LS1 243 heads, fast 102, holley 102 tb, 42lb injectors, SD Tune

Good Evening folks. I'm a somewhat inexperienced tuner, 95% of what I tune are cam swapped stuff here in my shop and personal stuff. I do LS swaps and most of my customers just want stock engines with a cam that sounds good.
With that being said, I had a friend drop of a car with a redone engine. The car is running a Speed Density OS and looks to have the 02 Sensors turned off along with LTFT. It does have a wideband.

2002 F-body with LS1 Car was cammed and Speed Density tuned by another tuner at one point for the initial cam swap. BTR N/A stage 3 cam.
New Parts with engine rebuild
243 heads ported by Wilkes Performance
Fast 102 with Holley 102 TB (I changed the ETC scalar from .0255 stock to .01875 per calculation)
42lb btr injectors (I changed the injector data in the existing tune)
104 lid
Car has full length headers and exhaust also.

I added 4 g/s on 12084 Idle Airflow table to everything >46 degrees.

Car ran and drove a couple seasons on the tune that is attached, minus a couple changes I made to try and get it fired up.

The car is running a Speed Density OS and looks to have the 02 Sensors turned off. I have done one SD tune on my 02 turbo camaro, so I'm new to SD stuff.

For the life of me, I can't get it to fire for more than a split second.

I went thru The Tuning Schools Heads/Cam process tree to no avail. I've been thru countless videos and threads the past 2 days, with no luck. I could use some guidance.

There is one thing, that I have not done, that I normally would. TTS taught us to not use someone else's tune, to grab a tune from their repository and start fresh.

Thanks for the help and guidance Gents. And if I'm an idiot, I'll will take my licks along with some learning.

MAP sensor not working, it's stuck at 52kPa the whole log. Verify your pinouts.

I'll check it out. Thank you, BlindSquirrel

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Originally Posted by blindsquirrel

MAP sensor not working, it's stuck at 52kPa the whole log. Verify your pinouts.

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So I called the customer. I thought I'd check to see if the intake was new or not. The FAST intakes have to be drilled for the MAP sensor. He said it was used and came off of a running vehicle. He accidentally told me it came off of a supercharged rig and has a 3 bar map on it. So I assume that is the issue. I'm going to change it over to a 3 bar SD tune and go from there.

You need to know exactly what 3 bar map so you can setup the linear and offset properly.

And FYI if it's stuck at 52 Kpa it's most likely a 2 bar map.

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Originally Posted by edcmat-l1

You need to know exactly what 3 bar map so you can setup the linear and offset properly.

And FYI if it's stuck at 52 Kpa it's most likely a 2 bar map.

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Yeah, I hadn't done a map since i did a 3 bar on my turbo camaro. Thanks for the reminder Sir.

You don't need the 3 bar OS, just put in the correct linear/offset.

Got the map sensor changed out to a stock LS1 Map sensor, runs now. I have not started on the tune yet, just got it running. The problem I'm having now, is at 192 degrees ECT, the car idle shoots up to 1800+ rpm. I'm not finding any correlation in the tune, when it happens the IAC count sky rockets. I know that VE is pulling alot of fuel when it idles up. But, it's pulling fuel when it idles normally as well. Any thoughts. I appreciate the help Gents.

sometimes it is easier to load in a stock LS1 tune file, and start fresh.
Especially if you are tuning an already bad tune.

It's not idling, ever. The TPS % is over 1% which means it thinks it's off idle and at some point the adder tables kick in. Need to adjust your TPS and/or throttle blade so it idles at .5 volts, then you need to do a TPS reset which will zero the TPS % at idle.

You can go as high as .65V on the closed tps voltage and it will still reset to 0% and not set tps codes. That gives it a little extra air around the closed blade for a cam and not have to drill the hole bigger. Although some of those aftermarket throttle bodies can be difficult to dial in. Not sure about the Holley.

You can get a successful TPS reset way up into the .7v range.

Usually when you see the TPS % get stuck high its because the throttle cable is sticky. Or there are some aftermarket throttle bodies that do not engage the TPS sensor tightly. I've fixed a bunch of these by putting a wrap or two of electrical tape on the shaft that drives the TPS.

Lastly it could be a sloppy throttle body.

When you see the TPS % stuck higher it means that at some point the TPS voltage was lower. It's storing the lowest voltage and calling that 0%

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Originally Posted by Alvin

You can get a successful TPS reset way up into the .7v range.

Usually when you see the TPS % get stuck high its because the throttle cable is sticky. Or there are some aftermarket throttle bodies that do not engage the TPS sensor tightly. I've fixed a bunch of these by putting a wrap or two of electrical tape on the shaft that drives the TPS.

Lastly it could be a sloppy throttle body.

When you see the TPS % stuck higher it means that at some point the TPS voltage was lower. It's storing the lowest voltage and calling that 0%

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And I have had many set P0121 codes at .7V and higher but if you want to say I'm wrong about .05V, go right ahead Geez. I have never had a problem stopping at .65V

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Originally Posted by 2xLS1

And I have had many set P0121 codes at .7V and higher but if you want to say I'm wrong about .05V, go right ahead Geez. I have never had a problem stopping at .65V

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I'm not trying to offend you. Just sharing personal/professional experience.

The PCM not returning to 0% shouldn't have anything to do with it being at 0.7+. Its more that it hasn't returned to the stored low voltage point.

Some aftermarket throttle bodies are built so sloppy that the TPS voltage will move between key on engine off to idle. Like the vacuum on the blade is moving the stop position


If the throttle body is sloppy or you can't get it to return to the same low v that it stored you can increase ECM 2600 as a bandaid fix. Going to far with it will give you a hesitation off 0%.

Biggest problem with setting them any higher than about .6 is setting the TPS zero with key on engine off, then when you start the engine the added voltage from the charging system bumps the voltage a few tenths and can cause them to read .4 or .5% which is right on the verge of off idle.

I've seen them work correctly as high as .7, and I've had issues with them at roughly .6-.7. My preference is to shoot for .5 so there is no problem. You have plenty of head room.

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Originally Posted by Alvin

Just sharing personal/professional experience.

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Yea, so was I.