Low BLM after tuning adjustments?...

[HouTX87]

I'll start from the beginning. I installed an extender chip to match my basic translator after a turbo upgrade. For a few weeks everything was fine, blm very close to 128 while cruising and around 133 at idle. Now I've made a few changes and now idle blm is around 116 and sometimes a little lower. Seems to dance around quite a bit while driving from 116 - 133 or so (these numbers are after the changes made below).

Iac was about 40-50 at idle so I made iac and tps adjustments and now iac is about 20 but goes up to around 30 when the fans come on. Tps is .46 at idle in park, .42 key on engine off. How much will iac settings affect blm?

I had set fuel pressure to 45 psi line off per the chip instructions. After a few weeks I checked the fuel pressure and it was down to about 42 psi line off. I thought that was strange so I adjusted it back up to 45 and since then I've noticed it seems to be inconsistent with the line off. Possible bad fuel pressure regulator?

Thanks guys. I don't want to start chasing a ghost. I have an LS1 maf that's only about a year old. Translator settings are on on off off , both knobs set to zero.

 

[we4Mateo]

If the pressure jumps around either: regulator, pump, or fuel filter.

What changes did you make?

 

[HouTX87]

After making the iac, tps, fuel pressure adjustments I didn't immediately notice if the blm had changed. A week later I relocated my vapor canister to the frame and tried running the air filter directly on the maf sensor which caused a bad fan wash problem and is when I first noticed low blm numbers as low as 105 and the engine would buck over 1/4 throttle. I reinstalled my cold air kit thinking this would fix it and blm came back up to 116. Runs fine now but the numbers are still quite a bit lower than what I had just a few weeks ago.

 

[we4Mateo]

Vacuum leak from moving the air canister? A vacuum leak should cause the bl's to go up though from the unmetered air. Hmmm....

 

[we4Mateo]

Back to basics. If fuel pressure is moving around, get that sorted first.

 

[HouTX87]

I think the difference in fuel pressure may have been from initially setting it with the engine cold rather than hot. Maybe that's why I observed a 3 psi drop with the engine hot. I'll check it again with the engine cold and see what I've got. I have an autometer electric fuel pressure gauge on the a-pillar.

 

[we4Mateo]

I think the difference in fuel pressure may have been from initially setting it with the engine cold rather than hot. Maybe that's why I observed a 3 psi drop with the engine hot. I'll check it again with the engine cold and see what I've got. I have an autometer electric fuel pressure gauge on the a-pillar.

So fuel pressure as boost rises is 1:1 and solid?

 

[HouTX87]

So fuel pressure as boost rises is 1:1 and solid?

I will verify again but it was last I checked.

 

[we4Mateo]

I wonder if you got some oil on your MAF from running the filter directly on it? Any MAF issue would cause this.

 

[HouTX87]

I thought about that too. I tried cleaning the maf, no change. I borrowed a spare ls1 maf from a friend so I'll see if that makes any difference. I'm going to double check the fuel pressure and tps adjustment tomorrow.

 

[HouTX87]

I thought I should update this thread. It turned out the fuel pressure was too high. Static fuel pressure was 48psi so I brought it back down to 45psi per extender chip instructions. Idle blms are now back in the 130's. Cruising blm's are in the low 120's. Apparently the fan wash issue was the root cause and I had tweaked the fuel pressure too much before I found that problem. Car is running great at 25psi boost but I made a third gear pull and o2 recall showed 830mv, no knock. Should use the wot knob in the translator to lean it out some?

 

[earlbrown]

I'd get a wideband or do some SERIOUS sparkplug reading/tuning before you start leaning out a WOT/full load mixture.

Internet quarterbacking can do a lot of things, but full load, WOT tuning isn't one of them. (well, it might fly once )

 

[HouTX87]

I'd get a wideband or do some SERIOUS sparkplug reading/tuning before you start leaning out a WOT/full load mixture.

Internet quarterbacking can do a lot of things, but full load, WOT tuning isn't one of them. (well, it might fly once )

Point taken. Sounds like I'm in good shape then without tuning further with a wideband? Just let the extender chip do its thing since it uses the full maf range at wot?

 

[GBGN1]

Wideband x2. Thought you had one already- Cam can weld the bung on the dp for you. Then you can do some real time tuning

 

[we4Mateo]

Point taken. Sounds like I'm in good shape then without tuning further with a wideband? Just let the extender chip do its thing since it uses the full maf range at wot?

I recommend only using a wideband for wot fuel adjustments, but some tuning can be done with the narrowband. 830, if at the top of 3rd after a good and long wot pull, is maybe too fat. Drop 2% off the wot fuel knob in the translator and try again and watch the KR gauge. Repeat until you are closer to 800 or high 700's at the top of 3rd after a long wot pull. You'll at least be closer. The NB is a bugger though. My car is solid at 10.8:1 AFR and my narrowband will report, at the top of 3rd mind you, anywhere from 730-820 on the NB. This is why only so much can be done with it. You are correct in that the extender chip reads airflow at WOT so no fueling changes needed with a boost change, but the AFR still needs to be set with the translator for max but safe performance for the overall wot fuel curve.

 

[HouTX87]

Wideband x2. Thought you had one already- Cam can weld the bung on the dp for you. Then you can do some real time tuning

Hey Brian. Yeah, Ive got an LC-1. Had the bung installed last year. I've gotten sidetracked with so many other things on the car and haven't finished the install. Now that this combo seems to be pretty well squared away it looks like it's time to get the wideband up and running.

I recommend only using a wideband for wot fuel adjustments, but some tuning can be done with the narrowband. 830, if at the top of 3rd after a good and long wot pull, is maybe too fat. Drop 2% off the wot fuel knob in the translator and try again and watch the KR gauge. Repeat until you are closer to 800 or high 700's at the top of 3rd after a long wot pull. You'll at least be closer. The NB is a bugger though. My car is solid at 10.8:1 AFR and my narrowband will report, at the top of 3rd mind you, anywhere from 730-820 on the NB. This is why only so much can be done with it. You are correct in that the extender chip reads airflow at WOT so no fueling changes needed with a boost change, but the AFR still needs to be set with the translator for max but safe performance for the overall wot fuel curve.

That's what I was thinking. Slowly bumping the translator to get the o2's closer to 800, but I'll play it safe and wait until I have the wideband working to see what the AFR looks like. With this chip o2's have been holding around 820-830 at wot. With my old TT 5.7 chip they were more like 790-800.

Thanks guys.

 

[Ttype6]

I made a third gear pull and o2 recall showed 830mv, no knock.

Just to be clear,the .780 number that is the standard number to shoot for needs to be observed at the top of third gear as the car finishes a complete quarter mile run. Going to full throttle,once in third,is not the proper way to check O2 numbers. You must run a complete quarter mile. The reason is that the numbers drop as the sensor gets hotter. If you complete a quarter mile run and turn around,and immediately do another one,the numbers will continue to drop even more. This shows how inadequate the narrow band sensor is at determining WOT air/fuel ratio. When you install a wideband,the number will stay the same throughout the quarter mile run. I you see .780,shortly after going full throttle,you are lean.

 

[we4Mateo]

...If you see .780,shortly after going full throttle,you are lean.

That's possibly true but not necessarily true. You could not make that conclusion based off of a narrowband number alone. I think that's the point of this thread.

 

[Ttype6]

That's possibly true but not necessarily true. You could not make that conclusion based off of a narrowband number alone. I think that's the point of this thread.

The acceptable safe number is.780. If anyone is shooting for this number,it's important to know that it must be observed at the end of a full quarter mile run. Is it deadly accurate? No,it's the acceptable/generally safe number to shoot for. If you're shooting for this number it must be observed at the end of a full quarter mile run.

 

[we4Mateo]

The acceptable safe number is.780. If anyone is shooting for this number,it's important to know that it must be observed at the end of a full quarter mile run. Is it deadly accurate? No,it's the acceptable/generally safe number to shoot for. If you're shooting for this number it must be observed at the end of a full quarter mile run.

I you see .780,shortly after going full throttle,you are lean.

You stated he was lean if he saw 780 shortly after going full throttle. I'm stating that you can not determine that from that data.

No disrespect.