Paxtonspeed

Just wanted to give everyone following an update.
I changed out the fuel injectors to the original 454 80-90 lb/hr injectors that came in the late 80's early 90's trucks.
These injectors were rated at 12-13 psi fuel pressure, so running them at 30 psi on the boat really makes them flow some fuel.
I had to cut my main BPW table by more than half. On first start, it was so rich, the engine almost wouldn't run. I was afraid it was going to foul the plugs.
Anyway, got it out on the 4th and did some tuning. She was really rich, so I had to keep cutting the fuel table down. I finally got her running back in the 12's AFR wise at a mild cruise.
I worked my way up to 5000 RPM and the AFR was around 10, so the good news is I have plenty of fuel now.

It was so hot out, that the wife and kids were *****ing at me to ride the tube. So, I had it good enough that we could tube and not drown the motor with fuel. Running in the 12's 3000 RPM up to 4500 RPM with 5000 RPM still being a little rich. The next time out I should be able to dial her the rest of the way in pretty easy.

These are the injectors, I was able to find a new pair local. The spray pattern looks good, no leaks, so far so good! Did a lot of research, this brand and part number seems to be the best aftermarket TBI injectors you can get.
https://www.summitracing.com/parts/smp-tj11

Trash

Great work!

Were you able to solve the spark advance/hard start issues you had?

Paxtonspeed

I ended up dropping the base timing to 5 degrees and setting low map/rpm timing to 15 degrees like you said. She fires right up!

Trash

Cool. Not to beat a dead horse but you have both the mechanical base timing set to 5 deg AND then the ECM value to 5 degrees as well correct? Bottom line is they should match regardless of your end value.

Paxtonspeed

Yes sir, they match, I made sure. It seems to me that the only reason you have to have them match, is so that what is reported in the data log matches what your timing actually is. Which is obviously a good thing and needs to be done.

I do have a question for you though. It seems like the injector flow rate setting in the ECM does not do anything. I changed the setting for the new injectors several times trying to lean out the mixture and it never really seemed to have an effect. The only way I could lean it out was by changing the BPW table. This is fine as long as it works, but I know in the automotive world, changing the injector flow rate can really change your global fuel delivery. Wondering if you could confirm this?

Paxtonspeed

Latest picture of the engine all together. Got my new K&N stainless steel spark arrestor. Had to make a new stud to mount it, and buy the kit to connect the hoses from the valve covers. The filter looks like a normal automotive filter, but has "Marine SAE J1928" on it.

https://www.summitracing.com/parts/knn-59-3364
https://www.summitracing.com/parts/knn-85-1362

SB

For the next person:

Spectre Performance 4215 Air Cleaner S-Stud
by Spectre Performance
Link: http://a.co/bNVwPYc

Paxtonspeed

Well I'll be darn.... I used a piece of 1/4-20 all thread, and a stainless locking nut.

Trash

To the best of my knowledge the injector flow rating scalar is INOP in the MEFI 1. Many of the parameters listed are either holdover from automotive work and or installed for future use. MEFI 1 only uses a subset of most parameters listed. The injector flow rating your referenced I believe was for fuel flow calculations for burn and or MPG readouts. In other words it was used for external gauge calculations and not internal engine controls. Another example of unused parameters are the BLM values, among others.

BPW tables should be your MAIN reference for tuning AFRs. However, Cold Engine BPW Multiplier vs Coolant will change the fuel values GLOBALLY. The same goes for Run Time BPW Multiplier vs Baro. I have used the two tables I just referenced but only after the tuning was dialed in on a warm engine. The other option to add or remove fuel over the entire table is to use the table editor tool box and select any number of cells, pick your function (i.e. offset, divide, multiply etc) and value then execute. This will increment the all cells selected.

Keep in mind the engine operates in a limited range in the fuel table, and spark table for that matter. The region is approximated by the example below of your fuel table. I apologize for my 1st grade crayon outline. This is the area you want to concentrate on. In fact when you log in scanner pro you will see the tables fill in in virtually the same pattern.

Paxtonspeed

Permanent wide band installed.