Beginner to tuning and engine falls flat on face at 4300 rpms.

I have a 2006 5.3l swap into a 87 camaro. Has a 218/218 .578 cam and home ported heads. Been running on a lightly modified stock tune for a bit now as I haven't had a chance to buy a wideband. Anyways I found a tune in the repository of a 5.3l with a 218/222 cam and figured it would be worth a try. I was driving around today logging and made one wot run and I'm pretty sure the fuel cut off came in at 4300. I didn't experience any knock there or anything. haven't noticed anything out of the ordinary in my log and was just wondering if someone with more experience could take a quick look. I'm pretty sure I may have a small exhaust leak on the driver side which is causing my ltft to be off.

Attachment 56198

Happens at 10:03.
Thanks!

At 3775 rpm the airflow starts backing up from .84g/cyl, then at 3950 rpm the narrow band O2s go to 50mv or less (extremely lean) and airflow is at .44g/cyl. That is what I see in the log. Without seeing a tune can't say which is causing which, but fuel delivery/fuel pressure is a very common problem in swaps. You see the thing with tunes in the repository is the person who put it there may know less about tuning than you.

Hmm yeah my fuel pump has just started to make a high pitched noise so I'll get a fuel pressure tester and take a look. Here is the tune if that helps. If it isn't the fuel pressure what would be the best approach to fixing the lean condition? Attachment 56216

Well definitely not fuel pressure held steady at 59 psi all the way through to 6k where I stopped. Means the tunes off at somepoint.

Try this. Report back with your findings.

Ok so went out and tested it. Same thing with less harsh results. Engine didn't lose power but didn't gain any either. More like a stumbling action then falling on face. i'm guessing the VE table values need to be increased more than what you already did? At 8:20 the o2 sensors go super low when I hit wot. Still leaning out. Only seems to happen in first gear though? I did a couple wot pulls on high way earlier on and one sensor seems to dip but the other doesn't. I also seem to have some odd negative timing spikes. As the timing gets pulled back with no input just randomly while going down the road. No knock detected so thats good :P. Thanks for the help so much!Attachment 56281

looking at your log, your about finished with that injector.

also your tune needs to be setup for SD and stick with SD for ease of process.

Quote:

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Originally Posted by Eloc

Ok so went out and tested it. Same thing with less harsh results. Engine didn't lose power but didn't gain any either. More like a stumbling action then falling on face. i'm guessing the VE table values need to be increased more than what you already did? At 8:20 the o2 sensors go super low when I hit wot. Still leaning out. Only seems to happen in first gear though? I did a couple wot pulls on high way earlier on and one sensor seems to dip but the other doesn't. I also seem to have some odd negative timing spikes. As the timing gets pulled back with no input just randomly while going down the road. No knock detected so thats good :P. Thanks for the help so much!Attachment 56281

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So it appears that your MAF is defective. Convert to SD entirely and fail the MAF properly. Also, turn the key on and bump the starter and see where your MAP sits with the engine off, key on. It should sit at atmospheric 0 which is based on your elevation. at or close to sea level, you should be at or close to 100kPa. If you are, then look at your inlet. If you're close to 100kPa with EOKO, you have a restrictive inlet. I've seen inlet tubes collapse at WOT and cause this issue. If you question it, remove everything from the inlet in SD, keep the IAT in play by removing it from the inlet tube and connecting it if needed. If you don't have a wideband, get one. Don't be tuning WOT by looking at O2 voltages unless you enjoy lackluster performance and replacing engines for fun on weekends.

Yeah I knew about the injector but its not hitting its max cycle yet? Figured I'd hit that first then worry about it lol. Brand new MAF sensor too :/. The IAT is in the same unit as the MAF. Not sure if IAT will run with the MAF sensor disabled guess I'll go find out. The inlet tubing could very well be a possibility using some plumbers black corrugated tubing 0.0. I'm a poor college student so these things take time to buy. Wide band might just have to be thrown on the credit card then.
@SultanHassing do I even need a MAF if I'm running SD. The only reason I haven't done that is because I thought it was a little more dangerous taking away the MAF safety net. And how is it not set up for stick? Pretty sure I had all automatic trans stuff turned off.

So i'm at 96kPA with key on engine off and 48kPA with engine off. I don't think its a restrictive inlet. It might be collapsing during a first gear pull then. I'll pull it off and check in a bit.
Thanks for all the help! Can't say how much I appreciate it.

as mentioned run SD and ignore your maf. it can still be connected and run perfectly fine with SD.

also depending on your OS your can have RTT

Just as an update to this as I just realized I didn't say what happened. I'm running SD and took the homemade inlet off and the issues seemed to stop. I also believe it may be because I had a little bit more than a quarter tank and in a third gen camaro they aren't baffled and under hard acceleration was starving the fuel pump.