5600 rpm limit I can not get rid of or find.

[SiriusC1024]

Yeah there's fuckery afoot. I get what you're saying, and it makes sense. The perfectly linear lines in rpm and MAF after an abrupt knee, followed by spark, is odd. If it's pressure related I'd think there would be more of a curve as flow approaches restriction, but that's just me.
fuckery.png

It would certainly be a lot easier dealing with this type of thing in person.

[SiriusC1024]

Also, what's with the goofy injector data? What's the part number of the injectors you're using? Then the Dynamic Hi/Lo Steady State changes?

[Alvin]

I suspect bad springs or a severe exhaust restriction.

You'll normally see MAP drop off hard if it is a intake restriction. His is pretty high.

[SkinnyG]

...

[abc]

Easy to eliminate possible exhaust issue, unbolt it and give a go!

[vr4508]

I'm still fighting this problem.
I pulled the exhaust and other than louder, made no change.
I swapped a set of known good coils from my turbo truck and no change.
I have restarted with two different tunes from the repository that were labeled as totally stock with no change from either. Both showed same OS.
I swapped ecu's with a different p59 ecu, segment swapped the necessary segments and used the downloaded tune from the repository.
I have run it in both maf only and SD only with the same results.
While its on the limiter the stock 02's are still showing its got enough fuel to still be accelerating in rpm.
INJ PW stays the same and shows no drop off. Thats why I tried the coils. I'm thinking at this point I'm losing spark.

The issue happens either moving or not. I can just free rev it to the limiter.
No tune changes have made any noticeable changes.
I get no codes during the event.
Throttle pedal position doesn't seem to matter. I can hit the limiter at 35% or 100% and it still just hangs there.
Its super consistent. I don't think its any type of mechanical problem. The way it acts is just too much like a programmed limiter. If I found some weird 2 step gacked into the factory harness I would not be surprised. Its just that repeatable. I have other logs of it but they all look the same so far.
I haven't spent any real time tuning it yet as this is essentially a road block that I would have to overcome at some point, but the truck runs and drives rather good the entire time its not having this issue.

Ghost in the Machine.

[blindsquirrel]

What is the valve spring installed height, and what is the seat pressure? Every single factoid you've described is exactly what would be expected when the springs are not able to handle the cam. Where did the springs come from, are they authentic or possible knock-offs from Amazon?

[edcmat-l1]

^^^ Agree. It is typical valve float. It even has a sound to it. The engine just flatlines. I've experienced it several times and each time it sounds almost the same. Hard to explain.

When you've ran out of all logical possibilities, its valve float.

[abc]

Cam, crank sensor? Short of that it does sound like a valve control issue after all that has been mentioned. How about put a timing light on it and see if the timing light does anything weird when the limit kicks in?

Pull a few springs off or buy an on the car psi checker. Verify seat psi and full lift psi. Your pressures do sound a little light to me. I'm thinking 140 to 160 on the seat and 380 to 400 over the nose is closer to where you need to be.

[blindsquirrel]

The spring (174005) Summit sells with that cam as a cam+springs kit are 140 @ 1.80. Not 125.

In the cam's description it says

pull strongly past 7000 rpm with as little as 150 lbs. of seat pressure

I am no math whiz but I am pretty sure 125 is not as much as either 140 or 150.

[Tody'shop]

I had motor felt like it was on the chip before and after buying a new MSD box and destributor then a new carb i had a guy come check over too see what i was missing and the valves were a little too tight. It was a hydrau;ic roller and i just set too cold i ges.

[Tody'shop]

The spring (174005) Summit sells with that cam as a cam+springs kit are 140 @ 1.80. Not 125.

In the cam's description it says


I am no math whiz but I am pretty sure 125 is not as much as either 140 or 150.

I'm with him if its at 125 and thats at 1.80 or 1.72 closer to 1.70 if so it drops another 10-15 pounds. I would check the spring rate again and if you have a install height tool make sure its shimmed correctly and is at the 1.80.