brennanw

Anyone have any tips for tuning part throttle. I'm running a 383 (70's era block and heads) with a stock cam and 9.5:1 compression with a 7747 ECM and 350 TBI. I've been able to get it to idle quite smoothly but any touch of the throttle causes the engine to stumble. Moving the throttle actually causes the timing to retard (as evidenced by my timing light). On my first attempts I used an ARJT bin. I increased the BPW from 135 to 138 and disabled the EGR and VSS switches. It idled well but stumbles off idle, caused by retarded timing off idle (I think). I gave up on the ARJT and used an ASDU bin. I made the same changes to this bin as I did with the ARJT bin and got the same results. Should I focus my attention on the Main Spark Table at this point?

FYI: I've asked the same question over here http://www.efi-tuning.org/forum/inde...ST&f=12&t=354& but haven't got much of a response yet. So I'm hoping you folks can help me out. Attached is the latest version of the ASDU bin that I used this morning. Change the .bmp to .bin. This bin gave me a great idle but no luck off idle. Still get retarded timing off idle.

Mc Firebird

i had a look at Accell's guide notes for setting up EFI from scratch they say set the whole advance table to 6degrees then work up from there.

I have never tried it but it sounds like a way to get started.

Grumpy

Try adding some MAP, and TPS Accleration Enrichment. Both tales are really minimial.

As you crack the throttle open the vac will drop, and yes, you'll see the timing retard some.

Grumpy

For a totally unknown megabuck engine that would be one way. But, it'd take forever just to do the main spark table.
Looking at a couple dozen similiar files, ie 747s would give more then enough of an indicator of where to start.

But judging from his .bin, I'd be adding some AE first.