Yesterday i was driving, and the car started to buck kinda like it was out of gas, i had a full tank. i look at hte wideband and its reading like 18-19a/f's. so i get off the gas and i push in the clutch. put it back in gear and it does the same thing. i put it in neutral drift and pull over. it starts to run fine again. then lateron it does the same thing. it has been doing it ever since. but it hasnt been quite as bad lately it has been like 16-17a/f's at partial throttle. The car has been dyno tuned and the partial throttle map is actually ritcher than a stock b16 with the injectors that i have. any ideas why this might be happening but most importantly why did it happen all of a sudden? any help is appreciated sorry if its hard to understand.

 

hmmm....even a change in weather wouldn't have that big of a change in AFR's. Maybe an injector failing.....i don't know. I'd stay out of boost until figuredout though

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy &raquo;</TD></TR><TR><TD CLASS="quote">hmmm....even a change in weather wouldn't have that big of a change in AFR's. Maybe an injector failing.....i don't know. I'd stay out of boost until figuredout though </TD></TR></TABLE>

It is really weird. It ran fine during tuning, street and then dyno a couple weeks later. I am having him wire in his wideband narrowband output into the ecu and see what happens.

 

I had the same exact problem once... It was my plug for my map sensor had a bad connection. Try wiggling your map sensor cable/plug while you have it idleing and see if that changes anything. If it does, you might have to re-pin it like I did or get a new plug and pigtale from a junk yard and wire it in.

HTH

 

i get that also every once and a while.

are you running in open loop or have the 02 heater dissabled? i think that has something to do with the problem.

 

He is in closed loop and the heater is enabled.

 

Def. check the map sensor.

 

i was going through this too earlier this week with my turbo ls. i disabled the closed loop and the vacuum a/f's cleaned up nicely. now i have it from 14.2ish to real high 12's on the vacuum/boost transition. problem is im still getting a little bucking at around 12 vacuum, when my a/f is about 14.1....

check your map sensor as others have suggested, and give a try with closed loop disabled.

 

If you have a wideband hooked up to your ecu for datalogging and then try to run closed loop you must make sure you wire the "Narrow band" output from your wideband unit to the ECU.


Also if you are having bucking issues at part throttle try adjusting your fuel cut in the boost table. most of the cars I have tuned like the fuel cut @ 12-14 with a stack map sensor.

 

yeah, i used the narrowband output on the wideband for the ecu and it didnt help. it ran fine. i thought it worked until i stopped and tried to go again and then it did the same thing. i pushed in the clutch and drifted over and than it ran fine again and it didnt do it again. than today when i went to leave it started to buck and was lean and i pushed int he clutch and stopped and then it ran fine the rest of the ride. its really wierd. i dont understand it at all. 93turbo16 is my tuner so he is the one that would have to make the changes with the fuel cut or running open loop. i'll check the map sensor though and see the condition of that.

just curious. what is the advantage and disadvantage of having close loop disabled?

 

When i'm in a gear and off the gas decelerating sometimes i get a cel. but it happened before i was turbo. i never bothered to check it because if i just restarted the car it would go away. anyway i checked it today and it was 1 which is the primary o2 sensor. however the o2 sensor isnt even hooked up the wideband is hooked up using the narrowband output on it. so that doesnt make any sense at all to me.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B16Civic93 &raquo;</TD></TR><TR><TD CLASS="quote">just curious. what is the advantage and disadvantage of having close loop disabled?</TD></TR></TABLE>

Closed loop trys to maintain a A/F ratio of 14.7/1 by adjusting your fuel map according to what your O2 sensor is telling it. If your "tune" is not atleast close to this in open loop you will have some issues. I usually disable closed loop and run a little on the lean side for part throttle, ~15.1-15.5/1. That will help with gas mileage a bit.

If you are having bucking problems at higher throttle positions, I would speculate that it would be your MAP sensor. If your ECU thinks you are is a high vacuum state it will cut the fuel off completely above a certain RPM.


As for the O2 sensor cell, it will only give you that code if the heater is enabled and you are not simulating the heater current draw. You can do this with a couple of resistors.

 

the stock 02 sensor is still in and hooked up. i just cut the wire for the narrowband input in the ecu and used the narrowband output on the wideband in order to see if it was the o2 sensor that wasnt allowing it to adjust properly. however i will go out and check the map sensor to see if anything is loose on it

 

checked the map sensor it is good. my map sensor has a vac line inbetween the sensor and the t/b i took it off and blew threw it and there was ntohin clogging it. i cant figure it out. the car runs ok one minute and the next minute it runs like total ****. i'm about to give up.

 

bump

 

I only have a wideband hooked up and I sometimes get that CEL code on 1 (primary o2 sensor). It'll turn on randomly for like 3 days then not come one for like 3 weeks. Either way it's no big deal and is not your problem since this happens to me as well and I have no bucking issues. Post your bin up, we'll take a look at it. Include what version of Uberdata you used

 

i think my car does this sometimes also, at very low rpms every once in awhile it will buck then be normal. i think i might check the closed loop disable option.

 

bump for more help.

 

I ran into the same problem working on a friend's car. Everything would be two full points leaner across the map for no obvious reason.

I don't have any idea on a definitive cause. I thought it was a function of increasingly high IAT's when the car would heat soak, but it doesn't consistently follow that pattern.

Mechanically speaking, there are a couple of things that need maintenance on the car, like a new fuel filter and main relay, but the fuel pressure remains constant, so I don't see either being a factor.

 

Uberdata runs like junk in closed loop.

 

anyone have any other ideas why it might be happening? it ran fine till i took it to the dyno then later that day it started doing it but the partial throttle was never touched.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dustin &raquo;</TD></TR><TR><TD CLASS="quote">Uberdata runs like junk in closed loop.</TD></TR></TABLE>

when closed loop is enabled or disabled?

 

when closed loop O2 is enabled, uberdata runs funky.

when it's disabled, it runs remarkably fine.

The reason for this? No idea. This is just my experience.

 

yeah currently mine is enabled. im getting a chip reburned tonight with it disabled and o2 heater disabled. ive been having some issues at lower rpms with it studdering sometimes and its been idling alittle funky every once in awhile. hopefully this fixes it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dustin &raquo;</TD></TR><TR><TD CLASS="quote">when closed loop O2 is enabled, uberdata runs funky.

when it's disabled, it runs remarkably fine.

The reason for this? No idea. This is just my experience.</TD></TR></TABLE>
bigwig and a couple other guys have been working on a fix so closed loop will disable upon map signal rather than map + tps. It sounds like they have gotten it working pretty well right now. This should help for a smoother transition into boost i would think.

Oh and i'm also having a similar problem on a guy's car i'm tuning. The car would run fine one minute and then the next minute it would be bucking all over the place at wot after like 4k rpms. I tried adding and subtracting fuel with no luck. It would even do it when the afr read alright. Then sometimes when it would happen the afr would jump all around. I think its a wiring issue because i used to have an afc wired in there before we put uberdata in.