Low idle.

[nickmcgill]

Hi Guys,

I recently did the "hose 10" mod on my primary turbo as listed on one of the other threads.

The after effect of this is there isn\'t manifold pressure being leaked back into the intake.

The downside is it\'s lowered my idle considerably.

On average when warm it will sit around 200-300rpm which is a little low for my liking.

It still idles fine and hasn\'t stalled from it as of yet but has come close. (Auto Trans)

I\'m guessing this isn\'t overly normal ?

Is it worth increasing the voltage on the tps to try raise the idle ?

The TPS is currently sitting on 0.54v at rest when idling.

[Marky]

Bear in mind the first graduation on the tacho is 500rpm - it\'s meant to sit around 7-800

[loner]

+1

No way your engine can idle at 200-300 rpm... it will be 700-800... normal.

[nickmcgill]

It sits just above the first big white line I\'m assuming its 500?

[titian]

Un do the "hose 10" mod. Before it goes Bang! : Mods without tune? Always end in tears/problems :\'( :\'(

The Boys at Fuji Industries do know what they are doing when they design their control systems for their engines. ;D ;D

[Marky]

Which would be why they removed it on the rev D and audm models

Mine had a high idle - around 1200rpm and hunting - removed this hose and the idle is now a dead rock steady 800rpm and never hunts. Nothing else changed.

Nick is this with the original ecu or the replacement one?

[ryn]

Mine idles fine now after I blocked the hose off properly.

[nickmcgill]

It does it on both ECU\'s

It\'s noticeably more rough since you had a fiddle with those hoses too so I\'ll re check them after dinner incase something is leaking.

[Marky]

Haha. Prob left something half loose

[B4_685]

 titian said:

Un do the "hose 10" mod. Before it goes Bang! : Mods without tune? Always end in tears/problems :\'( :\'(

The Boys at Fuji Industries do know what they are doing when they design their control systems for their engines. ;D ;D

I concur - Tried this mod - it alters the low-end boost characteristics which is good for a bit of a kick in the pants (more boost) but you are flirting with danger (esp. EJ208 with high compression) bringing more of a boost surge at lower RPMs with an engine designed for 100 Octane fuel (JDM Models) = pinging and big end problems...proceed with caution!

[Marky]

If you\'re getting pinging at under 3 grand you\'ve got bigger issues than forcing the factory BOV to leak can cause

Considering every other thing done to a turbo car will bring boost on faster - freed up intakes, exhausts - (the boost controller your car has for example) - removing this is no worse

If nothing else, it\'s probably healthier with the BOV acting as it should, not being forced to leak back to the intake slightly as per the factory arrangement

If yours is a revision D then it shouldn\'t have had the T-junction in the BOV hose in the first place anyway

[B4_685]

 Marky said:

If you\'re getting pinging at under 3 grand you\'ve got bigger issues than forcing the factory BOV to leak can cause

Considering every other thing done to a turbo car will bring boost on faster - freed up intakes, exhausts - (the boost controller your car has for example) - removing this is no worse

If nothing else, it\'s probably healthier with the BOV acting as it should, not being forced to leak back to the intake slightly as per the factory arrangement

If yours is a revision D then it shouldn\'t have had the T-junction in the BOV hose in the first place anyway

Interesting....got me thinking now...my rev-D does have the T junction so am wondering if engine was a swap out from an earlier version....turbos and injectors are Rev-D spec and ECU is rev-D (A4SH701H -JDM B4) so can\'t imagine why it would be retro-fitted...

Back to topic tho, now that I can tweak the idle with FreeSSM (http://developer.berlios.de/projects/freessm/) I might try the mod, adjust idle with software and log ECU for any variations to knock \'patterns\' using romraider....

[nickmcgill]

I used freessm to increase my idle by about 75rpm which fixed it up.

The rev D\'s do also have this T as I\'ve seen it on Devines one.

I tried reverting mine and the boost levels stayed the same with or without the mod although it is more responsive with it due to the bov operating correctly as per Marky.

[Swindog]

 nickmcgill said:

Hi Guys,

I recently did the "hose 10" mod on my primary turbo as listed on one of the other threads.

The after effect of this is there isn\'t manifold pressure being leaked back into the intake.

The downside is it\'s lowered my idle considerably.

On average when warm it will sit around 200-300rpm which is a little low for my liking.

It still idles fine and hasn\'t stalled from it as of yet but has come close. (Auto Trans)

I\'m guessing this isn\'t overly normal ?

Is it worth increasing the voltage on the tps to try raise the idle ?

The TPS is currently sitting on 0.54v at rest when idling.

From memory you should be at .8v on your tps. It may well be your problem.

[nickmcgill]

Realllyyyy that would explain a world of issues if that\'s correct.

I\'m getting a second hand throttle body tomorrow hopefully so will see what that\'s sitting at by default.

Can anyone else give feedback on that ?

[Marky]

I thought voltage at closed tps is meant to be 0.5v - plus or minus 0.05v (so 0.45 to 0.55) when measured at the ecu terminals

i cant be bothered re-googling it

[Swindog]

Ermmmm. Ill re check my sheet.

from memory .8v closed 4.7v open?

[Swindog]

maybe its .48v closed

google google time...

yes indeed marky you are right. .45-.55v closed but 4.7v open

[Marky]

damn, your google foo is stronger than mine

I get distracted too easi... ooh shiny