P219A P119F poor idle quality

[Shadow6]

2014 FRS, ~70k miles, only mods are OFT E85 tune and muffler delete.

I’m getting these codes basically as soon as the monitors set. The only notable symptom is a poor idle with a tendency to stall maybe once while cold.

I’m not up to date on all the technology, but I did notice slightly low vacuum at idle, so I used my smoke machine and found the throttle body gasket was leaking and replaced that. (Note Before putting the new throttle body gasket on the idle was much worse and I was also getting a P119E code, in addition to the current symptoms.)

Any thoughts on what I ought to look at next? I’ll try to attach my freeze frame data here as well.

Edit: I should mention, this car has been on E85 for a looooong time. Maybe since 2016?

Thanks in advance,

Joe






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[blsfrs]

I had those codes after an engine rebuild. The engine ran well but those codes would pop up every 4-5 drive cycles. I checked all over the forums and found a couple of previous references mainly suggesting the valves needed adjusting. With my tuner, we finally decided to "turn them off" since could not find the cause. So far we are living happily ever after.

[Shadow6]

Originally Posted by blsfrs

I had those codes after an engine rebuild. The engine ran well but those codes would pop up every 4-5 drive cycles. I checked all over the forums and found a couple of previous references mainly suggesting the valves needed adjusting. With my tuner, we finally decided to "turn them off" since could not find the cause. So far we are living happily ever after.

So your car was/is otherwise running fine?

I think I’m gonna throw an O2 sensor at it, though the current one tests fine with a multimeter so I’m not optimistic.

It seems like adjusting the valves on these things is probably a pain in the ass.


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[blsfrs]

Originally Posted by Shadow6

So your car was/is otherwise running fine?

I think I’m gonna throw an O2 sensor at it, though the current one tests fine with a multimeter so I’m not optimistic.

It seems like adjusting the valves on these things is probably a pain in the ass.


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I kinda doubt valve adjustment is the problem. If I remember the post correctly, the "dealer" told him that. Yes, it was running fine.


It may just be coincidence, but during the time my car was throwing those codes, my 1* cat was going bad. It finally got so bad, the car wouldn't make it out of my neighborhood. Compare readings on both 02 sensors, upstream and downstream temps, and if you can, upstream back pressure.

[RZNT4R]

Tigth valves is possible but they kinda inserted that diagnostic step at the very end of the workflow since it's an engine out thing.

here is a giant thread about it

https://www.ft86club.com/forums/showthread.php?t=115951

[Shadow6]

Yeah, I agree. I have a really hard time imagining it’s actually the valves—plus the threads dealing with the P219A/P119F/valve issue reference a Subaru and/or Toyota TSB that was specifically for low mile 2017+ cars, and I have a higher mileage 2014.

An update: a new downstream O2 sensor (Denso) I installed this morning does not seem to have fixed the code—I have P219A pending after a short test drive—but I swear the slightly rough idle and tendency to want to stall when coasting to a stop is gone.

I will take a look at what you suggested on the temps (and back pressure on either side of the front catalytic converter) and report back. I will say I haven’t done autocross in the car since covid, but it’s doesn’t feel down on power.

I’ve put an email in to OpenFlash Performance, I might try flashing it back to has to see if that changes anything. I’ve had issues with bad E85 throwing codes before, maybe all my local E85 is “bad” now.


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[blsfrs]

Originally Posted by Shadow6

Yeah, I agree. I have a really hard time imagining it’s actually the valves—plus the threads dealing with the P219A/P119F/valve issue reference a Subaru and/or Toyota TSB that was specifically for low mile 2017+ cars, and I have a higher mileage 2014.

An update: a new downstream O2 sensor (Denso) I installed this morning does not seem to have fixed the code—I have P219A pending after a short test drive—but I swear the slightly rough idle and tendency to want to stall when coasting to a stop is gone.

I will take a look at what you suggested on the temps (and back pressure on either side of the front catalytic converter) and report back. I will say I haven’t done autocross in the car since covid, but it’s doesn’t feel down on power.

I’ve put an email in to OpenFlash Performance, I might try flashing it back to has to see if that changes anything. I’ve had issues with bad E85 throwing codes before, maybe all my local E85 is “bad” now.


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To my knowledge, the down stream 02 won't affect how the engine runs. Some tunes even disable it's function. Just for giggles, clean the MAF while you're at it.

[RZNT4R]

Why downstream!? Did you even have a glance at the DTC description? It runs on the Crank position sensor and the upstream A/F sensor.

[Shadow6]

Originally Posted by RZNT4R

Why downstream!? Did you even have a glance at the DTC description? It runs on the Crank position sensor and the upstream A/F sensor.

Where do you get DTC descriptions? There are a bunch of shady/scammy websites that come up when you Google a DTC now, so it’s tough to sort through. This website indicated it was a sensor 2 issue: https://www.engine-codes.com/p119f.html. So I bought one since it was only $40.

I haven’t worked on many cars this modern, but in older cars (we race a CRX) Any code related to the oxygen sensor is often fixed by swapping a new one on.


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[RZNT4R]

That site says it's a NOx (nitrous oxide) sensor issue, which exist only on diesels. Note that trouble codes higher than the P0xxx range are manufacturer specific and can mean anything!

https://gt86stuff.onrender.com/t3Portal/

Repair manual -> Engine/Hybrid System -> FA20 Engine Control -> SFI System -> P119E,P119F,P219A; Bank 1 Air-Fuel Ratio Imbalance for Port Injection

[Shadow6]

Originally Posted by RZNT4R

That site says it's a NOx (nitrous oxide) sensor issue, which exist only on diesels. Note that trouble codes higher than the P0xxx range are manufacturer specific and can mean anything!

https://gt86stuff.onrender.com/t3Portal/

Repair manual -> Engine/Hybrid System -> FA20 Engine Control -> SFI System -> P119E,P119F,P219A; Bank 1 Air-Fuel Ratio Imbalance for Port Injection

Nice, thanks!


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[Shadow6]

So I got a chance to start going through the FSM helpfully linked above, and I’m able to determine that I’ve got a “lean imbalance” detected using the crank speed sensor. This matches up with my freeze frame LFTs and SFTs, which are both slightly positive.

The first test is using the Toyota diagnostic equipment to change injection volumes and look at misfire counts to determine which cylinders are causing the issue. I don’t have the Toyota diagnostic equipment of course, so instead I just did a long test drive while keeping an eye on my misfire count PID.

Cylinders 2 and 3 are normal, 0 misfires once warm. Cylinder 1 gives me up 3-4 at idle once warm. Cylinder 4 gives me up to 13 at idle once warm. All four stay at 0 at cruising RPMs. I do not get a misfire DTC.

I checked the intake manifold with a smoke machine, no leaks there now that I’ve replaced the throttle body. I don’t hear an exhaust leak.

So at this point the next steps involve the spark plugs and then the injectors (both port and direct). I’m thinking with 80k+ miles maybe I just throw a new set of plugs at it anyway and see if that changes anything, since they’re probably about due. Maybe swap coils around after if I’m setting the same misfires?

Any other thoughts?


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[blsfrs]

Originally Posted by Shadow6

So I got a chance to start going through the FSM helpfully linked above, and I’m able to determine that I’ve got a “lean imbalance” detected using the crank speed sensor. This matches up with my freeze frame LFTs and SFTs, which are both slightly positive.

The first test is using the Toyota diagnostic equipment to change injection volumes and look at misfire counts to determine which cylinders are causing the issue. I don’t have the Toyota diagnostic equipment of course, so instead I just did a long test drive while keeping an eye on my misfire count PID.

Cylinders 2 and 3 are normal, 0 misfires once warm. Cylinder 1 gives me up 3-4 at idle once warm. Cylinder 4 gives me up to 13 at idle once warm. All four stay at 0 at cruising RPMs. I do not get a misfire DTC.

I checked the intake manifold with a smoke machine, no leaks there now that I’ve replaced the throttle body. I don’t hear an exhaust leak.

So at this point the next steps involve the spark plugs and then the injectors (both port and direct). I’m thinking with 80k+ miles maybe I just throw a new set of plugs at it anyway and see if that changes anything, since they’re probably about due. Maybe swap coils around after if I’m setting the same misfires?

Any other thoughts?


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Is it possible that an inaudible exhaust leak could throw off your afr? Slight crack in the header? I saw a post where a leak at the header/overpipe gasket caused an afr problem. A small leak would be hard to hear over the noise of a Russian tractor engine. It's relatively easy to check and replace gaskets.

[RZNT4R]

Originally Posted by blsfrs

Is it possible that an inaudible exhaust leak could throw off your afr? Slight crack in the header? I saw a post where a leak at the header/overpipe gasket caused an afr problem. A small leak would be hard to hear over the noise of a Russian tractor engine. It's relatively easy to check and replace gaskets.

That's possible. The stock manifold halso has 2 flexible sections that I've known to crack on foresters and outbacks, but on an fr-s, those should be on 1-3 and not 2-4. Also, since it's being detected via crank speed, it's probably reasonable to assume it's not a situation of combustion being fine and then sucking in air in the exhaust path, one of the boys isn't doing the same work as the other 3.

OP, it's probably not your plugs, but if you want to do them go for it, sometimes having one less thing to worry about, is one less thing to worry about swapping coils when you've got a dodgy issue should be a given, but again, probably not your issue.

Since it's a a P119F it's doing it on direct injection, which would be a pain to swap around. My first instinct would be to put an oscilloscope on the injectors to get a feel for them without taking things apart but that's not a tool you can just whip out of your pocket, so you might just have to move them.