Left bank Lean Question - CuperCharger
Thread Starter
Joined: Oct 2000
Posts: 7,936
From: Puyallup WA
Left bank Lean Question - SuperCharger
Hello all,
I was just thinking about something that happened to me a few months ago, when I first got my SC, and thought I'd ask. I have a Vortech FMU. It's an adjustable FMU, and does not use discs to adjust, but just a screw and a bleeder valve.
The week after I installed my SC, I tuned it on a Dyno with a wideband O2 meter, as Loren suggested.
I tuned it to 12.5:1 across the band, with the MEVI.
However, about a week later, I started getting "left bank lean" codes, and to be safe, richened the mixture up. Haven't gotten a code since, but I'm slower.
Now I'm going to be Dynoing again tomorrow, and re-adjusting.
My question is this:
If my A/F is correct on the meter, then why would I get Left Bank Lean codes? Does that mean my injectors and/or T-Rex fuel pump aren't doing the job or something?
I wish I had an EGT Gauge. That might make this easier to understand right away.
Any ideas?
<Heh...I said "CuperCharger"...and now I can't change it!>
Thanks,
IanS
I was just thinking about something that happened to me a few months ago, when I first got my SC, and thought I'd ask. I have a Vortech FMU. It's an adjustable FMU, and does not use discs to adjust, but just a screw and a bleeder valve.
The week after I installed my SC, I tuned it on a Dyno with a wideband O2 meter, as Loren suggested.
I tuned it to 12.5:1 across the band, with the MEVI.
However, about a week later, I started getting "left bank lean" codes, and to be safe, richened the mixture up. Haven't gotten a code since, but I'm slower.
Now I'm going to be Dynoing again tomorrow, and re-adjusting.
My question is this:
If my A/F is correct on the meter, then why would I get Left Bank Lean codes? Does that mean my injectors and/or T-Rex fuel pump aren't doing the job or something?
I wish I had an EGT Gauge. That might make this easier to understand right away.
Any ideas?
<Heh...I said "CuperCharger"...and now I can't change it!>

Thanks,
IanS
Thread Starter
Joined: Oct 2000
Posts: 7,936
From: Puyallup WA
Originally posted by mtrai760
Are you still getting that code?
Are you still getting that code?
It only came up once by itself. Every other time I had to pull it.
I'll be doing some work this weekend, so I'll pull it then.
IanS
Re: Left bank Lean Question - SuperCharger
I throw a left bank lean code every couple of weeks. I'm on the 3.33 pulley and 8:1 disk. I think you're throwing the code because when you tuned it on the dyno, you only made a few pulls and everything is controlled. But on the street, the conditions are different and always changing. Temp, the way you drive, etc. Since just about every SC owner throws that code once in a while, I wouldn't worry too much.
Originally posted by iansw
Hello all,
I was just thinking about something that happened to me a few months ago, when I first got my SC, and thought I'd ask. I have a Vortech FMU. It's an adjustable FMU, and does not use discs to adjust, but just a screw and a bleeder valve.
The week after I installed my SC, I tuned it on a Dyno with a wideband O2 meter, as Loren suggested.
I tuned it to 12.5:1 across the band, with the MEVI.
However, about a week later, I started getting "left bank lean" codes, and to be safe, richened the mixture up. Haven't gotten a code since, but I'm slower.
Now I'm going to be Dynoing again tomorrow, and re-adjusting.
My question is this:
If my A/F is correct on the meter, then why would I get Left Bank Lean codes? Does that mean my injectors and/or T-Rex fuel pump aren't doing the job or something?
I wish I had an EGT Gauge. That might make this easier to understand right away.
Any ideas?
<Heh...I said "CuperCharger"...and now I can't change it!>
Thanks,
IanS
Hello all,
I was just thinking about something that happened to me a few months ago, when I first got my SC, and thought I'd ask. I have a Vortech FMU. It's an adjustable FMU, and does not use discs to adjust, but just a screw and a bleeder valve.
The week after I installed my SC, I tuned it on a Dyno with a wideband O2 meter, as Loren suggested.
I tuned it to 12.5:1 across the band, with the MEVI.
However, about a week later, I started getting "left bank lean" codes, and to be safe, richened the mixture up. Haven't gotten a code since, but I'm slower.
Now I'm going to be Dynoing again tomorrow, and re-adjusting.
My question is this:
If my A/F is correct on the meter, then why would I get Left Bank Lean codes? Does that mean my injectors and/or T-Rex fuel pump aren't doing the job or something?
I wish I had an EGT Gauge. That might make this easier to understand right away.
Any ideas?
<Heh...I said "CuperCharger"...and now I can't change it!>

Thanks,
IanS
I wonder if the left bank gets less fuel pressue from being on the far side of the fuel rail? ie.. the firewall side? Maybe the front 3 cylinders are getting more fuel(per pulse) then the rear side?
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