Strange DoD delete issue.

[ABaker2004]

Hello all,
Brand new to tuning anything. I just did a mechanical DoD delete on my 2007 Avalanche. I left the VLOM sensor plugged in, and on start up, I get the following codes:

P3449 Cylinder 7 Deactivation solenoid valve control circuit
P3441 Cylinder 6 Deactivation solenoid valve control circuit
P3425 Cylinder 4 Deactivation solenoid valve control circuit
P3401 Cylinder 1 Deactivation solenoid valve control circuit

Makes sense right? Idles perfect but the truck is in limp mode and will do like 5mph max. So, I purchased the MPVI3 and turned disabled the DoD, wrote the file, then got the P0171 and P0174 codes saying lean on bank 1 and 2, as well as a very obvious miss at idle and the stabilitrak message. I rewrite the stock file back in, and it idles fine again but has the cylinder deactivation codes again and back into limp mode.

Why would I get a lean on bank 1 and 2 code with the DoD disabled and not when it's enabled? I'm at a lose as I really want this truck back on the road.

[gtstorey]

You probably can’t get it into area that show the additional problems in limp mode or the other codes keep it from even running other test.

[ABaker2004]

I may have found the problem. I am an idiot mainly. I ordered the DoD delete that has the VVT cam and my truck does not have VVT. I really don't want to change the cam again but I'm just about certain that is my issue because the problem is at idle. Man I'm stupid. Please chime in and let me know if this is likely the issue. I can't believe I don't that. I've worked on cars for years and years and this is just the worst oversight I've ever done.

[gtstorey]

Are the vvt cams not all single bolt cams?

Even if it’s a VVT cam, as long as it’s installed in a locked position, I’m not sure that it’s a problem. Maybe not the best cam choice but should be able to make it run ok.

[ABaker2004]

Are the vvt cams not all single bolt cams?

Even if it?s a VVT cam, as long as it?s installed in a locked position, I?m not sure that it?s a problem. Maybe not the best cam choice but should be able to make it run ok.

Not necessarily. I'm not as familiar with GM's VVT, but it could be that the cam needs to be clocked at a certain position at idle and it's fixed at the position it's in now. It runs ok at higher rpm. Just at idle there is a miss and runs lean. I would assume it would run rich because it's not getting enough lift and there is too much fuel for the air that is let in...however I really don't know. I can think of no other reason this would be happening. If it was a true lean condition then I would be getting those codes with the AFM enabled on the stock tune, but I do not. I only get it when it is disabled.

[gtstorey]

I think you are wrong on the codes, unless you have really dug into when certain test are ran.

However, if the cam wasn’t installed in the correct position, then all bets are off. How did you “set” the cam if it’s a vvt cam in a non vvt motor.

[ABaker2004]

I'm just going by the codes that the OBD scanner pulled up. And there is a very obvious miss at idle. The cam was a single bolt cam and has a little dowel that lines up with a hole on the cam gear. I looked up my AMS order and I did indeed get the kit with the VVT cam. I'm not sure if the VVT cam is clocked different or not. However, I can show you the codes on my reader. I'm just not sure why it throws those codes. I get the flashing CEL too with the p0300 code for multiple missfires. Only when DoD is disabled though. When it is enabled I get the codes listed above. Which makes sense.

[gtstorey]

There is a hierarchy to dtc and certain test won’t run if other codes are already set. I don’t know what that hierarchy is without checking the service manual. And certain test won’t run until it enters certain “modes”, and it won’t enter those modes if certain other codes are set.

What is the cam part number? A quick internet search only turned up 3 bolt cams as non-vvt. But I’m not an expert on cams.

I think it just needs tuning for the new setup. Post a tune and log with it running on each tune.

[ABaker2004]

That actually makes total sense. What doesn't make sense is the fact that it will physically idle rough with the DoD disabled and not with it enabled. I'll see what I can do tomorrow with the logging. however, there are single bolt VVT cams.

This is the kit I ordered.

https://www.amsracing.net/products/h...39648468500679

[gtstorey]

I didn’t realize that some of the cams were available stock as single bolt cams without vvt. I thought they were all vvt with one bolt and 3 bolt without. So I don’t know where the tdc marks are in relation to each other or even if they can actually be installed using parts from one to the other.

[2xLS1]

What is the part number on the cam. The Gen 4 4.8L never had DOD and the same cam was use in it both with and without VVT.

[gtstorey]

If you can’t find out anything about the cam, I would probably do a compression/leak down test to see if the valves are closed at TDC.

[GHuggins]

That actually makes total sense. What doesn't make sense is the fact that it will physically idle rough with the DoD disabled and not with it enabled. I'll see what I can do tomorrow with the logging. however, there are single bolt VVT cams.

This is the kit I ordered.

https://www.amsracing.net/products/h...39648468500679

With those VLOM codes set it'll only run on 4 cylinders, so it'll usually ignore trims for code setting. With DOD disabled it'll normally ignore the VLOM codes.

[ABaker2004]

Not sure if I'm adding these log files right. The one thing that I noticed is with the DoD off tune, the commanded afr changes at the end. Not sure why.

[kevin87turbot]

You did good by adding the datalogs. It looks like its just running a little to lean. We just need a little more data on the datalogs to help you dianose the issue.

Add MAP Sensor (kPa)
Add B1S1 and B2S1 (millivolts)
Add individual cylinder misfires for all cylinders

Quick question...are you running the stock MAF and air tube?

[ABaker2004]

air tube. Been running one since 2017 with 0 issues

[protekautorepair]

I dont thinks theres any difference in VVT and non VVT cams in Gen 4 Engines. The VVT cams are machined to use oil pressure to advance timing through the timing gear and have a heavy mechanical spring to reset back to base timing. You set timing the same way on either configuration.

I did lots of cam/lifter jobs as a dealer tech and also deleted many VVT engines by swapping timing gear and front cover. We never had an issue.

I noticed the kit didn?t give new pushrods, if you have a miss at idle check if any of those are bent. Also when you had the heads off did you check if the valves all passed the WD-40(or gas) test with air?

[ABaker2004]

I replaced all valve seals and lapped the valves.

[gtstorey]

I replaced all valve seals and lapped the valves.

??
If this is a response to my post #12, you need to make sure the cam isn't so far out of time that it's holding the valve open at TDC. But it sounds like the cam position is probably the same for both VVT and non-VVT cams.

[gtstorey]

And did you confirm the pushrod length to confirm they aren't holding the valves open?