Nightmare Diagnosis - idle would pulse from 500 to 2000rpm 2-3 times then stall - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Longuy · 05-08-2020, 05:55 PM

Symptoms: After winter storage Reinstalled battery, drove car for around ¼ tank of gas, parked for the night, in the morning drove to work without issue. When leaving work car idled rough and had no power, put on 4 way flashers and made it home (work is a 10 min drive from home). Check engine light (CEL) did come on during drive home.

ECU scan came back with PO50A* error. Cleared error. Tried starting car, it would start, but idle would pulse from 500 to 2000rpm 2-3 times then stall. No other CEL.

Solution
Primary Issue: Faulty Mass Air Flow (running rich unspent fuel ran into catalytic converters)

Secondary Issue: Catalytic Converters Melted which plugged exhaust

*Error Code P050A is defined as Cold Start Idle Air Control System Performance.

Overdrive · 05-08-2020, 08:07 PM

...yikes. That sounds like zero fun.

Are you able to hook the car up to a battery tender when you store it so that you don't have to remove the battery from the car? Did you put any fuel stabilizer in the tank when you stored it?

Tcoat · 05-08-2020, 08:37 PM

Are your primary and secondary issues confirmed or theoretical?

soundman98 · 05-08-2020, 08:51 PM

mouse house in the exhaust?

Longuy · 05-08-2020, 09:14 PM

Quote:

Originally Posted by Overdrive

...yikes. That sounds like zero fun.

Are you able to hook the car up to a battery tender when you store it so that you don't have to remove the battery from the car? Did you put any fuel stabilizer in the tank when you stored it?

yeah we did put fuel stabilizer in..the car was stored to far from power and on a farm.

Longuy · 05-08-2020, 09:16 PM

Quote:

Originally Posted by Tcoat

Are your primary and secondary issues confirmed or theoretical?

They guys at Touge tuning/Guelph Subaru confirmed this

Longuy · 05-08-2020, 09:25 PM

Quote:

Originally Posted by soundman98

mouse house in the exhaust?

second thing I thought of after bad gas(we siphon the gas out also)... There was a mouse nest (suspect shrew bc no wire damage) under the intake too furthering the confusion. Touge Tuning traced all the wiring harness with no evidence of chewed wires. That wasn't cheap.

Tcoat · 05-08-2020, 09:29 PM

Quote:

Originally Posted by soundman98

mouse house in the exhaust?

And potentially the air box. Wouldn't be the first.

Longuy · 05-08-2020, 09:38 PM

MAF Spec is 2.21-2.69 kohms - Tested at 1.9 kohms

Here is the exhaust

soundman98 · 05-08-2020, 10:11 PM

what is it? i mean, i understand it's plugged, but with what?

Longuy · 05-08-2020, 10:30 PM

Quote:

Originally Posted by soundman98

what is it? i mean, i understand it's plugged, but with what?

It's the front pipe, with the second Catalytic converter. The first Catalytic converter carbon melted into the second, ruined the over pipe. Replaced it with a Tomei header and invidia overpipe and high flow catalytic converter front pipe. it now has that subie purr

Longuy · 05-08-2020, 10:34 PM

Quote:

Originally Posted by Tcoat

And potentially the air box. Wouldn't be the first.

fortunately it has a Jackson racing supercharger system which has a modified air intake and cone air filter

soundman98 · 05-08-2020, 10:38 PM

so a mouse house wasn't all that far off

Tcoat · 05-08-2020, 10:49 PM

Quote:

Originally Posted by Longuy

MAF Spec is 2.21-2.69 kohms - Tested at 1.9 kohms

Here is the exhaust

Well that sure ain't pretty!

05-08-2020, 08:37 PM	#3
Tcoat Senior Member Join Date: Jul 2014 Drives: 2020 Hakone Location: London, Ont Posts: 69,845 Thanks: 61,656 Thanked 108,283 Times in 46,456 Posts Mentioned: 2495 Post(s) Tagged: 50 Thread(s)	Are your primary and secondary issues confirmed or theoretical? __________________ Racecar spelled backwards is Racecar, because Racecar.

05-08-2020, 08:51 PM	#4
soundman98 ProCrastinationConsultant Join Date: Sep 2013 Drives: '14 Ranger, '18 Tacoma 4Dr LB Location: chicago-ish Posts: 11,330 Thanks: 35,240 Thanked 13,673 Times in 6,781 Posts Mentioned: 98 Post(s) Tagged: 0 Thread(s)	mouse house in the exhaust? __________________ "The time you enjoy wasting is not wasted time"

05-08-2020, 10:11 PM	#10
soundman98 ProCrastinationConsultant Join Date: Sep 2013 Drives: '14 Ranger, '18 Tacoma 4Dr LB Location: chicago-ish Posts: 11,330 Thanks: 35,240 Thanked 13,673 Times in 6,781 Posts Mentioned: 98 Post(s) Tagged: 0 Thread(s)	what is it? i mean, i understand it's plugged, but with what? __________________ "The time you enjoy wasting is not wasted time"

05-08-2020, 10:38 PM	#13
soundman98 ProCrastinationConsultant Join Date: Sep 2013 Drives: '14 Ranger, '18 Tacoma 4Dr LB Location: chicago-ish Posts: 11,330 Thanks: 35,240 Thanked 13,673 Times in 6,781 Posts Mentioned: 98 Post(s) Tagged: 0 Thread(s)	so a mouse house wasn't all that far off __________________ "The time you enjoy wasting is not wasted time"

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
How to lower direct pulse width below .88	solidsnake11	Software Tuning	2	03-29-2020 12:34 AM
Low idle/dip and stall/loss of power	GoZ21	Issues \| Warranty \| Recalls / TSB	5	12-08-2017 06:50 AM
Frs low idle dip and dies multiple times in a row	Dogster70	Issues \| Warranty \| Recalls / TSB	7	11-17-2017 06:44 PM
Rough Idle/Stall/CEL/SL - next steps?	CAnemone	Northern California	3	08-26-2016 12:55 PM
Turbo Rough Idle & Stall	BRZtoni	Forced Induction	40	05-25-2016 05:28 PM

User Name		Remember Me?
Password