Hey guys so the D15B2 blew its head gasket in my 91 hatch.

I had a D15B7 laying around so I threw that in.

Swapped over the intake,drivers side motor mount, etc etc.

The car runs fine at an idle but when you hit the throttle it will first hesatate then rev?

It also idles high.

It seems to be building pressure inside the block. if you pull the dipstick or remove the oil cap after it runs for awhile it seems to hiss and blow off pressure?

Its not a huge amount of pressure but its noticable.

First thing i thought was the PCV valve, but when I take the hose off the PCV valve and put my finger over top of the valve you can hear the ball tap up and down when the car is running so this means the valve is ok right?

I dont have a clue what else could cause this..Could the head gasket be blown and be pushing cyl pressure inside the block?

What else could cause the hesatation? could the timing be off a tooth?

the cam pully has "UP" marked on it.. when the #1 piston is at top dead center, "UP" is slightly to the left, should it be totally vertical? the two lines on the pully seem to run horizontal to the cyl head surfaces... i really hope this is simple and i dident put that motor in for nothing


If anyone has any ideas Im all ears. Thanks in advance.

 

idles high at startup when its cold out? or idles high all the time, no matter if it is warm or cold?

things that will cause what you are describing are a blown head gasket or leaking piston rings, a bad vacuum line route, or a bad PCV valve. If it was just the PCV, I would expect it to be a slow buildup, so the next question is: how fast does it happen?

What I am asking is: if you take off the oil cap, then put it back on, how long does it take to build enough pressure to cause the cap to hiss when you remove it again?

If it was just a bad PCV valve, I would expect it to take a long time, like 5 mins or more. If its like 30 seconds or less, I would be looking at piston rings or a head gasket, or a horribly misrouted vacuum line.

 

Idles high all the time, warm or cold

id say it takes about 45 secs - 1 min for the pressure to build up alittle

The ball in the pcv moves so doesent that mean the pcv is ok?


even if the rings or the head gasket was shot, would that cause the hesatation?

if you let it run for a while it seems to get worse.... if you let it idle for 5 min or so then suddenly open the throttle all the way it will hesetate very bad, make a pinging sound and die......lol

and it hesatates even if you take the dipstick out so theres no pressuse building up.

Any thoughts?

 

if the ball moves in the pcv, then it should be relatively good. they are cheap to replace though, so you may just do that to completely rule it out.

hesitation could be caused by timing, for sure, but the pressure buildup would not. is the pressure escaping or is it sucking in? can you get a boost guage or pressure guage from someone to see what your vacuum lines read, or can you tell it is escaping or entering?

sorry for the 20 questions, i just am trying to gather info to try and figure this out.

 

After listening again i think the pressure is sucking in....whats does it mean if its sucking in rather then pushing out?

Thanks again.

 

Bump