Calculated Load vs. Absolute Load

Tyler wrote:

Conclusion: Absolute Load is kinda useless. :lol: There's a reason no one in the industry teaches it's use. Not every vehicle has it, and it's not terribly useful on the vehicles that do. Oh well, it was fun to explore! This is how we develop diagnostic methods.

Agree Wish it would've lead us to some 'new discovery '... But hey this how it goes in our business :whistle:

Thread bump outa nowhere! :woohoo:

Ended up taking a class that helped answer some questions that came up in this thread.

1.) The 105% absolute load value I saw on the Enclave is perfectly normal. I'm told this is a product of VVT, and not unusual at all. Some have observed 110% on other engines at WOT. :cool:

2.) The OTC volumetric efficiency calculator is incorrect. I'll be comparing it to other brands of calculators in the near future, but for now I'm taking off the Service Info thread. This is why I got all kinds of wacky readings earlier... There IS a software issue, just not on the vehicle side! :blush:

3.) Absolute load is a mandated PID from 2012 onwards, but appears on some vehicles before that when the OE decided to use it.

So like I said earlier, I had an instructor inform me that the OTC calculator is NOT accurate. I believe him, but I wanted to see for myself.

Last go-round with the OTC VE calculator, I came up with this on a '11 Enclave:



That's not a bad reading, by any means. But what happens when I put it into another calculator? I found VE Calculator on the Android Play Store for free. Same values:



Different result:



This is closer to the 105% value we saw from the Absolute Load PID in Global OBD. The 5% difference didn't matter in this case, but what if you had a genuine low power complaint? That difference might end up leading you down the wrong path...

And here I was thinking that VE was a standardized calculation, and not open to interpretation. :lol:

What's that app? I've been disappointed with the play store offerings of VE calculators...

Tyler wrote: Thread bump outa nowhere! :woohoo:

Ended up taking a class that helped answer some questions that came up in this thread.

1.) The 105% absolute load value I saw on the Enclave is perfectly normal. I'm told this is a product of VVT, and not unusual at all. Some have observed 110% on other engines at WOT. :cool:

2.) The OTC volumetric efficiency calculator is incorrect. I'll be comparing it to other brands of calculators in the near future, but for now I'm taking off the Service Info thread. This is why I got all kinds of wacky readings earlier... There IS a software issue, just not on the vehicle side! :blush:

3.) Absolute load is a mandated PID from 2012 onwards, but appears on some vehicles before that when the OE decided to use it.

Oh man that sucks! In a good way ... So it's the calculator itself that's throwing us off

Although I saw different videos on YouTube where the OTC VE calculator was used... :S

Also have a VE calculator from the Android playstore. There's also one I saw on the Autonerdz channel. Only if you have Windows.

Anyway I'm excited to see this topic is back!

Noah wrote: What's that app? I've been disappointed with the play store offerings of VE calculators...

I found it under VE Calculator. Maybe it'd be fun to take several for a spin? See how much variance there is out there.

Another tidbit I got over the weekend is how valuable Absolute Load is for forced induction engines, particularly Ford Ecoboost platforms. Somewhere between 155 and 185% is a good value on those engines.

This is the video of that VE calculator I saw on Youtube:

I have a screenshot of a Tech 2 screen with the VE pid vs VE calculator and it is really close. I'll grab it off my other computer tomorrow.

gav09 wrote: I have a screenshot of a Tech 2 screen with the VE pid vs VE calculator and it is really close. I'll grab it off my other computer tomorrow.

Cool. I'd like to see that screenshot

gav09 wrote: I have a screenshot of a Tech 2 screen with the VE pid vs VE calculator and it is really close. I'll grab it off my other computer tomorrow.

I've seen that before! Very nice of GM to add that PID. But not all have it?

Decided to play a bit more with Absolute Load, this time on an '08 Escape. 3.0L engine, no VVT.



89% at the peak. This kinda makes sense compared to the '11 Enclave I tested earlier, which is supposed to use it's VVT at WOT to improve VE.

Still trying to build a baseline for what this PID should be doing on different engines. Maybe 80 - 90% for non-VVT engines, 90 - 105% for VVT?

Decided to play a bit more with Absolute Load, this time on an '08 Escape. 3.0L engine

New guinea pig is working out good I take it :whistle:

Whaaaaaaat? I never perform testing on my personal vehicles! :whistle:

Sorry about the delay but here is the screenshot. I don't remember what vehicle it was but 92.434% on the calculator and 92% on the scan data.

gav09 wrote: Sorry about the delay but here is the screenshot. I don't remember what vehicle it was but 92.434% on the calculator and 92% on the scan data.

Sweet! That's what I was looking at the other day on another GM, didn't have time to really play with it.

I wonder if they're actually taking the Absolute Load PID from Global and renaming it Volumetric Efficiency in Enhanced data? :huh:

gav09 wrote: Sorry about the delay but here is the screenshot. I don't remember what vehicle it was but 92.434% on the calculator and 92% on the scan data.

Thanks! Karma bump for you.
I'm also using Tech2 and I haven't noticed this PID... I'll keep it in mind that's for sure. Your VE calculator is from Windows store? Just asking cause we're talking about calculators since Tyler revealed that the one from OTC is crap and so we're on the hunt for a good one :lol:

Tyler wrote:

I wonder if they're actually taking the Absolute Load PID from Global and renaming it Volumetric Efficiency in Enhanced data? :huh:

Good question :S

COOL! Check this one out guys :woohoo:

Good timing huh? I seriously didn't know this was here. Thanks guys!

Sweet! I'll be watching that video later on tonight.

I also learned at Vision that Absolute Load is very useful for forced induction diagnostics, particularly on newer Ford EcoBoost engines. I'm told that a peak Absolute Load of 150-175% is typical on Ecoboost platforms. I ran into a '13 Edge with a turbocharger issue recently that became much more obvious once I started looking at Absolute Load.



This one had a wastegate problem that prevented maximum boost, and resulted in a DTC.

This shot is off a 'chipped' 3.5L F-150. Almost hit 200% Absolute Load. :ohmy:

Just watching Pauls video, there's huge discrepancies between the load data shown between the 3 vehicles. From memory the F150 peaked at 89%, his ute reached 99% but seem to be fairly related to what was being asked of the motor. The Lincoln however really seemed to jump around a lot and reach 100% when it didn't seem to be under any load. Just an observation.

Also, my understanding of this VE calculator is stripping back fuel delivery and spark timing and simply measuring the engine as an air pump. You guys agree that's a fair comparison?

matt.white wrote: Also, my understanding of this VE calculator is stripping back fuel delivery and spark timing and simply measuring the engine as an air pump. You guys agree that's a fair comparison?

I agree Matt. Volumetric efficiency is basically an indication how well an engine breathes. I don't consider it as a magic calculation that will solve our problems in the blink of an eye BUT I'm pretty curious what Paul's going to do with this.