Hesitation after cam/dod delete

[TorqueInd]

Hello!

2015 Yukon 6.2 got a TSP cam and dod delete kit a couple months ago.

Since I have been trying to figure out why I have a serious hesitation problem. I have efi live tuning and am working with the tuner via data logs. I have no cel and I am at a loss at this point.

I have pulled the injectors out twice now and re-sealed them. (There was issues with the compression seals). When I first put it together and got it running all was well according to the tuner however I did not change the compression seals on the injectors and I could hear compression passing on #6 cylinder. I pulled them back out, changed just the compression rings, then I started having problems. Had a average of 10% fuel correction between banks at that time. So, pulled them back out again. Found at least 3 of injectors didn’t seal very good. So, re did them and that brings us to now. I have about a 5% long term correction between banks. Swapped the plugs, no change.

So if I hold the rpm in park at any rpm it holds it then sputters a bit and comes back then sputters and so forth. Seems to pull timing out when it does this.

When driving it is fine at low rpm and low throttle. When I go for more than 30% throttle and over 2000rpm it hesitates quite bad. Lots of pinging going on too but no ecm timing correction for knock according to what I see on the PID’s. It is however, pulling up tk 30 degrees of timing out when it’s falling on its face like this.
At this point I’m looking for some advice on where to go. I don’t like the idea of giving up and taking it to a shop. I live in a very small remote town so no one has any experience with these engines cam’d. The only thing they have on me is a snap on scanner and I can do most of that stuff with efi live v8 dvt’s.

That brings me to - injector testing with v8 dvt’s - do I need to pull fuel pump fuse and run till it dies before testing through the software?

Is there anyone on here that is particularly familiar with efi live tuning on these whips?

Cheers,
Colton

 

[THarber]

It could be so many things.

Start with a TPS relearn and or replace it. What is the idle MAP reading? It will need to be higher than stock due to the cam.

What cam did you install? How did you adjust lifter preload?

What is the injector duty cycle?

 

[TorqueInd]

Thanks for the reply. I have been a bit too busy to look at the car for a bit, so I stole it from the wife this morning and took a data log on the way to work.

The cam is a 223/227 .635 112LSA from Texas speed. VVT is locked out.

Lifters were set by following the chiltons manual.

There was a idle relearn done to correct for dirty throttle body now being clean.

There is a definite discrepancy between banks of the engine on all fronts it seems. Even so, none of this really explains when it’s stutters so bad on partial throttle.

Here is a screenshot of the data from this morning at idle. I missed a couple important pids on this list, will add them for the drive home.

 

[THarber]

You have an injector leaking on bank 2 according to those numbers. The map readings are off too, you either have a bad MAP sensor or a vacuum leak somewhere. Look up the MAP readings via multi meter and check it or just replace it. It could also cause your injector issues. If it checks out OK, search for a vacuum leak.

Did you get the +32% fuel lobe with that cam?

 

[TorqueInd]

Thank you. I can’t tell you how helpful it is having someone with experience look at these numbers. I’m very green with efi live. When you say leaking, do you mean leaking compression, or passing fuel?

I feel like there is a lot of oil getting in the intake still even with the DOD delete. Should that not slow down or stop once DOD is plugged off? Or do I need a new PCV valve?

I was really on the fence about the fuel lobe but in the end I chose to go with stock profile. A power adder is appealing of course but not very likely. I did put LT4 head gaskets in with arp 2000 bolts so I kinda regret the fuel lobe choice. Just didn’t want to have a headache with the +32 cam but, here I am anyway..

Sure is nice to have a direction to head in. Can’t thank you enough for your help.

 

[THarber]

The DOD delete is not going to help with oil burn. Add a catch can for that. The PCV valve is actually built into the valve cover. Are you certain you installed the lines correctly?

Looks like an injector is leaking fuel but they could also be the source of a vacuum leak.

You're OK with the stock fuel lobes, if you used the +32 you would have had to also add lash caps which the manual probably would not have covered.

I'm no expert but know enough to be dangerous.

 

[THarber]

Also make sure you don't have anything loose and banging around like and exhaust manifold bolt or engine mount. This could set off your knock sensors.

 

[TorqueInd]

I think I’m going to change all the injectors. That brings me to questions…

Nominal flow? High flow? Does it matter if they are all the same? Should I go with ac delco? What is best for these engines?

The source of all the oil in the intake is coming from the line that goes from the VLOM to the intake around the throttle body area. The piece that connects the hose to the VLOM is plastic and if memory serves has a hex style nut for getting it in/out of the VLOM. Is this a filter? Check valve? I assumed it was a PCV valve but appears in wrong…

Tuner said I have a random misfire on bank 2 and a weird pulsation under full throttle on bank 1. ‍

 

[THarber]

Based on my limited knowledge of the VLOM I would replace it and the gasket or go to an older style LS3 valley cover. Did you replace all lifters when you installed the new CAM? If not that could be a cause of your misfire, I'd go over to LS1Tech and research it.

As for the lifters, I'd stick with stock unless you know how to properly tune the injector duty cycles. High flow is not needed for just the cam.

 

[TorqueInd]

The tuner I’m using is responsible for just that, tuning. They will make adjustments as required for up to a year after purchase of the tunes. It appears high flow injectors are actually cheaper, still gm original equip. I just want to get what is best, and don’t want to miss opportunity when changing the whole set out.

Also, I did find that the PCV valve is in fact located on the VLOM as I mentioned. I think I will change that out as well. There is a total of 3 crank case vents that go to the intake. A catch can would be nice but I haven’t found a kit for that yet, and home brew isn’t in my schedule right now. Changing the entire VLOM for a LS style does nothing beside look better and get rid of unused junk. Not worth it to me. All the ports are plugged as per the DOD delete kit.

Yes, all the lifters were replaced with DELFI LS7 lifters and trays. I do not believe the misfire is being cause by anything internal on the engine. It is random, not constant. There are no weird noises. Just stuttering under load and the vast fuel/02 difference between banks.