S13 blacktop sputtering hard under WOT

[RickyBobbyS13]

So I’ve got an S13 blacktop in my car and under full throttle it’s running like it has a boost leak. Sputtering and stops building boost. I’ve leak checked the whole car for any possible boost leaks and fixed any I found. Car starts, idles drives down the road fine just cruising but once I try to get into it it builds a little of boost and the sputters and stumbles all over the place. I’ve done plugs and coil packs as well as 255 fuel pump and new filter. Car runs a solid 10.0 on the wideband so it doesn’t seem to be any fuel issues.

Any insight is appreciated. Thanks.

[kyral]

You have way too much fuel. idk about your wideband but mine actually bottoms out at 10 and wont read any lower

is this a name brand 255?
how long does it take to recover?
does it instantly sputter and stumble when you get on it everytime?
and why are you running so damn rich

[RickyBobbyS13]

Its an ISR 255LPH fuel pump and yes my AEM wideband doesnt read anything less then a 10.0 on the gauge. It will run fine and drive fine under normal conditions(14.7 while cruising) and it only happens when really trying to get on it. Boost gauge spikes all over the place around 5lbs and runs like trash, as soon as i let off itll drop off and go back to running fine. I will be checking my injectors today to see if i have a possible stuck one at WOT?

[RickyBobbyS13]

Bump. Any ideas?


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[jedi03]

tune, flooding, coil pack...could be a lot there...

[RickyBobbyS13]

tune, flooding, coil pack...could be a lot there...



Brand new coil packs, spark plugs. Car is stock aside from intake/exhaust. Shouldn’t need a tune


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[blkvrtswp]

Describe how you checked for boost leaks.

[RickyBobbyS13]

Used a boost leak tester off the turbo and pressurized the system listening for leaks and using soapy water on everything


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[heywier427]

Why/when did this start occurring?

Plugs gapped to 28-32?

[RickyBobbyS13]

Been happening since I got the car; was told it never had any issues prior to me owning it but we all know how that goes.

Plugs are gapped to a .28 and am getting a “55” from the ECU.




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[heywier427]

Try unplugging the maf and see what you get.

I believe code 55 means there is no codes.

How the pcv valve?

[RickyBobbyS13]

Unplugging the maf makes it almost die out and run rough so I figure the maf is working correctly; haven’t checked the PCV or iacv. Also wondering if it’s something dumb like the o2 being bad or something.


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[nissansrdub]

Injector o-rings. One is probably torn or pinched.


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[blkvrtswp]

Hmm, boost leak test procedure sounds ok. How high did you see the pressure get to on your boost gauge during testing?

[RickyBobbyS13]

Maxed out 5lbs on my gauge which makes me think I have a faulty gauge as well. I will take a look at the injector o-rings when I get home as well. I ordered a pro sport electronic setup to see if I can’t get a true reading.

I am truly stumped on this as the car runs phenomenal aside from WOT or 0-full acceleration.


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[heywier427]

Or you have a ginormous leak somewhere! :)

Just unhook the boost gauge signal hose and run air pressure to it. Should easily go to 20-30 psi with an air hose. Maybe the hose to the gauge is split somewhere?

[RickyBobbyS13]

Very possible as well. Once I get this new gauge setup it should have much better material for the boost line itself.

This leak must be somewhere crazy because I have tested it and can’t find it anywhere.


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[blkvrtswp]

I would want to see 15+ lbs on the gauge to rule out boost leaks.

[nissansrdub]

Don’t forget to lube up the injector o-rings before popping the injectors back in


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[RickyBobbyS13]

So I’ve done it all. Still no change. Makes zero sense.


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[heywier427]

pinch off hose going to pvc valve?

How are your brakes? If you live in a not to congested area, or if you can drive to one, pinch off your brake booster line.

Are you able to do a pull, get it to mis, turn off the engine while missing, and then pull the plugs to check the color? Try not to get the turbo super hot while doing this.

Ripped diaphragm on bov?

[RickyBobbyS13]

Hoses seem to be clean to PCV valve, brakes are good. But I’ll try to pinch off the vac line to the booster. I’ll also do a pull to check the plugs and see how wet they are. I removed all the IC piping and re installed checking for cracks and holes and didn’t find anything.. bov has a good deal as well


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[heywier427]

Not so much to see if theyre wet, but the color. Which ever cylinder is missing, the color at the tip of the plug is going to be white/light tan, compared to the others which will be black if running in the 10's.

Could be worse. You could be working on a volkswagen :)

[RickyBobbyS13]

So after looking at it today; I turned it to key on power and heard what sounded like air coming from around the FPR, is that my mysterious leak or is that normal?


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