dyno results and A/F ratio

[Craig 94 TA GT]

Well, I'm all out of ideas. Bryan just replied and seemed to imply that it isn't the tune and either the dyno guy is trying to screw me, or I've got other problems. He said it's nowhere near blowing up with those readings. But has no idea why all those mods = junk horsepower gains, and the ridiculous torque readings. Sometimes I just want to get rid of this thing because I've had it with the problems. Or maybe I'll just take my chances and let the motor blow up if the dyno operator was telling the truth

[Kevin - Blown 95 TA]

We have about 40 or 50 dyno cells and three huge test houses of engines at work and there are guys that have probably lost 5 or more good years off their lives due to the stress of trying to get accurate hp numbers out of these things for the customers that are threatening to sue us. Same with the emissions guys and the sound guys and the electrical & EMC guys (me). I'm here to tell ya, that test instrumentation, if you take the uncertainty of measurement into consideration, is imperfect and anyone that takes dyno hp & torque numbers verbatim is dreaming unless you got the latest & greatest equipment and back-to-back samples on different dynos that agree - only then will you get any kind of confidence factor that you can work with. I also worked at a tune-up shop and the emissions equipment was almost always acting up. And those dyno guys that don't have the ability to properly take care of the O2 probes and put them in just the right spot on your car's exhaust, then the readings might just be anything. I wouldn't get all bent out of shape about what one "dyno guy" says unless you really trust him because you have worked together for a while. I'm to the point that I don't trust anybody. I have three of my own O2 sensor logging setups, and they are all like new in perfect condition, and even they don't all agree. Rant, rant, etc

[Craig 94 TA GT]

I'm not really sure what to do though. If the dyno operator was telling the truth, burning up stuff with my exhaust, then my motor will probably blow if I drive it hard, correct?
I guess the hp #s should be secondary because as you said, the machines are imperfect. In fact, if you look at the way our cars were tied down, the LS1 cars jolted like crazy after the run, and Steve's jolted a tiny but, but mine didn't at all, not one bit. I even have an insane shift kit on it, and it didn't move when it shifted. Not to nitpick, but just goes to show on how everything can be different from run to run.
I'm thinking that I should load the stock program back in and get a good A/F reading. Maybe I'll try to get it dynoed with A/F again, with the stock program for security, log the runs, and check the fuel perssure with a gauge. That may be the only way to tell if there's something truly wrong or not

[Kevin - Blown 95 TA]

Craig, if you use gasahol, it will show up lean cause that stuff is 10% ethanol which has a stoic of 9 but shows up as 14.1 in a 10% mix, not 14.7 like real gas, and it is fed into your engine by volume. It makes tuning an engine a nightmare. Some stations have it, some don't and those that do have UP TO 10%. Thank the farmer's lobby for crappy gas.

[Craig 94 TA GT]

That is interesting. I just dumped in a bunch of gas before the dyno at the local 76. That makes me wonder...
Bryan also told me to check my rocker adjustment. They may be too tight. I will tomorrow or Saturday, along with fuel pressure @ WOT.
Another thing I noticed is that after evey run, the A/F mixture gets leaner. As if, as you drive it harder, something in the fuel system is giving up a tiny bit. Again, you can't trust readings 100%, but I wonder if that should hint at something

[Craig 94 TA GT]

Can anybody please read this plug? It has less than 50 miles on it. It doesn't look anything like my previous set of plugs. It looks to be "painted" white at the entire tip. Again, that's < 50 miles. My previous set looked nothing like this. This plug is an NGK Iridium.

[fastTa]

White spots or hot spots on a plug are a sign of excessively hot combustion chamber temps caused by a lean condition.

Were all eight plugs consistantly white?

[Craig 94 TA GT]

I only removed 3 and they were exactly the same. White all around. Is this common for a lean condition with this many miles on the plugs?

[fastTa]

I only removed 3 and they were exactly the same. White all around. Is this common for a lean condition with this many miles on the plugs?

Technically you are supposed to read plugs only after a WOT run. But, when the insulator is that white, it is normally a pretty good sign of a lean condition. It is hard to tell but do you see any little contrasting black spots on the electrode? That would point to detonation as well. Detonation is also a cause of excessive combustion chamber temps which will either blister or turn the insulator white as well.

Have you checked your EGR lately. It's hard for most to believe, but the re-circulated exhaust gases actually cool combustion temperatures by diluting the air/fuel ratio slightly. Make sure the EGR vlave itself is not sticking and make sure the vaccum line to to EGR valve is not blocked or clogged. Without the "cooling effect" of the EGR system, the combustion temps will rise and and you will increase your chance of detonation.

[Craig 94 TA GT]

Thanks for the info Kevin. I don't see any black spots on the electrode...maybe a shade of gray in some areas, but that's about it.
I'm not sure if this counts, but after the 3 WOT runs at the dyno, I took it home, (~12 miles) and never drove it since.
The EGR is new, replaced about 6 months ago. Maybe I got a faulty one, but it was put on when the last set of plugs were still on. Maybe it doesn't count since I didn't read them after WOT, but they had no traces of any of this. I'll check the EGR again to make sure it's not sticking.

[fastTa]

Thanks for the info Kevin. I don't see any black spots on the electrode...maybe a shade of gray in some areas, but that's about it.
I'm not sure if this counts, but after the 3 WOT runs at the dyno, I took it home, (~12 miles) and never drove it since.
The EGR is new, replaced about 6 months ago. Maybe I got a faulty one, but it was put on when the last set of plugs were still on. Maybe it doesn't count since I didn't read them after WOT, but they had no traces of any of this. I'll check the EGR again to make sure it's not sticking.

Well if you were not running lean, that the 12 mile drive home would have turned the electrode back to a greyish-white color. So it would seem that you are in fact running pretty lean. Just gotta find out why now.

The grey deposits you see on the electrode are normal.

[Craig 94 TA GT]

So even with the pcmforless tune that leans out the mixture for max power, the plugs aren't supposed to look like that? Bryan said at this A/F ratio, it's at max power with no harm. Something still seems fishy though.

I'm still thinking the fuel pump wiring harness could be an issue at WOT. I think now I'll definitely load the stock program back in and do a couple WOT tests with a fuel pressure gauge taped to the windshield.

[fastTa]

So even with the pcmforless tune that leans out the mixture for max power, the plugs aren't supposed to look like that? Bryan said at this A/F ratio, it's at max power with no harm. Something still seems fishy though.

I'm still thinking the fuel pump wiring harness could be an issue at WOT. I think now I'll definitely load the stock program back in and do a couple WOT tests with a fuel pressure gauge taped to the windshield.

Well I doubt the PCM4Less tune is set to a target A/F ratio of anything over 13:1 during Power Enrichment mode (or more specifically the PE Multipler). Maybe 12.5 -13.0. If you were truly in the high 13's at WOT that is far too lean. I would contact PCM4Less.

[Craig 94 TA GT]

I did and Bryan said:
"The air fuel is slightly lean 13.5 or so. The target is 13.1 to 1 on an NA
car. Thus you are not going to melt anything down...
The cars I did for Hendrick Motorsports they insisted on 13.5 to one and
they are street cars too. I just personally like 13.1 myself. Leaner =
more HP.
On to your car, it does seem to be a bit down. Typical gains from the PCM
alone are 13-16 RWHP so I would have to wonder if there is possibly
something up with the dyno or the car. It would be nicer to know if it was
an apples to apples comparison on the same dyno."

And when I showed him the plug picture:
"Wow, that is super white. Time to look for vacuum leaks and a dirty maf as something is skewing your tune."

I just cleaned the MAF and I'm almost certain there aren't vaccum leaks. Then again, if I was so sure, I guess I wouldn't have had this problem.

[Kevin - Blown 95 TA]

It can be extremely hard to tell much about the mixture by reading a plug from an engine that uses unleaded fuel because there are a lot less deposits than from leaded fuel. I've seen NGK plugs white on the ground electrode like that from clean burning engines in my testing here at work, and I'm not sure exactly why, but it may or may not mean anything. Warning signs to look for is blistering of the insulator or little bead like deposits glass (melted insulator) or specks of aluminum (from the pistons) on the insulator and electrodes - then you've been overheating the plug & possibly detonating. If your car is healthy, and the scans show normal operation of the injectors and o2 sensors, BLMs in line, not too much ign. retard, it could still be the fuel, but one other thing to try is a (new) standard heat range Autolite in one cylinder to see if it looks the same. Remember that iridiums are meant to do a complete burn and the center wire electrode runs a lot hotter. it is doing it's job by giving you good combustion. Also check some other cylinders to see if it is the same for all, and from bank to bank.