Gas tank full no miss @ wot???

I went to my dyno tuner finally. With the H2C cam vs. the custom cam I had before I made 7 less horsepower. But my tuner said in reality I made just as much if not more. With the custom cam I ran 28 inch tires and 2.92 gears. With the h2c cam I ran 27 inch tires and 3.27 gears. Also the heavier g force 1000 hp axles. He said he was able to go to 160 before in 4th. Now only 140. I had actually protected the car pretty well. With my hz table I was running 11.68 to 1 afr. He adjusted it to the mid 12s.

So off I went back to Tucson. Still a miss at 5100 at wot in gears one and two. I definitely felt it was going to be the one and two clutch packs.

But when I stopped for gas and filled her up the miss went away. I then remembered posting here that I got the miss to go away by adding fuel to the hz tables. But I now remember that I also filled her up when I did that.

The miss starts coming back at 3/4 of a tank full. Is it coincidental or am I on to something? What if anything could be wrong with the fuel system where only on a full or nearly full tank of gas I get no miss?

I really need a good fucking log to look at or this is going to drive me insane. A miss, like engine miss or it hesitates, timing drops, does it fart? Please describe what "miss" is.

well. it stops revving for a quick instant. then starts revving again. sometimes i do not notice it in first. but when i hit second she comes back to 5000 rpm or so. 100 rpm later the rev from the engine goes away for 1/10th of a second and then continues like nothing bad has ever gone wrong.

but the log i showed you before does not show this. also when i ran for misses it did not show this.

you think it is driving you crazy. it is so so frustrating to me.

next Monday it goes to the dealer. I went up the ladder and if it is the transmission they are going to try to help me out.

Here is another way to describe it. It is like a short pulse and the car's reving goes away for 1/10th of a second.

Someone told me that is a classic symptom of either a tps being bad or maybe a solenoid on the transmission going out.

Maybe?

stock pump or a racetronix etc?

stock pump. 75K miles on the car.

Oncoming volume preset. Anything to do with it causing a slip in first and second at 5100 rpm? I looked at them and I must of changed them to a lower value. I upped them again to stock numbers. plus 10. It seems like the slip is gone. But I do not want to say for sure. I have been bitten in the butt before. I still have the vibration at wot after 6000 rpm. The dealer just put in a new driveshaft after the old one broke. Probably just a bad new driveshaft. Time to get the one piece one from g force.

Is the TB closing at all during that miss? It could be jumping around hitting a weird timing cell or some other TM doing this.

Hello,

The dealership did a complete obdii test of the transmission. It is completely normal. No abnormal slip. No particles in the transmission.

I had it dynoed and the engine is running fine.

The only thing the dealer can think of is my tune with the torque management.

Can I send you the tune with you critiquing where maybe something is going wrong?

I know my tuner turned off some of the diagnostics. So I copied his tune to my stock tune since there are so many diagnostics. Then I drove around and floored her a few times. The only code that came up with P0300. It stated more information to come. But none never came. I think the P0300 is normal with an aftermarket cam. It did not come up on the dash. I then flashed her back to his tune which is below.

tune

Need a log of it happening.

You say it goes away with full tank of fuel?
If so maybe when low on fuel, the pump is heating up and starting to give up and not flow enough?

Def post a log.

I think I spoke too soon on that one. I have noticed it with a full tank of gas.

The dealer today is going to run a fuel pressure test under load.

Also another obscure; but possible culprit is the Dynomax VT muffler.

Just coincidentally I starting getting a loose metal sound from the driver's rear side.

The dealer was looking for culprits and could not find anything.

Then I remembered the valve inside the muffler. I think it has broken. So maybe under wot there is some blockage there.

Sometimes the simplist culprit is the solution.

You changed rear tires. I had something similar when I went too large on the front tires. Try hitting the TC button and see if that stops it. If so then you have the wrong size tire combination. Disabling TC in my file did not solve the problem. Still had to hit the TC button. Went to smaller front tire and problem solved.

interesting. i will try that. if it works great. if not, still thanks for the heads up.

the fuel pressure checked out fine at the dealer. i just had them put in a camaro diff, g force axles, and a new driveshaft. it is vibrating on downshifts and on wot over 6K. they are working on the pinion angle. but they cannot guarantee anything. if it is not one thing it is another.

well that did not work. and to add salt to the wound the dealer gave me the boot and, voided my remaining warranty with the vin.

at any rate Andy from Livernois has been banging his head back and forth on this one also. He thinks he has it figured out.

The other custom cam had a smaller base circle. We used 7.425 inch pushrods.

The 2c cam pretty much takes a stock length pushrod. Also Brett from Landspeed sunk the valves .013. So at the most we should of had the 7.40 length pushrods. Or with the sunken valves maybe even 7.375.

But we have 7.425 inch pushrods. Andy sais that can and will cause a systematic miss.

We will see. They will go back to 7.40 next week.

Nobody measured the P-Rod length. Lol, valve float would explain everything.

p-rod length. insteresting. roller rockers?