368 LT5 Drinking oil

[RICHARD TILL]

Will a 90 model chip work? I have two extras. One is stock, (AUAH 8555) idled high but otherwise fine. The other one has Super Chip written on top and have never tried it. Bought it here on the forum. Wanna try either or both?

[Mitsumark]

Ok well my inbox awaits..I know I'm kinda new here but I have spoke to some of the forum members by phone..I promise anyone who can float me a chip a few weeks that I will not pull anything shady..I'd be ecstatic if I find it's the tune as I'm suspecting something worse..Atleast if I prove it's the tune it won't be a waste of another $500+ to get it on a dyno with a reputable tuner..

[Mitsumark]

Rich-Don't know if 90 will work..I thought they were yr specific.. Can anyone confirm?

[scottfab]

Originally Posted by Mitsumark

All plugs are ugly..Oil comsumption is bad regardless of how Im driving as proven by smoking at idle.

Oh, didn't know low rpm generated the ugly plugs. That rules out that.

[Franke]

They (mem cals) are year specific. Check the ZR1 specialist Marc Haibecks web site for info about each year for 90 thru 92. Looks like 93 to 95 are the same.

[XfireZ51]

Originally Posted by RICHARD TILL

Will a 90 model chip work? I have two extras. One is stock, (AUAH 8555) idled high but otherwise fine. The other one has Super Chip written on top and have never tried it. Bought it here on the forum. Wanna try either or both?

Rich,

A 90 memcal won't work because it doesn't have the knock sensor circuitry on board. Also, any memcal will work from 91-95 BUT it must have the correct model year Broadcast Code. 90 bin is an AYBK, 91 is a BFXB.
I suspect the 368 w intake cams is idling rich. The additional overlap causes the O2 sensor to think motor is lean and so it keeps increasing the pulsewidth. Like a systemic vacuum leak. Also if the calibration hasn't been modified to deal with the additional displacement, the ECM is trying to feed a 5.7L motor but that turns out to be not enough according to the O2.

OP,
Are you running Closed or Open Loop?

[Mitsumark]

Car is running a Heibeck chip tuned for a 368ci with IAT sensor relocated..I spoke to Marc through e-mail last night and he says that his tune would not cause this overly rich condition at less than 50% throttle.He suggests I check vac readings again and I get a scanner on the car to read the 02 banks.I will try to get access to one in the next few days..He said something about if the vaccume is above 50kpa the map sensor will command so much fuel the 02 sensors won't be able to control it..Now I don't know what that means,but I did put a vac gauge on it and got about 15-18" of vac..As stated I also checked for leaks and none were found..I also blocked the TB inlet while running and the car died immediataly like it should..I know these motors are prone to oil consumption but this is out of control..There is oil in the intake tract along with the PCV piping and on my plugs.The car has not yet thrown a code to point me in the right direction..Anyone have an LT4 car they wanna trade

[rkreigh]

it's frustrating but don't give up! the bottom end is likely fine so the really expensive fix is likely ruled out. at some point a trip to haibecks is in order. he's really not that far.

he'll fix you right up! I honestly don't think it's valve guides. they wouldn't drink oil like that. I think something is wrong on the crankcase breathing system and you are pushing oil into the pvc system and sucking it into the intake.

try plumbing in a catch can into the pvc and see how much oil dumps in.

good idea anyway, I need to get off my duff and add one.

[Karl]

I added a oil catch can after reading about them on the forum. So far I have less then 500 miles on it.

[Bob G]

call frank u he probably knows whats wrong !