I've had this problem since I bought the car but it seems to be getting worse as time goes on.
What happens is under a lot of load (low rpm, full throttle operation) or part throttle mid-rpm operation under boost there will be a sort of clicking sound, the engine will stumble for a split second, then go along with its business.
mods are a RB turbo back exhaust, FCD, high flow fuel pump. everything else is a stock 91 TII equipment.
I had a boost gauge hooked up a few weeks ago, and under full load in 4th it wouldnt go over 10psi of boost, but now that its getting colder i wonder if its spiking. But, the last few days here hasn't been much colder than 60 degrees when i was driving the car.
the sound i hear almost sounds like the coil is arcing to ground somewhere and not providing spark.
It did this once on a dyno and kicked out black smoke, which leads me to believe its a spark issue and not detonation.
Any advice would be helpful.

 

not even a GTFO or search noob?

 

what have you tested and checked? Post your diagnostics and help us rule out any possibilities. We can't help until you get us all the correct info.

 

What plug wires are you running? Stick to stock NGK if in the event you've got some unseen crossfire going on.

B

 

do you have an afc or a boost controller? thats just the first thought to come to mind, not related to your problem but its not cool to just let the turbo boost away at will and when boosting higher than the stock ECU allows (FCD) you need to add more fuel. black smoke is fuel, that I know, I would look into the spark issue and get back with more info. check your plugs, wires, coils, etc.

 

http://turblown.net/lines

 

Where in Ft Worth are ya? I'm in Grand Prairie.

B

 

well i've ordered the correct spark plug wires... the ones on there right now are way too long. now that the idiot cluster works, i could finally check the check engine codes, got a (15) - o2 sensor, (30)- split air valve solenoid, (33) - port air valve solenoid?
the check engine light only comes on in cold weather, and usually only in the morning when i drive to work. when i go out for lunch or drive home it never throws any codes.
i know i need to get the boost gauge hooked up permanently and a wideband o2 sensor would help too.
I'll check to see what the timing is set at as soon as i can, but it should be stock.
If theres anything else anyone can think to check, let me know. Somehow i don't think this problem has anything to do with the the occasional check engine codes i'm getting.

 

no boost controller. don't need one need to get the wastegate ported if anything.
i have some autolite spark plug wires on order as advance autoparts said they probably couldn't get the NGK's. will the autolites be fine or do i really need to stick with NGK?
i think i have spare set of coils I could swap out to test.

 

Actually living in Arlington now, working on getting my sheepskin at UTA, i haven't made it to any of the DFW meets yet, but hopefully I will be there Dec. 11th if i can find my vac leak first... lol, one week and the semester is over, then I will really have some time to get under the hood.

 

I'd go to a place that sells NGKs and NGK wires.

 

+1 on NGK's, they are trustworthy and efficient.

 

Ditch those things and go back to stock on the plug wires. Trust me on this. Give rx7.com a call, ask for Cris, and tell him I sent you his way to get a set of NGK plug wires.

B

 

You'll have to come see me sometime. I'll show ya what I do.

http://www.bdcmotorsports.com

B

 

exactly^^


mine did the exact same, scared the **** out of me because it soundend jut like you described...click....click....click, thought it might be knock till i finally noticed black puffs of smoke from the exhaust in the mirror

stuck my hand down by the plugs and rev'd the engine, the wires were arcing everywhere

these were stock wires, i changed to some 10.5mm ones and now no problem at all

 

Cool, i'll def get the NGK wires.
A little update... I pulled the plug for the trailing coil to disable it and the car ran beautifully. What I don't get is that the trailing coil is for emissions pretty much and has no real affect on the motor making power. so if thats the case, i don't get why the motor felt like it was loosing power whenever the popping occured.
Strange. At any rate, i'm going to swap the trailing coil and see if that helps, if not, i guess i'll look at the wiring harness, grounds and check the CAS.
Why did mazda run the tach off the trailing coil signal? I hate not having it work while the coil is pulled

 

I should post a pic of the plug wires on there now. you guys would cry. they are about a foot or 2, too long. I have them wrapped up and ziptied out of the way for the time being.

 

You just take away the cross firing when you unhook the trailing coil...... i did the same thing when i was waiting for my new wires to arrive, as that made the car act just about normal

the wires are the problem

jeez you sound like me, i had mine all ziptied too, which i am sure makes the situation worse

 

Haha, yeah its a mess. Welp, new wires here I come.

Can I jumper the pins on the harness for the tach so it will work? or does the whole coil assembly need to work for the tach to get signal?

 

Make sure you use NGK wires. Do *not* use aftermarket!!!

B

 

Can I jumper the pins on the harness for the tach so it will work? or does the whole coil assembly need to work for the tach to get signal?******************************************* ******************

No.

 

ok, i've got the NGK wires on, it had fairly new ngk plugs in it as well (changed 2500 miles ago at oil change)
the missfiring was still happening. i have an extra set of coilpacks, swapped the leading and trailing out. still missfiring. it's not doing it as bad as it was before, but it still happens some. again, if i dissconnect the trailing coils, everything is fine. its only when they're running that the missfire happens.

 

Nice, I may need your help tuning when I finally get my stage 2 BNR! I'll look ya up!

 

Do you the wires all tied together and stuff again with zip ties?

 

^ yeah they criss cross a little bit. I don't have a lot of the original hardware thats used to separate the wires.