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Discussion Starter · #1 ·
While running the car today got check engine light and found the following stored codes:

P0171 Fuel Trim System Lean bank 1-B
P0174 Fuel Trim System Lean bank 2-B
P1431 Fuel Level Sensor 2 Circuit Performance -C
P1433 Fuel Level Sensor 2 High Voltage -C
P1626 Theft Deterrent System Fuel enable Circuit -C

U1096 Loss of Communications with IPC
U1064 Lose of Communications with DCM

B2282 Battery #1 Fault DCM-LEFT
B2284 Battery #2 Fault DCM-LEFT
U1064 Loss Of Communication with DCM (No SOH Message Received -RFA

B2283 Battery #1 Fault DCM-RIGHT
B2285 Battery #2 Fault DCM-RIGHT

Cleared codes and only the following reoccurred:

P0171 Fuel Trim System Lean bank 1-B
P0174 Fuel Trim System Lean bank 2-B

Any input on what might be going on? No drivability problems. Have Haltech intake and that's it for mods aside from CLB.

Thanks,
Scott
 

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FRC Tom said:
You are sucking air. Check your filter and airbridge connections.
Also, you might want to get a pressurized can or two of Carburetor or Throttle Body and spray it near any vacuum lines and around as much of the area where the intake is mounted to the cylinder heads...this area seems to be a common area to find a leak on the top half of GM's motors.

Let us know what it was if you don't mind...it just might help someone down the road. :thumb:
 

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Discussion Starter · #4 · (Edited)
FRC Tom said:
You are sucking air. Check your filter and airbridge connections.
Thanks for the replies-- I was suspicious of this with the two lean codes that remained after clearing the all of the items.

What do you make of the rest of the stuff? Codes stored from other prior events? Any info on how long the system stores codes for would be most helpful-- bear in mind I'm moving from the very rudimentary (pre-OBD) system in my 87 GN to this.

I did recently have the fuel sending unit/fuel gauge issue with it dropping to E, but that resolved itself and I never saw a check engine.

Again, thanks.
-Scott
 

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more than likely, old codes that never got erased after the problems were fixed. how is your fuel gauge working? the fuel level codes are related to that, i think.
 

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Discussion Starter · #6 ·
Air bridge connections upstream of the MAF seem tight-- I'm going to start looking for other open connections and cracked vac tubes, but thought I'd see if folks had other ideas of good places to look.

After I clear the codes, it will recode again on idle or just light cruising so it must be a pretty decent leak somewhere. But where??

Thanks again,
Scott
 

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Discussion Starter · #7 ·
Problem solved.

Took off intake bridge and found a possible leak source at the plastic elbow connecting the filter to the MAF. Plastic had gotten soft (underhood temps, I suppose) and bowed in somewhat under the band clamp where the tightening bolt is housed. Took it off, gently molded the plastic back into it's original (round) shape, and re-connected band clamp using a bit less torque.

Interesting that a pre-MAF air leak could cause a lean condition-- I was originally focused on an upstream leak. Maybe the lack of diffuser screens in this MAF caused it to get out of whack when a bit of turbulence (from leak) was introduced. Just speculation.

Thanks to all for the tips. :cheers:

Scott
 
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