Help ASAP :Sr20red top back fires after a rev an wont go past 2k-2.5 rpms

[Keefs240sx]

Back fires after a rev an wont go passed the 2k 2.5 rpms what could this be jus set the tps .45 at closed throttle an set timing can the crank angle need to be rotated or what?

[di-devol]

Check your maf.

[KiLLeR2001]

When you can't rev past 2500, MAF is usually to blame.

[hardparkd]

is it nessicary for two posts ?
http://zilvia.net/f/tech-talk/437113-sr20det-stock-hesitate-when-you-give-throttle.html

[Hoffman5982]

ECU is in limp mode sounds like. Clean/replace the MAF

[Okinawandrifter87]

Double check the wiring on the maf as well.

[spartanmisfit]

I assume these problems are when youre parked? If you have a big enough boost leak it will cause the same problem. Check all of your couplers but sounds more like your maf.

[Keefs240sx]

Ok eating at the moment picked up maf cleaner an will.try that any thing else or should that be it? Btw wirespecialties harness so was told wiring was prolly good . Cleaning the maf should i take it apart an clean it or jus spray cleaner at the maf hole?

[Okinawandrifter87]

Then check for boost leak like mentioned above and cleaning MAF. Then go from there and report back with findings or resolution and we can help from there.

[theboy]

Are you running a stock setup with stock maf? I know the specialties harness allows you to plug in different maf's. Make sure your running the correct or your shit wont read it(i.e. stock setup wont read z32 maf unless tuned for it).

[Keefs240sx]

It's stock maf but the turbo is an external gated turbo

[Keefs240sx]

Came to reading up on some page my synapse bov needs to be recirculated. They say make it run rich if it is an then it's not getting enough air for that right?

[codyace]

You should recirculate, but it doesn't explain why it's not revving.

If the car is parked, not moving, can you free rev without issue? I'd look into a pipe being slightly off more than anything. MAF related (limp mode) issues usually occur around 4000 rpm

[Keefs240sx]

Car revs fine till it gets to about 2500 rpms.I finally got a quick responsive throttle now it back fires after each rev

[codyace]

unplug your maf, see where it revs too.

[Keefs240sx]

If it revs passed 2500 it's gonna be a bad maf? At work will try that at lunch an I got some cleaner an gonna try that first

[Keefs240sx]

Tried a new maf an still the same problem could it be the knock sensor? in desperate need of help so aggravating idk what to do if some one could get me there I can send a video of it so ya can see what it's doing

[slider2828]

Check your plugs, check O2 sensor. Could be a bad CAS.

Unplug your knock sensor, but usually it doesn't give a crap.

Put the ecu in diagnostic mode and see if anything comes up.

It can't be a knock sensor....

[Keefs240sx]

If I unplug the knock sensor still the same problem


How do I go about testing the 02 sensor?
Gap plugs at 28.?



Also if I turn cas it changes the idle an stuff so don't that mean its working?

An all coils are firing

[Keefs240sx]

I looked at this

Nissan MAF Wiring For Dummies - SR20 Community Forum - The Dash (http://www.sr20-forum.com/howtos/9138-nissan-maf-wiring-dummies.html)

But my car will start with out the maf plugged up, but I got the volts at the plug as in link above so can't figure out why an what's going on

[slider2828]

O2 sensor you measure the ohms between the to pins in the plug. You need a multimeter to measure.

Did you try the diag mode on the ecu?

[slider2828]

Otherwise it really sounds like your timing is off

[Keefs240sx]

Not yet got dark out an I did unplugg maf an car starts either plugged or not . I checked volts an got them from this link



Nissan MAF Wiring For Dummies - SR20 Community Forum - The Dash (http://www.sr20-forum.com/howtos/9138-nissan-maf-wiring-dummies.html)

[thizzen4]

check ur tps

[Keefs240sx]

Tps is set .45 at closed

Throttle response is there it jus won't go past 2500rpm it coughs bogs an backfires

[spools420a]

I would think eather a maf issue but i would do a boost leakdown test make sure a coupler is not torn or somthing good luck.

[xGUNKX]

Id check spark plugs and MAF.
If its stock MAF and you have external wastegate setup. Your supporting mods arent up to par and you need Z32 MAF and good tune

[Keefs240sx]

I got another maf from guy on here an didn't help I saw some things could it be the cts? Will do another boost test an see if I looked over anything any other ideas can go past 2500rpms

[xGUNKX]

Could be boost leak.
What kind of MAF. And check them plugs

[Keefs240sx]

Stock sr maf 52f00 gapp at .28?

[xGUNKX]

What are your mods?
You most likely cant run a stock MAF cause its not letting in enough air so you run rich.
Best bet is Z32

[slider2828]

Stock MAF is fine if you aren't running over like 300WHP.... Not a big deal and still shouldn't die out....

On the external wastegate, what lb spring you running and what turbo you running?

[Keefs240sx]

I have a z32 I bought for my 30r an tubular manifold I am waiting to put on after I figure out why it's doing this don't wanna put that on yet cause I low on funds wit my s2k build too so trying get 240running right right it's a eBay turbo right now that came on my long block I kno I'm gonna get ragged with that but it's not gonna be on long cause I gotta finish downpipe an stuf for new setup

[Keefs240sx]

Tried z32 maf an still same crap going on



Plugs are black as shit that still ain't gonna cause it to buck an cough an not go past 2500rpm ?

[xGUNKX]

If plugs are black they most likely arent sparking fulling. You're misfiring.
Change the plugs and watch the magic

[Om1kron]

Sounds like everyone else is about right.

The knock sensor could be causing the issue, it's a fucking dark horse and completely useless there is a fix for it by jamming a (1hz, 1ohm) resistor in the female plug, if that resolves the problem then your engine has a faulty knock sensor or it's sending a false knock or your shit is knocking just enough to retard timing. VERY RARE as it's normally audible.

The Maf may not be the problem, your shielded wire may be fucked up somewhere along the line in your wiring it sounds like more than anything very rare for the maf itself to go bad. Normally some kind of break in the wire.

You learn these things buy buying a bunch of spare parts lol.