Quote:
Originally Posted by Dougal
The aneroid fitted to the Isuzu 4BD1 type A pumps looks nothing like that. I know because my Isuzu 4BD1T has the aneroid. The fueling on the pumps without an aneroid is probably controlled on an RPM basis, there is no boost line involved.
If you add pressure to the back of that aircan, it will shut off most of the rack travel which will shut off most of your fuel and power.
I can provid pictures from inside the governors on my two injector pumps if anyone would like. One has an aneroid, the other doesn't.
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Thanks dougal for the information and others. I have rechecked with my IP mechanic, Wally, and he confirms it needs boost pressure. here are some of his thoughts, that sound reasonable to me.
Altitude compensators - are only on naturally aspirated motors. this makes sense to me, as if there is less oxygen, it needs less fuel. this can be accomplished by reducing fuel, when reduced barometric pressure is measured (which by the way is the definition of a ANEROID - measures pressure, barometric pressure, without liquid).
Aneroid - this is for Turbo engines, and will compensate fuel delivery to match oxygen, and boost pressure. If the IP does not see the boost pressure, it will meter less fuel. when the IP sees boost pressure, it adds more fuel. the IP and turbo are synched up so to speak, providing power, not providing insane amounts of black smoke. Also note, that a Turbo engine, with boost, is not as affected by altitude, and 'thin air' , as it is getting compressed air.
I installed my IP pump, and I must say it was not an easy task. There has got to be a better way of getting the IP pump gear to stay put long enough for me to insert it back into the timing housing.
But finally I hooked it all up, and I added boost pressure to whatever it is on the back. I just added a Tee to my boost pressure from the intake, and to the boost gage.
I can report that it now runs with significantly more power. great acceleration, smooth power, there is no black smoke, but now feels like a turbo boosted engine, with fuel to match. I do not have EGT gage, but I use a hand held point and shoot temp gage, getting exhaust temps in the 440 range. I have yet to run it up the hill yet, concerned still with varying opinions on the matter, and not having EGT protection!
I would like others thoughts. it seems that a IP needs some sort of signal from boost.