Nate's 1998 Z28 Project

[JoeliusZ28]

your avatar about sums it up.

But to Michael's point earlier - Jon agrees that it could very well be in the tune. I think it wouldn't settle down when the car reaches a stop the way it does if it was 100% a vacuum leak.

Either way, first step is the permatex delete mod.

[Dummybait]

Knights of Columbus! I'd like some Intake with that Permatex please!

[hoogiesngrinderz]

The way it idles high for a second or two after startup then settles to ~850 makes me believe that the Required Airflow tables are set too high

[nascarnate326]

When can you come take a look?

[hoogiesngrinderz]

I have tomorrow off. Did you find a new intake? Just saw on FB that you have it all back together.

[nascarnate326]

Engine is back together. All I did is went over the goop...with more goop. Figured I would see if I can hold off till the cam swap to get a different intake. I would rather get a fast intake than rush and get another LS1 intake.

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[nascarnate326]

Fired it up and it appears to be running correct. Revs like it used to, idles good...no noticeable issues.....besides.

Look at the fuel trims. They are negative...what did I do?

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[nascarnate326]

I have tomorrow off. Did you find a new intake? Just saw on FB that you have it all back together.

I just re gooped my LS1 intake. I get out at 5 tomorrow, so if you are available after 5 that would be sweet. I can provide food/gas/whatever you need.

[Darren]

You put that intake back on!?


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[hoogiesngrinderz]

Were those numbers after driving it a bit?

I think your VE tables are all off as well. Long term fuel trim bank 1 and 2 (LT FTRM1 & 2) are adding 18% more fuel overall in the fuel cell it's in. Short term fuel trim (ST FTRM1 & 2) will swing positive and negative very rapidly, the ECM does this based on the o2's. If the o2's read lean, short term will increase. If the o2 doesn't respond, increase again and so on until the o2 voltage swings. The longer short term stays positive, the long term trims will increase. This helps keep the engine close to stoich. Ever notice how some cars run like right after hooking up the battery but drive better after a few miles?

You're going to have to run a wideband to get your VE table in line. Cammed cars require less fuel at idle and more in the upper range. The spark advance is a bit high as well, I'm curious to see what knock/spark retard looks like with your setup.

[nascarnate326]

You put that intake back on!?


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What choice do I have? Its not like there a bunch of free LS6 intakes running around Charlotte Michigan.

Were those numbers after driving it a bit?

I think your VE tables are all off as well. Long term fuel trim bank 1 and 2 (LT FTRM1 & 2) are adding 18% more fuel overall in the fuel cell it's in. Short term fuel trim (ST FTRM1 & 2) will swing positive and negative very rapidly, the ECM does this based on the o2's. If the o2's read lean, short term will increase. If the o2 doesn't respond, increase again and so on until the o2 voltage swings. The longer short term stays positive, the long term trims will increase. This helps keep the engine close to stoich. Ever notice how some cars run like right after hooking up the battery but drive better after a few miles?

You're going to have to run a wideband to get your VE table in line. Cammed cars require less fuel at idle and more in the upper range. The spark advance is a bit high as well, I'm curious to see what knock/spark retard looks like with your setup.

Those were just sitting and idling. Ill take it for a drive tomorrow and see what it does. Wondering if my o2 sensors are causing problems as well. If your available tomorrow after 5 let me know.

[Darren]

I personally would have waited to replace it... I don't think I would ever have put that on a car. But that's just me.

[Lucky SOB]

From what I've read, you're probably going to be better off with an LS6 intake. Yes, the FAST may flow slightly more, but they're mostly hype.

[hoogiesngrinderz]

I have a LS1 intake on the shelf. I will be using it for an engine build soon but we can try it out, not hard to swap as you know. I might go LS2 top end on my 98. If I do, I'll have an extra.

[JoeliusZ28]

seems like prices of factory intakes have been hugely inflated by all the 5.3 swappers... they were a dime a dozen not that long ago.