Pls Help! Lack of power mid rpms - possible misfire
 

Hi guys!
So I have my gt86 2013 for 3 years now, only came to realize that it has a serious lack of power when I drove a couple of other 86 a few months ago;
I was thinking the clutch needed replacement but from 3 years ago up until now the car drives exactly the same... From approximately 2k till 4k rpms, flooring the gas pedal, the car accelerates hardly and it sounds like a truck if you know what I mean. Then past 4k rpms the engine sounds smooth and normal and the acceleration is amazing. Even when revving in neutral I could see there's a problem when I compared my car to the others of the same year btw.

I told my mechanic about the acceleration problem 2 years ago so we had the spark plugs replaced but that didn't change anything.

It only had aftermarket suspensions and Invidia N1 when I bought it, I then installed a catless header 10 month ago and 2 weeks ago got hold of an OFT so I put the stage 2+ tune.

When I put the catless header I didn't get any DTC for 10 months... but as soon as I got the stage 2+ tune I got an O2 sensor dtc which didn't come back for 2 weeks now after I cleared it, and also a P0301 (Cilynder 1 misfire) and this one comes back systematically (engine light blinks every couple of minutes when it occurs around 2.5K RPMs).

What's more interesting is that I have another ECM from a 2013 FRS and whenever I put that one instead of mine I Do get P0301! but also P0453 P0463 P2401 P2419 C1201. At this point I'm wondering if my ECM has been tempered with in order not detect these codes :bonk:

The lackn of power mid range is called the Torque Dip. All 86s had it. It's not broken, that's just how the engine behaves. If you have catless headers you need a tune specifically for that. Which stage 2 should be, but some people do have catted headers. The codes come and go because they aren't properly turned off for whatever reason. Your tune shoyld turn off the cat related codes because you don't have one anymore. The misfire is likely because you have the wrong tune loaded and the computer is trying to "fix" it, but can't.

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Ashikabi it's not a torque dip, there's a big performance difference between my car and the other 3 frs/86 that I drove that were also from 2013.

Sorry but I forgot to mention that I get some shaking at around 2500 rpms and that's when generally the computer detects the misfire, sometimes it's extremely rough.

Try resetting the ECU by disconnecting the battery or even retuning it. My FRS (catted, OFT) & BRZ (catless, ECUTEK) would have that problem whenever I'd disconnect the battery or update the tune. Sometimes, I'd have to reset it 2x. I'm not sure about your errors though.

Changed the ecu back and forth multiple times, tuned and untuned also multiple times...
The difference in power before and after the header and tune is minimal. last 86 completely stock I drove was way faster than mine with that header and tune.

Ok. That wasn't clear in the first post. Still sounds like tuning to me. What all mods do you have?

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Invidia N1, EL headers, body kit and suspensions that's all :iono:

You said you loaded stage 2 tune. I know "stage 2" is super vague and there is no 100% definition of it. Was there a description on the tune stating that it was intended for catless headers and catback and nothing else? Really only the headers matter. But if the tune included modification for an intake, like MAF scaling, then that would indeed cause problems

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Yes it's a stage 2 plus tune, OFT mention on their website that it is intended for catless headers, stock airbox which I have also

But are you supposed to have any other mods? I find it hard to believe that headers alone qualify as stage 2

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They state on their website that stage 2 is for catted and 2 plus is for catless, also anything after the headers is compatible

What about intake? Can you link that page?

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K that's pretty clear. You are running 91+fuel right?

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Indeed, we only have 95 and 98 here both make no difference either

Jesus, 98? You're not in America are you?

You could try retuning it. Use the same map, or it was my understanding that there was a library of OFT maps. Perhaps there is a different one that will behave better.

Have you checked your air filter? Run seafoam/fuel injector cleaner?

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Air filter is 1.5 year old replaced it myself. I'm in Dubai they have good fuel here but no Ethanol type unfortunately.

I'm curious how your octane rating compares to American. Here 98 octane would be low grade race fuel. The highest you can get at a pump without ethanol is 94 I believe. I'm gonna guess your 98 is probably similar to our 93/94. Regardless, that's fine, so long as it's not low end fuel for commuter cars. The OFT can read info from the computer while driving right? Can you watch your AFR and related values as your RPM climbs through the affected area?

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You have an OFT, do a datalog, bet your IAM is low.

Start here.

https://www.ft86club.com/forums/show...01#post1842501

Upload to datazap.

https://datazap.me/

Post link.

Get Help.

Profit.

RON vs MON ratings. We use an average of the two numbers whereas they just use the RON.
Take about 5 octane off any European (used in Dubai), Aussie or Japanese numbers .


Still stuck on what the tune is. If the stock cars were faster then why not just go back to the stock mapping and see what happens?

I think there is more to this story someplace.

As mentioned above if you have an OFT device, then datalog and post. That will show what's going on with your engine.

How about your wheels & tires set up? What's are their sizes? What's their weight?

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So I just took it for a quick ride and saved 2 datalogs;

https://datazap.me/u/02maher/log-164...og=0&data=1-13
https://datazap.me/u/02maher/log-164...og=1&data=1-13

Do this.

Get car to operating temperature. Cruise at a steady RPM for a few minutes, and then post it. It is easier to see issues at steady state but from what you posted your fuel trims look jacked up. It is harder to see when you are on/off throttle a lot. Looks like you have an exhaust leak though. Looks like you are on a V4 tune as the IAM starts at .7, it does climb to .73 which is a good sign.

Also, remove "boost" and add "injection mode" to the log. You do that on the OFT in a menu with what parameters you want logged.

IAM goes to 1 in the second log so fuel quality is probably fine. Fuel trims are definitely indicative of an exhaust leak near the O2 sensor

https://datazap.me/u/02maher/log-164...5?log=0&data=1
https://datazap.me/u/02maher/log-164...5?log=1&data=1
https://datazap.me/u/02maher/log-164...5?log=2&data=1

Last one illustrates the shaking that I'm experiencing after 2300rpm, still on certain occasion it's worse than that...

If there is an exhaust leak is it most probably before the headers?

Yeah, your LT fuel trims are maxed rich.

Simple stuff first. I would check where the header mounts to the cylinder heads, you may see black soot where it is leaking. I would also check from where the header mounts to the overpipe, and around the O2 sensors.

An indication it is leaking would look like this picture. See the soot?

https://www.miataturbo.net/attachmen...dium.sized.jpg

Thanks a lot I will take it to the garage tomorrow... Any other idea in case I don't find a leak there?

The Evap codes I've been getting with the other ECM could be related?

What codes are you getting? Absolutely could be related. I was going to say, for your fuel trims being maxed the AFR is remarkably stable. I was expecting more dramatic fluctuations. That weird stumble it was also bouncing between closed and open loop.

I have another ECM from another Frs 2013 and whenever I put it I get these codes

P0301 Misfire Cylinder 1
P0453 Evaporative Emission Control System Pressure Sensor / Switch
High Input
P0463 Fuel Level Sensor "A" Circuit High
P2401 Evaporative Emission System Leak Detection Pump Control
Circuit Low
P2419 Evaporative Emission System Switching Valve Control Circuit
Low
C1201 Engine Control System Malfunction


That's weird that I never got them on my actual ECM

They may be stored codes and not active codes. If you are not getting them currently I don't think it is related. I would just check the simple things as far as leaks first and we can go from there.

They come back after I erase them

Permanent codes require a full drive cycle to go away if the problem is resolved. Could take a bit of a drive to complete it, you have to go through X minutes of idling and X minutes of various speeds.

spark plugs/coilpacks ok?

The mechanic saw an oil leak on the driver side of the engine (not sure if it’s related to the issue) so we’re ordering the left valve cover gasket and spark plug tube seal to fix this issue and at the same time we’ll check for leaks and maybe swap some coil packs.

It took me a long time to get the seals from USA as they didn’t have it here in UAE and Oman. So I just replaced them and fixed the oil leak and also swapped the coil packs and spark plugs from left to right but nothing changed in the drivability of the car and I’m still getting the same misfire codes P0300 P0301… We checked the exhaust for a possible leak too but couldn’t find anything. Could it be the intake manifold that’s leaking or something else guys?

With weird symptoms, I always rule out a vacuum leak before going to other diagnoses.

I removed and sealed again the air intake manifold but it didn’t change anything. So I just took it today to a garage that’s specialized in sports car but they’re a bit expensive… They checked the car for half an hour and they told me it’s definitely the direct injectors (su00304461) and quoted me 1200usd. What do you think guys ����*♂️ ?

Update, just removed the port injectors and the direct injectors. DI looked all the same with intact and properly fixed O ring but quite dirty and with carbon built up. The port injectors on the passenger side where I’m having the misfire are both black (way darker than the other side). Took all the injectors to a specialist to have them checked and cleaned and he just told me that the dark injectors indicate a vacuum leak. Now where is this leak I don’t know but I might put a supercharger (sprintex 210) which will sit more heavily than the plastic intake manifold which can be problematic ??
If you guys have any leads where and what to check that would be much appreciated.