ok here it goes when i start my car and the car surges real fast at 1500 rpms but when it warms up it stops and idles real low and when i take off slow like not even really hitting the gas it does it but if i get into it a little it wont do it. what could cause this?

ive done a engine swap. 93 Civic DX

D15B VTEC
P28
oh and also i used the dx tranny and ive hear it will affect the feel of vtec because the long gearing is this true?

 

It could be your map sensor. and on that tranny, yeah it will make the RPM fall down pass the v-tec and kick again.

 

try iacv

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by d15-jdm-civic &raquo;</TD></TR><TR><TD CLASS="quote">ok here it goes when i start my car and the car surges real fast at 1500 rpms but when it warms up it stops and idles real low and when i take off slow like not even really hitting the gas it does it but if i get into it a little it wont do it. what could cause this?

ive done a engine swap. 93 Civic DX

D15B VTEC
P28
oh and also i used the dx tranny and ive hear it will affect the feel of vtec because the long gearing is this true?</TD></TR></TABLE>

check your pcv valve, it's the one thing people on here overlook and the cheapest way to start trouble shooting (it's like only $3). when they go bad they have similar symptoms to what you are describing.

as for the gearing, they are the dx is slightly shorter, but not enought to give you this problem.

 

is the pcv valve located on the back right on the intake manifold? if so the the D15B didnt come with it, (theres no mounting place or hole for the valve)

and ive changed the iacv but didnt do eny thing, but when i did it i still was using my p06 non vtec, and now i put a p28 vtec ecu.

(when i changed the ecu it stoped but i drove around for like 20-30 min and it started doing it again. do you think i should change the iacv with the p28 and rest the ecu?

oh also i used the d15b7 non vtec throdle body could that cause eny thing i still have the d15b vtec throdle body.

 

the pcv valve should be behind the valve cover on the intake manifold (all modern cars have pcv valve). it's been awhile since i've looked at a d-series.

 

also try unpluging your tps sensor cause that is also a common problem.

 

i highly doubt it, not to mention they are a pain to get out. try the pcv valve first, it's cheap and easy to replace.