narrow-band A/F gauge is reading VERY lean after a series of mods/engine-bay cleaning
03-23-06, 11:30 PM
#1
narrow-band A/F gauge is reading VERY lean after a series of mods/engine-bay cleaning
Anyways, the car in question is an 87.5 Turbo II. The important mods are:
~RA apex-seal rebuild w. 15k miles
~9:4:1 N/A rotors
~street-porting
~stock turbo w. ported WG
~full exhaust
~R-tek 1.7 chip
~Greddy Profec-B EBC
~Marren 750cc secondaries
~Walbro 255LPH fuel-pump
~etc.
Anyways, I just went through an extensive tear-down/engine bay cleanup that included the removal of the:
~A/C
~OMP setup
~FULL emissions removal/TB stripping
~installment of 2751 Engineering block-off plates
~redoing the engine-bay grounds
~redoing the fuel-lines
~replacing the fuel-injector O-rings
~replacing two broken wiring harness fuel-injector 'clips' (one primary, one secondary)
~replacing all of the leftover vac. lines
~replacing the stock turbo (with another stocker)
~installing a Thunderfab 80mm DP/MP in place of a 2.5" Bonez setup
Anyways, before I began the project the car drove and idled perfectly and my narrow-band Autometer A/F gauge would read a consistent 'STOICH' at idle and as the accelerator was pushed toward WOT, the reading would move into the 'RICH' area and stay their until redline at 7k RPM's.
Now, there's no need to debate the poor tuning ability of the narrow-band A/F gauges, but as a basic indicator, it did a wonderful job.
Since completing the project today and getting everything buttoned down completely, my idle has remained solid, my vac. pressure at idle has gotten better and overall the car is running wonderfully.
EXCEPT, I noticed that the A/F gauge is reading so lean that the red glowing "indicator dashes" are nearly invisible in daylight and *barely* visible at night. This is at idle, low throttle, WOT, past the secondary injectors kicking in--EVERYTHING. It just reads a faint and 'wavering' LEAN...
I'm worried, but I frankly don't understand. There are no vac. leaks, hence the wonderful vac. pressure at idle, no hesitations, it starts wonderfully with a solid idle etc... It's like, nothing is wrong AT ALL except for this worrisome gauge reading.
Now, I did have the O2 sesonor out for a couple days (wrapped gently in a plastic baggie) while the new DP/MP setup was waiting to be installed AND the wiring for the A/F gauge's "splice point" into the 'O2 sensor wire' is pretty hokey, but it's always worked unfailingly before these modifications...
Anyone have any suggestions where to start? BTW, earlier today I assumed it just wasn't working (because I couldn't see the faint LEAN indicator dashes) so I just ignored it and proceeded to tune my Profec-B to 11psi max. boost.
I've gone through the full 1st to 2nd gear powerband and most of 3rd with no hesitations, no strange noises and a solid pull to redline... Hmmm... Why would it be running lean (if at all)?
BTW, I'm posting this in the 2nd gen. section as well.
~RA apex-seal rebuild w. 15k miles
~9:4:1 N/A rotors
~street-porting
~stock turbo w. ported WG
~full exhaust
~R-tek 1.7 chip
~Greddy Profec-B EBC
~Marren 750cc secondaries
~Walbro 255LPH fuel-pump
~etc.
Anyways, I just went through an extensive tear-down/engine bay cleanup that included the removal of the:
~A/C
~OMP setup
~FULL emissions removal/TB stripping
~installment of 2751 Engineering block-off plates
~redoing the engine-bay grounds
~redoing the fuel-lines
~replacing the fuel-injector O-rings
~replacing two broken wiring harness fuel-injector 'clips' (one primary, one secondary)
~replacing all of the leftover vac. lines
~replacing the stock turbo (with another stocker)
~installing a Thunderfab 80mm DP/MP in place of a 2.5" Bonez setup
Anyways, before I began the project the car drove and idled perfectly and my narrow-band Autometer A/F gauge would read a consistent 'STOICH' at idle and as the accelerator was pushed toward WOT, the reading would move into the 'RICH' area and stay their until redline at 7k RPM's.
Now, there's no need to debate the poor tuning ability of the narrow-band A/F gauges, but as a basic indicator, it did a wonderful job.
Since completing the project today and getting everything buttoned down completely, my idle has remained solid, my vac. pressure at idle has gotten better and overall the car is running wonderfully.
EXCEPT, I noticed that the A/F gauge is reading so lean that the red glowing "indicator dashes" are nearly invisible in daylight and *barely* visible at night. This is at idle, low throttle, WOT, past the secondary injectors kicking in--EVERYTHING. It just reads a faint and 'wavering' LEAN...
I'm worried, but I frankly don't understand. There are no vac. leaks, hence the wonderful vac. pressure at idle, no hesitations, it starts wonderfully with a solid idle etc... It's like, nothing is wrong AT ALL except for this worrisome gauge reading.
Now, I did have the O2 sesonor out for a couple days (wrapped gently in a plastic baggie) while the new DP/MP setup was waiting to be installed AND the wiring for the A/F gauge's "splice point" into the 'O2 sensor wire' is pretty hokey, but it's always worked unfailingly before these modifications...
Anyone have any suggestions where to start? BTW, earlier today I assumed it just wasn't working (because I couldn't see the faint LEAN indicator dashes) so I just ignored it and proceeded to tune my Profec-B to 11psi max. boost.
I've gone through the full 1st to 2nd gear powerband and most of 3rd with no hesitations, no strange noises and a solid pull to redline... Hmmm... Why would it be running lean (if at all)?
BTW, I'm posting this in the 2nd gen. section as well.
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