Help sr20det backfiring and sputtering on deceleration

[EatSleepDriftS13]

I have a freshly rebuilt S14 SR20 with less than 500 miles on the rebuild. When I fired up the motor it was misfiring badly and would run pretty rough backfiring and sputtering like crazy. I adjusted my timing and set it correctly, put in new spark plugs and set the gap correctly, checked to see if all my grounds were good and replaced my coil packs with brand new ones from Nissan. After this my car stopped misfiring and ran smoothly except that I continue to backfire between shifts and deceleration as well as occasional sputtering from the engine. I am also having poor fuel mileage getting around 16 MPG babying it staying out of boost most of the time. Can anyone help me, I am starting to suspect that it could be something wrong with my Rom tune that I got from Enthalpy.

[Fuego]

What exhaust do you have? AFRs? BOV?

[EatSleepDriftS13]

For my exhaust set up I have a screamer pipe, 3 in downpipe , 3 in test pipe and a 3 in exhaust. I also have an HKS BOV and dont have any way of checking my AFR's

[TwelveAM]

Could be faulty injectors. What heat range spark plugs are you running?

[EatSleepDriftS13]

I am using NGK iridium plugs. I believe the heat range is a 6 or 7 for stock to mild horsepower

[manuelamarrero]

Misfiring is definately due to the plugs used in the car. A place known as Quail Roost Tire Center (http://www.qrtire.com/ourservices.htm). I am sure that you get satisfied with their services and advice. They offers wide range of auto repair services including Engine repair, oil changes, breaks, shocks, alignment, suspension, ac service etc.

[ultimateirving]

Are you getting any engine codes? Running rich will cause a lot of those symptoms. Are you sure the timing is set right?
Does it drive different when cold? Worse when warm? I'm thinking faulty temp sensor or wiring.

[S13MATT]

Are you getting any engine codes? Running rich will cause a lot of those symptoms. Are you sure the timing is set right?
Does it drive different when cold? Worse when warm? I'm thinking faulty temp sensor or wiring.

I'm his brother and we did this swap together.

Theres no engine codes, we set timing to 15 BTDC. His ECU is tuned by Enthalpy. We have it tune for 9:1 compression and running on 91 octane.

It doesn't drive different when cold as far as i know, but it seems as though are temp sensor is faculty.

My brother forgot to mention that his BOV is venting to atmosphere,

[fliprayzin240sx]

Could be the BOV leaking...

[Fuego]

Could be the BOV leaking...

This is my guess.

Also, a fatass exhaust on a turbo car is going to pop on decel, that's just the nature of the beast.

[TheRealSy90]

Sounds like it's running rich between shifts and on decel, which is most likely because your bov is not recirc'd.


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[mr.nismo.]

basically what the last two people said. uncirc BOV with muffler and i still will throw a blue flame or two

[tomdicaraus]

Misfires occur due to 1 of the various reasons like problem in spark plugs, injectors problem etc. As you said you also having poor fuel mileage then according to me may be problem is with the injector. you should visit to a good auto repair shop. I suggest you a best auto repair shop i.e. Transmission Experts (http://www.transmissionrepairgeorgia.com/services.htm), they are really helpful. Transmission Experts And More also offers a wide range of auto repair services including Transmission rebuilding, Radiators, Drive shaft repair, Breaks, shocks, alignment, suspension etc.

[EatSleepDriftS13]

Thanks for the help guys. seems to be the BOV for sure, going to get that recirculated soon.

[Fuego]

If you want another option, RS Enthalpy makes an anti-stall device that'll help with clutch in/neutral decel and idle. I'd also recommend tightening up the bov.. not so much that you run into major compressor stall, but it should help with the bogging.

All that said, recirc would would be the best fix.