Honda Civic / Del Sol (1992 - 2000) EG/EH/EJ/EK/EM1 Discussion

Low Fuel Trim under load in B16

Thread Tools
 
Search this Thread
 
Old Aug 12, 2018 | 02:45 PM
  #1  
1999AZhatch's Avatar
Thread Starter
Honda-Tech Member
 
Joined: Jun 2018
Posts: 63
Likes: 0
From: Tucson
Default Low Fuel Trim under load in B16

hey guys, need to pick some brainz....

I’ve got a 99 dx hatch with a B16a, running an EM1 harness and ecu.

No dtc, but I’ve felt like the car was feeling slightly under powered in certain situations, I.e. under heavy acceleration in third or fourth. Almost that ‘barely perceptible lean’ misfire that only people like us would notice but not like a full on ‘dead cylinder’ miss that is very noticeable.

Hooked up a scan tool:

everything looks normal during idle, LTFT is at like -3 to -1, not bad for a high mileage engine.

HOWEVER! Under acceleration, especially above 3500 rpm, stft drops to between -15 and -30. It’s trying to compensate for a supposedly rich condition and leaning way out.

is this normal?

what could be going on here? What are good things to check?

Last edited by 1999AZhatch; Aug 12, 2018 at 02:47 PM. Reason: Typo
Reply
Old Aug 12, 2018 | 03:29 PM
  #2  
2x0's Avatar
2x0
Honda-Tech Member
10 Year Member
 
Joined: Oct 2011
Posts: 2,374
Likes: 150
From: Franklin, KY
Default Re: Low Fuel Trim under load in B16

Bad o2 sensor
Reply
Old Aug 12, 2018 | 05:22 PM
  #3  
1999AZhatch's Avatar
Thread Starter
Honda-Tech Member
 
Joined: Jun 2018
Posts: 63
Likes: 0
From: Tucson
Default Re: Low Fuel Trim under load in B16

Always possible, though it did seem to be behaving on the live data on my scan tool.

its a cheap Bosch number, should I get a denso brand?
Reply
Old Aug 12, 2018 | 07:37 PM
  #4  
JRCivic1's Avatar
Honda-Tech Member
10 Year Member
Community Builder
Active Streak: 60 Days
Liked
 
Joined: Jan 2013
Posts: 10,050
Likes: 1,244
From: The South - Roll Tide !!!
Default Re: Low Fuel Trim under load in B16

Yes, a quality O2 sensor is a good idea. Check for an exhaust leak. Also, what fuel pump do you have installed in the H/B ???
Reply
Old Aug 13, 2018 | 10:30 AM
  #5  
1999AZhatch's Avatar
Thread Starter
Honda-Tech Member
 
Joined: Jun 2018
Posts: 63
Likes: 0
From: Tucson
Default Re: Low Fuel Trim under load in B16

I’ve got a fuel pump I took out of my em1 parts car. Runs about 28-30psi at idle
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
terbear4god
Forced Induction
5
Jan 10, 2013 01:32 PM
eastbay92cx
Honda CRX / EF Civic (1988 - 1991)
3
Dec 9, 2010 06:53 PM
Powelly
Forced Induction
44
Jul 11, 2010 12:02 AM
awdriscol4
Honda Civic / Del Sol (1992 - 2000)
6
Apr 26, 2005 02:45 PM




All times are GMT -8. The time now is 09:18 AM.