Idle Issues after FastIntentions Long Tube Headers

FX-32

Hi!
It's been practically a year since I'm having a weird issue with my idle since installing Long Tube Headers from FastIntentions (black ceramic coated, no wrap)

My issue is that AFR in both banks goes up and down, like from 10 to 20, in both banks at same time mostly.
I put a wideband AFR sensor were the Y-Pipe ends and it show the same as my Ecutek OBD info.

What I've done so far:
In october 2020 I put the headers, drove for a few days and then upgraded my 2008 ECU to a newer cloned ECU from a 2009+ 370z in order to get Ecutek Racerom features.

Then I noticed the bad idle. I installed:
- New OEM Denso O2 sensors, carefully extended, nothing changed
- New OEM Denso Spark Plugs and OEM coilpacks, nothing changed
- New fuel injectors, I put Injector Dynamics 1300x and tune, nothing changed
- CJM Fuel system with Walbro 450lph fuel pump, same issue as before
- Ported Upper and Lower intake manifolds with new gaskets, same issue
- Tuned with speed density instead of MAF, same issue
- Changed the rest of the exuast system, I had a Stillen catback and put a Motordyne resonated Y-Pipe with a stock almost new 370z exhaust to the end (resonators and muffler pieces). Same issue
- Downstream O2 sensors disabled by ECU and 4Bar MAP sensor. Nothing changed.
- New PCV valves, tried connected properly, then with catch cans, and vented. Same
- New cloned ECU to discard the ECU, it acted differently altough it had the same software and tune but nope, it still was idling weird.
- Installed a TopgunZ ACE kit, obviously didn't expect this to solve that issue but It was "scheduled".
- Lightweight flywheel and clutch (just to handle the extra torque)
- Oil pressure is correct, overkill yes but I change oil every 1000 miles so internally it's "like new"
- New exhaust manifold gaskets, studs and nuts. Tested for leaks by five different shops and all of them say "No Leaks Detected"
- Boost leak tested: No leaks (that means a healthy intake manifold, right? or not necessarily?)

I went this week to a very reputable dyno tuner to get a E85 tune, the car makes about 600whp (with stock y-pipe back), no knock at all (did a 4th gear pull with Ecutek datalogging and evaluated the logs). At this dyno tuner they left it idling at about 1000 - 1100 RPM and told me that because of my Long Tubes that the AFR acts like that.

I noticed some variations in AFR while driving and got back to a reputable remote Ecutek Master Tuner who showed me, evaluating the logs together, that this tune has some issues with fueling, it's mostly lean, and I can see that as well while driving on the wideband gauge I put. He suggested that I have an exhaust leak in the headers since day one, that's why I went to so many exhaust shops, to test for leaks and everyone say that I don't have leaks (I wonder how exhaustive that test is, if it's only by hearing and smelling or with proper smoke tool).

The only thing left to do for me is to put a Tomei Headers and test pipes, but not only is more money to throw parts and see what happens, but also a lot of work (I do all the work on my workplace's parking lot because I don't have a garage and I live in an apartment), and the long tube headers is one of the hardest jobs and I don't want to get in there again, and I'm running the risk that it couldn't solve the issue and end up with an inferior header installed and having to do all the work again to put it back as it is now.

So, to recap, My remote tuner says it's an exhaust leak, and the dyno tuner says it's because of the long tube headers, says no leaks at all (no boost leaks and no exhaust leaks)
I expected this dyno tuner to solve this but he says it's just annoying but not an issue, while driving I also see my AFR Gauge fluctuating a lot.

I was thinking in trying UpRev with stock 2008 ECU but since I have boosted and E85 I was told by many people that it's inferior and might need multiple maps depending on ethanol concentration to select them manually (Ecutek is automatic)

Any ideas or pointers what could I try next?

FX-32

Attached some logs screenshots of my idle if that helps visualize my issue>

One minute idling


a bit of zoom


more zoom



Anyone of you noticed something like this with any long tube headers?

Attached Images

	idle1.png (61.5 KB, 95 views)
	idle2.jpg (78.2 KB, 93 views)
	idle3.png (51.4 KB, 94 views)

FX-32

Double post - please delete

fryzia23

you wrote the idle started acting up right after the ECU upgrade. Don't you think you should start there to make sure the ECU is not the culprit of your issue?

Rusty

You started off with the LTH's. Then changed the ECU. Noticed the problem. Then threw more mods onto the motor without fixing it. With everything you done. You just compounded the problem. Go back to when it first happened. You changed the ECU, with ECUtec and then noticed it.

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"The Difficult Anytime, The Impossible By Appointment Only"
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FX-32

Yes, it makes sense.
How would you suggest to try the ECU thing?
Now with this big fuel injectors I do need a tune no matter what, to start the car.

Is there any possibility that my car is not compatible with Ecutek?

What options do I have to test it without having to put OEM sized injectors?

I am open to any suggestions and ideas, I really wish to solve this

Rusty

Who is your tuner?

__________________

浪人 - 殺し屋
"The Difficult Anytime, The Impossible By Appointment Only"
http://www.the370z.com/members-370z-...o-journal.html

FX-32

Last one to tune it was Z1 Motorsports, so if I need a re tune I have to come back there or have their E-Tune.
Otherwise start a tune from scratch with another tuner.

Tuner was Jon at Z1, It took them two entire days to tune my car because of this issue. I paid both days the pre inspection to fix this issue but it is still bad.

NorthStyle

I'd reach out to Eugene (ByThaBay) on the forum (I'd usually also include Seb at Specialty Z but he seems extremely swamped with work so it may take a bit before he is able to get to you).

Also, as Rusty said: you kept adding parts without fixing the initial issue. Not sure why you changed the O2 sensors, plugs, or coilpacks if none of those parts were experiencing issues prior to the ECU swap (minus plugs when boosting).

EDIT: Why did you have to pay the "pre-inspection" fee twice if it was not successfully completed the first day?

JARblue

I suggest trying to fix it the right way instead of the convenient way. Hopefully you can figure it out with the smorgasbord of mods installed, but it's entirely possible that you'll have to go back to the original configuration pre-SC to figure it out.

__________________

FX-32

Well, forgot to add that I went to Z1 twice yes, but about four weeks apart from the first visit to the second. On my first visit they run out of time, I was all day in there, and they told me to schedule another day to finish it because they wanted me to weld the wideband sensor where the y pipe meets in one single pipe. So I did, I got a cheap MIG at harbor freight and put it where they asked me to, and could not schedule earlier. It came in handy for me because I decided to go E85 and purchased a Zeitronix flex sensor as well so I got the E85 tune as well.

On my first day, the receptionist Kelly told me that pre inspection was optional, but highly advised, she said they check for boost leaks, spark plug gap and things like that.
I opted for the pre inspection yes, and they found a boost leak, and told me that the boost reference was not right (although I copied it from someone that has no issues)

I paid a second pre inspection, because the car was still with that issue and maybe the second time they might find something else, and here is the first red flag for me. They told me that spark plugs were badly gapped for boost (she was correct, they were new denso oem from the box, my bad),
Red flag because, didn't she told me they check for that in first place? they did not, but well, second time there and it was done so I'm ok with that.

Then they told me that 5 out of 6 coilpacks were bad, which I believe it could be possible, not bad bad that they don't work but maybe weak?
Without a doubt I opted for the improved Z1 coilpacks, everything they need to fix this car I said to myself... Unluckily for me, they didn't have Z1 brand in stock, but only OEM which in theory are inferior but also much more expensive. Again, whatever needed to finally fix this, I felt happy because maybe that could be causing this issue.
Second red flag, and I didn't noticed it earlier so now its late to complain, but I got charged $180 (plus tax I think) to install the 6 coilpacks... they had to remove them to check the spark plugs gap, and then re install them, all included in pre inspection, but since I opted for new parts I got charged for installation!. Again, my fault because I didn't notice it before, but it feels like paying lets say 1000 to change gallery gaskets and 1000 extra if you decide to change the chain or water pump, it has to be done anyways...
Third red flag is that I lost NATS (Nissan Anti Theft System), it was working before Z1 and I don't know why they needed to disable it, probably it was needed yes, but after I left I don't have any more support from them, I called twice asking for the ROM file in case something goes wrong wile recovering nats at a dealer or whoever is capable of fixing it (they recommended me a dealer or friend with dealer tool access), and after my second call asking for it it felt like You calling again??

Anyways, after leaving the shop, the car felt much better overall, I really like it and I think they did a great tuning job with what they had, but it is still wrong and I don't consider its safe or right to use it like it is.

Sorry for the long text brick , and thanks everyone helping me with any input

JARblue

You're in a tough spot no doubt. Sorry to hear that Z1 didn't help much. I think it would really be a good idea to listen to NorthStyle and reach out to Eugene Turkov. I get that you may not want to start over with a new tuner but you gotta start thinking about the money you've thrown at the problem without any real guidance (how much of that is wasted?).

He may not be able to solve the problem with a tune, but he will definitely help steer you in the right direction of the problem if he cannot solve it. The level of detail this guy uses when analyzing engine tunes is meticulous and methodical. He actually has algorithms developed to analyze the data from logging. Most tuners want short logs (2 min at most kinda thing) to analyze because there's too much info - Eugene wants ALL the data so he can run his algorithms to look for various flags in the data and get the full picture.

PM him at ByThaBay and link this thread and see what he has to say

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redondoaveb

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Fast Intentions "Stage Seb" twin turbo #098- Specialty Z/Tial-Xonarotor/CJM/Ecutek/HKS/KW/SPL/Hotchkis/Rohana/Toyo
700+whp

FX-32

Just in case someone runs into the same issue, here's an update:

All the problems I had, has been fixed now!

The car had many small details here and there, and I managed to catch all those ghosts and I don't want to get rid of the car anymore due to frustration.

I got for the third time, a full new exhaust from headers to tailpipe. This time, I opted for Z1 shorty headers (ceramic coated and wrapped by me)
Then a custom made CBE, true dual (no H-Pipe or anything similar) 3" with borla resonators and a nice big borla silencer, with very nice looking carbon tips. All made by a local shop in Cummin GA, I really like their custom exhaust work (I don't know if I can or can't mention the shop's name).

That seemed to be a night and day difference, somehow my car never liked the Long Tube Headers.

Then, Eugene told me that I was reaching only 9 PSi of boost, so I tried three different serpentine belts, and a new RPM belt on the SC side. No change, My tensioner broke and got an upgraded version (much easy to adjust and change the belt on the Vortech).

I purchased a boost leak detector from Z1, 5PSi and no leaks, 10PSi and all good, 15PSi and still holding great... I started moving pipes and hoses and then I heard a leak, it was on a reference line for the fuel pressure regulator, Z1's fault because they put zip ties and once the engine bay got hot, it started to leak, that's why the car felt awesome some days (mostly in the mornings) and felt lacking other times.

I put some metallic spring clamps and done. I'm in love with the car now, it was a long journey full of small issues.

Also heads up to Eugene, he is really awesome, very very knowledgeable and is always there willing to help. We are still fine tuning with datalogs but so far I'm happy with how it is now.

JARblue

Great news! Good work on diagnosing all of the issues. Now go enjoy your G!!

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