sr20de will backfire if I go 25%-100% throttle

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nongkong122
Posts: 2
Joined: Sat Jul 01, 2017 8:06 am
Car: sr20de

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please help me my sr20de can't run.

if I go 25%-100% throttle it will backfire on exhaust and intake but if I let off the gas it will fine. idle is fine and only run with advance timing distributor. if i run normal timing it will mifire on intake and no power and rpm very slow,sound like very retard timing (I set new timing but still crap)

in neutral if I easy on throttle it will rev to 3000rpm and cut, but if I quick throttle it will backfire on intake and no power and engine will die if i dont let off gas

if in gear it will run like crap, can't run. backfire misfire on intake and no power at all

black smoke on exhaust and I check spark plug it very rich (very very rich!!)

I changed
spark plug
coil
distributor
maf (unplug and plug make no differrent)
ecu
check injector ok
check timing ok
check tps voltage (around 4v on idle)
check maf voltage ok

i check ecu code and it tell me
12 13 21

but i check it again today it have only
13 (i unplugged temp sensor and no differrent)
:wtf2:

still can't run please help me

sorry for my bad english
Last edited by Rogue One on Sat Jul 01, 2017 10:19 am, edited 1 time in total.
Reason: Revised title


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Hijacker
Posts: 15759
Joined: Wed Aug 13, 2003 4:57 am
Car: '92 240sx Convertible
'94 F-150
Location: Fredericksburg, VA

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Have you checked all the intake plumbing to see if there are any cracks or leaks?

You say you've checked spark, but do you know if it's a strong spark? How old are the distributor, spark plug wires, and spark plugs?

I can't remember if the DE has the bypass valve for the catalytic converter. The DET has one above the exhaust manifold. It allows air to bypass the motor to help light off the cat when the car is idling.

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centralcoaster33
Posts: 2769
Joined: Tue Apr 05, 2005 10:41 am
Car: 240SX #5-1997
Location: Central Coast, CA

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Vacuum leaks, injectors and TPS come to mind. For TPS, try like you did the MAF. See how it acts when unplugged. It should work, maybe drop 300-500 rpms when idling, but should run okay. Also, check voltage for open and closed and see that it is a smooth transition between the two, not just closed for idle. You don't have to have the engine running to test this voltage/ resistance. Check for vacuum leaks as you see fit. Check your injectors for resistance in ohms with your voltmeter.

Also, if you haven't been using it already, use your FSM. It has all kinds of diagnostic procedures for this type of stuff. Keep track of your codes and check them after each step as you work. Use the FSM or have a list ready of what each code means. Look here for your FSM:
http://www.nicoclub.com/archives/nissan ... nuals.html

PS - Welcome to NICO Club!

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PapaSmurf2k3
Site Admin
Posts: 23998
Joined: Thu Nov 21, 2002 3:20 pm
Car: 2017 Corvette, 2018 Focus ST, 1993 240sx truck KA Turbo.
Location: Merrimack, NH

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Also verify fuel pressure.

You can always pull a vacuum line or induce a leak after the MAF (before the throttle body) if you're in a bind. That will lean it out.
Or run it on E85 :)

nongkong122
Posts: 2
Joined: Sat Jul 01, 2017 8:06 am
Car: sr20de

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Thank you all guy. Now this car run better than before. I do some new wiring TPS,MAF,Coolant sensor.

Now idle very smooth and throttle very smooth and no backfire of misfire, perfect a/f and not rich or blacksmoke anymore and can rev to redline very easy

But
It only perfect when it is in neutral !! :wtf2: :wtf2:
If it in gear and put some throttle it run like it cut some fuel or something itself and no power at all. It Cut like my head on roller coaster but it very better than first. It like fast slow fast slow fast slow

I wonder Can it be
Knock sensor
IACV (unplugged and plug make no differrent)
O2sensor (unplugged and plug make no differrent)

Do you guy have some iacv,knock sensor,o2,ignitor wiring pls help me i think previous owner had bad wiring :confused:

Sorry for my bad english

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PapaSmurf2k3
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Posts: 23998
Joined: Thu Nov 21, 2002 3:20 pm
Car: 2017 Corvette, 2018 Focus ST, 1993 240sx truck KA Turbo.
Location: Merrimack, NH

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Check your engine grounds too, or add some more just to be sure.
If you shake your wiring harnesses around those sensors, does the car stumble?


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