Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB

- Issues | Warranty | Recalls / TSB (https://www.ft86club.com/forums/forumdisplay.php?f=72)

- - 2013 FR-S Misfire and Rough Idle (https://www.ft86club.com/forums/showthread.php?t=134503)

2013 FR-S Misfire and Rough Idle

Hello everyone, I'm new to the forum, finally approved to post. I have spent the last 2 weeks doing research on my issue and am nearing a dead-end and was hoping to see if maybe someone had better ideas.

The car is a 2013 Scion FR-S that I picked up wrecked out of Florida for my fiance. Light front end damage, no airbag fired, just took out the radiator support above the crash bar. I have the body all done from a Series 10 front clip I found not far so everything pretty much swapped over. Was hoping to have a quick weekend project, and would have been that way if it wasn't for an engine issue I then encountered...

The car started and drove off the delivery truck, down the street and into the garage. had a big vacuum leak due to cracked intake pipe/box etc past the maf sensor, no biggie. After the bodywork was swapped over, I tapped off the cracks in the intake pipe and fired the car up to add coolant. The car ran for probably a good 15 minutes while I did some other stuff with the fenders and burped the coolant system.

During this time I saw the gas line came on, so with the car running (I know I know) i popped the lid and added some gas from the canister I had (93 pump im 95% certain.. slight chance was 87 but highly doubt it)

Car kept running, after about 5 minutes I closed the hood and went for a spin around the neighborhood. Car felt awesome, im excited to get it on the road, after this I drove it to the gas station right across the street from the neighborhood.

Filled up 93 pump gas, and topped it off like I do my GS400 and Supra, so it was really full. I go to crank the car on and its having issues starting, finally starts but is running rough as hell. The CEL comes on pretty soon and goes into the limp mode with the traction and abs lights on. I get it home and park it.

Over the next couple of days I have read a few codes, but only 1 consistently stays on, and is first to come on: P0303 cylinder 3 misfire detected. Other codes I have seen is Bank 1 Lean (cant remember code).

Here is what I have done so far... (thinking it had to be fueling related..maybe car sat way long with bad gas, had a crapy filter, had junk in the tank, etc ect):

1) removed and tried to clean out the injectors (fed 12 volts while pumping some fuel). They all seemed to fire ok.

2) Removed coils and swapped to a different cylinder
3) changed all plugs (I am not a master at plug changes, can do all 4 in maybe 2 hours start to finish lol)

4) changed the intake manifold (thinking maybe there was a fracture) with all new gaskets.

5) Changed all seal on the injectors (including 1 of the direct port injector seals -this ended up not being all that bad either) and also swapped them places to see if problem would go to a different cylinder

6) opened up the tank and drained about 1 gallon of fuel out of it in case I was over pressuring the system somehow by topping off..

7) checked all possible fuses under the hood

8) checked and double checked all vacuum line connections.. I don't know how I could miss something with this after so much looking..

9) swapped MAF sensor

10) installed an undamaged intake pipe

last night after the last steps did not work I am simply out of ideas.. the car is on a recall for the valve springs, but I would know a failed spring... the engine simply seems to misfire, no weird rattling noises.

Not sure if maybe the coil wire got damaged though I don't see how since its way down under the intake and ran perfectly fine for like 20-30 minutes until I filled up.

My only idea is maybe trying a different fuel ecu thats mounted to the 1st bank...? Since the Lean code is also coming on (and after testing injectors as well as swapping them place, and doing new plugs with a different coil on each cylinder) could it be that this cylinder is simply not getting a fire pulse from the injector ecu......?

Any and all input would be VERY much appreciated as I am starting to lose my mind...

Thanks all,

Roman

I have not done a compression test yet either simply because I am pretty certain nothing mechanically is wrong, but tell me if I am wrong..

Hello aemravan and welcome to our forum - :clap:

Well now, here was your first mistake - :eyebulge:

"The car is a 2013 Scion FR-S that I picked up wrecked out of Florida for my fiance."

Trust this ol boy, fiancées don't like used, wrecked stuff.

OK, it appears that you have done a bunch of stuff to try to fix the problem.- :thumbsup:

Now, although I have a 2013 FR-S, I have no idea what is wrong with your car, however, I'll ring up ol @steve99, who is one smart cookie, to see if he has any ideas.

What would I do? I'd take it into my local shop and have them figure out what was wrong and fix it. Then go home and take a nap and wait for their call.

humfrz

One of your live data pictures showing SHRTFT at +20% while the other is at -9%, if you had a bank 1 lean, that means fuel trims were maxed and the AF sensor was still asking for more fuel. there is a difference between these two states... With that said, it's counter intuitive because it often smells like unburnt fuel, but a misfire makes a bank go lean as seen from the AF sensor, because it throws a lot more air into the exhaust than it does fuel.

OR, Cylinder 3 may have a condition that makes it miss before the others when the mixture goes very lean. Welcome to the fun non-ignition misfires! It would be silly not to check fuel pressure as the problem surfaced post fill-up after the car sat for a long time (assuming since it was a wreck), there may have been deposits in the fuel thank that got kicked up and clogged the system. Checking the fuel pressure for the high side is easy enough with a scan tool, for the low side, well, you'll need a fuel pressure gauge.

If that checks out, check compression. That checks out too? Move the injectors to other cylinders.

Quote:

Originally Posted by RZNT4R (Post 3214448)

The fuel pressure is around 500-700 psi on idle for the high pressure line. I would find it very interesting if there was low pressure but only cylinder 3 had the misfire issue. Also, all injectors, coils and plugs have been changed/swapped places.

Sent from my SM-N950U using Tapatalk

Allrighty then, how about compression?

I have a compression tester on the way, really wish I did it when I had all the plugs out...but no big deal. Should be able to get some numbers monday evening once it arrives. Also found a reasonably priced injectors ecu on fleebay for like 50 bucks so figured at this point it may be worth a shot.

humfrz good thing it was her idea then ;)
We were looking for a project car to work on together that she could then drive so we can get rid of the Altima she has now before it gets too old. Aside from getting frustrated with the misfire thus far its been a really fun experience (at a really decent price too ;) )

It seems a bit suspect that it ran fine till you refueled it.

Then it runs crap tgrows lean cel codes and one of your pictures shows +20 % fuel trims.

Im just guessing here but either you have an exhaust or intake leak. They usually snd fuel trims positive

It possiblle car has some weird tune in it as lots of these car tuned. If it was tuned for e85 id expect big negitive fuel trims if you put petrol in it.

Idle vaccum should be about 10 psi below atmospheric ie atomspheric is 14 psi so idle manifold pressure should ve about 4 psi unless its got a leak.

If fuel trims are high at low rom and idle but ok once you get to 3000 rpm or so its likely exhaust leak if idle vaccum was ok

It might have some tune for turbo or supercharger and they pulled it off

Quote:

Originally Posted by steve99 (Post 3214723)

Thanks for in the insight Steve! Certainly appreciate it.

I will try and get the car idling some-what solid and check the manifold pressure.

Regarding the fuel trims, I think the screen captures may be a little deceiving as they were all over the place while I took the picture, I think maybe because the engine speed was not consistent and a couple of time sit would drop really low, to like 300-400 rpm and then spike back up to 1300. There is another insistence within 15 seconds where the fuel trims are actually negative if I am not mistaking.

For a tune/super/turbo charger, I am about 99.9% certain this car has never had anything done do it, possibly not even regular service. I am basing this from the condition of the interior as well as the contents left behind in the trunk of the vehicle when I got it:

1) numerous women's clothing items, including a very large set of ...uh..what I hope.. were somewhat clean underwear, lotions, etc
2) beach-going stuff for a child, along with many other small childrens toys
3) the vehicle was wrecked and surrendered to insurance right after, there definitely was nothing taken off in the shape of a turbo due to the fact that I have removed various shapes and sizes of remains of the factory intake box/pipe etc.

I am going to get some compression numbers (at least on the troublesome cylinder 3 ) this evening after work to see if I can rule that out. If that checks out I will proceed to look for a vacuum leak until the fuel injector ecu shows up as aside from that I am simply lost to what the issue could be.

Thanks again for all the input. I'll follow up as soon as I have any more results or information to share.

Well damn.. good news/bad news. Found the culprit...

Cylinder 1 compression: 180.

Cylinder 3 compression: 90.

Didn't bother checking 2 and 4 as its pretty obvious.

Here is my next thing to figure out... the VIN number pulls up to be under recall that isn't done yet... I am assuming it shouldn't be an issue with Toyota if this indeed is a valve spring issue... what is the best way to be certain that this indeed is a valve spring/recall related issue?

My other issue... the car isn't registered yet, because it is a salvage title car it still needs to go in to the shop for a pre-inspection with the inspector, then a final after the body is repaired (a 1 week process for me so no big deal..) after the final inspection it needs to be inspected to be registered....well.....bc the CEL was cleared non of the systems are initialized, nor will they be due to the issue.. I guess I need to call up Toyota and see what would need to happen.... just wonderful! So much for a 25k mile car :) lol Should have done deeper search into early year issues.

I just can't believe of how much of a timing coincidence it ended up being with the damn fueling of the car....

You can remove the valve cover in place, should be possible to inspect the valve springs/lash without engine removal.

Or if you've got an air compressor, you can probably (depending on the specific one you bought) use part of you compression tester to send air into the cylinder and test for leaking valve(s).