# sr20det idle problems help



## s13drifter808 (Apr 23, 2006)

so the problem is my idle is steady when i start it and then let it run for a while so then i rev it too 2,000 rpm and the idel drops like its gonna die out then it bounce back up. so when im driving like in first gear then shift back to nuetral it drops again then bounce back up again. it does that in all gears. 

any one know whats wrong could it be my maf or blow off valve?


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## rogoman (Dec 16, 2004)

The BOV could be leaking or there may be leaks in the piping connectors; do a vacuum leak check with a vacuum gauge.


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## 180typeX (Jun 25, 2006)

do you have a open atmosphere bov, if so it will not work correctly with the maf sensor.


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## s13drifter808 (Apr 23, 2006)

yah i have an open atmoshper bov? so what should i do resirculate the bov


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## rogoman (Dec 16, 2004)

180typeX said:


> do you have a open atmosphere bov, if so it will not work correctly with the maf sensor.


That's not true. There are many KA-Ts and SR20s running around with atmospheric BOVs and have no problems; these folks are using OEM MAFs.

Remember the BOV only operates when you're coming off from boost; it's function is to protect the turbine wheel from a damaging reversion back flow. At all other times, it's closed. 

Besides, the BOV is located between the turbo and throttle valve, while the MAF is located on the other side of the turbo, near the air filter. Any opening/closing effects of the BOV will be negligible to the MAF.


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## s13drifter808 (Apr 23, 2006)

so anyone else no whats the problem?


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## 180typeX (Jun 25, 2006)

Hey rogo man, first off the the KA uses MAP, not MAF. Second your are correct the maf is located before the turbo but what does the air have to go through to get to the BOV? Filter>Maf>Turbo>Intercooler>Intake. The Maf sensor has already compensated for this air so if you release it into the atmosphere the ECM gets confused for a second and may cause the mixture to go extremmely rich. As far as it only operates when your coming off boost, this is true but the engine is still running therefore still requires a correct signal from the MAF. As a nissan tech I have seen this problem a few times. I'm not saying that this is for sure the problem but it just an idea. Just route the air from the BOV to the intake pipe between the Maf and the turbo.


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## ExileinOblivion (Jan 24, 2005)

hey dude when i installed my sr it ran exactly like yours... its actually a common problem, you can clean the maf wires using brake cleaner i believe which is what my mechanic did and that cleaned up the connection to balance the idle. CHECK YOUR TIMING! 15 degrees is perfect. another thing i did was change my plugs and set the gap to .35. i also cleaned out the plug slots with wd40 and brake cleaner to get rid of the shit that has collected while it was sitting in the warehouse and protect against moisture. its also a basic thing but after you do those reset your ecu and check it for codes, just google sr20det computer code diagram. if that doesnt work you might have a in your filters or a leak in your vacuum somewhere just double check all the connections for brittleness and cracking.


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## 180typeX (Jun 25, 2006)

Just correcting myself, I know that not all KA's use MAP.


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## rogoman (Dec 16, 2004)

180typeX said:


> As far as it only operates when your coming off boost, this is true but the engine is still running therefore still requires a correct signal from the MAF. As a nissan tech I have seen this problem a few times. I'm not saying that this is for sure the problem but it just an idea. Just route the air from the BOV to the intake pipe between the Maf and the turbo.


Routing the air from the BOV to the intake pipe between the MAF and the turbo is exactly what Nissan did on the SR20DET OEM setup.


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## 180typeX (Jun 25, 2006)

Exactly, thats why having it dump into the atmosphere causes the signal from the maf to the ECM to be off. The maf is sending a signal to the ECM that there is X amount of air entering the engine but the blow off valve is releasing some of that air into the atmosphere therefore causing an incorrect signal.


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