'99 & up Upgrades and Aftermarket - 7.3L EngineUpgrading or adding OEM or aftermarket equipment to your 1999-Up Super Duty or Excursion with 7.3L Power Stroke diesel engine. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.
I've got either a very dumb or very esoteric question regarding "fooling" the Manifold Air Pressure sensor (with a Boost Annihilator or the like) so you can run higher boost without causing de-fueling due to overboost.
I'm under the impression that the MAP sensor is used, at least in part, to determine how much fuel to feed to the engine. Is that wrong? If it's not, then why aren't you under-fueling at boost levels that are higher than what you're showing to the MAP sensor? It seems to me like the system is running open-loop instead of closed-loop at that point.
Early 1999 (2/98) Cali-spec F-250 XLT SD CC 7.3 2WD Short Bed Auto - Triple Gauges - Ford AIS with Fender Sleeve mod - Banks BHA - NCHornet CCV mod - BTM - '06 seats - John Wood trans - 6.0 trans cooler - DP-Tuner F5 chip 40T/60T/80E/120 - ITP Overboost Annihilator - DI Regulated Return - Terminator dual HPOP - Airdog
The map sensor is designed as a feedback device to adjust fuel to keep boost within the Ford design parameters. If it sees 22psi(my regulator is set at 22psi) it thinks it is doing its job perfectly and maintains the fuel at that flow rate. If it sees over boost(24psi in my truck) it defuels around 20%(so I have been told). After boost drops into normal range it will reset in about 30seconds or less on my truck.
The old way to bypass the MAP from throwing a code is to ground out the green wire on the map. That is no longer used as far as I know.
I never liked the blow-off valves. To me, it defeated the purpose of building higher boost if it was going to be blown off under the hood.
Anywho, this is my "redneck reckoning" of how it works,
__________________ My Truck: Early '99 F350 CC LWB 4X4
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2001 F350 Crew Cab 7.3L
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It has to do with the programming of the '99-up PCM's I believe. Self protecting in overboosted conditions. Kind of like it cutting back on a 1211 code as well. For overboost, I use a 20PSI non-adjustable regulator on the MAP line. Works beautifully. I check with my Banks 6 gun, because that reads the PSI that the MAP sees. It has NEVER gone over 20#'s. I run right around 30 PSI max. I also used to run SPDiesel's EBP "fooler". Although, it never worked. I always got the backpressure code. Mabe I got a bad one? I dunno. I now run the EBP sensor in line with the MAP line feeding my regulator, so it basically sees boost pressure. And not drive pressure. It is that way because I have my drive pressure guage plumbed into the spot for the EBP.