Strange Idle - after fuel pump swap (E85)
 

Ok - so I’m coming to the experts for this one.

Here's the ISSUE: https://www.youtube.com/watch?v=XC_BoHgy2jA (not sure how to embed the video, have tried youtube / youtube hd in brackets)

Watch the first 35 seconds.


2016 370z Nismo
Z1 Cold Air Intake
FI Test Pipes
Greddy GT Exhaust

AEM’s 340LPH E85 Fuel Pump (runs strictly E85)
1050cc Injectors
Tuned by Seb (V5 Ecutek)

The Issue: For the first 5 - 10 minutes, my AFR and IDLE will be a bit wonky, as in, my AFR is pretty steady at 14.7 - Driving is normal - feels fine, BUT at idle - my AFR goes anywhere from 13-15.5 and my RPM goes from 700 (once hit 675) up to 950 and goes back and forth. This ONLY happens once or twice during the first 5-10 minutes of driving. This is cold or not, so I could drive the car for 30 minutes. Shut it off, turn it back on 15 minutes and it will happen again.

After the 5-10 minutes my idle is perfect.

What I’ve done:

Retuned with Seb
Battery Check - Completely normal.
Cleaned manifolds and throttle bodies.

Talked to the dealership and my performance shop. Dealership says everything is good. Seb says if there’s an issue (which he can’t see one) maybe it’s the WB O2 sensors.

My next step would be maybe a vacuum leak check?


Do you guys have any idea what I should look at or is this just the nature of a Z with E85 and my mods?


Thanks guys.

Have you tried the idle relearn procedure? There's a feature that should allow you to do this on the phone app or proECU (i think)


Edit: I'll give my car a cold start. I have ID1050x injectors, but i'm on the standard fuel pump. other than the slow ish cold start, i havent had any issues that i noticed once it was actually running

Here's a quick video. I had to pull it out of the garage, but it wasn't doing anything too crazy.

I should note that I do have brand new widebands (a product of troubleshooting something else) so I am not 100% sure if this helps. I'm by no means an expert, but maybe it has to do with the startup/cat-warmup procedure? I'm just throwing out theories.

Yeah I’ve done the idle relearn through ECUTEK and the dealer said they’ve done it as well (like the video you showed).

Also I should say - I’ve got a fuel gauge on my car and fuel psi is right around 56-58. Seb says that’s perfect.

Thanks.

I wonder if I should just put new WB O2s in and see if that takes care of it.

Also I should say there’s is 0 performance loss - just this annoying idle dip once or twice during first 10 mins of driving.

So on a cold start. Mine does pretty much the same thing. But I don’t actually see any idle dip until I drive it for a few minutes.

Almost like once it gets gas - it has to relearn idle. Does that make sense?

I didn’t do the idle learn procedure in the video. I just did a cold start. If your car behaves the same way when cold, I think that’s normal man. I think if you posted a video of what’s happening it would help.

Yeah I will do that tomorrow.

Good idea.

That's just the nature. Have same setup with same issues. Once your 100% 85 it will somewhat go away .seems like the computer is trying to read the content as its coming in.my car takes a bit longer to start once the engine is warm as well

So I’ve been running e85 for almost a year now, but my fuel pump is 2 months old.
I’m at 75% ethanol content.

Been retuned and everything.

You think it’s just the nature of the Z on e85?

Use smaller injectors?

Ok so I caught a smaller dip this morning - it tends to happen like this - and only a few times during the first 5 - 10 minutes of driving..

This just normal? It’s at just about 10 seconds - 15 seconds — something like that… It dips down to 700 and boosts up to 900


https://youtu.be/GzlKLDryw68

I dont know to be honest. that could be your a/c compressor turning on or off, or it could be something else.

What is the injector dwell time when wfo?

I really wish I knew how to answer that :/

I’m so not smart when it comes to these. I rely on my shop, seb, and you all :)

Anyway you can tell me how to figure that out?

Any codes? Looks like a vacuum leak, or you need a re-tune because ur leaning out on fuel trim 4 a reason.

No codes.

Runs at 14.7. Except for this slight dip. AFR will go from 13-15.5 during the dip or prior to the dip.

Got retuned by seb 2 months ago (issue was happening then as well) because of new fuel pump and ecutek went to v5.

Here's another one today.

This is what usually happens once or twice during the first 5-10 mins of the drive...



www.youtube.com/watch?v=XC_BoHgy2jA


I tried embedding this video, but for some reason - it keeps coming back with a play error.

:tiphat:

You’re a saint.

Thanks.

So I’ll just throw in my experience as I’m similar setup with aem pumps in radium kit running 51 psi, stillen intake, stillen exhaust, Bosch ev14 550cc injectors tuned by seb and on e85 and my idle is completely fine so I’d say just a hunch but less to do with running e85 on a z and more to do with the 1050 injectors. That’s a lot of injector for an NA car anyway and from what I’ve ever heard and read is the larger the injector the harder it is to get a controlled idle as that’s where the engine is pickiest and the hardest point to control a large injector.

That was my thoughts too. Too big of injectors. That's why I asked about the injector dwell time. Dwell at WOT should be around 80 to 90%. If it's more, the injectors are not big enough and will lean out the mixture. If it's less, The injectors are too big and will cause idling issues.

Ok. So that narrows it down a bit.

I’ll talk to seb - maybe I need smaller injectors.

Thanks guys.

It is all in the tune. I run 1700cc injectors and have no issues. Do you need that large of an injector NA. That would be a no.

Yeah, I’m not having the same issues with 1050cc NA. The car runs smooth for me.

I guess I meant to say it’s not impossible just much more finicky and needs tighter controls at idle as well as really good injectors and for an NA engine not necessary so why bother with the headache. Known others with high boost 4 cylinders that require larger injectors and most have always noticed a decrease in idle stability after but have to deal with it as it’s needed for high boost levels and no way to do a multi injector setup.

You could do a multi injector set-up. BUT.......how much MONEY and time do you want to throw at it?

It is always NA at idle. It just requires more fine tuning for the tuner with larger injectors.

So if you guys were me, do I go back to seb and ask him again?

He’s already aware of what it’s doing. Said tune looks solid / maybe it’s the WB O2?

Again it’s not stalling or anything - it happens 1-3 times in the first 5-10 minutes of driving and then it’s like it learns and adjusts fine. AFR is perfect other than when this happens. I can probably live with it. Just wanted to make sure it isn’t going to cause a future issue.

I’m aware of this which is exactly the issue. Essentially you need a fire hose at WOT to put out the fire but now your still left with a fire hose at idle to put out a mild camp fire. So your trying to control a trickle out of a fire hose without completely flooding the campsite.

Am running 1050x injectors having the same problem at idle when cold start, after driving the car for a minute, then i go to idle, the revs are planted at 900rpm(that's the setting), but i know its a tune issue 100%. Because the ECU fine trims everything, i also noticed that at warmer OAT 80F+ the car does not have this issue.

LOL, you guys have no idea. The only issue I hate is for flex fuel tuning. When you fill up with 93 oct. instead of E85 it sends the ECU into a freak out mode. The idle is for chit, all over the place This little idle issue op has stated is nothing to worry about. You want to know why I stay on E85 all the time, this is it.

I’m running E85 on Ecutek with a flex fuel setup, GT-R injectors, AEM 340 pump. No idle issues.

Can’t say I’ve experienced the same issue (only have 91 here but shouldn’t be that different). Switched back and fourth 3 times already this month and ecu adapts immediately without any noticeable change.

With 1700cc injectors, this is a freaking issue. LOL

Which is exactly what I and others were saying and you said in previous post it’s all in the tune and you have no issues. Now you say you have this issue and with 1700cc injectors this is an issue.

So which is it? You have no issues or you do have this issue? Both can not be true.

Just a refresher.

Whatever, you don't get it because you have no idea what I am talking about.