LOL.. his bandwidth limit was exceeded yesterday, guess I was lucky to get files 1 and 2 :^) I've got 3 now, looking at it.

I'm always thinking crane when it comes to springs, dunno why, guess it's because I've been really happy with them.

-Christian

 

A few things I'm seeing in the datalogs... The dyno runs look like they were done with the motor cold in open loop. The O2's also are very low initially and slowly climb from 450mv up to 800 at 6000 rpm. The car looks to be running very lean especially at lower RPM's and I wonder if this is from running in open loop...

-Rob A.

 

Howdy, a little birdie asked me to check this out and see if I could add anything. I think Christian is on the right track with some damned good advice here. I'd love to see the dyno graphs in addition to the datamaster logs.

Voltage (lack thereof) will kill the car, and this 88 on the MAP is bad voodoo.

The TPS I think you'll find that if you adjust it down just a tad that it won't spike then drop. I've seen that too many times before. Might have to grind out the sensor to get the adjustment you need. This will also throw off the fueling calcs, so it's not a good thing.

That cam is famous for falling off kinda early, but it should also peak better, then fall. :-) So, that's not it.

The person who said you can't adjust LT1 cams is wrong, I do it with every LT1 cam I install, just drill out the cam sprocket and use a cam bushing, like the old school. I've had to move a lot of cams to get them right. Gotta love quality control. So yes, that could be the problem.

A cylinder missing can be deceptively smooth, so verify that everyone is getting fuel and spark.

Post up the dyno graphs (or data, I have a dynojet in my shop) and run down some of the things that have already been posted here and you'll find it!!

Good luck!!
-jeff

 

I'm gonna check out my valve springs this weekend and i have some Comp R' lifters on the way just for the hell of it. The car pulls really hard down low and acts like its a heads and cam car but then it falls off quick above 5k. So maybe i'm wrong but i think that rules out being down a cylinder and probably the cam timing. I'm also gonna look into the Charging/volts thing too. The car only says its has about 12.5 volts. Milkman what do you mean the 88 on the MAP is bad voodoo? I assume that means its bad but what do you mean? and what should i look for? Also what are you talking about the with the TPS sensor? The car has a stock TB with the TPS in the stock location. Also Milkman my friend made links to the Datalogs and they are in this post. I can try to get you a scan of the dyno graph.

 

Thanks Jeff, good to see you man, always appreciate your feedback.

There are two things the 88 MAP could indicate:

(hopefully) it's reporting low because the reference voltage that feeds the sensor is dropping because of a charging problem, like the TPS.

The alternative is that the 88 MAP is real and you've got increasing vacuum in manifold at WOT (signs of valvetrain issues, restricted airflow, or backpressure)

Personally I'd take care of the voltage before anything. Just run it down to Autozone, they' can run a test for you, I'm thinking an alternator is a lot cheaper and easier than lifters and springs. Why not give it a try first.

Hope this helps,
-Christian

 

its raining today so i'll try to run it down to autozone tom. I'll still keep the comp R's on order because i'll switch out the OEM ones sometime just for extra insurance. I really appreciate all the help from everyone. I'm just a little punk college kid trying to have a nice/fast car and i'm still learning when it comes to cars. This has really gotten me down. I'm thankful for everyones help and i can't wait to get it straightened out. Thanks Mike

 

if one of his cylinders weren't fireing, wouldn't the guy tuning the car see that?
i'm having similar problems, mods in sig, car just went 12.8, should be more like 12.2, my car does have a -slight- stumble at just under 2,000 rpms and vibrates just a little under a load in 6th gear 1500-1900 rpms., and my power will sometimes completely stop for .5 seconds or so in 3rd or 4th gear,
the car IS NOT dyno tuned yet though, maybe me and u have a similar problem. let me know when u get urs figured out. good luck.
i definately don't want to pay the $$ to dyno tune my car if my problem can be fixed before hand.

 

if i find anything out i'll let you know mystic.

 

Make sure it isn't your coil. Bad coils are notorious for making garbage high rpm hp, while a fuc*ed opti is notorious for low end or all-around miss.

Mike

 

No worries, we're all young punks on the inside, that's why we love our Camaros.

I just got a chance to look at the last datalog, I'm doubling my money on the alternator.

There is one other possibility, that's the ground side of the reference voltage provider. This is an easy one to fix, Find the ground junction on the passenger fender, remove each of the ground straps, clean each connector as needed, tighten them back down, then cover the connectors in silicone to help block again future corrosion.

I'm still leaning toward more alternator, since voltage is falling at high rpm under heavy load.

You airflow was up on the last run, that's good man, signs of potential powaahh..

Keep us posted,
-Christian

 

I got the alternator checked while it was still on the car. The guy said it was pulling 13.5-14.0 volts. The volt gauge in the car says less than 13 volts and my scanmaster says 12.4-12.6 volts any reason there is a difference between the two? Why would they be different? anything i should check?

 

Most of the time the wiring harness gets old for the fuel pump & you get a huge voltage drop, if you run a separate power cable to the fuel pump using a relay I bet your datamaster voltage will go up, its just that the pump is killing the rest of the system voltage, mine did that & running a separate harness from racetronix fixed the problem.

 

The coil has probably 25k on it and the opti has about 35k on it.

 

If you've cleaned up the main ground junction block, I'd say it's time to start checking things like reference voltage for the sensors and fuel pump voltage. Turn on the ignition and check the reference voltage going to the TPS and MAP.

Like Matt was saying your fuel pump might be causing a big voltage drop, they do that as they get old. A larger guage wire can handle the current, while the factory might be causing a load, hence lower system voltage.

Hope this helps,
-Christian

 

ok I will look into it. If the fuel pump is eattingto much juice can i make my own "Harness" i assume just replace the old wire with a much bigger one. Is that all it takes? and do you mean i should check the voltage of the TPS and MAP while the car is shut off then while it is running an look for diff.