3rd generation rx7
 

Hi guys . I'm new to this site . I've Hurd good things about it and how there is so much help and knowledge here . So I figured to ask .I have a twin turbo that's misfiring only when I accelerate . I mean when I drive normal it has no issues but when I give her gas she misfires and backfires like a shotgun . I took it to the dealership here in NS and they said it could be your spark plug wires or coils . So I took it home and took it apart and I seen the coils checked the for cracks but they were not broken so I figured it's just a bad coil somewhere . But then I seen wire connected to the bolts on the coil but they cut so I grounded it cuz I couldn't find out were it cut . Put it back togather and took it for a drive and still misfiring on acceleration. Any suggestions on if coils can do that and how to determine that's what it is . Thank guys and hope I hear back soon .

3rd generation rx7
 

i don't know alot about 3rd gens, but from any engine standpoint, if it idles good and drives nicely fine, i doubt its your coils, rx7 coils are VERY robust and don't fail very often

plugs and wires could add to the problem, but i doubt its your whole problem

has it just started to do this? has the car sat for any period of time? when was the last fuel filter change?

and FYI, almost NO mazda dealer has ANY clue when it comes to these cars, they havent seen them in 20+ years, the mechanics the dealers DID have with the knowledge on these cars are long gone

Factory Service Manuals ---> Mazda RX-7 Reference Materials

Start with the inexpensive things first. Change your plugs. Do them one at a time, with a little anti-seize on the threads. I recommend staying with NGK but note the differences in the leading (lower) and trailing (top) plugs. If the wires look old and beat-up, change them as well.

I think what you're referring to is the coil harness. They can get a bit brittle from heat and age and if it's lost continuity...or broke a wire, then it should absolutely be replaced. Here in the States, IIRC, they're $120 or so.

Thank you for the reply . But I did change my plugs first then the wires but it didn't fix the problem. I thought coils weren't bad . But fuel filter hasn't been changed since I got it . Could that be it ? . It drives n idles good . But the minute I give her gas to take off she backfires and misfires . And I agree Mazda dealership know more about rx8 not rx7 . It's too complicated for them I think .

3rd generation rx7
 

they barely know the rx8s, all they do is change the engine, they know nothing else lol

In my opinion you're describing an ignition problem. Timing isn't advancing as it should. Consider replacing that coil harness and check your crank angle sensors and trigger wheel. There are troubleshooting guides in the FSM.

It wasn't the harness that was damaged. There was a little ground wire that came off the little bolt holding the coil . It's a ground wire . I reground that wire . But made no difference so it made me think I damaged it while I took it apart . I'm ordering the coils I think tonight . But how do I test the coils ? Any idea lol

Did it drive fine when you first purchased it? Is this a recent issue? Have you checked your MAP sensor? Could be several things. Is the ECU possibly in limp mode? Have you checked for ECU codes?

I had it for cpl of years now. And it drove fine before . But last summer before I put it away in Oct it started doing that . I figured once I too it out this year I'll fix it . But I don't know to be honest . I'll check my map sensor tomorrow n see if that's OK .

http://www.teslasources.com/misc/icdatafile.pdf
CAS inspection FSM page G-17
Coil inspection FSM Page G-21

Ihey buddy . I just reset my ecu and she drove fine now :) was so happy to get back in my seat again lol. Now time to get the gt35r . You know anyone got one fir sale?

That's great news!

I need to upgrade my turbos lol . I want more power

Sounds like it was in limp mode. So it was a timing issue as the ECU will not advance timing unless vacuum is present at the upper intake manifold. No boost. Whatever caused it will likely return.