RacerHog

2-5 Min. !!!! Wow..I'm going to guess you mean to the 'rich side'?.. Sounds like the O2's are not telling the PCM to pull the fuel away????

mopwit

Good observation Bob!! Actually it tended to the lean side but that was more a function of the internal IAT correction algorithm of Megasquirt ECU which followed the PV=nRT equation to the letter, but did not take cognizance of thermo dynamic realities.

The reason the O2 sensors did not correct is because I prefer to tune my cars in "open loop" as opposed to "closed-loop" which relies on the O2 sensors to correct fuelling. Tuning "open loop" allows me to tune all the corrections (IAT, CLT, Barometric, Warm-up) and fuelling tables more or less correctly so that the engine will run well under pretty much ANY condition without relying on the O2's to make it run right. This means:
1) I don't have to fit them at all (once the car has been tuned)
2) which in turn means the car can run on leaded fuel - which we still have around here
3) it makes the install cheaper since WBOs are quite pricey
4) if the O2 sensor should fail, it will not affect the car's performance.

Tuning open loop is how I found that MS' IAT correction algorithm was too aggressive and I also found that the MS manual was wrong with what they state should happen when a car moves from lower altitudes to higher altitudes ito fuelling. They are of the view that fuelling should be enriched as you climb in altitude when I found it to be quite the opposite.

ZombiePopper

Ok, off topic, but...Its required lol
I gotta see some pics of your Jensen!
I looked at your link but you need to get some pics of that beast from further away lol
Cool car!

mopwit

Just for you ZP!

demetri

Does the car have headers? Just curious, I could not see the typical exhaust manfilds you see in 440's, and I would be very surprised if anybody manufactures 440 headers that can fin in an Interceptor ...

mopwit

Yes, they are 4-1, manufactured by a local firm (TNT). My '72 Interceptor also has the same headers made by the same firm (enamel coated in case of the '72).

On the '74 the header on the steering side interfered with the steering column box but on the '72 there is a lot more clearance in the same spot.