Spark help

[Stokes1114]

I have a 93 k1500, 5.7, 7427 running $E6. I have yet to touch my timing tables and probably wont until all the parts swap onto it in a couple weeks. However, one of the things Ive noticed is that when datalogging my spark advance at idle is not what is commanded in my table. Around 20 is commanded, but Im only getting around 15. If I tap the gas a bit it will go to 20, but at idle its about always lower 5* or so. I have looked at all the biases (I think) and I cant seem to find anything. Is this normal behavior for it to be consistently lower, or higher for that matter? Just trying to wrap my head around it all.11987 Im using advanced $E6 v250 xdf and modified A201 adx.

[dave w]

The attached .xdl files are from a $E6 vehicle I worked on a few years back. The spark data seems normal to me.

dave w

[dave w]

Attached .bin file for data logs in previous post.

dave w

[Stokes1114]

Thanks Dave I'll take a look at the files and get back with any questions

[Stokes1114]

DaveW, was this with the stock swirl port heads?

[dave w]

DaveW, was this with the stock swirl port heads?

Maybe the files I attached were not helpful. It was almost 3 years ago when I did that tune. I'm not the best at record keeping, so I don't have information if the heads were the stock swirl port or not.

Attached is the .bin file I ended up with on my 93 K1500, with the following engine modifications.
Bone stock Swirl Port heads with performance valve springs (Z28 springs) and 1.6 roller tip rocker arms.
Bone stock L31 Vortec roller cam and lifters.
9:1 Compression Ratio
Modified Stock TBI intake, throttle bores enlarged to 54mm. Also radiused the throttle bores.
454 Throttle Body with Cop Car Injectors (65lb)
Shorty headers, with 3" single cat back exhaust system.

0 - 60mph in slightly over 7 Seconds!

The performance fell flat at 4500 RPM's.

dave w

[Stokes1114]

Thanks Dave, I finally got some gunk cleaned off my timing tab and was able to mark the groove on the balancer with a silver sharpie. I got the timing light from my dad and checked base timing with the est wire disconnected and It was retarded about 3-5 degrees. I am guessing this is why my timing that shows in my datalogs is off of the commanded at times. Most of the time really. I was going to adjust it to 0 or a bit advanced if she liked it, but I couldnt get to the bolt on the dizzy with the wrenches I had. I will wait until next weekend when I swap to the DUI distributor, LT1 cam, holley 300-66 intake and other small pieces. I always thought that the truck would seem like it would just fall off at certain rpms. I live high in the mtns so going up certain passes in 3rd between 30-45 mph it just barely gets up. I am also looking into torque converters..most likely just an s-10 or similar. I am hoping after these parts go on I will have a bit more torque. Which after hearing from you about your truck and Fast on his van, it sounds like its proven to put out a bit more with the right combo.

[Fast355]

Maybe the files I attached were not helpful. It was almost 3 years ago when I did that tune. I'm not the best at record keeping, so I don't have information if the heads were the stock swirl port or not.

Attached is the .bin file I ended up with on my 93 K1500, with the following engine modifications.
Bone stock Swirl Port heads with performance valve springs (Z28 springs) and 1.6 roller tip rocker arms.
Bone stock L31 Vortec roller cam and lifters.
9:1 Compression Ratio
Modified Stock TBI intake, throttle bores enlarged to 54mm. Also radiused the throttle bores.
454 Throttle Body with Cop Car Injectors (65lb)
Shorty headers, with 3" single cat back exhaust system.

0 - 60mph in slightly over 7 Seconds!

The performance fell flat at 4500 RPM's.

dave w

You can think that tiny little L31 cam for that. It fell flat in the 4,500 rpm range in my stock 1997 Express too. It actually felt slower shifting it at 5,000 rpm with the stock cam. Even the hotter L31 marine cam only peaked at 4,400 rpm. The Marine cam peaked at 4,400 rpm but has good power up to 5,200. By comparison the F-car LT1 cam in my brothers 99 suburban felt strong until 5,500 rpm.

Stokes, at that speed it likely needs to drop to 2nd to have good get up and go.

[Stokes1114]

I have noticed in my bin, (probably xdf) there are 2 different locations for idle spark max mph limit. One is under idle spark parameters and the other under idle parameters. They both have different values as well. One is 4mph and the other 40mph. Does anybody have any idea what is going on there? Im sure I am not the first to notice this. I am using $E6, BDKA