I have a JDM ITR motor with P73 JDM ECU, Everything is stock except for a 255 Walbro fuel pump,

however, when my clutch is disengauged and when the car is moving, it will idle at around 1,500 to 2,000 rpm, which i dont' think its normal, but when the car comes to a complete stop, it will idle back normal at around 750 to 900 rpm,
So I figure it might be my fuel pump thats making my idle so weird when moving, so I put back a GSR fuel pump in there, and it just did the same thing, but now my idle fuel pressure is at 43psi instead of 55psi with the walbro.

Is it because my walbro that messed up my injectors or FPR or something? or is it that I am missing a vacuum hose here (I just found that it might be missing that today), here is a picture



Before I pay 85 dollars per an hour to have it check out and fix by a shop, can someone help me out and see if I can fix this problem myself?

Thank You

 

Any comments or susgestions are welcome

 

My 95 Helms manual looks a little different, but it does have a vacuum hose that goes to what looks like the same location, but it doesn't say where the other end goes.

I'll look a little more in the book.

 

b18b has a hose that goes from there to a black plastic container--can't verify what it is exactly, my car isn't near.

But i've had a number of idle problems in the past and pulling out that hose everytime had nothing to do with it.

 

As far as I can tell, it should go to the EVAP canister, along with another hose that connects lower.

 

I couldn't find a port on the canister that will connect to the TB port,

But when i put my Apexi Power FC on the car, the car will not have the idle problem, my shop said the FC overwrite something so it will idle normal, so is it some sensors problems? any ideas?

 

Block the open vacuum line on the TB.

 

I maybe be wrong but I think you can cap that one off.

 

ok, but does anyone know what else could have it to idle like this, i have searched and notice some people have the same exact problem but no one can really solve it yet....

 

is your car warmed up all the way?

 

yes, its warmed up all the way

 

ive heard that vac leaks will cause this type of idle bounce...does the ecu trip a code of any kind?

 

the CEL is not on, but will the ECU give me codes if I go check for it?

 

what year is it i think i have the codes for the 90-93... besides on some models it wont stay on

check and see what codes it has stored in it be jumping the computer connecter and counting the long and short flashes on the ecu, or cel

 

that plug in the TB is for coolant

 

for coolant, so I just cap it off, or connect it somewhere?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gsr dood &raquo;</TD></TR><TR><TD CLASS="quote">that plug in the TB is for coolant</TD></TR></TABLE>

no it's not.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HGL1668 &raquo;</TD></TR><TR><TD CLASS="quote">for coolant, so I just cap it off, or connect it somewhere?</TD></TR></TABLE>

just cap it off, that's not the cause of your idle issue though.

 

the nipple is for the evap canister

it does not enter the inside of the manifold, the hole for it is before the throttle body plate and having it un-capped will not affect idle, I have beed driving with it open for a few months

 

anyother opinions?

 

the 1500 rpm idle when in motion when youre not in gear is normal, my LS motor did it and I never geave it a second thought

maybe try cleaning your IACV and FITV if you have one

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DC2 Mang &raquo;</TD></TR><TR><TD CLASS="quote">the 1500 rpm idle when in motion when youre not in gear is normal, my LS motor did it and I never geave it a second thought

maybe try cleaning your IACV and FITV if you have one</TD></TR></TABLE>

yeah usually this is the issue to most idle issues. i believe for vacum you only need the map sensor connected.

 

Cap it off!