hondachris1994

I know it has to do with ur ecu, but what will ur car do if it is in loop mode? Will it affect the idle, like up n dn idle?

Nevaeh Speed

I thought loop mode what the way you check ecu codes. I don't think it's smart to drive around with the car like that.

My friend just drove around for 30 min or so with his 05 wrx like that, and now his ecu isn't sending a singal to the main relay to give power to the injectors, mass air flow, fuel pump, plug a or "84" on the ecu, and about 5 other sensors... Thats sucks for him, but he's learned his lesson.

SVOboy

I believe you mean open loop versus closed loop mehbe?

It just refers to how the ecu is read by the car and what sensors and all that function, I believe. I've never understood it as well as I should.

hondachris1994

I want to know because my cel is on for knock sensor and someone said my ecu could go in loop mode cause of the cel

SVOboy

They prolly mean open loop, I dunno about that being the truth (dunno much about knock sensor stuff), but you'll need to fix your knock sensor to do stuff like vtec. The ecu sees that the knock sensor ain't working so it tries to take it easy on the engine by not letting vtec hit, or so I think.

hondachris1994

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SVOboy &raquo;</TD></TR><TR><TD CLASS="quote"> The ecu sees that the knock sensor ain't working so it tries to take it easy on the engine by not letting vtec hit, or so I think.</TD></TR></TABLE> vtec works but it hesitates in higher gears,btw im gettin my ecu chipped so it eliminates knock sensor all together

strtciv93

the person was probably talking about limp mode, not loop mode.

SVOboy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by strtciv93 &raquo;</TD></TR><TR><TD CLASS="quote">the person was probably talking about limp mode, not loop mode.</TD></TR></TABLE>

Mehbe that too.

Talk to drdisco69 about chipping, good dude,

schardbody

open loop is when the mode of operation when operating temps havent been reached. closed loop is when its at operating temps. thats the basics, it gets alot deeper than that. but so you know, anytime the CEL is on its in "open loop" and doesnt rely on the input sensors to the extreme to determine the correct a/f ratio. basically the ECU becomes "limp" or uses settings that will work well enough for all conditions. this will cause idle problems to an extent, like maybe some surging. also at WOT the ecu goes into open loop. hope that helps

hondachris1994

yeah that helps,cause my car idles up and down for about a min until returning to idle and vtech is hesitant in higher gears.

Relic1

*cough* VTEC not vtech.

not to confuse things
open loop - ECU runs directly off fuel/ignition maps in ECU
closed loop - uses O2 to determine correct A/F

open loop is used for tuning and starting/warming the engine up, closed loop is used for normal driving.


which ECU are you running? chipped? engine?

hondachris1994

p30 but im gettn chipped p28

Relic1

what engine?

stock P30 or chipped?

SVOboy

I'd think b16 if he has a knock sensor, right?

hondachris1994

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">what engine?

stock P30 or chipped?</TD></TR></TABLE>b16 jdm stock ecu

Relic1

if the stock ECU is causing idle problems like this it's either a bad ECU (highly unlikely) or something wrong with the engine/install.

**edit** my bad. I read above that you have CEL for knock sensor.
it will run very different with that CEL. it could also be your AICV bad.
when mine went bad it caused it to idle like that and it didn't throw a CEL. but when I was tracking it down causing a CEL for what ever reason made it worse when it was cold but it leveled out nicly when it was warm.

hondachris1994

yes the cel is on for knock sensor

Relic1

sorry I edited my post after reading above that have a CEL for the knock.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">**edit** my bad. I read above that you have CEL for knock sensor.
it will run very different with that CEL. it could also be your AICV bad.
when mine went bad it caused it to idle like that and it didn't throw a CEL. but when I was tracking it down causing a CEL for what ever reason made it worse when it was cold but it leveled out nicly when it was warm.</TD></TR></TABLE>

hondachris1994

I just put a new IACV on and still the slight idle up n dn between 750 n 1250 only for about 30 secs, though could cel for knock have anything to do with that? limp mode?

schardbody

yes, it will, the ecu wont see the air/fuel ratio, therefore it cant correct for on/off throttle inputs, and that will give you an erratic idle.