Hi all - before I rip my hair out further (which at my age can leave me with nothing).... I've got a: ~3600lb vehicle 700R4 3.73 gears '062' Iron Vortec headed 350 Cam is 207/212@.050 .450 valve lift 112 LSA Shorty headers w/flowmasters TBI (from the 350 w/stock injectors) Edelbrock square bore 4bbl intake w/adapter plate 1227747 ECM (hopefully I've covered all the details) Question is, what would the best BIN be to start with? I've tried an ASDU, and ASDZ - but they both run so rich I'm spitting liquid! Not to mention bizzare idle issues. I was thinking taking a TBI'd Camaro (etc) one, since that would be in the right area for weight, gearing etc. Then I'll fine tune it with Tunercat. Any recommendations for a specific one? A better starting point?? I'm going nuts here, so.... help... please! Thanks!

Well, Camaros didn't run '7747s, so that doesn't help. I would use ASDU over ASDZ for a starter calibration. Then drop some Vortec spark advance tables into place.

After that do some VE work and get the idle to settle down. The cam isn't too radical, should idle OK. Then you should be able to drive it and adjust the rest of the VE table(s).

Will most likely need some additional injector flow. So once drive-able crowd the high load, high RPM area and see what the engine needs for fuel. Once that fuel delivery is dialed in go back to the low speed tuning (it'll be rich after you crank up the fuel delivery).

RBob.

I would honestly use ARHT, it has the least comprimises for emissions and fuel economy and setup more for making power.

Ok, cool - thanks both.

Using the Vortec timing tables (which I'll have to hunt down!) - what would you recommend as a starting base (mechanical) timing setting? I tried looking it up for a '97 C1500 (what the heads came from I think), but they don't list it. I've only got about 3* in there right now, and it spins over REALLY quickly while cranking (and I'm not even running a huge battery).

I really need to go harvest the Zeitronix W/B out of my turbo car and stuff it in this one for a while...

With that cam I would use a base timing of 4 or 6* BTDC. Be sure to also set that value in the calibration.

If you do use ARHT note that it is a stick calibration. Otherwise I too would have recommended it. Will need to clear the Stick/TCC flag along with setting up the TCC tables. IAC settings will also be different.

RBob.

I'll do that, thanks.

On further pondering, and checking a video I took of the engine the first time I started it.... I'm pretty damn sure I've got a massive intake leak!

It won't idle below about 950 - and last night (when I was REALLY tired I might add!) I saw the IAC count go to 0, yet it was still idling high! That should have clued me in right there. Not to mention, the ONE time I had a chance to drive it up/down the driveway it almost gave me whiplash where now it feels like a 90hp 4cyl. yet I've not really changed anything.

So... maybe the close to stock code I was using wasn't that far off??

I'm going to do a bit more testing today, then swap the (somewhat problem prone from what I'm reading) intake gaskets for a $et of the rubber/plastic compo$ite one$.

Yup - HUGE leak(s).

It's still running really rich, but I can deal with/fix that. At least it's now down to a reasonable idle. Socketed my ECM last night, so I'll slap the ROMulator on it and start tweaking.

Thanks again for the help.

Hi again...

Do you know off hand if the ASDU is/was a manual trans? I was looking at the target idle speeds, and they're all REALLY high for an automatic. I mean, I can change them, that's easy - but if all the fuel and timing curves are targeted at a manual.... I might be better off to start with something else.

Target Idle RPM Vs. Coolant Temp.

Deg C RPM
55 1800.0
65 1400.0
75 1200.0
85 1200.0
95 1000.0
100 937.5
115 800.0
120 575.0
135 450.0


2nd question... do you happen to have a copy of a timing table from a Vortec headed engine with an auto? I can't seem to track one down.

ASDU is for a 5.7l, 700R4, 1/2 & 3/4 ton pickups and vans, Fed emissions.

The ECU may be incorrect, this is what I see for idle speeds:

RBob.

Wholey snappers... totally different!!!
Ummm, I think I'm going to hunt down a 'fresh' copy of that BIN. Looks like mine had been altered. And who knows what (well, without going over every paramater!) else has been changed too.


Any idea where I might find those timing tables?

There are several posted in this thread:

http://www.thirdgen.org/techboard/di...ark-table.html (vortec spark table)

Note that the RamJet engine uses vortec heads.

RBob.