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-   -   Problem w/ rx-7 AFM. (https://www.miataturbo.net/general-miata-chat-9/problem-w-rx-7-afm-20441/)

honeydesean 05-03-2008 02:27 PM

Problem w/ rx-7 AFM.
I just got and installed a rx-7 AFM for my 1.6 NA and something is amiss.

The car basically will not idle(or really run w/o me giving it gas). As soon as the RPMs approach idle speeds the car begins to stumble hard and then it dies.

I got it from a guy on this board and I have no reason to suspect he's trying to scam me, so I'm wondering what the problem is.
My old AFM had crapped out on me(i'm pretty sure) and was making my car run like crap, so I'm also wondering if maybe there's something up w/ my car besides the AFM thats not letting it idle.

Please help!

Thank you,

Braineack 05-03-2008 05:23 PM

vacuum leak anywhere?

honeydesean 05-04-2008 10:22 AM

would that be enough to mess with the engine that bad?

I'll double check under the hood today, but I don't remember seeing anything disconnected.

honeydesean 05-04-2008 10:35 AM

oh and my plugs(which are about a week old) were black as hell when I checked them yesterday. I'm assuming this is from driving it around a little with (what I'm assuming was) a bad AFM, not sure if knowing it's been running rich is useful but whatever. I do need this figured out soon, I'm graduating and moving back to chicagoland in a week.

Braineack 05-04-2008 01:14 PM

do you hear a click just before it dies? did you tune the rx7 afm at all?

honeydesean 05-04-2008 02:48 PM

Well, it "runs" now. As I was cleaning the rx-7 afm, i noticed the guy who painted it black did such an awesome job that they didn't mask over the damn connector pins on the AFM... so those are clean and it will run.

now it's having the same problems I was having with my old AFM in(which I guess hadn't gone bad after all)

the car will bog down if I don't feather the throttle to accelerate and while I'm at speed the car will tick back and forth between running alright and bogging down somewhat. The onset of this problem originally only happened at low RPMs(would only bog say from a stoplight, and run fine anywhere above 2k). Then after an admittedly thrashing country-road run one afternoon, it was having these 'bogging' issues throughout the RPM band.

It's been suggested that the O2 sensor may be the culprit over on CR.net, any support for this?

*And no, I haven't tuned the rx7 AFM. I wasn't aware I had to do anything (i saw you could adjust the spring tension, but I wasn't going to mess w/ that unless needed).

Braineack 05-04-2008 03:09 PM

yes, you need to loosen the tension about 7-8 clicks on stock injectors.

honeydesean 05-04-2008 05:53 PM

Done. It runs better when it's not bogging down, but it's still bogging down all over the place.

honeydesean 05-04-2008 08:43 PM

Replaced o2 sensor w/ a bosch universal for the time being. I have 1-2 extra o2 sensors back in my garage at home, so i just paid the $20 to try a new o2 for a week and then I'll put a legit one back in.

car runs better, but I still have to put the AF ratio in check manually w/ the gas pedal(ie slowly depressing it to accelerate) or else I get the same bogged down feel.

oh and Braineack, mebbe change the topic title to something like "car bogs down under accel" since it's not the AFM. I'm just hoping this might get more people checking the thread so it's not just you fielding all my questions, I feel like I'm almost pestering you at this point. Thanks!

honeydesean 05-05-2008 03:24 PM

anybody have ideas for the car not running right still?

honeydesean 05-06-2008 10:05 AM

took it to a shop, the coil for cylinder #3 was misfiring.

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