3.4 camaro, new here

[Jonsgreasemonkey]

Hi there,
I'm new here and thought I would share, as well as ask a few questions.

I've got a 95 Camaro (auto trans) with a 3.4 as my daily driver. I rebuilt the engine when I got it. right now it has Headers, intake, ignition, and a catback. It's a pretty stout dd...



...However it does seem to have an issue. It has a really hard time reving to 4500rpm, it'll make it, but it really slows down doing it. The highest i've EVER been able to rev it to is 5200, and at WOT, it wont shift out of first. It will rev to 4grand, then slowly make its way up to 5200, then it just stays there, as if it's limited.

Recently, I put it on the dyno, and the results were, interesting:


At WOT it runs 10:1 A/f ratio and floods the engine. It looses ALL power. Heres a vid:

http://www.youtube.com/watch?v=Q2FTwwF6Opw

Those two spots were it pauses are 4500rpm, and 5200.

Also: I've been working on this to try and solve the typical 3.4 bottle neck. But I'm not quite done.



Thanks!

[geoffinbc]

What engine management parts have you serviced? Can you get a datalog for us? Welcome

[Jonsgreasemonkey]

I've replaced both o2 sensors, the tps, the egr, the iac, the map, and I've even swapped computers with another 3.4 to no avail.

I can't give an exact data log, I forgot to have him print it, but the a/f ration steadily drops, and reaches 10 at 4000rpm. Thats pretty much all I know.

[IsaacHayes]

Replaced the coolant temp sensor that feeds the PCM?

[Jonsgreasemonkey]

I've replaced the one thats under the intake manifold.

[86FieroSEv6]

Have you done a back pressure test of the exhaust? Specifically the catalytic convertor/s?



Oh.....before I ferget ..... wilkommen!

[Jonsgreasemonkey]

Thanks!

Good point, it's the stock cat and s-pipe, with a z28 muffler.
I can see through the cat, and none of the pipe looks damaged. How would I go about "testing" it?

[bszopi]

Tap on it to see if anything sounds like it is rattling around inside.

[bob442]

unbolt the cat and see if theres an improvment. sure sounds funny, but alot like the cat.
mine took a shit at 90,000km, and how another way to check is to take if for a spin, and measure the tempature of the exhaust before, at, and after the cat, if the cat is considerbly hotter thats a pretty stout confermation and easy eanough to do with a infrared heat gun

[Jonsgreasemonkey]

I went a ahead and gutted the cat. Massive Improvement! Thanks guys!.
I'm still going to try and fab up a new intake, i'm gonna try and use a lt1 throttle body, that should give me better throttle response, ect.

[bob442]

i would imagine using a vortec throttle body might be an easier approch and cost less, there basically identical to an lsx and would be alot easier to make a mounting plate. i think they are 70mm so could possibly be too big, but, you never know...

[ForcedFirebird]

Nice job on the intake, but you know that's not the real bottleneck, right?

[tkoforpresident]

hey man welcome. I've also got a 3.4 (93 firebird)

What are the odds of me getting one of those intakes?

[Jonsgreasemonkey]

Nice job on the intake, but you know that's not the real bottleneck, right?

Yeah, the heads on there suck too. I was just making this on as an experiment.

If I can get a tig welder and a good system of making it, I'd be happy to happy to sell a few. That one is just my mock up, I haven't even finished it yet.

[Jonsgreasemonkey]

i would imagine using a vortec throttle body might be an easier approch and cost less, there basically identical to an lsx and would be alot easier to make a mounting plate. i think they are 70mm so could possibly be too big, but, you never know...

Thats not a bad idea. I'll look into it. I was just planning one buying an lt1 intake and trottle body from a junkyard and cutting off the flange and welding that on.