1990 c3500 Tuning and EBL Flash II assistance

[MisterGrimm]

Grimm from Atlanta here. Today I'm here to humbly ask for some guidance from those who are smarter than me with regard to both timing my engine and tuning the EBL FLASH II system in my 1990 C3500 Dually. I hope this is the correct section to post this in..

The engine is a fresh build, though this truck had a 454 in it from the General once upon a time before I owned it. I am a technically savvy journeyman mechanic, but tuning fuel injected stuff is all new for me and I'm currently at a loss.

I guess that I'll start by listing the engine specs. It's a big block 454. According to the build sheet, the engine was built with:

• eagle CS 4" Stroke crank
• king racing xp rod & main bearings
• forged I beam connecting rods
• speed pro coated skirt pistons 10:1 comp
• comp extreme energy cam
• high volume oil pump & pickup
• 2.19 - 1.880 stainless epr valves
• cast oval port heads (stage I port & comp valve job)
• 10 degree moly retainers and locks
• 924.16 comp springs
• roller rockers
• Hedman mid-length headers
• standard 454 tbi throttle body for this year truck

From the printout provided, I can see that the engine builder was running this at 18 degrees BTDC on the "run stand". It didn't specify if this was advanced or initial. I don't have much big block hands on. This seems like a lot of initial timing to me, and frankly the engine doesn't seem to like it either, but I may have missed something in the tune and I've also been seeing MIL code #33.

• My first question is: what should the base/initial timing be set at on the engine realistically? The original emissions diagram on the air cleaner said 4 degrees BTDC.
• My second question is: besides setting the SA Initial timing setting in the BIN to match, what else do I need to adjust?

I began with the 1 ton truck bin (EBL_F_2013). I disabled EGR in the bin, as this provision is not in place. Is there anything else that might be relevant to the tune that is important, which I might be overlooking here? The charcoal canister is still there if that matters. Lastly, as I briefly mentioned, it had been indicating MIL code 33 as "on" for the brief time I had the truck running. Sensor is there. It's plugged into the rear of the TBI throttle body in a T with the vacuum modulator from the transmission.

The transmission is a TH400, though I'm fairly confident that even though it's new, because I've been working on this in my free time over the course of a wide span of time, it's nuked. its currently only got Reverse and four neutrals... but that's another story for another day.

I appreciate any and all guidance, and my truck does too!

 

[PlayingWithTBI]

From the printout provided, I can see that the engine builder was running this at 18 degrees BTDC on the "run stand". It didn't specify if this was advanced or initial. I don't have much big block hands on. This seems like a lot of initial timing to me, and frankly the engine doesn't seem to like it either, but I may have missed something in the tune and I've also been seeing MIL code #33.

1st - fix your MAP issue. Maybe your vacuum going to the TH400 is leaking, allowing low vacuum reference to it.

My first question is: what should the base/initial timing be set at on the engine realistically? The original emissions diagram on the air cleaner said 4 degrees BTDC.

Yes, normally you'd set your initial timing at 4° on a 454 but, depending on your cam and setup, you may want to go higher for startup. For example, I set my 383 to 10° with the EST wire disconnected AND set the "SA - Initial SA" (in Scalars) to 10° also. This way, your timing tables won't be skewed by 10° but it'll start easier.

My second question is: besides setting the SA Initial timing setting in the BIN to match, what else do I need to adjust?

Here's a link to an Excel Spreadsheet in which @84Elky set up starting with "All In" at 3200 RPM. You can fine tune it based on your Knock Counts at certain speeds. Use the one from post #8 which has some corrections.
www.thirdgen.org/forums/diy-prom/761049-spark-advance-table-example.html#post6301288

Spark Advance table example needed - Third Generation F-Body Message Boards

DIY PROM - Spark Advance table example needed - Trying to understand the sa tables vs actual engine excelleration vs mph at the foot pedal. Found this graph from older thread here and compared it to my bin which is a lot different. Can there be a good/simple reason?...

www.thirdgen.org

You may want to increase the fuel pressure so your Injector Duty Cycle doesn't go too high when trying to achieve desired AFR. A WBO2 sensor is a great tool for this, just wire it in to one of your ADC connections and run VE Learn based on it instead of using the NBO2 one. Playing with PE AFR , AE (like a pump shot), "SA Launch Mode" will help too. RBob explained a lot of it in his "Calibration Help" utility. YMMV

 

[MisterGrimm]

Thank you sir. I appreciate the knowledge, always! I will get into that asap, and I'll post results. I'll start spraying the carb cleaner around the throttle and see if there's an actual leak there. Then I'll start digging into the hoses and all that jazz...