newbie needing some direction

[huffound]

Swapped LQ-4 with mild cam, stock MAF, long tube headers, LS-6 intake, DW 42# injectors, 4L80E w/2500 stall.

Truck runs reasonably well but I need help with cold starts. The idle is about 300 RPM lower than requested. It slowly after about 90 seconds finally inches up to requested RPM. I have no idea where to begin.

less important is trying to change when the TCC locks up. Currently I have to be going about 52 MPH for it to engage.

Like the title says...I'm definitely a newbie and don't know where to begin.

I'll include my injector data. Can someone tell if I have the correct data in the right places...please

[murfie]

Under fuel oxygen sensors, I would raise the ECT that enables closed loop to 135*.( looked at a stock tune, its 131*, my guess was close). This should help with what it looks like, is it puting a lot of fuel into your cold start idle, for no reason.

Injector data looks fine, the values will change slightly, thats normal, there's a sticky about why it does it.

Friends truck had the stock converter and wanted it to stay locked up for normal driving. This is the TCC table I setup for him, that he liked. Id imagine the same thing would apply for a 2500 stall lock up converter. Make sure you have your tire size calibration set correctly for accurate speedo readings.

4L80 TCC apply-release.PNG

Also if you are going to keep STFT in OL enabled, I would setup your EQ ratio table to go to the 1.15 PE you are commanding at higher MAP values. I would recommend just disabling this since you are not stock any more, and probably not wanting to target stoich all the time.

something like this if you keep it enabled. just so it doesnt mess with your commanded PE after removing all the PE delays/ RPM limits.
OL EQ.PNG

[huffound]

Thanks for the reply.

Murfie; Also if you are going to keep STFT in OL enabled, I would setup your EQ ratio table to go to the 1.15 PE you are commanding at higher MAP values.

Me: I'm not sure exactly what you mean by keeping the STFT in OL enabled or even why that is a good thing or bad thing. I'm not really sure what this means. I definitely don't know how to disable what you are mentioning.

This swap set up is in a '70 C-10 that I use as my daily driver not really into hot rodding it. Just want it reliable, fun to drive and occasionally quickly "up to speed" when getting on the freeway

Any help is appreciated....as I said.... I'm a definite newbie

[murfie]

ITs definitely not a good thing for power or reliability. Fuel mileage if the engine is designed to get away with it, which is not true now wit your mild cam and other mods. Your truck has narrow band oxygen sensors, so they only know three things, rich/lean/ stoich. not how exactly how rich or lean. The vehicle you have the ECU/ motor from normally just ran stoich even at WOT. Your Power enrichment is setup to remove the delays and RPM limits that make it do this, This is good. Under fuel> open loop/ base> open loop you should disable short term fuel trims open loop. If you were stil targeting stoich that would be fine, but you are targeting power enrichment which is slightly richer from stoich, so the fuel trims will fight what you are commanding.

STFT OL.PNG

[huffound]

thanks again. I'll disable and see what happens.

I did change the tire size....after Googling to see where...

I am in the process of changing the TCC stuff now.

I have a '69 Camaro, '72 Blazer and '69 Chevelle i'm needing to restore and plan on swapping to LS based engines.

You think one of tuning school courses are worth the time / money? I'm a 64 yo retired guy that likes old school looks but a few modern touches to keep it interesting. I did add some neat modern touches to the old truck when I repainted it.

I cannot thank you enough for your time and advice. I'm going to load the changes now and give it a go....

[huffound]

Loaded tune. Cold start didn't change at all.

I'm not sure what i'm seeing on the LTFT but seems like it's making some big time adjustments.

Something is really pulling a lot of spark out. I have no idea what or where

startup08212020.hpl

[5FDP]

How complete is your exhaust and what fuel pressure are you running??

Add cylinder airmass and knock retard to your logs as well.

The MAF and VE have fuel pulled away from it too. So it's either an exhaust leak, low fuel pressure or the MAF/VE needing more fuel to stop the lean problem that the o2 sensors are showing.

I wouldn't command stoich either right away on cold start. Setting the whole open loop EQ ratio to 1.00 isn't what I would do. I would have a modified table that is similar to stock that slowly falls down to stoich above 120-130 degree coolant temps. Start off around a 13.0 afr and leans out to stoich at operating temp.

[huffound]

Exhaust is complete to rear axle. I'll have to rig up a gauge for the fuel pressure.

Could it be that my MAF sensor setting are way off?

You completely lost me here. "I wouldn't command stoich either right away on cold start. Setting the whole open loop EQ ratio to 1.00 isn't what I would do. I would have a modified table that is similar to stock that slowly falls down to stoich above 120-130 degree coolant temps. Start off around a 13.0 afr and leans out to stoich at operating temp. I have no clue what you mean.....sorry for being such a DA....

[murfie]

He's talking about the open loop EQ table I posted. It's right above where the STFT in OL enable/disable is.

I like commanding stoich in OL anytime fuel trims could effect it.
Easier to line things up between closed loop and open loop when it finally gets to temp and the trims bring it to stoich any way.

[5FDP]

Someone or you has altered the MAF and VE tables on this truck but I don't know how it has been done. With the changes this engine has doing much of anything without a wideband o2 sensor is pretty hard. Tuning using fuel trims only gets you so far.

When comparing this tune with a stock 6.0 tune, the MAF and VE have lower values in them. Lower values means less fuel and that is may be why the fuel trims are so positive because it's having to add in a ton of extra fuel just to make it happy.

If you click on the open loop EQ ratio table you will see that the table is set to 1.00 for 99% of the cells. If you looked at a stock tune the values would be higher when the engine is cold and it would slope downwards towards 1.00 at operating temp. Engines run better on cold start with more fuel, it's the same thing as a choke on a carb but with fuel injection.


If this was my truck I would copy a stock MAF table and stock VE table back into this tune. Create my own open loop EQ ratio that better suits my needs and start over tuning the MAF/VE with a wideband from here.

[huffound]

I do have the stock tune from when I first read the computer. I'll load that one but I'll input the new injector data.

I did look at the stock EQ table and it's exactly as you say.

Trying to get the truck ready. My daughter is getting married next Saturday and they want to drive the truck away from the wedding.

I appreciate all the help. Most of what you are saying is way over my head but I'm willing to try to learn

[murfie]

Nah I would equate it to a choke, the injectors are behind the throttle, so anytime it's closed they are in a choke. Usually modeled by the increased follow rate at higher vacuums in the injector data.


I would say it's more for fuel not evaporating as fast off cold valves and cylinder walls, so the actual final afr of burnt fuel is less than it should be. I think there's other parts of the calibration that define this as well.