Quote:
Originally Posted by olddog
For the self tuning systems out their that do not control the timing, congratulations you have replaced a carburetor.
I too have an old MassFlow system that uses an A9L EEC IV. He claimed it was self tuning because Ford programmed the EEC IV to correct the fuel tables based on the O2 sensors. If you have a bone stock 5.0 and used 19 lb./hr injectors the system is as perfect, as Ford made it, which is pretty darn good. As you move away from a stock 5.0 the system becomes less perfectly tuned for your engine.
Later MassFlow chipped the ECU to correct for some of this, but not all of it. I talked with them several times. He insisted that Ford knew more about timing curves than me and all my internet tuning buddies would ever know. I tried to explain to him that Ford did not use the same timing tables for every engine, and that the combustion chamber design impacts how much timing an engine needs. I was not about to pay him to send me a chip if he was going to keep the standard timing tables. I gave up and ended the last phone call. I'm quite certain we both thought the other was an idiot. At least I still do.
That all said the A9L gives a total WOT timing of 28 deg. If you have 36 lb/hr injectors like me, the mass flow sensor was curved to tell the ECU that 19/36th of the true air flow was entering the engine. This gets the fuel right, but wait. Also the ECU thinks the engine displacement is 302 cid. The ECU uses these two numbers to calculate the engine load. The engine load is used to determine how much timing the engine needs. Well if you had a 572 cid engine these two lies would cancel out and all would be good. So for my 347, at anything other than WOT the load is calculated to be significantly lower than it is, so I get way more timing than I need. However my engine does need closer to 34 deg at WOT. I could actually feel a big power change by going from WOT to slightly less and getting the ECU to switch out of the WOT timing map.
Bottom line they left a lot of power on the table. Engines ran pretty well with the fuel correct, but power suffered.
The new system MassFlow is now selling, looks to me to be a great system. The only problem I saw was them not wanting to admit their previous mistakes and recommending that you shouldn't change most of the parameters that you need to change if you have a non factory stock engine. It looked to me to have it all. The fact that they force you to buy a new wire harness, rather than sell an adapter, it put the price tag too high for me. If they had offered it before I had gotten the Quarter Horse chip and everything else to tune my own ECU, I might have went that route.
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Your story is interesting....
I had an early ODB1 mass flo system on my roush 427sr. Last summer the computer took a dump and with no replacement parts available and lack of interest to spend the money to replace with a new Mass Flo or other system I took the motor back to the spec'd carb/intake from roush.
It runs SOOOO much better to my surprise.
I wonder if some of the issues you pointed out contribute to this or my system was faily over the years and not properly controlling the motor.
Jeff