Engine tuning

I seem to have knack for coming up with questions that nobody can answer! The following for example, previously posted in the V8 section but just thought I'd bring it "home" to you guys.

...Hello, have a question about tuning my 4.0 V8. She has cats but no O2 sensors. They're not missing, they were never fitted. No plugged holes in the pipes and no loom to the ECU. So can anyone tell me what the ECU uses to decide the mix and timing and what are the "trims" that it learns over time and that can be reset to default with diagnostics?

Also, how would one tune it? Basically I'd like to very slightly advance the timing and also make the mixture a teensy bit leaner. I'm guessing since its open loop there must be a way to manually tune because what would you do if your emissions were out of kilter? Any advice would be highly appreciated!....

Cheers!

Are you saying the mixture is rich. Why would you want to advance the timing?

T4 TestBook has a tuning section for open loop cars, find an independant with TestBook! But you may find it will just tune to RR specs. If you have mega bucks then change the engine management to megasquirt or similar.

To be honest just learning through trial and error. Yes mixture seems rich. Consumption is up and it smells like its being overfuelled. The timing thing, years ago on my carb car with distributor ignition I found that minutely adjusting the spark timing at the distributor often achieved a smoother and even slightly peppier engine response. Would appreciate your guidance on this?

Good to know about testbook, there is someone who has it but I won't be able to get to them for at least a week. Have never heard of megasquirt. I still regret that in the early days I missed out on a Tornado chip on ebay at only 200Euros because I didn't know what what it was or that it costs 800 pounds!

Fist replace air filter as may bee clogged up a bit and will make engine run rich apart from that get it put on diagnostics and get faults read

i do that meticulously, changing air and fuel filters, checking plugs and wires (magnacor blues) keeping maf sensor and stepper motor clean, using a fuel conditioner every now and then to keep the injectors good and so forth. also do the diags, no fault except an intermittent cam /crank sensor mismatch. already sent off for a new cam sensor. also with my hawkeye i can clear faults and reset ecu trims whenever i want which is usually after a filter change. when i do it seems to run even richer for a few days. any ideas?