LQ4: bogs off the line like a Quadrajet

[1986MCSS]

Hi Folks. I just got my HP tuners MPVI2 last week, and am learning as I go. The Wideband is not hooked up yet; that is next week's project.
Car is a 1986 Monte Carlo SS with 3.73 gears. Tranny is a 4l80e. Engine a 6.0 with stock bottom end, and a CBM motorsports LS450 cam (220 and 228 duration @50, .581 and .588 lift). Computer is a blue/ green P59 from CBM as well as the harness.
Stock Truck injectors, Stock truck 75?mm DBW TB, corvette fuel regulator set at 58psi,

Anyway, I figured this thing would roast the tires off the line, but it doesn't. It seems to have plenty of power higher in the RPM range though.
I looked at the trans stuff, and didn't see anything limiting torque, however I have no idea what I am doing yet.
I will be taking more logs this week to sort out my cruise control issue. If any of you experts sees something in my file/s that looks obviously wrong, please let me know.

What I looked at:
TB opening goes from 16 to 96%
Injectors are only at 68% in WOT
Spark/ Advance, no red flags
1 instance of knock detected
BR Jerry

[blindsquirrel]

Please add cylinder airmass to your channels list - trying to make sense of the spark advance tables without cylinder airmass in the logs is like trying to plot a course on the Stargate without the 7th symbol...

I never saw MAP go higher than 84kpa - either you're logging the wrong channel (the SAE ones can be goofy sometimes), or you have an air intake restriction somewhere.

Fix your damn power enrichment! It's still stock (i.e. effectively disabled). When it does finally start working it's too lean down low, and too rich up high. For now set the throttle hot enable to like 40%, min torque to 20%, rate to 2.00, delay to 0.00, and EQ to a flat 1.16. You can fine tune it later if you need to, but for now let's just get it operational, ok?

EDIT: Also since the rest of the engine TM is mostly disabled, it looks like you forgot the max torque vs RPM table. That can be set to max to turn it off.

[1986MCSS]

Please add cylinder airmass to your channels list - trying to make sense of the spark advance tables without cylinder airmass in the logs is like trying to plot a course on the Stargate without the 7th symbol...

I never saw MAP go higher than 84kpa - either you're logging the wrong channel (the SAE ones can be goofy sometimes), or you have an air intake restriction somewhere.

Fix your damn power enrichment! It's still stock (i.e. effectively disabled). When it does finally start working it's too lean down low, and too rich up high. For now set the throttle hot enable to like 40%, min torque to 20%, rate to 2.00, delay to 0.00, and EQ to a flat 1.16. You can fine tune it later if you need to, but for now let's just get it operational, ok?

EDIT: Also since the rest of the engine TM is mostly disabled, it looks like you forgot the max torque vs RPM table. That can be set to max to turn it off.

Thank you sir. I am taking some logs with those changes. BR Jerry

[1986MCSS]

Posted a couple more. It does have better response now. Removed the cone air filter temporarily, didn't seem to make much difference. Added Cylinder Airmass

PEEQ updatesTableto1.16.JPGmontesnorkel.jpg

[5FDP]

Make sure fuel pressure isn't dropping, the o2 sensors are going lean at higher rpm.

The hot/cold throttle enable I would do 60% and not 40%. Then raise the MAP kpa enable up to 85% instead. I find this works way better. But it's your car and find what works for you.

You can also set all cells of the ETC TPS MAX in the torque mngt tab to 100%, it should make the throttle more responsive.

COT needs to be disable too.

[1986MCSS]

Make sure fuel pressure isn't dropping, the o2 sensors are going lean at higher rpm.

The hot/cold throttle enable I would do 60% and not 40%. Then raise the MAP kpa enable up to 85% instead. I find this works way better. But it's your car and find what works for you.

You can also set all cells of the ETC TPS MAX in the torque mngt tab to 100%, it should make the throttle more responsive.

COT needs to be disable too.

Thanks Guys! The Car is alot more fun to drive now. Like you mentioned, O2 sensor voltage seems to be going lean after 4400 RPM, even though the ECM is commanding more fuel. I strapped my Gopro to the fuel rail gauge, and it shows about 62 psi normally, and dips to 56 on WOT if I stay in it a couple seconds.

I have a Walbro 255LPH in Tank FP. I planned to upgrade to the 450 when I install the LSA Supercharger , maybe I should upgrade sooner than later...LSA.jpg

[5FDP]

I wouldn't be that worried about the fuel pressure drop if it's only 6psi like that. The fuel pressure if right around 55-60 is more than fine, you'd just need to be concerned if it was 60psi and dropped 10-15psi or more.

The MAF/VE need a little still. The engine is lean at idle and part throttle with the fuel trims having to add in 10-15% and it's going a little lean in the upper rpm as you can see the o2 sensors slowly fall. Once a wideband is all hooked up it will be easier to tell.

[blindsquirrel]

Holy cow, that thing is a dog. My bone stock other than tune 5.3 makes 390 lb-ft at peak (3800-4000 RPM) with 5* less spark. Your cylinder airmass takes a nosedive as RPM goes up. MAP is still flatlining at only 85 KPA at WOT. Something is bad wrong here.

[1986MCSS]

I forgot to mention that I am in Reno. We are at 4500 ft. My MAP sensor is the LS1 1bar 16212460. I figured that may be why the reading is 84kPA with Key on , engine off

[blindsquirrel]

Current baro where you are per https://forecast.weather.gov/MapClic...lon=-119.81380
is 1024.72mb (102.4 KPA). Here in MS it's currently 1017.2mb (https://forecast.weather.gov/MapClic...&lon=-88.74778). 84-85 KPA is not correct for your location according to NWS.

Your LQ4 with a big cam and whatever other goodies is 60lb-ft and 140HP down on my stock cammed, stock air intake pipe, stock air filter, stock iron manifolds, stock catalysts, stock single exhaust and stock muffler 5.3L LH6. In your last posted log I'm seeing a torque peak of 326 at only 3300, which is very low engine speed for a bigger cam. And only 236 HP at 4100. My stock 5.3 with a 190-whatever degree cam has tq peak at 3800-3900 and HP peak at 5800. Your cylinder airmass is in line with what it should be at peak tq for that power level, but it should not drop off like that as engine speed increases.

I don't think this is tune-related. You've got a rubber coupler going flappy and sucking closed in the air intake somewhere, or the intake manifold stuffed full of rags, something major going on. Or cam installed a tooth out of time.

[Jeff7577]

I forgot to mention that I am in Reno. We are at 4500 ft. My MAP sensor is the LS1 1bar 16212460. I figured that may be why the reading is 84kPA with Key on , engine off

This needs to be fixed. KOEO should read actual barometric pressure because if it isn't fueling calculations are going to be incorrect. Did you change the MAP characteristics to match the different sensor?

[SSUte01]

84kPa is what you would expect at 4500ft altitude. Weather services correct the pressure to equivalent at sea level for comparison purposes. As to whether there's another issue, I didn't review the log or tune