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Ok i turbo'd my 1.8l v6 and from the day i put it on the road it has been running lean durring vac and in the yellow from 0+. I put in a fuel pressure gauge to see what was wrong and it turns out I couldnt get more then 45 psi, So i put in a walbro 190 fuel pump tuesday. Now if i turn the fmu up as far as it go's before stalling at idel (60psi) and it still shows lean. I put the fmu back down to 48 psi (stalling problems) and change the gauge to the other o2 sencer thinking it might be that one gone but still the same readings. I pulled the plugs and they are black with carbon,know dosnt that mean its runnign rich? when driving it feels like its running rich. Ok a little more info the fuel pressure is alway 48+, oil is 50psi and the water temp is 140-150 (was 180 before the turbo install) and it stalls the odd time durring a stop or a real slow roll(clutch in or out) oh and they are the 2.5l injectors and rail. Can any one help me with whats wrong? Jeff?

How does the exhaust sound? Is it very deep/bassy with the odd pop? If so it is running rich at idle. Do you have a 4 wire 02 sensor? The air/fuel gauges are all but useless, get an EGT gauge, mount the probe 2" from which ever exhaust port is furthest from the point of fuel entry on the rail. You should be about 800-900' at idle, 1000-1200' for cruising at a constant speed and above that when accelerating (generalization).

stock o2 sencers 4 wires and it sound deep with the odd raspy sound some times oh and the engine light comes on but i think thats from the o2 reading.

You need to check for codes before you can say for sure.

sounds like the o2 sensors are bad, if they read lean all the time then the ecu will dump lots of fuel in to try to make the mixture richer. <p>This would also explaine why the A/F meter reads lean all the time.<p>try hooking up the A/F meter to your vitara's o2 sensor (befor the converter) , if it reads properly then I would change the MX-3's O2 sensors and start over.<p>P.S. DONT use cheap universal O2 sensors, if need be, I will get you some Bosh or factory mazda ones at my cost, but I dont want you to have more problems caused by cheap defective O2 sensors (I have seen it happen)

I was having similiar rich problems with my 4 cyl and it ended up mostly being me no recirculating the BOV back in the system. Just a thought.

It can´t be the problem as the V6 has a VAF, and I suppose that he must have the BOV before it (in the airstream direction)

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by BATTOSAI:
It can´t be the problem as the V6 has a VAF, and I suppose that he must have the BOV before it (in the airstream direction)<hr></blockquote><p>unless the car is equipped with a map sensor, then it CAN be a problem if not vented back. it's still lost air that was accounted for, meaning more fuel was added. when that air doesn't reach the cylinders and the fuel still shows up.....rich.<p>but since this happens under normal driving, i don't think this is the problem.
[ June 13, 2003: Message edited by: cre8v mx3 ]<p>[ June 13, 2003: Message edited by: cre8v mx3 ]</p>

What is the voltage that you are seeing from your 02 sensor? You should be looking for a steady .8-.9V under load, idle should still be about .55-.75V. Check that out first before you go throwing away any 02 sensor, but again, do as Curt said, spend your money once instead of twice. <p>Do you have a boost gauge? What are you seeing at idle for vaccum? Should be about 17-20'.<p>Another thing I would look at is your water temp sensor as you mentioned it is only seeing 150'. Since the ecu uses this info to determine open and closed loop you will want to make sure that it is in spec.

ok its reading lean guys not rich I just think its running rich. The bov is before the vac so its letting out unread air and im having the prolem at ible not underboost please read the first post and thanks for all the help anyways. For the others that fallow me the vac is 17-20 at idle same as before the install. Im thinking that Curt is right when i first start the car is will show pined green but them in about a minute it drops to lean. What do's spark plugs in a lean running engine look like? I know my car was running rich before the install, i put the 2.5l injector earlier in the year and that was running rich all the time and the car feels the same know as then. I might still have a pair of o2 sencers lying around from the 2.5l probe i sold last year i will look this weekend for them. Any one else have any other idea? what is a real good way to fined out if my car is running lean?

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr> ok its reading lean guys not rich I just think its running rich. The bov is before the vac so its letting out unread air and im having the prolem at ible not underboost please read the first post and thanks for all the help anyways. <hr></blockquote><p>First off, patience is a virtue and required when troubleshooting.<p>Second, you need to be really clear about your setup. Are you saying that the VAF is before the BOV? The Vaf should be after the filter but before the coldside of the turbo. the BOV should be between the TB and the i/c. What I recommended is proper methods of tuning and should be followed when going this route. The A/F gauge from Autometer is just a pretty light it is far from accurate. If you can tell me the voltage you are seeing at the 02 sensor then I can help you some more. Otherwise, your on your own as it could be many things.

are you sure your bov is set correctly? if ANY air is escaping, it could cause a problem.

"First off, patience is a virtue and required
when troubleshooting."
I was beingn patience i was just trying to stop the direction this was going and put it back on track and i said it very nicely! <p>
As for the set up it go's air filter-turbo-intercooler-bov-vaf-tb as for the vaf being before the turbo I have never seen that and dont understand why you would put it there. The vaf should messure the air just before it go's into the engine so the engine knows what its getting, not at the filter. I will try to get the reading this weekend but right know i have to run im do to be in a car show in 2hours.<p>[ June 13, 2003: Message edited by: mrspanky79 ]</p>

hmmm.....you must be right. Not like I have ever done the FI thing before.

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by mrspanky79:
[QBThe vaf should messure the air just before it go's into the engine so the engine knows what its getting, not at the filter.[/QB]<hr></blockquote><p>but are you positive that the contstruction of the vaf can withstand pressure above atmospheric levels...and still be accurate? they were made for a n/a motor, thus it should still be in the system as just that.