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Discussion Starter #1
I've done a lot of research on this topic, and I've yet to fix the problem. My Miata is the 1.6l, with I/H/E, some other mods. A lot of people have seemed to have a similar problem, where it feels like there is a lag at WOT anywhere under 4k rpms..
My problem seems to have started recently. I seafoamed my car (tiny bit in crankcase, 1/3 into intake manifold vacuum line). Changed oil after, and shortly after started feeling this lag.
I've changed my spark plugs and cables and it hasn't helped the problem. I've even changed the o2 sensor. I don't think my cat is clogged either. And this problem doesn't seem to be only when it's cold/hot..
It feels like when I step on the gas, there is no power difference between 1/2 throttle and WOT until above 4k or so.. That's the best way I can explain it.
Also, no CELs, Still getting 29mpg, slightly advanced timing.
Any information will be helpful...Thanks
 

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That's just the v-tec, perfectly normal...

did you check to see if the throttle cable is taut?
 

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OK..you have a 91..mileage?..check the crank pulley for even the slightest bit of wobble..check your timing again
 

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Slightest bit will lead to problems..investigate promptly..check for a wonked keyway or separated membrane in the crank pulley..it is two pieces held together with a rubber section. Crank key issues will lead to loss of power in the lower rpm range due to shifted timing..when you get up in the range, the timing gets right and the car runs better..
 

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Timing. Had the exact same problem. My intake manifold cam was off by a tooth. NO power until about 4k rpm.

Time for a timing belt change?
 

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That would make sense. Would I just replace the key? I remember seeing a writeup on what to do but I can't remember.
depends on if there is damage. if there is, your options are to try the loctite fix, or do like what some do and figure out a way to weld it on there.
 

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Any crank pulley issues call for immediate attention.

stop driving the car...pull it apart and find out what is damaged..replace parts as necessary..Crank pulley, key and crank bolt for starter
 

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I'd say stop driving the car now. I ignore the symptoms on my car and it became worst.

yours for sure have the SNC problem.
 

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Discussion Starter #14 (Edited)
I read a writeup and I saw that the crank keyway failures mostly just happened on SNC..and my pulley has 8 slots (not snc), leading me to believe this may not be the problem.
(writeup- http://www.miata.net/garage/hsue/crank/loctite_6.htm)

Well I was driving on the freeway today and I threw a CEL for about a minute then it turned off. I got home and did the paperclip method and I'm throwing code 17 and 26. I just changed my o2, so why would it be throwing code 17?? And I honestly don't know much about the code 26..can I be throwing that code because I have my charcoal canister removed?
Keep in mind I have the RX-7afm..
 

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Keep in mind I have the RX-7afm..
We tried running the rx7 NA afm on our chumpcar to little avail. Spent two hours on a dyno fiddling with it as well. In the end the results were similar throttle response seemed to have gotten worse over the 1.6 flapper and we only saw gains up top. Gas mileage also decreased so we gave up with fuel economy in mind for the endurance race.
 

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Ah yes and it never idled quite the same either. Reliability over 20 hours of racing > a few hp.
 
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