It might not hurt to also install your stock MAF sensor for now just at least until you get her running with no missfire codes just to rule out that your fancy Lingenfelter MAF is not causing your problem. But i seriously doubt that your Lingenfelter MAF is causing this. Strange things do happen when we put lots of go fast parts on all at once. Good luck.

 

That's my fear right now, if only because it's the last thing I want to check and also because I can't see if anything is misaligned. I don't know what could have moved though, the individual runner 0-rings were all pressed snuggly into the channel. The spacer plates did move on one side though when I was dropping the blower, but I lifted that one side and slid it over, and all the bolts aligned with the head so you'd think everything should have lined up and tightened up.

I did notice before I took anything apart that on the driver side head there was some oil around the front of the valve cover, but I never once had the lean codes before and have had the valve covers off twice since and nothing seemed odd.

I have the valley cover with the front vent like on the right in the below pic, but when I was dropping the blower in place, I could have sworn I stuck my finger in between the bottom of the blower and top of that vent and there was enough clearance to get my finger in, so I don't think that's causing problems



I know and I might end up doing that, but I did get rid of the misfire codes by raising the misfire sensitivity tables at idle. The problem I'm having now is that I've read about how unscreened MAFs can cause the same lean codes I'm seeing, but my tuner disagrees they are MAF related based on fuel trims when I'm out of the throttle.

You're completely right it would have been easier to simplify things and then add other parts after the other newest parts are all running correctly. Lessons for next time I guess!

 

You have got to find this vacuum leak. I installed a intake manifold last year, thinking i set it down nice and straight, and ended up with a vacuum leak from the intake gaskets. wasted lots of time looking other places until i found the leak with some brake clean and had to lift the intake a second time wasting lots of time, but got it fixed.

 

That's what I'm worried, that I'm just wasting time with small things up top like checking hoses for cracks (new hoses too).

Here's something I noticed today: A week or so ago I checked the bolts holding the TVS to the heads and a few were loose. So I retorqued them and just now I checked 6 of them (the first 3 on each side looking at the engine) and the two corner ones were still tight, but the two in the middle on each side were loose again.

So I've got two thoughts on this; the bolts are backing out for whatever reason, or the gaskets need to be compressed a few times before everything seats.

What I'm thinking about doing now is taking each bolt out individually, adding loctite, and torquing them all down. At the same time I might put hose clamps on each vac line connection, and possibly re-do the EVAP connections (remove the factory unidirectional clip-on fittings and replace it with just hose and hose clamps).

Then drive it, datalog and check fuel trims. If still all fucked up nothing left to do but pull the blower and inspect the gaskets and spacers.

One other thing today I checked on, the barb at the rear of the blower for boost reference still has the rubber plug on it, I took the plug off and it's perfect.

I might also take the MAP out and silicone around it, although it came with an O-ring on it and it was tight to press in.

 

Change of plans, I decided to take the maggie off. It's unbolted and unhooked from everything, I just ran out of light for the day so I'll take it off tomorrow. While unbolting it I think I might have found the problem, or at least problem areas connected to the problem.

In this pic you can see the spacer plate between the maggie lower manifold and the head, and right below the injector, you can see a discoloration which to me could be fuel and/or oily residue likely caused by a leaking gasket. Problem is this stain/discoloration is on nearly every cylinder below the injector. So something must be really off:



So my plan of attack now is the take the maggie off and check the intake o-rings, and remove the spacer plates and scrape off all the RTV sealant I had put on (possibly too much and it's pushing the spacer out).

I think this will also be a good time to remove the valley cover and reinstall the original AFM one. The front vent on the AFM delete one is not doing me any favors, and the AFM one is flat at the front. So IF by any chance that vent is causing the blower to sit high in one corner and not be able to go flush, this is just one more variable I can eliminate by going to a completely flat design.

I wish there was enough time to order an AFM-less one that doesn't have that front vent, but I'm not willing to sit and wait any longer. I could grind it and weld it flat, but again, more waiting.

I've got a couple feelings about putting the AFM one back on, primarily that since the AFM is disabled in the tune, and I'm also not going to connect the rear connector obviously, there should be no effect of the AFM going on inside the solenoids, so there's no reason not to reinstall the AFM valley cover in my mind.

Following closely with that thought, in the below pic it seems as though all the AFM solenoids can unbolt from the valley cover, so if that's the case, I'll try that tomorrow before I reinstall it.

 

So yesterday I took the blower off and it was easy to see the vent on the front of the cover was coming into contact with the bottom of the maggie, so I replaced the vented cover with the AFM cover I took off originally, only difference is I didn't connect the electrical connector at the rear.

So the blower sat completely unobstructed and felt like it sealed/seated better to the heads. Great I thought, I did a couple other small things but long story short, bolted it back together, let it warm up and took it for a drive. First half of the drive was great, idle seemed smoother, vac gauge showed more vacuum (16inHG at idle), nailed the gas and it felt great. Parked it for about 15 minutes, then not even 5 mins into the drive I notice oil pressure has dropped to about 15 psi at idle in drive and park. Went up to 40ish with very light throttle, so I drove it home carefully and parked it.

This morning I fire it up and it goes to just below 40 psi at startup, then by the time it reaches temp, it's gradually lowered to around 20 psi.

Not sure what to make of this now. Only variable is the valley cover, and I understand the interaction of the solenoids as it relates to shutting off the AFM lifters, so it's quite possible this plate is causing the pressure drop, but I'm just not visualizing how just yet. The AFM-less valley cover blocks off the oil passageways to the AFM lifters, but so does the AFM cover to my understanding, at least when the conditions are there for it to remain in V8 mode. I know that oil circulates from the pan up through a passageway to the oil pressure sender, then from there circulates through the AFM cover and when the solenoids open, pressurized oil goes the the AFM lifters, and they shut off. BUT, if I have no power going to the valley cover, the solenoids should remain closed (I am assuming) and therefore no oil could get through, so it should act just like a AFM-less cover.

I'm having a hard time figuring out the interaction of the rear electrical connector on this cover. There's about 5-6 wires on it, so do they just control the operation of the solenoids? Would I have any benefit from plugging it back in?

Two things that are making me think the pressure drop could possibly NOT be related to the AFM cover are that if someone eliminates the AFM in the tune (just like I have done) and doesn't change the cam or lifters (for the sake of argument lets just say they want to be in V8 mode all the time), then their oil pressure won't drop like mine suddenly has.

Also, I haven't yet changed the oil or filter and have driven between 60-70 miles since putting everything back together.

To make matters worse, on the drive home, at low speed (i.e., <20MPH) I was still getting the p0171 and p0174 lean codes. So now I don't know what the ****. I found evidence of the maggie not sealing properly, completely eliminated that sealing problem and I'm still getting the codes. What gave me some hope on the first half of the drive though, was two conditions that usually set off the SES light and lean codes, accelerating hard and/or letting off the gas completely and coasting for a distance, did NOT set off any codes.

 

**** i dont even know what to say to help you, this is way over my head.

 

Plug the AFM solinoids back in, you said it's turned off in the tune anyway and that way you know that oil pressure is not pushing them around because they aren't powered. I don't know that will help but it's easy to try and you have nothing to lose.

Concerning the lean codes..... is there anything other than the MAF that you haven't tried yet?

 

Tried for about half an hour this morning. Problem is the bottom of the maggie sits right on top of the female connector thats on the back of the valley cover, which is making plugging the male connector back in extremely difficult. I either have to cut off the plastic tab that secures the two connectors together, or unbolt a couple bolts holding the maggie down at the back, lift it up slightly so there's enough room to connect the plug. I agree it's an easy check to see if it makes a difference. I just can't see how that would help me because I'm not really understanding how the cover could be dropping my oil pressure. Oil flows to the solenoids, but if they aren't powered, and they're closed, then oil can't move any further, so I shouldn't loose pressure. But if they're open, and oil flows through them to the default AFM lifter locations, then I can see where the pressure drop might be coming from. But the conditions to have the AFM deactivate cylinders are much fewer than to have 8 cyl mode, so by default, the solenoids should be shut, and when AFM is called for, power sent and solenoids open.

And nearly everything substantial has been covered except the MAF. I am 100% positive the seal between S/C and head is better today than it was two days ago. That was the only area I thought might have a vac leak, and in my opinion it did, so what's left now IF there still is a leak? I could put hose clamps on every single vac connection but then? I could take the press on connections out from the EVAP system and replace them with hose clamps but I'm really not seeing where a vac leak could be hiding now that is big enough to throw the SES light and make blackbear tell me the ECM is making significant adjustments to the fuel trims. And why only at very low speed, and why not at idle? Why only when I'm driving around at like 10 mph?

This thing has beaten me today, I'm going to take a couple days to think this one through.

 

I'm just blue skying here because I don't have a good understanding of how AFM works, BUT, intuitively I'd say that it's actually they other way around. The solinoids are open supplying oil pressure to support the lifters during default operation, and they close when you want the lifters to collapse and stop pushing on the valves.