Ok, some of you on here should know of the crap my car has been putting me through for almost two years now. Finally got face to face this last weekend with Alvin from PCMforless to work on the tuning. We road tuned for 2 hours friday night, and then headed to the dyno on saturday. Friday night we put it through a couple of WOT 1st gear pulls and the car just felt like it was missing something. When Alvin first showed up the car was running pig rich, absolutely ridiculous. Even after cleaning up the road tune, using a wide band and keeping it in the 13-14 range for normal driving, the car only got 98 miles on 13 gallons of gas. Definitely NOT right. At the dyno, he didn't get a chance to work on the fuel/spark tables because he was working on some part throttle/tip in stuff, but with a couple of pulls with about a 12:1 AFR, the car pulled 358-360 HP and 350-355 TQ at 5500 RPM. BUT!!!!!! It leveled off at that point. Power curve just stopped climbing and stayed right at that point up to 6500 RPM, and the TQ curve continued to drop like normal. The car just felt soft.

Dyno sheet seen Here

Our dyno session ended before he could finish the tune because both power steering pump bolts pulled the threads right out of the accessory bracket and the car threw the belt. It DID NOT want to run on the battery, even with a charger on it. So that was that.

Now here's the problem: It's a big Joe O cam that should easily pull to 6500 RPM. Something is wrong, but I can't for the life of me figure out what it is. Alvin had to lean EVERYTHING out using the VE talbes, tuned out the O2's completely, but watching the voltage on the O2's while driving, they were dead in the 900 MV's (still good though, they cycled fine at idle) even though the wide band was showing in the range of 13-14 AFR. I believe there's still the same underlying issue of the car running way too rich, but can't figure out why. At a 1200 RPM idle, the car pulls about 70 kPa on the scanner. Not much for that RPM setting. I.E. it's pulling WAY low vacuum still.

It doesn't hard start, runs extremely rough until about 1800 or so RPM where it cleans up quite well. And is way down on power.

Any ideas??? Could a slightly off cam install cause these issues???

 

Check piston to valve clearance and if there happens to be some bent valves.
How does the valve geometry look?
Assuming no MAF, if you converted to MAF, change it out with a known stocker.

 

PTV clearance is fine, running nowhere near enough lift to get there. Valvetrain geometry checked out good just about 4 weeks ago when I put a brand new set of Comp R lifters in. Those aren't too tight as the power would have nose dived in the upper ranges instead of just held flat. No maf, it's a 93 speed density car with no obstruction in the induction.

the part that really concerns me (other than the missing power) is that even with a decent A/F ratio the car only got 98 miles out of 13 gallons. I know it's a big cam but that's about 1/3 of what I was getting with my 224/230 and heads setup which was running pig rich too.

 

If vacuum is low and gas mileage is low then maybe there is a vacuum leak? You say just running around town the O2's were in the 900s? I can run mine in the 200's around town with no ill affects like knock retard or audible knock. However Alvin is supposed to know whats going on with SD cars so Id trust what he is doing... though I agree 98 miles on 13 gallons is terrible.

 

No I know he know's what he's doing, I've been working with him for over 2 1/2 years now. But even he said this car is unbeliveable picky, and does the strangest things for no reason, and he's never seen anything like it before. That 98 miles to 13 gallons was AFTER he went into the VE tables and leaned everything out. He thinks that the cam may not be installed properly. There's no vacuum leak to be found. I've searched and searched.

 

Could you try another ECM? I know those are chip ECMs but try a different one just to see....
Fuel filter good?
Fuel pressure good?
Injectors flowed/matched?

Just odd.....

 

Used the ECM from both of my cars, no difference. Fuel Filter brand new (<1K miles). Fuel pressure 43.5@ WOT (vacuum line removed), 41 PSI @ idle (1200 RPM, low vacuum). Injectors swapped out with 24# injectors and according tune, still crazy rich.

 

Hindsight: In late October/Early November last year, I was driving around with a set of stock lifters with 78K miles on them (thanks TQdrivenWS6 for those). While the car wasn't running perfectly, it wasn't completely bottoming out the fuel trims on the rich end and at idle was pulling a split blm instead of showing full rich and trying to pull fuel. And the car felt plain NASTY. Scared the crap out of me when I did an 85% throttle 2nd gear pull. It just doesn't feel like that now, and this is after swapping in another set of Comp R's.

So..............

I NEED to know some fairly precise limits of stock style lifters (I.E. regular old Comp or Crane lifters). Will they take near 7K (probably around 6500-6700, maybe a touch more) and 150# of seat pressure and about 350# of open pressure???? I'm just not too trusting of Comp R lifters right now.

 

I think it would be safe to say that you would be at the limit of the stock lifters in terms of seat pressure. And I am sure they wouldnt like 7k rpm. I have seen that comp R's do not like a lot of pre-load, like only a 1/16 of a turn. But it seems like your narrowing down your problem. I would swap in some stockers just to see what happens. Just drive it around and take it easy to see how it feels. Good luck man.

 

When I ran Comp R lifters I did the zero lash thing and cinched them down. I did not do the 1/16-1/8th turn on them, zero lash and set the poly locks.

 

Mine are set at 1/16 of a turn. They're not too tight and hanging a valve open though, because if you look at my powerband it's doesn't nose dive at all.

 

Maybe this needs to be looked at in another light:

What would cause too much fuel to be making into the system???

Leaking injector: Not the case.
Possibly grounded out injectors???
Weak Spark -- tried two optis, multiple coils, plugs and wires, ICM, all no help.
Fuel pressure too high/low: Within specs, brand new pump, brand new regulator.

Other ideas??

 

So did you actually check fuel pressure at WOT or just by pulling off the vacuum line? Could a leaky vacuum line cause issues?

Good luck with it though.

 

Haven't checked it @ WOT. Planning on doing a bit of interactive tuning on the dyno via the www. Bringing a FP gauge and vacuum gauge with me to help too.

 

Have you looked at the spark at the plug, does it look week? If it looks like a strong spark you could cancel that thought. Maybe your plugs are fould due to you driving it previously driving it before you had it leaned out? If all else fails put the stock lifters in it, you said it ran great then and you put in the comp R's and you started having problems. I have been seeing more and more people having problems with these. Just cause the motor isnt droping off doesnt meen its not happening. It almost gives the same effect of valve float. I know my car would level off in power with my stock 155k mile springs. Maybe try setteing the lifters to zero lash like someone else said. Since that would be easer than pulling the intake.