You probably read my recent thread concerning being jerked around by IST on my mass air upgrade. Well, it gets worse. I put it all together and tried running the car today. Well the mix is so damn rich you can't even stay in the same vicinity. Black smoke coming out of the exhaust, uneven idle, wants to die. I adjusted the fuel pressure down to about 38 lbs. - and that improved things a little. But still WAY too rich.
The engine is a Blueprint Engines HO 5.0 with flow-honed intakes halves - otherwise stock. I had been running it with a speed/density EFI system, but wanted to upgrade to Mass Air. The Ron Francis harness I have been using has provision for a mass air sensor connection. Here's what I put on the car (the "kit" IST sold me): Professional Products 75mm polished throttle body with polished 75mm EGR spacer, 30 lb. disc-type (as opposed to the original 19 lb. pintle-type) injectors (flow-matched - supposedly), new O2 sensors (OEM, I guess), new OEM air idle control, new "improved" BAP sensor, Ford EEC-IV A9L (it's a manual transmission car), and....what is SUPPOSED to be a 76mm mass air sensor calibrated to 30 lb. injectors. When I measured the inside diameter of this new MAF, it came to a whopping 82.5mm. Obviously, I called IST immediately. "That's correct", they said, "76mm is just the EFFECTIVE diameter of the MAF, the ACTUAL diameter is going to be much more." Sounds ridiculous now, but I bought it then. So, I bought a huge aluminum elbow and connectors. Had to buy a special reducer sleeve to mate everything to the 75mm throttle body, of course.
So here are my thoughts - hopefully someone with way more knowledge than me can help: I think I got screwed on that 82.5mm MAF. My guess is that it should ACTUALLY measure 76mm inside diameter. I am also not sure about the sensor itself. The numbers on it are AFH60M-19. If that '19' denotes that it's for 19 lb. injectors, that might be part of the problem. The sensor reads the quantity of air and sends a signal for the 19 lb. injectors to open for a designated amount of time - but if it is actually sending that signal to a set of 30 lb. injectors - well, a whole lot more fuel is going into the engine! Does that make sense?
Anyone have a recommendation? Thanks. Eric