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Feb 6, 2003 | 05:02 PM

VetBoy89

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Burning Brakes

Joined: Apr 2002

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From: Patterson CA

BLM question

My BLM count is 156 at idle, engine at op. temp, trans in park, a/c off.

This means I'm running rich right? On my Autoxray scanner the rich/lean flag is bouncing back and forth from Rich to Lean instantly and constantly.

All other scanned info looks ok. My plugs look fine and the exhaust doesn't smell too bad. Is this something to worry about, and if so how do I get it down? 128 is the normal number right? My O2 sensor is about 8 months / 24,000 miles old.

TIA

Feb 6, 2003 | 05:26 PM

Aaron's 87

Melting Slicks

Joined: May 1999

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From: Sarasota FL

Re: BLM question (VetBoy89)

156 is lean. Could be bad injectors, O2, exhaust leak, among others. Rich/lean is supposed to bounce back and forth. I would try to find out what's wrong, I think the upper BLM limit is 160.

Feb 6, 2003 | 05:30 PM

VetBoy89

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Burning Brakes

Joined: Apr 2002

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From: Patterson CA

Re: BLM question (Aaron's 87)

Quote:

156 is lean. Could be bad injectors, O2, exhaust leak, among others. Rich/lean is supposed to bounce back and forth. I would try to find out what's wrong, I think the upper BLM limit is 160.

DOH, now that you mention it...I do have an exhaust leak, it's where the front y-pipe connects to the pass. side exhaust manifold, but I've tried a bunch of ways to fix it and it always leaks...Any ideas?

Well guess I'm just gonna have to get headers :jester

Feb 6, 2003 | 06:12 PM

VetBoy89

Thread Starter

Burning Brakes

Joined: Apr 2002

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From: Patterson CA

Re: BLM question (VetBoy89)

Thanks for the clarification on running lean not rich. Would this be why my fuel mileage went from 20mpg to 16mpg average?

Also, what harm am I causing by continuing to run like this?

Feb 6, 2003 | 06:56 PM

ittlfly

Safety Car

Joined: Feb 2002

Posts: 4,212

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From: Sun City West Az

Re: BLM question (VetBoy89)

BLM of 156 is lean... (are they both at 156?) Should only be one side as that's where the leak is. The ECM is adding fuel to compensate so there goes your milage. Are the intergrator(s) around 128? If it / they are up high (on the same side) then your system is approaching the "not in control" mode and will set a code. You are going to have to deal with it one way or the other.

Feb 7, 2003 | 11:22 AM

VetBoy89

Thread Starter

Burning Brakes

Joined: Apr 2002

Posts: 755

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From: Patterson CA

Re: BLM question (ittlfly)

Quote:

Thanks for the info. Excuse my ignorance, but how can I check both sides? I am using an AutoXray connected to the ALDL and it just shows one listing for BL and it is ranging between 150-156 at idle. The integrator only has only listing also and it is at 128.

And actually I think both sides are leaking, although the pass. side is worse and the drivers side is barely noticeable. The way I know they are leaking is that when it is real cold outside and I start it with the hood open I get exhaust steam venting up.

Has anybody ever installed gaskets between the EM and the front y-pipe? If so, where did you get them and what kind? I’ve tried adjusting them to make them mate up better but to no avail.

Thanks guys. ;)

Feb 7, 2003 | 11:46 AM

ZylaRace

Drifting

Joined: Mar 1999

Posts: 1,931

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From: Norcross GA

Re: BLM question (VetBoy89)

Some engines (LT1) have an O2 sensor on both sides of the engine rather than just one (most L98's). You should only have the one.

Feb 7, 2003 | 01:31 PM

ittlfly

Safety Car

Joined: Feb 2002

Posts: 4,212

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From: Sun City West Az

Re: BLM question (ZylaRace)

My bad...I should have checked on the year of your car. You have only 1 O2 sensor and that explains why you have only 1 reading from the BLM and intergrator. If you can find a way to seal those leaks, your problem should disappear. :D