Hemi VVT and P000B /P0014 codes. Please help

[FlyinRyan]

Recently did 2 Hemi VVT cars. Both turned out great, both using the same cam. I am leaving the neural network turned on on both. Both are using a Phaser Limiter.

Both are throwing P000B and P0014 codes. I've disabled the codes for now, but I believe they are showing up because my VVT settings are likely not correct.

I keep seeing references made to changing the VVT settings.....I'm trying my best to get learned up on cam timing as I've been tuning fixed-cam pushrod and OHC motors for the last few years.

With the Dodge VVT system, I see that normally they are set up for 14 degrees of sweep. Limiters hold them to 7 degrees of sweep.

Does this mean that the biggest difference in cam angle between my max advance point where VVT is enabled (900-1000) rpm can only be a max of 7* retarded from that point?

[RandomEnthusiast]

Yes. They can only go x amount of advance or retard because it's a bigger cam than stock. So I would turn off nn and tune everything and rebuild the phaser table.

[Hemituna]

Only 14degs?? Maybe in just the WOT tables??
For example, the 6.4's swing the cam about 24 crank degs in the WOT tables, close to the max of 28ish.
These tables can be reworked as some of the big swing is not needed when modded, and especially if it has a bigger cam with limiter.

[FlyinRyan]

Only 14degs?? Maybe in just the WOT tables??
For example, the 6.4's swing the cam about 24 degs in the WOT tables, but over 40 in the PT tables.
These tables should be reworked as most of the big swing is for emissions, so helps to be reduced anyways, and especially if it has a bigger cam with limiter.

Sorry, I should have clarified. I'm going off of Comps instructions for their Phaser Limiters......and it looks like their information is incorrect, or not consistent with what we see in the calibration. This explains why I was so confused. I was looking for a difference of 14 in somewhere, be it the WOT tables or elsewhere ....I couldn't find it.

I guess my next question that what value represents "full advance" so that we know where or from what value to start retarding from.
I do not believe the values in these tables (WOT to be specific) represent true cam angle, but rather they are offsets of whatever cam angle really is? Maybe I am wrong here? Obviously whatever changes are made to the intake side need to happen on the exhaust side too.

[GFB Performance]

Did you get this sorted out?

[TURBODAN101]

I am having the same issue after changing to a comp cam. If you have figured this out at all please pm and give me a heads up.

[Hemituna]

Been playing with these a bit lately, so this is my understanding so far...
The VVT V8 engines (lets talk 6.4 here) have a single phaser for the cam.
Be aware both lobes are on the same stick, so advance and retard together with the LSA unchanged.
Cam position is referenced by the exhaust C/L deg. Intake C/L number is really just a calc of of LSA,
but still is good to have those tables correct as no's are probably used for intake flow no's.
You can log for cam position and exhaust degs for commanded pos.
Stock engines run cam at full advance at start up until vvt enable rpm.
So they generally command full advance at idle. eg. 133/134 exh C/L and 107 Int C/L on stock 6.4L 120.5 LSA
I haven't actually measured a comp cam in an engine yet to determine where C/L's are actually at but I figure Comp have it sorted.
So we just need to make it all work.
Full retard stock is like 28 crank degs (14 Cam degs) although in some tables there are bigger numbers than mech pos.
I think these are used to command some of the other timing tables that do emissionsy/weird stuff. We don't wanna go there.
When fitting a cam and limiter a few things happen.
Full advance stays same 133/134 degs ex....but cos the cam is bigger, the int valve would tag the piston.
So Comp grind enough retard in the cam to prevent this at phaser full advance. Cool.
Now when we go phaser fully retarded with retard ground into cam,we have lots of retard. Too much, so they add a retard limiter.
This stops the ex valve getting tagged by the piston if we did try and retard too much.
So we only have 7 cam degs (14 crank degs) of retard allowed from full advance now.
This keeps everything happy and no crashing parts.
So where to set the VVT tables?
Max adv is a good start. So 133 or 134 in all ex tables and 107 ish in the intake (using 120.5 LSA no's for time being)
Be aware that if you try to go bigger than full adv exh numbers it seems to use strange timing maps so be ready for that one.
The VVT comp cams really are a bit too big, so generally love as much advance as you can get.
Can try retarding at the top rpm, but you will find power usually drops.
Exh Retard is a smaller exh C/L number, advance is a bigger exh C/L number...obviously the opposite to intake C/L numbers.
These numbers above usually stop it running into the retard limiter which is causing the codes.

Hope this helps.

[GFB Performance]

Those codes are being set because the ECM does a cam sweep just after startup to verify all is well and since the cam travel has been mechanically limited it thinks there is an issue. You have to disable those codes or they will keep coming back. Chrysler uses .006 or "advertised" specs when referring to cam specs. I believe this may be why the numbers are different in PT vs WOT where they use .050. Just my theory

[Hemituna]

I've done a ton of logging/cam tuning on these and haven't seen evidence of a start-up sweep.
When you fire the engine, the cam is fully advanced and logging its position shows that it doesn't move.
In fact, when in P/N the cam doesn't follow any tables and stays at full advance no matter what you do with the rpm/throttle.
Only when in D and speed is over 2 kmh does the cam move.
And it then goes wherever you tell it to within the mech limits.
The PT & WOT tables only work once the vehicle is moving.
If you inadvertently command the cam to go past where it is now mech limited, it will trigger codes.
All of the tables need to be revised as they move too far when using a limiter.
The cam tables use Lobe C/L as the reference. Lobe C/L numbers are unaffected by differing cam lift measurement values.
So using .006" or .050", the duration will change but C/L no's remain the same.
It all kinda makes sense after a while

[GFB Performance]

I understand the center line is the same regardless of using .006 or .050 I was referring to why the numbers look so different in PT tables vs WOT. In wot the lowest number may be say 109.6 and in PT it may be 93. That's just my theory and I could be completely wrong. As you state it really doesnt matter because it needs to be changed anyway. As far as the cam sweep on startup (during certain conditions) I'm positive I've read that somewhere and I'm thinking it was Tech Authority but I'll have to dig around. However if you say the log doesn't show it then that's hard to argue with and I have no reason to doubt it or you. It wouldn't be the first time I've read something that was incorrect or that I incorrectly read lol

[06300CSRT8]

I have very limited experience messing with the VVT stuff, but one question or point I have is I thought there weren't any PT cam tables; the one we see is purely for calculating spark but is not a command table for cam timing. I thought you were always in scavenging, max airflow (closest to a PT table if you will), warm-up, or WOT. From there its got the high/low baro interpolation. I could be wrong.

And I will never understand why comp chooses to grind the cam retarded to avoid PTV issues on the intake side but then a limiter on the exhaust side for the same issue? Why not just use limiters on both ends and grind it a few degrees retarded so the cam makes max power without much tuning? You wouldn't have to max out the advance if it was setup this way, stock cam timing would be pretty good.

[Hemituna]

Hey, I have read the same as you, and assumed it did a sweep too. Only when I started logging did I not see a sweep. Also you need oil pressure to retard so that ain't going to work on initial crank either. And the codes don't appear instantly, usually not until you drive it, so it all kinda adds up.
Logging position vs commanded, you can see a discrepancy when commanding beyond mech limits.
Those extreme numbers in the PT tables, ensure that it is against the stop and depending on the commanded number, then use different timing tables at different airflows(emissionsy eco type stuff).
You can run into issues using stock tables with a PD blower cos it hits PT airflows that it was not meant to and weird things happen to cam/ign timing.
If you put performance orientated numbers everywhere in the tables, no more such issues.

I understand the center line is the same regardless of using .006 or .050 I was referring to why the numbers look so different in PT tables vs WOT. In wot the lowest number may be say 109.6 and in PT it may be 93. That's just my theory and I could be completely wrong. As you state it really doesnt matter because it needs to be changed anyway. As far as the cam sweep on startup (during certain conditions) I'm positive I've read that somewhere and I'm thinking it was Tech Authority but I'll have to dig around. However if you say the log doesn't show it then that's hard to argue with and I have no reason to doubt it or you. It wouldn't be the first time I've read something that was incorrect or that I incorrectly read lol

[Hemituna]

WOT is for WOT obviously.
Max Airflow is for airflow calcs only
Warm up is for warm up
PT and Hi/Lo baro, I always make identical as these are used during PT or when not in WOT
If you don't have a PT table, then Hi/Lo baro is used at PT.

Regarding Comps strategy on cam set up.
I have to say it is well thought out.
The cam on any 6.4 is fully advanced at start up and while in P/N. Haven't yet found a table to change this but have HP tech working on it.
Only when in gear and moving does it follow the cam tables (and then it is good...1/10th deg accurate generally).
If you had an advance limiter, you would have a code on start up (lack of advance).
So let it be fully advanced and grind a known amount of retard in the cam.
Now limit the retard and adjust the cam tables to command less retard than is allowed by the limiter.
All sensors are happy, just the numbers are a little screwy.
The fact that you need full advance on these cams, is cos the Int lobe is too big with the PTV clearance you have with stock pistons.
A smaller lobe would allow more advance at low rpm and then you could get some retard in it up top.

I have very limited experience messing with the VVT stuff, but one question or point I have is I thought there weren't any PT cam tables; the one we see is purely for calculating spark but is not a command table for cam timing. I thought you were always in scavenging, max airflow (closest to a PT table if you will), warm-up, or WOT. From there its got the high/low baro interpolation. I could be wrong.

And I will never understand why comp chooses to grind the cam retarded to avoid PTV issues on the intake side but then a limiter on the exhaust side for the same issue? Why not just use limiters on both ends and grind it a few degrees retarded so the cam makes max power without much tuning? You wouldn't have to max out the advance if it was setup this way, stock cam timing would be pretty good.

[06300CSRT8]

Interesting, on the few I tuned both the intake and exhaust PT tables were all one single value (100), yet in logs was never anywhere near this value, but instead between this number (100) and what I see in the hi/low tables, but never exactly either of them, and certainly no where near the PT tables.

WOT is for WOT obviously.
Max Airflow is for airflow calcs only
Warm up is for warm up
PT and Hi/Lo baro, I always make identical as these are used during PT or when not in WOT
If you don't have a PT table, then Hi/Lo baro is used at PT.

Regarding Comps strategy on cam set up.
I have to say it is well thought out.
The cam on any 6.4 is fully advanced at start up and while in P/N. Haven't yet found a table to change this but have HP tech working on it.
Only when in gear and moving does it follow the cam tables (and then it is good...1/10th deg accurate generally).
If you had an advance limiter, you would have a code on start up (lack of advance).
So let it be fully advanced and grind a known amount of retard in the cam.
Now limit the retard and adjust the cam tables to command less retard than is allowed by the limiter.
All sensors are happy, just the numbers are a little screwy.
The fact that you need full advance on these cams, is cos the Int lobe is too big with the PTV clearance you have with stock pistons.
A smaller lobe would allow more advance at low rpm and then you could get some retard in it up top.

[Hemituna]

I see same thing in stock files. The PT tables seem to be for ign timing interpolation with regard to cam pos.
That is why I make all PT, Hi/Lo Baro tables the same, so nothing is messing with my cam/ign timing.
Logging seems to follow nicely the values set in the tables.
In my early days of VVT blower tunes I had some weird random deto rattles, where knock/timing seemed to come from no-where.
But it was increased airflow values messing with the stock cam and ign tables.
So now I tighten it all up and have had no more probs.
This maybe some explanation why a lot of tuners find the pistons fragile. Random cam and ign timing will break a piston real quick.
I've attached a 2015 SRT Jeep with Whipple 2.9L running 9psi on stock piston/cam 6.4L tune with VVT numbers that work real well.

[WS6HUMMER]

Can someone please dumb this down for me lol. I've done a few of these cars and never experimented with the VVT WOT tables, does advancing or retarding really help make more power & if so what direction do you go?

[PurpleRam]

no more power , but you can help launch by retreading the cam earlier.