New here, looking for ideas as to why my SR runs like poo

[Boune]

Hey all,

Been lurking around these forums for a few months as I bought an S13 back in October 2013. Recently the car has acted up to the point where I can't drive it, however, so I figured I'd post and ask a greater comunity with actual knowledge of these motors lol.

When I bought it, the car had a NIStune ECU, Venom 800cc injectors and what I was told was a z32 MAF (of course I took it as such and my dumbass didn't do any more research than that lol). The car ran decently for about a month when I put it on the road, but about a month and a half ago it all went downhill.

Driving it one night barely idling by a police station, the car started running rough and no longer boosting. So a friend (who is much more mechanically inclined than I) started looking at what could be causing issues. The coilpacks had a bad ground so they weren't sparking a whole lot, he regrounded them and they are now fine. Put some new plugs in it. Checked timing and everything seemed alright. Ordered a new z32 MAF and installed it to no improvement. After fighting with it for a month I gave up and sourced out some stock parts (ECU, MAF, Injectors) and installed them this weekend, the issue pretty well stays the same..

I start the car it runs 14.8 AFR, then after a few minutes of idling it goes down to 10 AFR and just puffs out black smoke. I tried taking it for a drive to see what it would do and as soon as it starts boosting, it leans out and it's like I hit a wall.

Any insight on this would be greatly appreciated as not many people run SRs where I live. The motor is a redtop also, which might help with diagnosing the problem lol!

[Boune]

LOL yes. Did an oil change on it a few weeks back. The oil was getting some fuel in it

[Boune]

nope, idles perfect until the AFR goes to poo

[Ka-t in progress]

If the car had a tune,and 800cc injectors installed ,then running the stock ecu and maf is not gonna fix your issues as the stock ecu isn't tuned for that set up. Sounds like you may have an inter cooler pipe loose or leaking. I would check there first.

[Boune]

Originally Posted by Ka-t in progress

If the car had a tune,and 800cc injectors installed ,then running the stock ecu and maf is not gonna fix your issues as the stock ecu isn't tuned for that set up. Sounds like you may have an inter cooler pipe loose or leaking. I would check there first.

I also swapped back in some stock injectors along with the ECU and MAF. Thanks for the tip, I'll take a look at my IC piping.

[blksylv]

I noticed that you said that you had some fuel in your oil, have you checked your injector O-rings?

[Boune]

Originally Posted by blksylv

I noticed that you said that you had some fuel in your oil, have you check your injector O-rings?

Just did, one had a shred. Going to try it and see what it does lol

[jedi03]

Check tps an fuel pressure reulator /fuel pressure? But sounds like intercooler piping probably bad coupler

[mr.nismo.]

What fuel pump and fpr setup do you have


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[Dboyizmlg]

Could be a small boost leak, check that.
Also check your vaccum

[dorkidori_s13]

sounds like a bad MAF, fuel supply problem or boost leak!

before throwing parts at the car like you have, especially if the car was running normally for a while when you first got it, start looking at the things that cause these issues... most people cheap out on silicone couplers and tbolt clamps. a lot times kids know will just buy cheap ass, paper thin couplers to use on the intercooler piping (or the chinese made shit the intercooler kit comes with) or those throw away screw clamps that are only good for two uses at most.

go thru your engine bay and make sure ALL of your clamps are VERY secure around your couplers. make sure ALL of your vacuum lines are healthy rubber and dont have any splits in them (especially around the nipple area). also, do yourself a favor and get some smaller zipties to clamp the vacuum hoses over the nipples.

even the slightest vacuum leak can cause HUGE issues with your SR, and again, most SR swaps these days are cheaply done and just ghetto shit! most younger guys dont take the time or the money and do things correctly! just slappy slappy, hey it runs, who cares!

if youre having a fuel supply problem, it MAY be time to replace the fuel pump... ESPECIALLY if its a walbro. walbros cannot be run below quarter of a tank of gas (especially in hot places like vegas or phoenix). walbros NEED the gas to keep them cool otherwise the motor/amplifiers in them blow and they stop working! you wind up running into fuel starvation and the motor will no longer run above 4000rpms at mid to full throttle (youll just rev bounce).

MAFs have a habbit of getting very dirty very quickly which, again, will cause major issues. Z32 or SR MAFs are known for being the bitchiest things on the planet! even if you have a small amount of dust/dirt built up on the wires, kiss your hope for a normal running motor goodbye. i clean mine using a mix of B12 carb cleaner (sprayed at the wires and applied on a q-tip) along with MAF cleaner.

when diagnosing these problems start at the point where the air enters the motor. and work from there. if your car is running lean, then you have a leak on the intake of the turbo, if its running rich, you have a leak after the turbo. if youre 100% sure you dont have a boost/vacuum leak, then move on to the MAF. if youre 100% its not the MAF, then move on to the fuel components like your fuel pressure regulator, fuel lines and fuel pump. if youre 100% sure its not the fuel components, then move onto ignition... see where im going with this?

also, one MAJOR thing you need to check is the torque on the intake manifold. get a torque wrench and make sure the nuts on the studs from the head are properly torqued to 14-15lbs AT MOST!!! minimum torque on them i believe is 13lbs. DO NOT TORQUE THEM OVER 15LBS OR YOU RUN THE RISK OF STRIPPING OUT A STUD!!! INVEST IN A TORQUE WRENCH, DO NOT GUESS ON THE TORQUE AMOUNT ON MOST COMPONENTS OR YOU WILL BREAK SHIT!!! there are 2 sets of nuts, the ones on the head and the ones on the runners going to the intake plenum.

also, reset your timing back to 15deg BTC, set your TPS voltage to .45 volts when shut, reset your idle using the IACV... having a messed up TPS will really screw with your SR as well!

[cotbu]

Originally Posted by dorkidori_s13

sounds like a bad MAF, fuel supply problem or boost leak!

before throwing parts at the car like you have, especially if the car was running normally for a while when you first got it, start looking at the things that cause these issues... most people cheap out on silicone couplers and tbolt clamps. a lot times kids know will just buy cheap ass, paper thin couplers to use on the intercooler piping (or the chinese made shit the intercooler kit comes with) or those throw away screw clamps that are only good for two uses at most.

go thru your engine bay and make sure ALL of your clamps are VERY secure around your couplers. make sure ALL of your vacuum lines are healthy rubber and dont have any splits in them (especially around the nipple area). also, do yourself a favor and get some smaller zipties to clamp the vacuum hoses over the nipples.

even the slightest vacuum leak can cause HUGE issues with your SR, and again, most SR swaps these days are cheaply done and just ghetto shit! most younger guys dont take the time or the money and do things correctly! just slappy slappy, hey it runs, who cares!

if youre having a fuel supply problem, it MAY be time to replace the fuel pump... ESPECIALLY if its a walbro. walbros cannot be run below quarter of a tank of gas (especially in hot places like vegas or phoenix). walbros NEED the gas to keep them cool otherwise the motor/amplifiers in them blow and they stop working! you wind up running into fuel starvation and the motor will no longer run above 4000rpms at mid to full throttle (youll just rev bounce).

MAFs have a habbit of getting very dirty very quickly which, again, will cause major issues. Z32 or SR MAFs are known for being the bitchiest things on the planet! even if you have a small amount of dust/dirt built up on the wires, kiss your hope for a normal running motor goodbye. i clean mine using a mix of B12 carb cleaner (sprayed at the wires and applied on a q-tip) along with MAF cleaner.

when diagnosing these problems start at the point where the air enters the motor. and work from there. if your car is running lean, then you have a leak on the intake of the turbo, if its running rich, you have a leak after the turbo. if youre 100% sure you dont have a boost/vacuum leak, then move on to the MAF. if youre 100% its not the MAF, then move on to the fuel components like your fuel pressure regulator, fuel lines and fuel pump. if youre 100% sure its not the fuel components, then move onto ignition... see where im going with this?

also, one MAJOR thing you need to check is the torque on the intake manifold. get a torque wrench and make sure the nuts on the studs from the head are properly torqued to 14-15lbs AT MOST!!! minimum torque on them i believe is 13lbs. DO NOT TORQUE THEM OVER 15LBS OR YOU RUN THE RISK OF STRIPPING OUT A STUD!!! INVEST IN A TORQUE WRENCH, DO NOT GUESS ON THE TORQUE AMOUNT ON MOST COMPONENTS OR YOU WILL BREAK SHIT!!! there are 2 sets of nuts, the ones on the head and the ones on the runners going to the intake plenum.

also, reset your timing back to 15deg BTC, set your TPS voltage to .45 volts when shut, reset your idle using the IACV... having a messed up TPS will really screw with your SR as well!

Good shiitake!!

[scott883]

sounds like an SR.