ShadowClown

I have an '88 13bt manual, with a series 5 engine, tranny and drive line a 2 1/2" exhaust and an HKS intake, I know my factory boost guage is stuffed becasue it only goes up half way on the guage, so I got an Autometer boost guage. I can boost up to 9 or 10psi with this but it cuts out, is this a boost cut or fuel cut?? I know it should only be boosting about 7psi but with the exhaust and intake mods would it be enough for the boost to creep up to 10?? the car kinda farts when boosting high all other times its sweet as. It accelerates hard but gives about 2 seconds of pulling power then a second of * faaaarrt * noise and looses all power, then power comes back again for 2 seconds...untill i let it off boost. Also while i was doing this last night when i let the boost off the guage went all the way to 15psi then back down??

ShadowClown

i can spell gauge.....jus not up there

also what happens if I take the standard b/o valve that vents into the intake off and face it upwards and block the hole in the intake?? is this bad?? it sucks in air which would be unmetered so its probably not good, but should it suck air off boost? isnt this a 1 way pressure valve??

13BAce

It could be fuel cut. Do you have a fuel cut defencer? It sounds more like detonation or something because with fuel cut you'll never hit 15 PSI.

If you want to vent the stock BOV to the atmosphere you'll need a one way check valve to prevent air coming back in. Check out http://www.teamfc3s.org/info/articles/blowoff.html for a how-to.

ShadowClown

im not sure if i have a FCD or not? the 15psi i mentiond was only hit for a breif second, a really big boost spike when i changed from 2nd to 3rd i think, im not sure why tho.?

think i need a real bov....

13BAce

Boost spikes would be caused by the wastegate not being able to handle the exhaust flow.

Scott 89t2

I give you a week before your engine blows!

sounds like fuel cut. the exhaust and intake are definatly enough to hit 10psi.

ShadowClown

so if it is fuel cut the car would be running lean, wouldnt it?
causing detonation? the killer of rotaries...

i should get a rich/lean mixture meter to find out for sure.
if it is hitting the fcd, whats the next step? bigger injectors, new computer, new fuel pump....or all 3 at once??

this is a most annoying problem, I can however get it to do it at 8 psi if im goin hard up a hill. would this still be the FCD?

would it have these symptoms if the wastegate wasnt working??

thanks 4 ur help so far.




--- Sorry 4 all the Questions but I'll never learn unless I ask ---

Scott 89t2

the only ways to get rid of the fuel cut is to either buy an FCD, or get an upgraded ECU chip like www.mdrace.com by putting the FCD on you are lieing to the computer about how much boost you are running, there for anything over 8psi or so and you should also be adding fuel mods. a bigger fuel pump should be ok for 10 psi. I am running an FCD but I don't like having it. I'll most likely be getting a chip like above before the spring time. what you also really should do is port your wastegate. if you are spiking to 15psi durring shifts that is not good.