Need help Running lean

[dthquazi1]

when ever i begin to boost i run real lean but whenever the bov opens it richens out. I have a 3in maf and translator in blowthrough and no safc anymore. I can't figure this one out.

 

[KRAZYKOREAN]

well it seem you must vent...and how are you exactly knowing you are running really lean...and please dont say its a autometer air/fuel ratio gauge... also what setting do you have the gm mas trans at..

 

[DMS-WhiteGSX]

Originally posted by KRAZYKOREAN
well it seem you must vent...and how are you exactly knowing you are running really lean...and please dont say its a autometer air/fuel ratio gauge... also what setting do you have the gm mas trans at..

He's right. Those guages are really horrible. As unreliable(arguable) as it is, I would have kept the SAFC to check secondary o2 voltages.

How do you know you are running lean?

 

[dthquazi1]

well yes i am running the autometer but thats just to alert me when someting may be going wrong then i pull out my trusty logger and check the voltage which some or most of the time drops to 0.00 volts until the bov opens.

 

[crankbender]

Check and make sure you are running on all 4 cylinders. Start the car and pull the plug wires 1 at a time. If it doesn't bog the same troubleshoot that cylinder.

 

[dthquazi1]

i did that by disabling the injectors with the logger

 

[crankbender]

Try switching to draw through.

Also have you tried just tuning the maft?

 

[dthquazi1]

yeah tuning does nothing for it. I have tried the stock maf and it still does it.

 

[GSntncT]

Originally posted by dthquazi1
when ever i begin to boost i run real lean but whenever the bov opens it richens out. I have a 3in maf and translator in blowthrough and no safc anymore. I can't figure this one out.

Check your plugs. Does the car misfire when it's "apparently" going lean? If not, and your plugs are fine, then check your front 02 sensor. Just like you can foul plugs, you can foul a senor too. That what I had to do when I was having the same prob.

 

[dthquazi1]

the plugs are brand new so i will check the o2

 

[crankbender]

So it does this when you use the stock maf in draw through right?

 

[dthquazi1]

yep, it does.

 

[crankbender]

Fuel pressure regulator maybe.

What do your fuel pressures in the rail look like. You could be overrunning the stock FPR at low flow rates making you have high fuel pressure. Then when you boost it drops the fuel pressure down and you run lean.

 

[dthquazi1]

how could i check those. I am running the 255 but it didn't do this before. It just started after my tranny install. I also blocked the egr though. Could that be doing it?

 

[crankbender]

you need to know what that fuel pressure is doing. The 255 will overrun the stock fpr pretty much every time under low usage.

Also the car doesn't use your O2 sensor during WOT so if it is messed up and reading leaner than it should then it will cause the lean reading also.

Check the grounds on your exhaust pipe

 

[dthquazi1]

you mean the ground on the downpipe. I dont have that connected as far as i know. Would that be causing it? I haven't had it connected for a long time though and it has been ok.