Updated running issues thread......

[steveomiami]

Its a 1992 JDM wrx with a z4(or is it z6) ecu......(the 260 hp one) The car has the stock intercooler, i just put a MBC in place of the stock unit, It has 3 inch turbo back exhaust I don't think it has a cat, it appears to have stock injectors, it has an apexi intake. Currently its running with the MAF plugged in and it has a rough idle around 1000 rpm sometimes surging up and down a little bit. If I unplug the Maf it will idle around 1500-2000 rpms. If I unplug the MAF while the car is running it dies. The ICV appears to have a little damage to it because there are little magnetic bits floating around in there. When driving it feels gutless/little power like its surging back and forth and holding back. If I try to take off i can hear the turbo spool and my aftermarket gauge hits about 7 psi with the car pulling some then bam it hits a wall before it even hits 4000 rpm. The first time it had a big puff of black smoke. The car does not smoke normally. I'm thinking fuel pump or clogged filter maybe. This car is new to me and i am new to turbo cars so i am new to the sounds but it also seems like the BOV releases air when shifting when I'm not under boost yet

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[tairyhesticles]

Did all of these problems arise when you put the MBC on, or were they pre-existing? When a Bov leaks, it is letting out air that the MAF has already accounted for. it will put in X amount of fuel for the X amount of air it read coming in.
If the Air/Fuel ratio is too low, then your car will run rich and shoot black smoke, sometimes flames too (especially if you say it's catless). Your BOV is opened and closed by boost pressure/ vacuum, so check your vacuum lines for any leaks. Also check your I/C and charge piping for any holes.

That's my .02 anyway.

[steveomiami]

I bought someone else's problem for a good deal so the problems are pre existing. how can I test my BOV?

[TommyAtomic]

Do you have any gauges installed that might further tell you whats going on?

Check and possibly replace all of the vaccuum hoses you rerouted when installing the MBC.
Boost/vacuum gauge is vital if your using an MBC. What is your max boost. Right now? Do you have any extra hoses that are unaccounted for (hanging unplugged and loose)?
Is it possible you've reversed a hose or that something that was already worn out is suddenly causing you an issue since its been connected to the MBC.

Also have you tried adjusting your idle up a bit by rotating the IACV? Did your problems start after you installed the MBC or after you opened up the IACV?

[steveomiami]

I have a boost/vacuum guage, The MBC is set very low its a voodoo 3 with ceramic ball bearing. I disconnected the one on the strut, unhooked the electric plug and hooked the one from the turbo on the bottom of the voodoo(input) and the one from the top of the voodoo to the wastegate. If I let it boost it goes up to about 7 psi. There are no hanging or loose vacuum hoses. i have been looking for leaking ones but found none yet. The car had the problem when i bought it already. It also had 2 bad coils that i replaced, maybe theres a third one going out but i don't think that would cause that instant cutoff that I'm feeling. I already did a compression test and that was good. I have been playing with the iacv but does that affect anything while under throttle?

[dirtslayer]

What's your idle vaccum? Seems like a pre turbo leak. the ecu would be attempting to account for unmetered air if u have a leak possibly causing the smoke

[steveomiami]

Its idling pretty rough but i just checked it and its 12 lbs vacuum.

[dirtslayer]

Def have a leak. Get some starting fluid spray and spray down all vac hoses/components/ basically anything after maf oring to the heads

[steveomiami]

what should the reading be? what will the starting fluid spray do

[dirtslayer]

Oh boy, good luck.

Ok, a decent running engine idle vac without having race cams should be around 18-21hg. If lower something is leaking.

And the spray is highly burnable by the motor, so when a vac leak is present it will suck in the spray and idle up

[steveomiami]

yeah i figured out the ether thing right after i sent the mail haha never used that trick

[tairyhesticles]

Originally Posted by dirtslayer

Oh boy, good luck.

Ok, a decent running engine idle vac without having race cams should be around 18-21hg. If lower something is leaking.

And the spray is highly burnable by the motor, so when a vac leak is present it will suck in the spray and idle up

This guy's got it right. Low vacuum and low boost definately = vacuum leak. Even with the mbc on, you are running lower than stock boost. Good luck with your new nightmare! happy searching!

[tairyhesticles]

And if you want to check for a leak in your charge piping/ bov, look into a boost leak tester. You can make your own for about $10 with an air pump and some plumbing fittings from a local hardware store.

[steveomiami]

The boost is low because i set it low i havn't tuned it at all yet....now off to find that vacuum leak i hope you are all right

[dirtslayer]

Let's make a bet. If I'm right and its a leak you gift me the jdm wrx and if I'm wrong ill paypal a dollar to you

[steveomiami]

haha good try

[dirtslayer]

Go fix it, I wanna know! And btw if ya dnt mind, how much did u get it for?

[steveomiami]

i got it for 1400 because of the issues its having and it was overheating a little(thermostat was stuck) I stole it!!!!!!!!

[dirtslayer]

!!!!!!!!!!!!!!!!!
Pics now needed

[tairyhesticles]

1400 is a steal, a rolling shell is worth that much! Agreed, let's see some pictures.

[steveomiami]

Is the cat in the up pipe? Could a stopped up cat cause these symptoms?

[tairyhesticles]

All pre 2002 wrx's come factory with a catless uppipe. And your symptoms don't match those of a plugged catalytic converter.

[TommyAtomic]

Originally Posted by dirtslayer

Oh boy, good luck.

Ok, a decent running engine idle vac without having race cams should be around 18-21hg. If lower something is leaking.

And the spray is highly burnable by the motor, so when a vac leak is present it will suck in the spray and idle up

The amount of Vac your gauge is reading is low very likely something is leaking. But what it reads will really depend on what your idle RPM is set to.

What RPM are you Idling at?

[steveomiami]

I think that reading was taken around 1000 rpm

[dirtslayer]

That's low still