Running olsd with Maf

[2000Phoenix]

Hello, I have a better grasp on tuning and got the car set up for olsd on a 2000 ls1 fbody p01 upgraded to a 02 operating system with stock injectors mild cam and 1 7/8 headers . Issue I'm having is the Florida temp swing has me chasing my wide band as it goes from 69-98 degrees daily. Iat relocated in the bumper and temps come done pretty quick and go up by 10 degrees sitting in traffic. I am wanting to run open loop with maf so the close loop can handle the temp swings at low throttle driving and then PE can come in when I command it at wot. Im not sure what all needs to be changed to do this as I read people mentioning the best way to run olsd and fix the lean rich issue with the iat weather swings but i could not find the steps anywhere.

[2xLS1]

Hello, I have a better grasp on tuning and got the car set up for olsd on a 2000 ls1 fbody p01 upgraded to a 02 operating system with stock injectors mild cam and 1 7/8 headers . Issue I'm having is the Florida temp swing has me chasing my wide band as it goes from 69-98 degrees daily. Iat relocated in the bumper and temps come done pretty quick and go up by 10 degrees sitting in traffic. I am wanting to run open loop with maf so the close loop can handle the temp swings at low throttle driving and then PE can come in when I command it at wot. Im not sure what all needs to be changed to do this as I read people mentioning the best way to run olsd and fix the lean rich issue with the iat weather swings but i could not find the steps anywhere.

That in bold makes no sense. I think you need to study up on the different terminologies and what they mean.

[2000Phoenix]

Sorry let me try saying it a different way can I use speed density with the maf sensor?

[2xLS1]

No Speed Density is running with no input from a MAF sensor. If you want to know if you can use a MAF with a custom SD OS then yes but it is not running Speed Density mode then with the MAF not failed. You can run 100% off the MAF or a blended VE + MAF depending on what RPM you set the High RPM Disable at with either a stock OS or a SD Custom OS. Even with a SD OS you still have to fail the MAF for it to be running in SD. Then there is OL and CL. OL is running with no feedback from O2 sensors, CL is running with feedback from O2 sensors. You can combine either of those with the other modes I described.

[2000Phoenix]

Thank you for clarifying, and sorry for the confusion so i I can stay in sd 1bar and just adjust the rpm and enable ltft or stft? Also is there anything else I need to do like changing dfco. I know I need to put the maf values back in just want to make sure I’m doing this right to blend as you stated between using the maf blended ve at a certain rpm until I hit pe? I will set it to 4K rpm for part throttle is my plan then use wideband for wot. Hoping it fixes the afr temp swing.

[Fast4.7]

I would move the IAT to a position just ahead of the throttle body. On my L31 with a marine intake and a Bosch T-Map I ran with the IAT in the MAP making it a MAT. Keeping the IAT as close to the engine as possible helps steady the fueling. In stop and go at lose speeds your manifold air temps are alot higher than 10?F difference.

[2000Phoenix]

Yes they are swinging like night and day. I am not boosted and only seen the iat in the intake on boosted cars. Do you think it will be ok running N/a? Also i for some reason my scanner is showing zero in all the maf, lftf, stft scans. i have tried re polling, ltft enabled, stft disabled, and temp are at normal settings for general fuel tab. Codes are on for error on second for maf. I also checked the math on the scanner and everything for the fuel trims are good. No pink showing. I can't add the attachement for some reason. Scanner and editor up to date. Am i missing something? Thank again for your help on this.

[CaudleDynamicsLLC]

Also second the motion to have the IAT sensor in your actual air intake tract. I see that as a must more than a should or aught to. This is to get accurate fueling calculations (air density is very dependent on temp) and to correctly control the ignition timing, since if you optimize the timing for best power on pump gas you will probably be on the edge of knock and DO want high IATs to pull a bit of timing (which you can determine how much/at what temps is appropriate for your application through careful datalogging).

[2000Phoenix]

Also second the motion to have the IAT sensor in your actual air intake tract. I see that as a must more than a should or aught to. This is to get accurate fueling calculations (air density is very dependent on temp) and to correctly control the ignition timing, since if you optimize the timing for best power on pump gas you will probably be on the edge of knock and DO want high IATs to pull a bit of timing (which you can determine how much/at what temps is appropriate for your application through careful datalogging).

Thanks for the clarification as I have only seen it done on boosted cars. Going to mock up a coupler tube to put it right in front of the tb this weekend. Still trying to figure out why all the fuel trims in the scanner readying zero.


I am not sure why but i cannot get my maf, ltft, stft will not show in the scanner and they are showing zero's. Re poll re sync done and DTC's, Ltft are turned on. PE is not at zero or anything and Stft are off. I don't know if i need to remove the wb or if there is something im missing. Math parameter shows volumetric and air temp missing in pink. Im sure this is something simple. Could some one tell me what im missing?

Thank you for your time.

[CaudleDynamicsLLC]

In that log, the fuel system status channel is reporting OL - not ready, meaning it never went into closed loop, and thus the STFT and LTFT would not be updating.

[2000Phoenix]

In that log, the fuel system status channel is reporting OL - not ready, meaning it never went into closed loop, and thus the STFT and LTFT would not be updating.

Could you advise what factor I am missing that is causing this?

[CaudleDynamicsLLC]

... on tuning and got the car set up for olsd on a 2000 ls1 fbody...

I thought it was purposely set up for Open Loop.

May be best to start back with a factory stock tune file for that vehicle (or the 02 OS vehicle) and make sure it functions correctly - goes into CL.

[Fast4.7]

You need to put your IAT just ahead of the throttle body, then start over with the factory closed loop settings to re-enable fuel trims. I prefer to disable long term fuel trims when I am tuning and tune strictly off short terms. I disable PE until 99% TPS. Disable the canister purge and EGR. Then I fail the MAF and run in speed density while adjusting the VE tables. Copy the high octane spark table to the low octane map while tuning the VEs as the PCM will run off the low octane map with a failed MAF. Once you get your VE table between 0 and -5% it is about as good as it will get. Re-enable the MAF and adjust dynamic blend from 4,000 rpm down to 400 rpm. Copy back in the low octane spark table. Now you are ready to work on the MAF table. Get it to where the fuel trims run between 0 and -5%. One both VE and MAF tables are tuned you can re-enable the dynamic blend. My IAT varies from ~20F to 170F with nearly no swing in fuel trims. Once I am done with the fuel tables I turn long term fuel trims back on.

[2000Phoenix]

It was purposely put in to ol at first but now I want to enable the maf to blend a mix of the ve/maf hoping it fixes the afr swing at part throttle due to iat temp swing. Now I can’t get it to go in to closed loop. @fast4.7 iat has been moved in front of tb. I am thinking it is not a tuning issue but mechanical. I took a step back and check all the scans again noticed my 02 sensors will stay at .450 and think they are not letting the car go into close loop. Anyone ever encounter this?. Going to change them to see if that fixes the issue. @caudledynamicsllc like 2xls1 stated I should be able to use any of the custom os and blend it to use the ve/maf. Sd ol was working fine in scanner until I tried re enable close looped. I will confirm after change front 02 sensors. If anyone else has any idea what else could cause the car not to go Into closed loop would be helpful. Thanks

[2000Phoenix]

You need to put your IAT just ahead of the throttle body, then start over with the factory closed loop settings to re-enable fuel trims. I prefer to disable long term fuel trims when I am tuning and tune strictly off short terms. I disable PE until 99% TPS. Disable the canister purge and EGR. Then I fail the MAF and run in speed density while adjusting the VE tables. Copy the high octane spark table to the low octane map while tuning the VEs as the PCM will run off the low octane map with a failed MAF. Once you get your VE table between 0 and -5% it is about as good as it will get. Re-enable the MAF and adjust dynamic blend from 4,000 rpm down to 400 rpm. Copy back in the low octane spark table. Now you are ready to work on the MAF table. Get it to where the fuel trims run between 0 and -5%. One both VE and MAF tables are tuned you can re-enable the dynamic blend. My IAT varies from ~20F to 170F with nearly no swing in fuel trims. Once I am done with the fuel tables I turn long term fuel trims back on.

I will try this before putting in the new oxygen sensors to see if the ltft start scanning. Thank you again

[Fast4.7]

I will try this before putting in the new oxygen sensors to see if the ltft start scanning. Thank you again

My guess is it is tune related, not 02 sensors.

[2000Phoenix]

You need to put your IAT just ahead of the throttle body, then start over with the factory closed loop settings to re-enable fuel trims. I prefer to disable long term fuel trims when I am tuning and tune strictly off short terms. I disable PE until 99% TPS. Disable the canister purge and EGR. Then I fail the MAF and run in speed density while adjusting the VE tables. Copy the high octane spark table to the low octane map while tuning the VEs as the PCM will run off the low octane map with a failed MAF. Once you get your VE table between 0 and -5% it is about as good as it will get. Re-enable the MAF and adjust dynamic blend from 4,000 rpm down to 400 rpm. Copy back in the low octane spark table. Now you are ready to work on the MAF table. Get it to where the fuel trims run between 0 and -5%. One both VE and MAF tables are tuned you can re-enable the dynamic blend. My IAT varies from ~20F to 170F with nearly no swing in fuel trims. Once I am done with the fuel tables I turn long term fuel trims back on.

I thought your instructions were all for the tune but I could not find the Disable the canister purge and EGR anywhere. I have it already removed Egr and pump from my the vehicle. Also where is the dynamic blend? Are referring to the high rpm disable? Also os upgraded so no low ve table.

[2000Phoenix]

So it is normal for the 02 sensors to sit at .450 in the scanner? I thought they suppose to fluctuate a little depending on the rpm?

[5FDP]

.450mv means they are unplugged or have a power/ground issue in the fuse block/harness somewhere.

[2000Phoenix]

.450mv means they are unplugged or have a power/ground issue in the fuse block/harness somewhere.

Thanks for clarifying. Going to get her in the air tomorrow ti see if they are bad or the headers burnt the wire due to something coming loose.