Ej swap idle issues

Any thing and every thing ever asked about how to do an EJ conversion to an L series and MY. Includes Brumby and Coupe.
Post Reply
MrTong
Junior Member
Posts: 5
Joined: Mon Feb 20, 2023 8:26 am

Ej swap idle issues

Post by MrTong » Thu Feb 26, 2026 1:43 pm

Ej22 uneven idle
Hey guys, Having some issues with my Ej22 (obd1) (motor has been rebuilt about 3 months ago) swapped Subaru L Series after the car sat for about a month. Started with needing a jump, but now I'm chasing a few weird symptoms. Only code I get is code 33, which hasn't hindered running since the swap.

Harder to start when warm (cranks ~5 seconds) Rough idle that smooths out when throttle is applied
Exhaust has a "misfire" type sound at idle
RPM takes a a few seconds to drop back to idle after revving
Occasionally shakes a bit when shutting off or at idle
While driving, revs seem to hang/stick around 4000 RPM, then suddenly get better after letting off slightly Feels like a "dead spot" or sticking point in the throttle, I've cleaned both the iacv and the throttle body and it seems to be a bit better but that 'exhaust misfire' sound is still there.

Anything else worth checking? I have a new MAF sensor waiting to be put in, before the car sat for a month everything ran fine. Can get videos of it running when I'm back t the car later today.

Cheers
Cheers, Reily

92 L series
5 stud swapped
EJ swapped

User avatar
El_Freddo
Master Member
Posts: 12683
Joined: Tue Oct 04, 2005 10:00 am
Location: Bridgewater Vic
Contact:

Re: Ej swap idle issues

Post by El_Freddo » Mon Mar 02, 2026 9:03 pm

G’day Riley,

Clean the throttle position sensor. If it’s anything like the gen1 unit you can pull the cover off and clean up the contact tracks then properly reset it following the factory procedure.

Check for vacuum leaks.

That’s all I have atm.

Code 33 = ?
"The lounge room is not a workshop..."
Image
El Freddo's Pics - El_Freddo's youtube

MrTong
Junior Member
Posts: 5
Joined: Mon Feb 20, 2023 8:26 am

Re: Ej swap idle issues

Post by MrTong » Wed Mar 04, 2026 7:39 am

Hey Bennie,

Got all sorted, ended up being a MAF issue, which was interesting as it only must have started going bad. Replaced with a new one and shes running mint. Code 33 is VSS (Vehicle Speed Sensor), which I've had since doing the swap. Dave included the module for the GPS speedo, but either ive doing something wiring-wise, or it must not be sitting right (spoken to dave about it and hes said if its not hindering the running of the car then leave it).

Cheers for the reply anyhow, really appreciated
Cheers, Reily

92 L series
5 stud swapped
EJ swapped

User avatar
El_Freddo
Master Member
Posts: 12683
Joined: Tue Oct 04, 2005 10:00 am
Location: Bridgewater Vic
Contact:

Re: Ej swap idle issues

Post by El_Freddo » Thu Mar 05, 2026 9:25 pm

No worries mate, glad you got it sorted. I didn’t suspect the AFM being the issue!

Hope to see you again at Subinats 8)
"The lounge room is not a workshop..."
Image
El Freddo's Pics - El_Freddo's youtube

Post Reply

Return to “Fitting EJ motors to MY & L series models”