going way lean at 3800rpm
08-07-2009, 07:22 PM
#13
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June of last year. No real calibration it has always sit around 14.7 to 15 at idle and cruse, and throughout normal daily driving it seems to work. I don't understand how it would be so consistent as to the time that it fails only under hard WOT acceleration or load... 80mph uphill passing on the highway or towing. dont want to rule anything out until I know for sure its not an issue. Spent the day looking for vacuum leaks, couldn't find anything.
08-07-2009, 07:29 PM
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Over time it will need to be recalibrated under load/WOT.
Maybe you can get some dyno pulls & check the w/b against the readouts.
What was Nelson's assessment of this situation?
Maybe you can get some dyno pulls & check the w/b against the readouts.
What was Nelson's assessment of this situation?
Last edited by bai78; 08-07-2009 at 07:34 PM.
08-07-2009, 08:08 PM
#15
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They think the injectors will not push enough fuel but they sent me a new tune anyway. That is half the reason i put the popits back in, they worked, with the first tune. now they dont work with either tune.... and very little boost.
They also mentioned the wide-band that's why I put one on order today. sitting in the driveway w/ a scan tool the O2 sensors read the same as the wideband (rich /lean) so i discounted that as an issue. Now I'm willing to try anything.
It's not pinging or popping when it gets lean I just haven't stayed on it very long when it goes lean and unless I'm looking at the gauge i cant feel it lean out. it just doesn't seem to have the power it had(seat of pants). i haven't had the opportunity to put the scan tool back on since i hit nelsons up for the tune.
i would love to do the dyno thing but the budget just isn't there since i had to replace the tranny and rear end this year. I was driving about 15mph when the rear end locked up. That's another reason I don't want to just throw parts at it.
BTW when does your Tahoe build its boost , And your running a pusher pump & fmu to get to 75psi?
They also mentioned the wide-band that's why I put one on order today. sitting in the driveway w/ a scan tool the O2 sensors read the same as the wideband (rich /lean) so i discounted that as an issue. Now I'm willing to try anything.
It's not pinging or popping when it gets lean I just haven't stayed on it very long when it goes lean and unless I'm looking at the gauge i cant feel it lean out. it just doesn't seem to have the power it had(seat of pants). i haven't had the opportunity to put the scan tool back on since i hit nelsons up for the tune.
i would love to do the dyno thing but the budget just isn't there since i had to replace the tranny and rear end this year. I was driving about 15mph when the rear end locked up. That's another reason I don't want to just throw parts at it.
BTW when does your Tahoe build its boost , And your running a pusher pump & fmu to get to 75psi?
08-08-2009, 08:24 AM
#16
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If you are just checking the sensors for a stoich reading, you will get that 99% of the time if everything is running fine. This however will not tell you if you are running rich ir lean under load or WOT. Your wideband will do that for you.
Sorry to hear about the tranny & rear end problems. You don't have to necessarily get a dyno tune, which could run $500 or more depending on who you use. My dyno time was $75 for 3 pulls. In between each run the FMU would just get tweaked for optimization. Perhaps you can find something like this in your area & not have to drop a ton of $$$ on the runs.
My Tahoe makes boost around 2700 ish RPM. My blower is a centrifugal kit rather than a roots/screw unit. I am running an inline pump as well as an FMU with the stock spider poppet injectors. Currently, I am in the process of upgrading to an intank 255 lph high pressure Walbro. The stocker is dying on me so why not upgrade!
Sorry to hear about the tranny & rear end problems. You don't have to necessarily get a dyno tune, which could run $500 or more depending on who you use. My dyno time was $75 for 3 pulls. In between each run the FMU would just get tweaked for optimization. Perhaps you can find something like this in your area & not have to drop a ton of $$$ on the runs.
My Tahoe makes boost around 2700 ish RPM. My blower is a centrifugal kit rather than a roots/screw unit. I am running an inline pump as well as an FMU with the stock spider poppet injectors. Currently, I am in the process of upgrading to an intank 255 lph high pressure Walbro. The stocker is dying on me so why not upgrade!
08-10-2009, 01:01 AM
#17
Sorry to hear about your broken diff.
http://cgi.ebay.com/ebaymotors/Bosch...=p4506.c0.m245
$120 for your sensor, you paid too much. Look at this.
Replace your sensor and it will fix your WOT "lean" reading. The "lean" reading is not correct, your sensor has gone bad. They don't last that long.
http://cgi.ebay.com/ebaymotors/Bosch...=p4506.c0.m245
$120 for your sensor, you paid too much. Look at this.
Replace your sensor and it will fix your WOT "lean" reading. The "lean" reading is not correct, your sensor has gone bad. They don't last that long.
08-20-2009, 09:50 PM
#18
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Wow I love my truck. It's been three months since I have done a good WOT merge onto the highway and it still puts a grin on my face. Put the new O2 sensor in and that was the issue. Replaced the poppets with the new injectors and used the old tune, it runs real strong. I would recommend the upgrade to anybody, it is definitely more responsive to the throttle inputs than than the poppets. That is by seat of the pants testing anyway. Thanks for all the help figuring out what the issue was.
On a side note: lesson learned.....Always double check your work no matter how excited you are to do a test run. After two or three runs around the neighborhood I was confident in the truck not going lean. I pulled the waist gate and put the spring back in, then put it back on the truck. Jumped in and took it for a drive, got out to the back road and punched it. Watching the fuel gauge closely the truck pulled harder then even harder, best it has ever pulled. Then about 4500rpm I started leaning out and could hear the detonation in the engine..... boost gauge read 20psi
anyway connected the waist gate back up on the side of the road and all is good. Well OK if i could always run 20 pounds without blowing up then it would be good.
On a side note: lesson learned.....Always double check your work no matter how excited you are to do a test run. After two or three runs around the neighborhood I was confident in the truck not going lean. I pulled the waist gate and put the spring back in, then put it back on the truck. Jumped in and took it for a drive, got out to the back road and punched it. Watching the fuel gauge closely the truck pulled harder then even harder, best it has ever pulled. Then about 4500rpm I started leaning out and could hear the detonation in the engine..... boost gauge read 20psi
anyway connected the waist gate back up on the side of the road and all is good. Well OK if i could always run 20 pounds without blowing up then it would be good.
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