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-   -   hesitation as I rev and a backfire at 6.5k (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/hesitation-i-rev-backfire-6-5k-784029/)

cheesebox 09-02-08 10:22 PM

hesitation as I rev and a backfire at 6.5k
 
Well it hesitates a bit as I rev, then when I hit 6.5k Boom I get a loud backfire, Any ideas?

l4nc3r 09-03-08 09:04 AM

Welcome to Rotaries.

Hesitation at ~3800? Normal.
Backfire at 6.5? Normal.

texFCturboII 09-03-08 09:24 AM

Not quite....

Hesitation at 3800 rpms, while may be "normal" for some, is usually corrected by re-doing your grounds, particularly the main ground for the ECU on the block.

Backfire at 6.5rpms, well in that case, yes.... welcome to rotaries. Especially one with emissions controls removed.

cheesebox 09-03-08 09:55 AM

Okay, I cleaned all the grounds I could find, I dont see excessive resistance from engine - battery
Battery - Chasis
Chasis - engine

I never had this backfire before. its REALLY loud, Maybe its because of my 3" exhaust now but its quite serious sounding and I dont even want to push my car that high anymore.

texFCturboII 09-03-08 10:08 AM

Yup, that 3" exhaust would help. So it backfires and sputters and won't let you redline? Check that the TPS is in adjustment.

cheesebox 09-03-08 11:51 AM

? I think it would let me redline, it just makes a HUGE backfire like a gunshot, then i let off the gas cuz I dont want to break nothing

HeyITZthatFC 09-03-08 12:59 PM

the backfire sounds normal to me at RPMs like that and a 3" .

CyberPitz 09-03-08 01:10 PM

Would tuning it help the backfire?

AreExSevenProject 09-03-08 01:36 PM

its called emissions removed. I believe its from the air entering the exhaust and meeting the new exhaust or something liek that. Is this a N/A with a 3" exhuast. Because really you dont ever want it that big unless you are just going for all sound and those nice flames. You can downgrade size or put cats on.

And btw...you want to rev your car that high at least once everytime you drive it or say hello to a rebuild in the near future. Oh and if you start shooting flames say bye bye to the nice rear bumper lol.

cheesebox 09-03-08 02:16 PM

no its a T2, The backfire is BAD, the entire car kinda jerks, then if I try to rev through it, it backfires and pops more. this DID NOT happen before!

HKSpoweredFC3S 09-03-08 03:44 PM

Its backfireing as you let off the throttle?? or is it backfireing while your still giving it throttle?? Backfiring under throttle isnt good, it eats at your apex seals. other than that, its perfectly normal to have backfire from all the exsese fuel being burned off from your exhaust.

and if its hezitating that badly, theres an issue.

HKSpoweredFC3S 09-03-08 03:49 PM

Try talking to icemark or arroncake.

cheesebox 09-03-08 04:22 PM

Well heres the deal, It does it UNDER THROTTLE, only when I am trying to get going really quick, at WOT I get a massive poop on my head at 6.5k when the car jerks and BOOM like a gunshot it backfires, i tried to do rev past it and BOOM BOOM BOOM BOOM keeps backfiring.

CyberPitz 09-03-08 04:26 PM

Sounds like not all of the fuel is getting burned off and shot straight out into the exhaust where it keeps backfiring.

First thing that comes to my mind is coils/plugs/wires?

cheesebox 09-03-08 04:30 PM

oh yeah, Stage 2 BNR turbo, 720cc secondarys RTEK 1.7 Full 6an Fuel System parrallel rails, SX regulator @ 42 psi, I have tried 45 and 38 problem persisted. KNOWN GOOD walbro pump in tank, no leaks, NOT ONE it holds at 25 psi for 30 minutes when the car is off, just as SX says it should with a perfect regulator. I have a Denso Supra pump as a back-up but I dont believe I need it. Just put in new plugs 7 cold and 9 cold, I had 9's all around before. I am 98% sure I got my plug wires right. Torqued to 16lb's. Recently installed a Fuel kill switch because I had it flood at Auto-X and it sucked balls. Every so often my Coolant buzzer goes BZZZZZZZ but I have burped the system about 5000 times I am not loosing ANY coolant, my buzzer is just stupid, extremely stupid. I use Valvoline Vr1 20/50 oil. My car is white, my left bolster on my drivers seat is ripped, No radio :-0 oops too much info!

cheesebox 09-03-08 04:31 PM

oh and I have a innovate wideband but It wont communicate with the XD-16 and confuses me, so it hasnt been installed yet.

CyberPitz 09-03-08 04:44 PM

Well, dangit, you just shot through my expertise, which happens to end at "Stage" in your post :P

cheesebox 09-03-08 05:05 PM

okay its really a custom turbo by Tim, T04E compressor housing 360 thrust bearing and a whole lot of weird spinny things that go woosh, Better?

cheesebox 09-03-08 05:07 PM

oh and im running stock boost, no controller less then 7 psi.

cheesebox 09-03-08 08:12 PM

Could it be my spark breaking up? what else can I check?

fcdrifter13 09-03-08 08:33 PM

Is your WG ported if not you are hitting fuel cut perhaps

HKSpoweredFC3S 09-03-08 09:32 PM

Sounds like your fuel is trying to cut. You probably have boost creep.

cheesebox 09-03-08 09:33 PM

Wastegate ported to 38mm as big as can possibly go, RTEK has anti-fuel cut built in.

HKSpoweredFC3S 09-03-08 09:47 PM

Im stomped =( nothing more that I know.

cheesebox 09-03-08 11:16 PM

alright well thanks man :( Im also confused by this, I wish I had a timing light to reset my timing,


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