Very high negative fuel trim at idle - Page 3 - S2KI Honda S2000 Forums

Go Back  S2KI Honda S2000 Forums > General Interest > S2000 Under The Hood
Reload this Page >

Very high negative fuel trim at idle

Notices
S2000 Under The Hood S2000 Technical and Mechanical discussions.

Very high negative fuel trim at idle

 
Old 03-13-2019, 05:04 AM
  #21  
Thread Starter
 
Join Date: Sep 2007
Posts: 125
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Originally Posted by Thomas Guide View Post
What's that darth vader sucking sound that happens at 7, 16 and 38 seconds in? Is that also part of the issue? That sounds awful!

I'm chasing a very similar issue as you (read down a few posts where I resurrect the thread):

https://www.s2ki.com/forums/s2000-un...aning-1168151/

In terms of the popping sound I had my injectors cleaned and it resolved it, (that's actually a misfire), but I think one of my injectors is leaking causing a high negative fuel trim.

This weekend I will finally be able to test the Fuel pressure using the Honda Fuel Pressure gauge and adapter, so I will be able to determine if I have a Fuel Pump issue as well.

Afterwards you can see the laundry list of items I'm going to replace (Regulator, Dampner, Coil Packs, Injectors, Spark Plugs, and O2 sensor). If none of those fixes the issue then I have no clue what else is causing the fuel pressure issues.

I will report back...
I essentially replaced all those things you listed. Hopefully doing another set of injectors today. If that doesn't work I'm just gonna dump my car off at Inline Pro and have them replace the fuel pump and screen. If it's gotta come out to be looked at might as well replace it right? BTW I've already read through all your previous posts and the linked posts within those threads trying to find solutions to my issue. I think I've reached the end of the internet. Information overload.

Last edited by kikkomon; 03-13-2019 at 05:26 AM. Reason: typo
kikkomon is offline  
Old 03-13-2019, 05:51 AM
  #22  
 
flanders's Avatar
 
Join Date: Aug 2013
Location: Sweden
Posts: 2,634
Thanked 123 Times in 120 Posts
Default

Just another suggestion, probably not likely but there is also another fuel source that might affect things.
The fuel purge valve should only open above 149F coolant temp, it purges fuel vapor from the EVAP canister to the intake manifold.
flanders is offline  
Old 03-13-2019, 05:57 AM
  #23  
Thread Starter
 
Join Date: Sep 2007
Posts: 125
Thanks: 0
Thanked 0 Times in 0 Posts
Default

That thought had run through my mind after reading Billman's post on his how to EVAP testing procedure. My high negative STFT's are constant with engine cold or hot and only at idle or just off idle. How can I check if the purge valve is bad? I checked for vacuum leaks all over my engine bay already including this valve.
kikkomon is offline  
Old 03-13-2019, 06:56 AM
  #24  
 
flanders's Avatar
 
Join Date: Aug 2013
Location: Sweden
Posts: 2,634
Thanked 123 Times in 120 Posts
Default

It's a simple open/closed valve, try blowing through it. With no voltage it should be closed and 12V open.
flanders is offline  
Old 03-13-2019, 07:19 AM
  #25  
Thread Starter
 
Join Date: Sep 2007
Posts: 125
Thanks: 0
Thanked 0 Times in 0 Posts
Default

So i took another peek under the hood. Not sure if inline pro replaced the FPR vacuum hose but they may have. I noticed a pinhole in the hose at the FPR. I replaced the hose. I started it up cold and there is no longer popping and gurgling. Although my negative fuel trims aren't as high when I took it for a test drive. Highest it got was -14 at idle but stayed a bit under that most of the time while at idle. After I shut off the vid I touched the gas and the idle bogged down. Did it again and the car stalled. It did that twice. Maybe idle learn procedure required. I didn't do that after resetting the ECU yesterday. While pulling out of my driveway I could feel the car slightly hesitating. After I got it on the road it didn't seem to be doing it much but it's cold outside. Here's a vid of the cold start this morning. You can hear the difference compared to a video in my previous post. I got on it a little and can smell a bit of exhaust inside the cabin with the windows rolled down a bit. I was moving at a pretty good pace. Do you guys think there's an exhaust leak somewhere ahead of the O2 sensor?


Last edited by kikkomon; 03-13-2019 at 07:22 AM. Reason: Added info.
kikkomon is offline  
Old 03-13-2019, 07:23 AM
  #26  
Community Organizer
 
s2000Junky's Avatar
 
Join Date: Jun 2007
Posts: 28,071
Thanked 198 Times in 187 Posts
Default

Seems much improved. Now reset the ecu/pull batt terminals and let it idle/re learn.
s2000Junky is offline  
Old 03-13-2019, 07:42 AM
  #27  
Thread Starter
 
Join Date: Sep 2007
Posts: 125
Thanks: 0
Thanked 0 Times in 0 Posts
Default


Originally Posted by flanders View Post
It's a simple open/closed valve, try blowing through it. With no voltage it should be closed and 12V open.
The bottom port doesn't let air pass through. The top port does. I'm assuming the top port connects to the metal vacuum tubes and the bottom ports heads down to the air pump.

Last edited by kikkomon; 03-13-2019 at 07:42 AM. Reason: typo
kikkomon is offline  
Old 03-13-2019, 07:51 AM
  #28  
Community Organizer
 
s2000Junky's Avatar
 
Join Date: Jun 2007
Posts: 28,071
Thanked 198 Times in 187 Posts
Default

Originally Posted by kikkomon View Post



The bottom port doesn't let air pass through. The top port does. I'm assuming the top port connects to the metal vacuum tubes and the bottom ports heads down to the air pump.
You guys are referencing two different things. Your diagram is showing the air pump circuit, which I believe is totally a closed loop, isolated form anything evap related.
s2000Junky is offline  
Old 03-13-2019, 08:55 AM
  #29  
 
flanders's Avatar
 
Join Date: Aug 2013
Location: Sweden
Posts: 2,634
Thanked 123 Times in 120 Posts
Default

Correct^ they are two different things.
Check the picture I posted again, it shows roughly where all the parts are located as well.
flanders is offline  
Old 03-13-2019, 09:24 AM
  #30  
Thread Starter
 
Join Date: Sep 2007
Posts: 125
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Originally Posted by flanders View Post
Correct^ they are two different things.
Check the picture I posted again, it shows roughly where all the parts are located as well.
That thing hiding under the intake manifold with the green service cap? Hard to access. I was fiddling with it this morning looking for loose vacuum lines.

On another note, I just got back from Inline Pro to show John, the owner, what it was doing. We went for a drive and low and behold the car ran beautifully. In fact we hit [email protected]#[email protected]# and it screamed HONDA POWER of DREAMS!. I fiddled with a number of things this morning. I'm curious if I inadvertently fixed something. I used a bore brush and stuck it in that EVAP port on the right side of the throttle body and on the other side of the intake as well. I pulled all the vacuum lines off the intake and the IAT and checked for debris as well. They all seemed ok. The number 4 injector wires have bare spots right behind the clip. Do you think this could have any bearing on anything? I would think not personally. Fuel trims a bit better. Idling at around -8 to -12 and spiking to -14 coming to a stop. I'll take another look at the EVAP purge solenoid if I can find and access it.


Last edited by kikkomon; 03-13-2019 at 09:31 AM. Reason: H key stuck
kikkomon is offline  

Quick Reply: Very high negative fuel trim at idle


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands