Misfire all cylinders - Rich no CEL

[Celigts]

Replaced all 8 injectors after having them cleaned and the problem still persists where I’m misfiring in all cylinders.

Car runs rich at idle -7 to -12%

All parts below replaced in attempts to fix the Misfires, So problem persists before/after these parts were changed out.

Changed sparks about 30k miles ago.
Aftermarket Coilpacks at the same time. (Delicious Tuning packs)
New OEM O2 sensor
New OEM MAF sensor
New OEM Map sensor
New Evap solonoid
New all 4 OCV valves
New PCV valve
New Throttle Body - grams
New TRD intake

Just got back my cleaned Injectors Port/DI from CSG and installed those.
Anything in the logs point to the problem?

Here’s my most recent idle logs
https://datazap.me/u/celigts/injecto...?log=0&data=19 (right after new injectors idle
https://datazap.me/u/celigts/cold-id...?log=0&data=19 (clean MAF cold start idle - Next morning)
https://datazap.me/u/celigts/clean-m...?log=0&data=19 (OEM header installed cold idle log - LEAN)

[Butterballz]

Have you tried changing the coilpacks back to OEM? I was chasing misfire too that wasn't isolated to one cylinder. I replaced my coilpacks with IP quad spark and thought that since it was new and reputable, it couldn't have been the coils. After spending tons of money on everything else, I replaced the coilpacks back to OEM and it fixed my problem lol.

[Celigts]

Originally Posted by Butterballz

Have you tried changing the coilpacks back to OEM? I was chasing misfire too that wasn't isolated to one cylinder. I replaced my coilpacks with IP quad spark and thought that since it was new and reputable, it couldn't have been the coils. After spending tons of money on everything else, I replaced the coilpacks back to OEM and it fixed my problem lol.

My tuner did tell me Delicious Tuning coil packs are cheap Chinese made coils so they more than likely are crap.

I sold my old OEM ones for dirt cheap so now I’ll buy some new ones. Fuck. I hate doing coils/sparks not a fun job 😂

[AussieBRZ]

Originally Posted by Celigts

Replaced all 8 injectors after having them cleaned and the problem still persists where I’m misfiring in all cylinders.

Car runs rich at idle +7 to +12%

Changed sparks about 30k miles ago.
Aftermarket Coilpacks at the same time. (Delicious Tuning packs)
New OEM O2 sensor
New OEM MAF sensor
New OEM map sensor
New Evap solonoid
New all 4 OCV valves

Anything in the logs point to the problem?

Here’s my most recent idle log.

Ignore the others as they’re old and mostly testing.

https://datazap.me/u/celigts/injecto...?log=0&data=19

Maf volts seems high , possible dirty maf sensor
Manifold pressire at idle seems high , not pulling good vaccuum, possible intake side leak



Also check DI injection computer and mouunt bracket all botle in and tight especially the hard to reach lower mount bolt on DI copmuter on side of engine

[Celigts]

Originally Posted by AussieBRZ

Maf volts seems high , possible dirty maf sensor
Manifold pressire at idle seems high , not pulling good vaccuum, possible intake side leak



Also check DI injection computer and mouunt bracket all botle in and tight especially the hard to reach lower mount bolt on DI copmuter on side of engine

Appreciate you,


Done a vacuum leak myself and at a shop.
No leaks.
Unplugged and RE-mounted the ECU at least 5 times…
Intake I’ve had stock and I was told vacuum leak and I not only replaced the intake with a TRD intake I swapped throttle bodies to Grams…

New MAP sensor
New MAF sensor

[RZNT4R]

I would be surprised if it was the coils as the misfires apprear to be a symptom, not the cause. Misfires create LEAN exhaust gases, so your STFT would go UP.

It's counter intuitive as you'd think "dumping fuel in the exhaust would read rich", but while it's dumping fuel in the exhaust, it's dumping 14x more air in the exhaust.

But anyway, I would equally be surprised it if was injectors because cylinder one goes to shit both in DI and PI. mentions of low intake vacuum may be onto something, I just went to mine and it idles at 4.3 PSI/29.7 kpa, so yours is definitely high... Might have tight valves, how high is the odometer?

[Celigts]

Originally Posted by AussieBRZ

Maf volts seems high , possible dirty maf sensor
Manifold pressire at idle seems high , not pulling good vaccuum, possible intake side leak



Also check DI injection computer and mouunt bracket all botle in and tight especially the hard to reach lower mount bolt on DI copmuter on side of engine

New logs after I cleaned the MAF on cold start.

https://datazap.me/u/celigts/cold-id...?log=0&data=19
UPDATED IN ORIGINAL POST

[Celigts]

Originally Posted by RZNT4R

I would be surprised if it was the coils as the misfires apprear to be a symptom, not the cause. Misfires create LEAN exhaust gases, so your STFT would go UP.

It's counter intuitive as you'd think "dumping fuel in the exhaust would read rich", but while it's dumping fuel in the exhaust, it's dumping 14x more air in the exhaust.

But anyway, I would equally be surprised it if was injectors because cylinder one goes to shit both in DI and PI. mentions of low intake vacuum may be onto something, I just went to mine and it idles at 4.3 PSI/29.7 kpa, so yours is definitely high... Might have tight valves, how high is the odometer?

131k miles original engine.

Cleaned all 8 injectors through CSG so I’d be shocked if that was the culprit. Installed them yesterday.
Cleaned intake valves as best I could with Seafoam and CRC while the intake manifold was off.


New all 4 OCV’s
Just cleaned MAF and posted logs above.

Low intake vacuum ��
I’ve tested myself and had a shop do it. No leaks.

Any suggestions to plug in points on how to test? Maybe I did it wrong?

[RZNT4R]

Best way to check for intake leaks is to shower the mating surfaces, hoses and connections with brake cleaner while watching the STFT. As soon as you hit a leak it'll shoot negative.

That's significant miles, might be worth looking at the valve lash.

[Celigts]

Originally Posted by RZNT4R

Best way to check for intake leaks is to shower the mating surfaces, hoses and connections with brake cleaner while watching the STFT. As soon as you hit a leak it'll shoot negative.

That's significant miles, might be worth looking at the valve lash.

Did I miss any hose clamp locations?

These are the locations I tested.

No leaks found when spraying brake cleaner.

[RZNT4R]

what about at the base of the manifold where it meets the heads?

[Celigts]

Originally Posted by RZNT4R

what about at the base of the manifold where it meets the heads?

I just replaced the injectors and bought a new intake manifold gasket.
Problem persisted before and after i replaced these injectors.

Also yes, I checked that. No leaks.

[AussieBRZ]

Looked at new logs seems same as before


Negitive fuel trims, noticed you have aftermarket intake, the maf mqy nor be scaled for this intake


Manifold pressure still seems high for idle normally id expect arround 10 psi of vaccuum so at atmospheric of 14 psi id expect idle manifold pressure to be round 4-6 psi or so yours is 8 ps so possible intake side vaccuum leak


Is your tune using speed density ?


what is manifold psi with ignition on but engine off should be close tovatmospherix about 14 psi


if its an NA car on petrol with stock injectors and map sensor load a stock tune on car do you still get misfires ?

[RZNT4R]

Mine idles below 5 psi, but his not only has low intake vac, it's also idling too high.

That's a TRD intake, it's fine with stock tune, that's what I've got in mine.