Timing and vacuum advance - theory and practice?

[Autoholic]

I'll start by saying I'm not a mechanic, so you made me do some research to understand what you wrote about modis and verus.

My last comment was mostly directed at carb'd engines though. So were you commenting on what Heo wrote?

[chris401]

No but I would like to see what the fuel is doing as well. Like he said timing probably is not important if it is not pulsing the injectors.

Verus: My last couple of years I was looking to buy my own full grown scanner. The tool man was trying to peddle off the new Versus. I used it for a couple of weeks and it did have more modes and graphs but was still slow on the Asians and would often lock up. OTC is a well laid out tool but was not complete. Some pids were not there and would not read one of the Ford cam banks. Other than factory specific equipment the Snap On and OTC are the only tools I remember working with. My tool peddler is now a Cornwell dealer so I will be posting what I find there in the NON-FE Discussion Forum.

[Autoholic]

well, on a EFI vehicle I'd just hook up a PC with the software needed to tune the ECU if I really wanted to see everything and forget a scan tool. Focusing on engine braking is a bit beyond what a scan tool is designed for IMO. If you really want to see all the information, you need tuning software and ideally an aftermarket ECU.

[chris401]

well, on a EFI vehicle I'd just hook up a PC with the software needed to tune the ECU if I really wanted to see everything and forget a scan tool. Focusing on engine braking is a bit beyond what a scan tool is designed for IMO. If you really want to see all the information, you need tuning software and ideally an aftermarket ECU.

Moved to the nonfe section so Jay does not throw us out on our keyboards.

[Tobbemek]

Tobbemek or others,
Do you use a scanner? I am curious about timing values when engine braking. If you downshift with throttle closed what are the timing values? If I ever noticed I do not remember, this discussion got me to thinking if anything after 2003/4 would change timing to assist in engine breaking.
Thanks

Sorry to much going on right now my bookkeeper is hunting me with a torch and my wife left me yesterday morning with horses and kids and and and but unfortunately she is coming back Monday evening and then all the real troubles start again    she heights dose kind of yokes.
I don't use a scanner and i really  don't know in what direction the ECU takes the timing on a modern car when engine braking.
I do believe its retarded fore emission causes , everything today is about emission Look at VW trying to sheath manipulating the ECU   
The 70 boss 429  boss 302 and 428 Cj have dual vac canisters for retarding on engine braking to get better emission.

Modern Fuelinjected engines cut of the fuel during engine braking
over 1500 rpm so i guess the ign timing is not important then

Another good reason to not have over exposed transfer slots on idle, when engine braking having super high int. vac. sucking a lot of fuel that is washing the cylinders. Independent car manufacturer have shown cylinder /ring wear on injected vs carburetted engines be almost half.

I left a well paying carrier in automotive with two certs shy of being a master. I understand how it works but somehow I cannot get my question across the board. You seem to understand engine management better than some who do just test out but that still does not answer my question.

  I hate working on new cars don't do it fore a living. I do have a VAG COM program fore  my own cars we have 3 AUDI A6 TDI
in the family its more a necessary evil to fix them and they shore can fowl you. A tiny crack in a vac hose almost impossible to find can throw tha MAF sensor in limp  mode     A healty 427 so serenade is what its all about, guess now one on this forum could have missed to watch the 68 Holman MoodyMustang at you tube winning the 60 corvette anniversary. Yheaaa seen it many times.

[Tobbemek]

A tiny crack in a vac hose almost impossible to find can throw tha MAF sensor in limp  mode 

Should have been can throw the ECU in limp mode, hooked up on OBD II show a faulty MAF 
was late last night and i sure hate my bad spelling.