your vacuum, wire the SSV actuator in the open position, then go log data.
If the SSV was closing then wiring/taping it open will show up in the log, right?
Make sure you test all hoses, check valves etc. to pinpoint the actual failure