98 L29 BBC 496 stroker P0101 after new heads

[MTcamaroguy]

After building engine with stock heads compression was too high and ran out of air @ 4,000 RPM. Installed Edelbrock Performer RPM Cylinder Heads 60455 and got the compression down to 11.4:1. Now have some RPM (about 4,700) but setting a P0101 at upper RPMs and also has an odd stumble\miss under light loads 55mph and 10% throttle. I have removed some fuel at lower RPM\lads since changing heads but lower RPM ranges is still removing fuel (LTFTs around -7) higher RPM and loads are near 0.

I cannot find an intake leak and believe I'm puling more air for any given load\rpm and that is causing the P0101.

Is tuning the MAF my best option. I have a wide band O2 (AutoMeter Sport-Comp Digital Gauges 3379) but it is not installed yet and I have not yet purchased the Pro-link. Before doing either I want to confirm I am gong down the right path.

EDL Post Block v3 New O2 v5 Dist Timed MAF no changes P0101 v2.hpl97 K3500 87oct EDL v3 revert Fuel Removal 0TDC.hpt

[SiriusC1024]

Engine Diag>Airflow>Maximum Delta Airflow. Increase values by 30% and see how that works.

Yes you're on the right path. Of course airflow will need tuned. MAF may need a little work, but that VE table is so bad right now.

[MTcamaroguy]

Stock VE.PNG
Returning VE table to stock hoping that fixes my drivability problem.
Changing the limits on the P0101 should help prevent the fault from setting but will it do anything for my drivability?

I have 2 other Vortec trucks that I compared the MAF tables to. One is a 383 stroker, the other a stock 454 BB. Mine and both of the others are identical.

I should have mentioned earlier but engine also has a 224/230 .510 lift cam, long tube headers and free-flow 2.5 exhaust.
Intake system is completely stock except for a Volant "cold air" air filter and box.

[MTcamaroguy]

Putting in the sock VE table has seemed to fix most everything

[SiriusC1024]

Well, it's not stock. You really should tune that. Do you know how? I'll help out if you want.

[MTcamaroguy]

Always looking for assistance.
Reading forums has got me little until your assistance.
Watching videos all talk about using a wide-band and disabling either the MAF or MAP to tune the other.
I have made some changes to timing. Adding some at lower loads and removing some at upper. Also upped redline and moved some shift points.

[SiriusC1024]

Post your current file, please.

[MTcamaroguy]

Always looking for assistance.
Reading forums has got me little until your assistance.
Watching videos all talk about using a wide-band and disabling either the MAF or MAP to tune the other.
I have made some changes to timing. Adding some at lower loads and removing some at upper. Trying to keep it just below where it detects knock.
Also upped redline, increased line pressure, decreased shift time and moved some shift points.

[MTcamaroguy]

97 K3500 87oct stock VE No P0101 delta change upshift 10p red.hpt

Latest tune attached.

[Alvin]

P101 basically means there is a big mismatch between the VE and MAF.

[SiriusC1024]

Yep. I'll be working on it.

[SiriusC1024]

Might not start, but should. We'll see and make adjustments. Flash the tune and get a log.

[yanick]

hello, I'm looking to do the same thing 99 c3500 454 vortec => 496 stroker kit. did you keep your oem maf? did it read hi enough or since you got more displacement and more air it fall out of range?

[MTcamaroguy]

VEv3.PNG
After uploading supplied VE truck idled but as soon as any moderate throttle was given engine would fall on its face and just wouldn't go.
I took your tune alone with the stock VE and did some merging, a lot of reading and video watching and used the O2s with MAF disabled to dial it in pretty close. Ordering interface for wide-band.

[MTcamaroguy]

hello, I'm looking to do the same thing 99 c3500 454 vortec => 496 stroker kit. did you keep your oem maf? did it read hi enough or since you got more displacement and more air it fall out of range?

So far stock MAF is not a bottle neck. I think the stock intake or at least the throttle body are. I can hit 5,000 RPM but there isn't any point to it. Power drops like a stone past 4,500, just runs out of air. For what I want (towing and hauling) I don't foresee the lack of upper RPM power being a problem. Time will tell.

[SiriusC1024]

Stock cam? That's why.

[SiriusC1024]

VEv3.PNG
After uploading supplied VE truck idled but as soon as any moderate throttle was given engine would fall on its face and just wouldn't go.
I took your tune alone with the stock VE and did some merging, a lot of reading and video watching and used the O2s with MAF disabled to dial it in pretty close. Ordering interface for wide-band.

In that tune it's setup to running SD mode which means that MAF is ignored and only the VE table is used. Since VE is most definitely going to be off from stock that means problems are to be expected. The point is to run that table and make adjustments to it based on fuel trim feedback.

[MTcamaroguy]

Stock cam? That's why.

Cam is a Comp 224/230 .510 lift, mildly bigger than stock. Wanted something that would work well below 5,000 (tow rig) and compensate for the increased displacement. Roller rockers to but I cannot see that being a factor, stock ratio.

I will try your file again and see if I can use the LTFTs to do some fine tuning. See where it ends up compared to the one I worked on.
At the time I didn't have the time and needed to use the truck so stock VE table was in for a few days before I could play with it. Life, it get in the way sometimes.

[yanick]

So far stock MAF is not a bottle neck. I think the stock intake or at least the throttle body are. I can hit 5,000 RPM but there isn't any point to it. Power drops like a stone past 4,500, just runs out of air. For what I want (towing and hauling) I don't foresee the lack of upper RPM power being a problem. Time will tell.

ok thank same for me I want to tow

[Busted Knuckles]

Any progress on this?
I have modified the top half of the L29 clamshell by having runner dividers milled out for about 3", I am going to use a long round burr to smooth the end of the divider and close up the openings. Purpose of this process is to enlarge the individual port openings where the plenum makes its final split, the original ports were only about the size of a stock small block intake port at the split. I plan to use this on a 489 stroker with a smallish (212/218 or so) cam for towing along with worked open chamber large oval heads. I'll get a pic of the intake clamshell to show how the machining was done.
Thanks in advance for all the help!