Having Torque Pro running now, I'm monitoring more than I have typically. I just recently replaced my turbo center cartridge and put in a WW2 and am seeing great boost, maxing out at 25PSI with the WG still connected. What I'm also seeing though is that my Boost:EBP ratio is running about 1:2.5 or 1:3 most of the time (like 10PSI Boost to 25 or 30PSI EBP). That seems wrong to me but I don't know.

When doing the turbo work, I removed the EBPV and replaced the pedestal so I know that's not part of the issue. I know it's about time to clean the EBP tube again, I haven't done it in a LONG time, maybe that will help bring it closer to a 1:1 ratio (which I think it should be?).

Anyway, what should the ratio be and, other than what I've already mentioned, what else should I check on if this is in fact not good?

My mileage is pretty poor as well, I'm getting about 12.5MPG empty just driving around town without my foot in it really. I do have a 2" lift, Ranch Hand grill guard and 4x4 but my average around town used to be more like 15MPG. I have 273k on the engine and original injectors so I know that it's about time to do those but I'm wondering if this might also be negatively effecting my mileage?

Thanks for the feedback!

 

With Engine at 140*F or >; 25 PSIG EBP is within specifications at WOT. Actually, it's right on specification.

EBP: Exhaust Back Pressure Sensor: Feedback input; PCM uses this to monitor and control EPR operation; 5.0 volts in, 0.8-1.0 volts/14.7 psi KOEO or at idle, increases with engine RPM/load, decreases as altitude increases. PID: EBP (pressure), EBP V (volts)

EPR: Exhaust backpressure Regulator: also EBP regulator Output: For quicker engine warm-up at cold temperatures. If the IAT is below 37°F (50°F some models) and the EOT is below 140°F (168° some models) the PCM sends a duty cycle signal to a Solenoid which controls oil flow from the turbo pedestal. This causes a servo to close a valve at the turbo exhaust outlet. The PCM monitors the EBP input to determine if the EPR needs to be disabled to provide power for increased load, then reapplies the EPR as load demand decreases until EOT or IAT rises. PID: EPR (duty cycle), EBP (pressure)

BARO: Barometric / MAP: Manifold Absolute /and EBP:Exhaust Backpressures: All three should indicate atmospheric pressure (14.7psi at sea level) and read within 0.5 psi of each other, Key On Engine Off.

EBP: Exhaust Back Pressure MGP: Manifold Gauge Pressure and RPM: Camshaft Position Sensor: At full throttle in neutral, EBP should be below 28psi; at full throttle in fourth (manual) or third (auto) gear, MGP should be 15psi.

(Note: with the engine running, MAP and EBP values are "Pressure + Barometer". For example, if Barometer is 14.7 and there is 2psi of boost, MAP will read 16.7. Also, there is a calculated PID called "Manifold Gauge Pressure" that doesn't have the Barometer pressure added in).

 

So at what point should I be concerned about it? Since the mileage is where it is and I haven't monitored this before to have a baseline, I'm not sure if I'm seeing a problem or if it's just doing what it's supposed to.

I've read elsewhere that ideally Boost:EBP is at 1:1 but I don't remember if that was for the 7.3 specifically or my other turbo engine, which is gasoline and more for fun performance than work.

 

Wouldn't the truck be reaching max power, and therefore max boost at full throttle in 3rd (auto)?

In that case, would the Boost be 17 and the MGP would be higher maybe something like 27?

 

OK, so I hadn't really looked at specific readings but on the way home I hit WOT a few times to see what it was showing. Consistently, I'll see boost go to 22 - 25 and EBP go to 45 - 50. I haven't tried WOT in neutral to see what that is.

If I was going to log to see if there might be a problem, what should I monitor? I'm thinking -

Boost, Oil Temp, EBP, MAP, Throttle Position

Anything else?

Also, I'm I correct in that EBP does include barometric pressure so I need to subtract that out? I'm at about 500 - 800' above sea level so if that's the case then my actual EBP would be more like 30 - 35 but, that's still higher than the 25 mentioned above.

Like I said, I don't have a baseline for this so there may be nothing wrong, I just don't know. I'm just trying to determine for sure one way or the other and whether or not this might be hurting my mileage or if it's more likely aged injectors.

My daily driver is down with turbo problems that are going to be expensive to repair so this is probably the first time in a couple of years that I've driven the 7.3 around town unloaded. Towing mileage hasn't been great (9 - 10) but I'm towing 8k - 10k, not very aero-dynamic when doing so and will tow at 75 - 80 MPH whenever I can so I didn't really think much of it. Only getting 12.5 or so unloaded and at a top speed of 45 - 50 to and from the shop with easy acceleration and RPMs rarely over 1750 tells me something is up, I just don't know what...

 

You shouldn't do it unless under load.

I don't know if your software is capable of "recording a session". If it is:

Do a 0-70 MPH WOT Run and record the following:

BARO: [4.6 volts/14.7] this should be within .5 PSIG of the MAP psi at sea level, decreasing as altitude increases. (Volts)/100 kPa (14.5 psi).

Manifold Absolute Pressure (ATM) [Min 0.00 Max 50.0]

Engine Oil Temperature Input (EOT) (*F) [Min 0.00 - Max 250.00]

Engine RPM (RPM) [Min 0.0 - Max 3,500]

Exhaust Back Pressure (PSIG) [Min 0.00 - Max 60.00]

IAT: [3.897volts@32°F, 3.09@68°F, 1.72@122°F]

Injector Control Pressure (PSIG) [Min 0.00 - Max 3,500.00]

Injector Control Pressure (Duty Cycle) (%) [Min 0.00 - Max 100.00]

Mass Fuel Desired MFDES: (mg) [Min 0.00 - Max 100.0]

Fuel Injector Pulse Width (mS) Scale: 10.0 [Min 0.00 - Max 0.50]

Transmission Fluid Temperature - Volts (V) [Min 0.00 - Max 5.00]

Transmission Fluid Temperature - (*F) [Min 0.00 - Max 230*F] #2001 and later MY

Vehicle Speed (MPH) [Min 0.0 - Max 100.0]

VFDES: Volume Fuel Desired (Cubic mm) [Record Displayed Value]

* Note Minimums and Maximum Values for each PID.

* From a Stop, on a safe level roadway, clear of obstructions, begin from a stop to 75 MPH with the AP going steadily to the floor. DO NOT allow the pedal from the floor until 75 MPH is reached.

Doing the above will provide you some good information. One being a "Base Line". Others being the General Health of the power plant and it's components. i.e.: HPOP , Injector, Turbo Boost and much more. Everyone should run a performance diagnostic test to determine "how things look".


IMO it should be driven from time to time in order to identify anomalies before "you get left". Which, 99% of the time its unnecessary.



Fuel Mileage is not worth even thinking about until you can determine the health of your system.

This sounds like a Boost Leak. Perhaps a Fuel Pressure Delivery or HPOP-HEUI System shortcoming.

However, you're stating 25 psig boost?

Even more reason to get some data for comparison. Stock, 15 psig is min specification. So, you're certainly exceeding that.

Are you monitoring you Exhaust Gas Temperatures (EGT's)?

 

I'll get the rest of this in the next few days but yes, I do monitor EGT's. The turbo work and new wheel dropped those about 200 degrees and they rarely exceed 1200. I can climb them up to 1300 - 1400 on an incline towing if I want to but I really have to get my foot into it to do so. I'm only monitoring EGT on the driver side though, since Torque pulls Trans Temp and Boost, I'll probably pull one of the analog gauges and pop another Pyro in there for the pax side EGT.

I have AE as well, Torque is just convenient because it runs on the Android. I think it will monitor most of this.

And yes, I am maxing out at 25 PSI boost, both on the analog gauge and the ECU gauge. Prior to the turbo work and new wheel, it maxed at 20 PSI. I attribute the gain to the wheel. If I'm losing boost, I don't know where it could be, I went through it all recently, boots, up piped, down pipes, intercooler, the whole works, it's all tight.

Also, it does get driven frequently even when the DD is right but then, it's always pulling a load. Even with the DD in top condition, the 7.3 was getting 2k - 3k miles a month, just not often unloaded.

 

Much confusion taking place here.

Boost is not MAP, it is MAP minus Baro

EBP is not akin to a "dirty boost", it is more like a "dirty MAP"

Exhaust Gauge Pressure needs to be compared to boost, and EBP needs to be compared to MAP.

From the 2015.5 Torque Pro PID thread:

Long name:Barometer
Short name: BARO
PID: 221442
Max/Min: 15.0/10.0
Unit: PSI
Equation: ((A*256)+B)*0.03625
Header: C410F1
The Min/Max values above are for realistic altitudes, but those who traverse the Rockies may see lees than 10 PSI (over 10,000 feet). If you do, you can change the Max/Min to 15.0/9.0.

Manifold Absolute Pressure
Short Name: MAP
PID: 221440
Units: PSI
Max/Min: 45.0/0.0
Equation: ((A*256)+B)*0.03625
It is important that this reads the air pressure of your altitude in PSI (same with EBP and BARO) with Key On Engine Off, then it just adds boost to that while running. [LINK]

Manifold Gauge Pressure
Short Name: Boost
PID: 221440
Units: PSI
Max/Min: 30.0/0.0 (stock) 40.0/0.0 (performance)
Equation: (((A*256)+B)*0.03625)-[221442]
"-[221442]" subtracts the Barometric sensor (located on the PCM on some trucks, external on others) reading from the MAP reading - and this gives you just the boost pressure above atmospheric pressure.

Exhaust Back Pressure (Absolute)
Short Name: EBP
PID: 221445
Units: PSI
Max/Min: 55.0/0.0
Equation: ((A*256)+B)*0.03625
It is important that this reads the air pressure of your altitude in PSI (same with MAP and BARO) with Key On Engine Off, then it just adds Exhaust Back Pressure to that with engine running. [LINK]. 53 PSI is sensor limit. Exhaust or boost leaks can make this reading very jumpy during WOT tests.

Exhaust Gauge Pressure
Short Name: EGP
PID: 221445
Units: PSI
Max/Min: 30.0/0.0 (stock) 40.0/0.0 (performance and/or engine braking)
Equation: (((A*256)+B)*0.03625)-[221442]
It takes the Exhaust Back Pressure(PSI) and subtracts the device barometric pressure reading, giving you the backpressure above atmospheric pressure. Exhaust or boost leaks can make this reading very jumpy during WOT tests.


1:1 works on a GTP38R, but not on the stocker. With the stocker, as you climb into the upper reaches - the turbo falls "off the map" and you see the EBP/MAP separation.

 

OK, I did some logging this morning. I think I got everything asked for except is didn't pull any values for Baro or Trans Temp (used the wrong method). Trans temp was around 180 this morning. It has MAP so that should cover the Baro.

Not sure how to upload the log file here so I just put it where it could be linked to -

http://www.texashogtraps.com/files/log.csv

 

Good stock turbo, hot tune.

As I mentioned earlier, the EBP and MAP will part ways in the higher boost range. 10 PSI is about right at that boost level.