Here's the pull

 

A better look at the AFR

 

Did your tuner know what injectors you have? Sometimes they make a difference.
Based on the dyno, hate to ask, but was ASR on/off?
Running that lean, without a code or to state obvious, tells me the engine is being told the engine is running RICH, ie O2 sensor? . Datalog would help here.

 

Yes he did know what injectors Steve.
ASR was off.

I did have a issue with the bank 2 forward sensor but I replaced it. Bank 1 never threw a code so I didn't bother it. The rear 02's have been tuned out.

I do have a data logging program I could run but that PCM will not start the car now so that is worthless.

 

This sux. Is the tuner going to reflash your PCM?

 

Yep, pretty much...........

I just got the file late last night. He wanted to see it so I'm waiting to hear from him now. I would think he would reflash if it can be. I can't see where the car would have locked up the VATS or whatever happened to the that PCM. We'll see, at this point I just want it squared away. You know how that goes I'm sure.

Thanks for you input!

 

it's not too lean, if fact through the power band it could be a tic leaner than the 12.5 your graph shows. The undulating hp through the power band should be the concern. Perhaps valve train, spark issues?

 

 

I'd check the plugs wires and the rocker arms.

You mentioned VATS and a no-start condition. VATS is part of the CCM, not the PCM.

 

Tuner said to hook the PCM back up and see if I could get any codes. If it reconigized the Tech 1 it was probably still good. It did that and no codes were thrown. I turned the switch to start and the damn car fired right up! This is over my head boyz! I'm taking it to a dyno shop that can tune it on the dyno. If there is a problem somewhere they should find it.

Thanks for all your advice and help! -Mike

 

You should find/fix the problem before retuning.

 

I agree.
I would try and be prepared by making sure all is right first (if at all possible). My short list would be to check lash (will also give a clue to lifter issues, test spring pressures inspect rockers etc.), spark (wires, cap coil etc.). Typically dyno opertators may not trouble shoot the car and if they do I would imagine the co$t would go up dramatically. When going to the dyno I would also datalog the pulls myself to see what other things maybe going on, which may shed some light on things. The other thing is, I am not sure why they are spinning for the most part a stock (less cam) motor up that high anyways (it was all done long before 6200).

 

No advice to offer, but I sure hope you can get it sorted out quick!

 

That sucks something is wrong as it layed down more power before the cam swap. I would THINK the stock tune would have ran O.K. and certainly wouldn't have done the whole no start thing regardless though. It looks to me like you have issues as in plural. Could be a vats issue and something else as simple as an ignition problem like a burnt coil wire a weak coil,the rockers could be set incorrectly, but it seems to me it's issues compounding. You'll work it out though, wish you were closer I would love to help out, not that I'm much help but sometimes a second set of eyes even with half a brain helps besides I got a wicked set of tools I would first check the obvious,while having the tune reflashed though. You could have gotten the wrong tune bro, I hope so alot simpler than the cam was boxed wrong or some other crazy *** scenario.

 

I won't argue that the graph looks like they spun it WAY past the peak, but if everything was working properly, that cam should make plenty of power all the way past 6200. I would expect the peak HP to be around 5500-6000, depending on the rest of the setup.

The question is why wasn't it acting like it should. My first guess would be spark timing, but not on an LT1. Unless the PCM really was screwed up. Hmmm. Possible I guess, but in my experience it's usually a good idea to check the last thing that was changed. It wouldn't be too hard to at least pull the valve covers and look everything over, go back over the valve lash setting (this fixed a no start / horrible backfire problem after my cam swap, after the lifters "pumped up" the rockers were too tight and the valves were never completely sealing the chambers. I know, rookie mistake). Are you sure it's firing on all 8? If you've got headers, there's an easy way to tell. Run it for about 15 seconds, then quickly tap each header. If they're all HOT, you're good. If one's cooler than the rest, it's not firing. Don't touch the headers too long though, it might hurt a bit.

If you think the cats may be plugged, it shouldn't be too difficult to disconnect them from the headers / manifolds and run it to see if it's better that way. The O2 sensors probably won't like it, but it shouldn't hurt anything to run it open.

Other thoughts: valve float, weak/no spark, cam timing...

Good luck, and have patience. It will all get worked out and you'll LOVE the result.

 

This is a stock PCM vs the PCM I just had retuned. The stock pull was done before the cam swap. Maybe the tune just didn't take or as mentioned a corupt file. They just look so similar. I'm going to take both PCM's with me when I go to RPM. They say it's not uncommon for these pcm's to crash after multiple tunings. I'm hoping this is the case here. We'll see. Maybe the damn motor is just wore out...........


This is all four pulls. The best one being when I installed the 1.6 roller rockers. The cam, roller rockers and headers were all done on the PCM I just had retuned.

 

This valve lash question keeps popping up here. Here is how I adjusted the valves.

I do it with the engine running and at operating temp. I loosen the rocker until the rocker starts tapping. I use a "T" handle allen wrench to turn the lock while tightening the nut on the rocker. You can feel the rocker tapping through the handle of the allen wrench. When I can't feel it anymore I tighten the nut 1/2 turn more and lock it down. Pretty simple and has always worked in the past for me. Is this the wrong way to do it? Should I have stopped at 1/8 or 1/4 turn for more lifter pessure? The lifters are new and so are the springs. These springs aren't supposed to create valve float until 7K. I didn't think it was neccessary to check spring pressure unless the heads had been redone. Mine are stock. -Mike

Cam gear installation:
Put the sprocket on the crank snout with the 0 degree advance slot over the keyway. Made sure the dot was at 12:00. Put the sprocket on the cam with the dot at 6:00.

There are no backfires at anytime. If it's misfiring I can't tell it. I can't check misfires because the crank sensor is tuned out.

Isn't a 52mm TB supposed to be good enough up to 400hp?

I asked Lloyd if he had ever had a cam boxed wrong or the wrong one sent out and he said no. I suppose there is always a first time though.

 

[quote=reoch999;1571876707]I won't argue that the graph looks like they spun it WAY past the peak, but if everything was working properly, that cam should make plenty of power all the way past 6200. I would expect the peak HP to be around 5500-6000, depending on the rest of the setup.

The question is why wasn't it acting like it should. My first guess would be spark timing, but not on an LT1. Unless the PCM really was screwed up. Hmmm. Possible I guess, but in my experience it's usually a good idea to check the last thing that was changed.

Thanks reoch

I'm pretty sure about what I did. I'm not so sure about what the tuner did so that is here I'm heading with this. Get that out of the way first then move to something else if that doesn't turn up anything.

You are correct. This cam is supposed to give good power through out the rpm range from 1900 to 6200 with a stock bottom end. Guess what my tuner set the limiter at.........6700. yeah right, like I'm going to spin it that high. Maybe I should and just start over.

 

To me it should have become obvious to the dyno operator that at least at this point it just isn't making power up there....shut it down until other things could be looked over.
exactly, This would give me reason to believe whatever is going on was happening (to some degree at least) regardless of the ECM exchange. (however, there are a couple areas that are better before the last tune). Bin files can become corrupted, when they do typically other things happen, may put it in limp home mode, fans will go on, sys. light etc.etc. I don't re flash the entire ECM, so I can't tell you about problems inherent to that method.
I would be interested to know if it was pulling timing via spark knock, did you run your own data log on the runs?

I know that in the past others get the rocker arm adjustment you state to work. I personally am not a fan of doing it while running and I believe it is not as accurate as doing it cold.
Comp used to recommend a .030 preload. The method I use is find the heel of the cam; Exhaust, as it starts to open adjust the int. Intake, just before it closes adjust the exhaust (1/2-3/4 turn is fine). A 52mm will support 400 hp, and I doubt the motor is worn out.

 

General rule of thumb:

All cams will run the best with the Intake Center Line installed @ 2 degrees advanced. This means if you have a lobe separation angle of 111 the best point for maximum power without hurting peak torque is 109 degrees measured at the Intake Center Line. If the cam is installed straight up at 111 peak power will be the same but peak touque will suffer. If the cam is installed at 107 peak torque will increase slightly but peak power will fall off more than torque is gained. If your cam does not behave this way you have the wrong cam in the engine.