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Topic: Proper injectors for stock Speed Density 5.0 (Read 5758 times) previous topic - next topic

Re: Proper injectors for stock Speed Density 5.0

Reply #45
Also, further to the question about how I deleted the smog system, I removed the steel pipe to the back of the cylinder heads, cleaned out the threads the best i could with a 5/8 tap and brake clean, and plugged the holes with bolts and high heat thread sealant.  I removed the pump/bracketry, and shortened the serpentine belt.  I removed the hoses and air diverter solenoids, but I did NOT disconnect the 2 vacuum solenoids on the cowl behind the strut tower; I left them plugged into their harnesses, left the vacuum lines connected, and simply capped off the lines that used to go to the air diverter solenoids.  I assumed it would be better to leave them plugged in and connected to vacuum, so the computer didn't register them as missing/defective, was I wrong?
1988 Cougar LS - Cinnabar/Rose Quartz Metallic two tone - 3.8 V6 - Rescue
1988 Cougar LS - Cinnabar/Rose Quartz Metallic two tone - 5.0 V8 - Survivor

Re: Proper injectors for stock Speed Density 5.0

Reply #46
That you clear keep alive memory, then get 10 good minutes says that your fuel trim adaptive is biasing rich. Super rich. Since your load sensor is the map, and probably the primary sensor for establishing fuel adaptation, I'd start there. You have no way of monitoring the output of this sensor, and if you had the live data value, I'm not sure reference data is available. The hard fact is that you have no way to test the output vs actual vacuum. If live data were available in parameter form, you'd compare it to an actual vacuum gauge. You need a known good sensor and a another 12v reset. You can also check for vacuum leaks, but based on the magnitude of your error, it would have to be a big one.
I believe it's likely that your MAP is reporting less vacuum than actual. Keep in mind that the MAP itself can be leaking vacuum internally.

Re: Proper injectors for stock Speed Density 5.0

Reply #47
https://troubleshootmyvehicle.com/ford/4.9L-5.0L-5.8L/how-to-test-the-map-sensor-1

Found this guide to testing MAP sensor function...Suppose I'll try testing and possibly replacing that, as well as spray the brake clean around the intake
1988 Cougar LS - Cinnabar/Rose Quartz Metallic two tone - 3.8 V6 - Rescue
1988 Cougar LS - Cinnabar/Rose Quartz Metallic two tone - 5.0 V8 - Survivor

Re: Proper injectors for stock Speed Density 5.0

Reply #48
That's a really good article.  If you do the bench test, be certain the output not only scales down, but does so with accuracy vs the table in the article.  It's a good idea to put vacuum to the sensor, and just check to make sure it HOLDS that vacuum for several minutes, because if it's leaking, it will give an inaccurate output.