Thread: :: Solved:: Catalytic Converter?

Just bought my comp g. Had a bad motor. Two pistons where chipped off. Got a donor motor, installed it no issues idling at all. I've got a tech2 at work (this was happening before as well) updated the pcm to address some issues known by gm.

Went to do a crank learn it it will rev up to 3k if I do it gradually. If I do it quick or (if I'm just trying to accelerate while driving moderately) as soon as it starts producing boost it hesitates. Almost like I hear the sound of air coming out of the air filter.. little bit of sc whine then it hesitates... I don't want to push it because something isn't right. I'm starting to think the c.c. is clogged and thus maybe the reason the old motor gernaded.. It looks untouched at 139k miles. Anyone have any other ideas? I'm just going to have a straight pipe put in delete the cat and resonator tomorrow just figured I'd see whos had experience with a scenario like this.

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Let me add there is no cel. And when it's revd up good (first time I tried the crank learn) it will make weird/bad noise.. sorry for the description and the end dies. When I start it back up the exhaust smells bad.. not not like eggs, it's kind of like smoke or oil maybe and then it starts to idle fine.. hmmm

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Wheee, vac leak?

Get a scanner on it. Are the fuel trims pegged @ 16.4?

Converter could have been damaged from the chipped pistons as well.

Short term fuel trim says 14%
Long term is sitting at 16%

Fuel trim learn enabled.
Fuel trim cell 0%

If those are what your talkin about. Doesn't seem like it has a lot of exhaust compared to the other 3800s I've checked here at work

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If the LTFT's are sitting at 16.4 at idle.

You have a vacuum leak.

Yeah the 16 is at idle if I give otherwise some gas it drops. I guess I'll have to assume that it means % but it doesnt have a 16.0 or . In general just says 16.

Guess I'll look for an vacuum leak... still having the cat and res. Taken out.

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On the intake manifold to egr tube is there supposed to be a gasket?

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Took it in ended up being the catalytic converter was clogged. Also had the resonator removed at the same time. Car sounds awesome and runs like a champ. Still kinda interesting to know why my long term fuel trim are at 16

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As said before you have a vacuum leak somewhere. Check all lines and such for the issue.

And now that the cat is gone your check engine light is going to stay on unless you have a tuner program the codes out.

I'm not worried about the cel. Theres really only the vacuum line at the T on the intake that goes to the map and to the boost solenoid. Where else should Inge looking

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That CEL will ruin some of your MPGs though.

I wish I had a diagram of all the 04+ vacuum lines, maybe someone else does.

I'll just get an o2 emulator.

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