Here is what volvo shows with running this module/distributor on their carbed 5.7.

Again, looking at this shows why many timing their engine thinks these modules have no advance. Most all of it is in at normal idle speed.

Another reason these dist’s/modules good on bigger cammed performance engines compared to tbolt iv dist’s /modules especially

You can also hook the Daytona Sensors box too it, of course, like you can with other type dist’s…if you want programmable timing. Simple, just bypass module and use dist as magnetic pickup.

So, turns out one gauge was in fact 8psi low, and the manufacturer (Marshall instruments) is sending me a free replacement (bench tested prior to shipment).

Injectors are in process of cleaning then testing tomorrow probably.

^^^M instruments, i knew (somewhat) the old man. Recently passed. He liked to come out here from out west , to my neck of the woods in nh, skiing and climb mt washington. He was a character and tough as nails !
His son and daughter that now run it, are nice peeps.

Just some fun facts.

Btw: if gauge is engine mounted it should be dry type, not liquid filled. The glycerin expands when hot , and if too hot it pushes against gauges diaphragm which makes it read lower.

I may have experience in this. Just few hundred times a year. Lol.

These gauges are in fact liquid filled -- with silicone. Not sure if silicone behaves the same way as glycerin under heat. But if I see lower pressures when hot I'll know why!

Yep, still not sure where cuve or advance would be coming from as I only know the module to convert the pulse to something ecm can use.
Now heres my "test" for sake of discussion : If I hook my MSD Ignition 8998 to those 2 pins coming from dist pickup to input side of module (I often do this trouble shooting) using it as a signal generator, I can simulate the engine going anywhere from 10 rpm to 10,000 rpm, a standard brand module will smolder after 30 seconds much above 5000 if the rest of mefi is plugged in, a merc or dui will take 5600 briefly in air, more if mounted to something to pull heat from it i ended up mounting one on aluminum as a heat sink .
Anyways, IF I go in the mefi ecm program and I set timing to say 15 degrees in every map vs rpm table, top to bottom, plug my lqaptop in, set it to scanner pro or plug a merc scan tool in, crank the signal generator between idle and 5000, it will show it commanding 15 degrees of timing top to bottom.
Now, if a mefi motors on my dyno, I again set those timing tables to 15 degrees from top to bottom, I set my actual jumpered timing at 8.1 to correlate those tables (FALLING REFERENCE ANGLE IN REGARDS TO NEXT PHYSICAL TDC" TO 8.1 degrees) rev motor, it will show that 15 degrees thruout the rpm range (it may vary a tiny bit lower from cam deflection, chain stretch as you rev it higher) but in general. So if the ecm dictates when to fire the coil based on timing tables, if the module started doing its own version, where would timing actually be and what would be controlling it?

how do you know the compressor gauge is accurate?
I have a tire gauge that has the best tolerance out there,forget the brand off my head,I use that digital gauge to test w/.but the spread on your gauges is enough send them back.

the last half of what your talking about is how I've been setting timing,seems I'm always doing blower motors,I have a program thats just for setting timing.the whole map is 25°top to bottom,left to right.makes timing a snap.

IF you re-read my post more carefully, you'll see that I DID send them back. Then the manufacturer DID test and confirm that one was faulty.

i know what you wrote,thats why I send you were right to send them back,,just on the spread of the readings.