d16z6 runs poorly

[INJEN78]

d16z6 in a 93 del sol si
all new gaskets in the top end(intake manifold,throttle body,head gasket)
just did head gasket and timing belt(timing is dead on)
firing order is correct
throwing a cel for the o2 but its been doing this
now i had swapped the z6 manifold for a y8..bolted everything together and started it up..it was surging,let the car warm,something popped and it idled fine.shut the car off let it cool.started it and it was surging..well the headgasket blew somewhere in the mix(i think that was the pop)
so i bought arp head studs,new gaskets and put it back together..well here we are at square one..the idle was surging from around 1400-1600 really quickly..
i turned the heat off in the car and it regulated at 1500 no more surgine..but now i cant get the idle to go down at all..
ive tried messing with the dizzy(ignitoon timing) ive double checked all my hoses and everything..even retightened all the nuts and bolts..idk what to do

 

[eg6sir]

hmm.. idle adjustment screw on the throttle body?, tps?, fast idle valve?

 

[ricksautomotive]

how about the fast idle valve? they go out on alot of hondas. you rarely even find them at junk yards but they go out very often. they cause the idle to rev up and down around where youre idle was bouncin back and forth....depending on if the idle adjustment screw has gone out. these valves generally get jammed up from corroding coolant....normally because people dont spend money on coolant services. and this usually starts with the first owners back in 93 in your cars case so this doesnt necessarily mean you are to blame.

 

[eg6sir]

take the FITV off and see if the spring is stuck..

 

[INJEN78]

well i screwed the little white plastic ring in on i believe the fitv??
i cleaned the iacv..nothing happens when i unplug the iacv except a code for that..
i was told to bypass the fitv and see if that solves anything
but also when i unplug the vacuum hose for the map it doesnt do anything either..
the idle is only bouncing from 1500-1700 really quickly..sounds just like a rotary engine..
but ill take it apart again and check everything

 

[INJEN78]

ok so i bypassed the fitv,didnt work
took it all apart,cleaned it all out,new gaskets,didnt work..
i have no idea what is going on..

 

[eg6sir]

idle adjustment screw?

 

[eg6sir]

hell, could be a vacuum leak.. have you checked for any?

 

[INJEN78]

i have..sprayed some wd40 around the intake mani..
which one is the idle adjustment screw?? pix please?

 

[efhondakid]

i have..sprayed some wd40 around the intake mani..
which one is the idle adjustment screw?? pix please?

Brass flat head screw on the top of the TB, near the MAP.

 

[INJEN78]

ah ok..ill def. try it

 

[efhondakid]

ah ok..ill def. try it

Im willing to bet a large sum of money that isnt your problem though, if you had a constant high idle then I would lean more towards that, my bet is its a vaccum leak, connector plugged into the wrong sensor, or your colant lines that run the the FITV and/or IACV maybe be ran wrong.

 

[crxhfz6]

one picture i the idle screw. the other is the two holes for the idle valves. one way to check for leaks is cover both holes when the car is running and it should die. if it does not then you have a leak. if it does die then you can check each hole individually to see which one is causing th problem. the top hole is for the eacv and the bottom is the fitv.

 

[INJEN78]

well i know the coolant lines for the fitv and iacv are run correctly..ive got one line run from the water bong on the back of the block going to the bung on the fitv closest to the front of the car..another line run from the bung on the back of the fitv to the bung on the iacv closest to the passengers side..then a line from the bung on the iacv closest to the drivers side to the bung on the manifold..im going to try plugging those holes and see..i rlly dont know wtf is going on..i can usually diagnose stuff like this..

 

[INJEN78]

ok so plugging the top hole inside the throttle body completely shuts the car off..plugging the bottom hole slows the idle a little bit..
but i just started it cold..and the outside temp is colder and it went to 2100 rpm and stayed there..no idle surging..so fitv is def. bad..now what about the iacv?

 

[crxhfz6]

does it surge when the iacv is unplugged. i think its supposed to run around 300 rpm when the motors warm and its unplugged. when i checked mine with a bad iacv i couldnt adjust the idle lower than 700 with it unplugged

 

[INJEN78]

took the iacv off cleaned it.took the fitv off again and cleaned it..now its surging bad..like 1700 to 2300..it does surge with it unplugged..if i plug both holes now it idles a little lower..i am about to just sell it

 

[eg6sir]

sounds like a vacuum leak..while the motor is running.. spray some carb cleaner around the fitv where it connects to the throttle body and the iacv ..

try buying new gaskets for them(they're like 10cents a piece.. little rubber gaskets) and dont tighten them down really tight, you'll crush the gasket.. only needs to be hand tight

 

[INJEN78]

ill try it..im about to just put the z6 intake mani back on..cuz it only started doin this shit when i put the y8 on

 

[crxhfz6]

Yeah if it still runs with both holes plugged it for sure a leak