sr20det cutting out and misfre

[bmxer882x]

Alright so I've been battling this since day one. I cant figure it out.
Whenever idling it doesnt seem to have a miss but anywhere 2k and upwards i notice a small hesitation. Also i randomly have a huge power loss when driving. Feels as if i lose a cylinder. That doesnt happen alot but when it does my afr max's out lean.

Idling when warmed up it's idling at 11.2-11.5 which is way to rich. Cruising is around low 14's

So far i have:
checked the coils resistance trying to find a set to swap and test
checked fuel injectors resistance
checked the fuel injector harness voltage- fixed and all spraying
changed the coolant temp sensor
checked the tps voltage and resistance
changed the plugs to bkr6's gapped to .30
changed maf from sohc maf to sr
checked for vac leaks several times
checked for boost leaks with a homemade tester thing
im running a j4 ecu

Another thing i have noticed is there is a considerable amount of fuel in my oil, it has 1,500 miles and im going to change it this weekend.

Any ideas of anything else i can check?

[dorkidori_s13]

could be a number of things...

1) boost leak
2) bad o-rings on injectors
3) bad piston rings (no compression on certain cylinder)
4) MAF needs to be cleaned
5) vacuum leak
6) re-gap your plugs to .25 to .28
7) bad coilpack (rare)

check your plugs, see what your motor is doing (lots of black carbon, lots of white burning etc etc)

[bmxer882x]

plugs look normal.
compression was even when i put it in, dont remember exact number, it was within spec but was 2k miles ago so it cant be that bad.
everything else on ur list i've done besides the injector oring, can i take the fuel rail off and see if they hold pressure or will it shoot off with pressure?
also if it was an injector why would my afr gauge max out lean when it feels like i lose a cylinder, shouldnt it go super rich? due to straight fuel being dumped?

[dorkidori_s13]

ok, didnt notice the lean bit lol

are you still running the OEM SR injectors? have you messed with your intercooler piping at all?

with boost leaks, leaning out means you have a leak before the turbo (on the intake tract) or around the MAF, basically its the motor taking in un-metered air. anything after the intake with boost leaks creates a rich condition (air escaping before hitting the intake manifold and mixing with the fuel for combustion)

[ultimateirving]

Try getting a fresh set if coil packs. Could be your problem based in the cutting out and randomness. I had a bad coil that allowed my car to run and drive but shittily when I punched it

also take off all the boots on the coils and inspect them for cracks and discoloration

[bmxer882x]

injectors are stock sr injectors, gonna change the orings and check fuel pressure tomorrow. see if that helps at all.

intercooler piping has no leaks.
stock sr intake with all the holes plugged and bov is recirculated.
I dont think its actually going lean, just the cylinder shutting off is making my afr gauge read like that.

Going to see if the other guy in town with an sr will sell me some coils. or at least let me borrow a set. I highly doubt its the coil but its worth a shot... because the miss tends to stay in cylinder 1 and i have moved the coils around... and they visibly look fine.

[jerry_beans]

Had something similar to that on my sr. I had a bad maf and a cracked coil pack. When I swapped out the z32 maf for a working one it ran "better" but sounded like a boxer engine. Turned out my #2 coilpack was cracked. Found a good one locally within 20 minutes on craigslist and problem solved!

[JDMxJosh]

i had the exact problem on my SR.
Problem with mine was the timing. Did you check that?

[ultimateirving]

Also back in the day I had an issue with the stock side mount and it's recirculate function was leaking under boost back into the intake.

Do you have an smic or fmic?

[bmxer882x]

definately going to relook at coils. but i inspected them pretty well. Gonna look for a set reguardless.

Timing was set to 16 degrees when i got it running. Ill reset it to 15 once i check my fuel pressure (going to do now)

it has a cxracing fmic, seems to hold fine no leaks found.

thanks for all the extra ideas guys i appreciate it.



did a bit more testing, im completly losing cylinder 1 when it cuts out. I swapped coils and nothing. its getting spark so i would assume not fuel on cylinder 1. any way to check the injectors? like pulling off the fuel rail and turning the key and seeing if it sprays?

car has took a dive last few days, it was cutting out only after driving for 30+ mins, now its all the time. very rarely does the cylinder actually fire. im thinking clogged injector. and it going from 4/3 cylinders is messing up my wideband.

[bmxer882x]

pulled the fuel rail had someone turn the key, 3 cylinders spraying fuel cylinder 1 no fuel at all. I'm so excited finally getting close to getting this thing running right :D


edit: wasnt getting voltage to the injector, only had 9 volts, traced the ground wire to the ecu and wala! the pin was loose. bent it a little into shape and it runs on all 4's again with 13 volts at the injector. still have my slight miss tho. and still runs rich. but at least its not a ticking time bomb now.

could a bad coil test good on a resistance test but still be faulty? its not always not working just causing a slight miss.

[ultimateirving]

pulled the fuel rail had someone turn the key, 3 cylinders spraying fuel cylinder 1 no fuel at all. I'm so excited finally getting close to getting this thing running right :D


edit: wasnt getting voltage to the injector, only had 9 volts, traced the ground wire to the ecu and wala! the pin was loose. bent it a little into shape and it runs on all 4's again with 13 volts at the injector. still have my slight miss tho. and still runs rich. but at least its not a ticking time bomb now.

could a bad coil test good on a resistance test but still be faulty? its not always not working just causing a slight miss.

Great news the injector harness sounded like an easy fix.

To answer about the resistance test i think it may be possible to be faulty but still pass the resistance test.
Its probably something small that is causing the idle hiccup.

Does it break up under boost?

[bmxer882x]

the lean bit is fixed, it was when my cylinder stopped getting fuel and was shutting off.

it doesnt really have any issues, just if i sit there at a stop and rev it up to like 3k i notice a hesitation. driving i cant notice it. but boosting my afr hits high 10's which is way to rich. and just doesnt feel like it should

[bmxer882x]

ok, gonna bump this post as i havent figured it out. swapped coils same thing.

One thing i have noticed, around the back of my valve cover there is some oil, and with only having 1,500 miles on it.. thats pretty bad for my mileage. Gonna replace the gasket but is there anyway that it could be my hesitation? A small crankcase leak aka vacuum leak?

[steve shadows]

Coil pack harness ground? I didn't see this but I also just scanned the post.

[bmxer882x]

it looked fine, cleaned it anyways with no change. forgot to mention i did that and the injector ground.