Early 1999 f350 7.3L with cat, 4 inch Banks exhaust. Bought this truck about a year ago, had to replace the EBPS tube because it was cracked and tried to clean the sensor but it was pretty gummed up. I've been trying to research this but couldn't find the right information. I believe my EBP reading might be incorrect from what I've read online. My mpg is rather low also at about 11-12 mpg with 35's. Just wondering if my EBP sensor is bad or dirty or something else might be wrong. I have a scangauge 2 and the values are as followed.

KOEO

MAP - 13.9-14.0
EBP - 19.4

KOER (idle)

MAP - 13.9
EBP - 19.9-20.0

Driving conditions

MAP - as high as 20
EBP - as high as 29

MAP was usually about 8 lower than EBP whether WOT or just cruising. I read that MAP was supposed to be around 14.7 at sea level and decrease as altitude increased which makes me believe something is wrong.

Any thoughts or suggestions, Thanks

 

MAP says you're about 1400 - 1500 feet above sea level, EBP says you're in Hades. They are supposed to agree as to where you're parked.

 

I'm at about 1380ft elevation so the MAP is correct, now why would the EBP be so off? If it was bad would it read anything?

 

The EBP sensor reads exhaust backpressure... that's some sooty stuff for a sensor to have its face in for over a decade. The real question is "How did it last so long?" Many people remove it and clean it, and this sometimes fixes it. I tried cleaning and it was nice sensor removal/installation rehearsal for the real event. There is a tube that brings the exhaust to the sensor, this is to keep the direct exhaust temperatures away from the EBP sensor. This can plug up with soot, so people come up with clever ways to clean the tube.

There is a cleaning procedure posted in the forum, and there is a procedure for removing the sensor. Don't just throw a wrench on it and start twisting, you'll damage the mounting plate if you don't put a counter-wrench on the fitting below it. The sensor is located directly in front of the engine (top-center) and behind the cooling fan. You'll see the tube going to the passenger-side exhaust manifold.

For reliability, I strongly urge you to stay with OEM sensors and controls. You can save a lot of money on ebay the first time around... but replacing the sensor you just replaced sucks all the savings from said Superduty service.

Not addressing the sensor will cost you as well - it harms your fuel economy and performance. [LINK]

 

Without a scanner, is there a way to see if a EBPS is malfunctioning? I'm experiencing poor mpg myself, just curious.

 

Other than a scanner the only way to tell would be if the check engine light comes on. But then you would at least need a code reader )to determine the exact fault) and all but 2 of the codes only set the check engine light(MIL) after the 2nd consecutive fault. see the footnote at the bottom:

Here are the codes for the EBP system (Borrowed from klhansen).

P0470Exhaust back pressure sensor circuit malfunction
Causes: Biased sensor, open signal return
P0471 Exhaust back pressure sensor circuit performance
Causes: Plugged, stuck or leaking hose ³
P0472 Exhaust back pressure sensor circuit low input
Causes: Open/grounded circuit, biased sensor, PCM
P0473 Exhaust back pressure sensor circuit high input
Causes: Circuit shorted to 5v, biased sensor, PCM
P0475 Exhaust pressure control valve malfunction
Causes: Open/grounded ckt., solenoid open/shorted, failed PCM
P0476 Exhaust pressure control valve performance
Causes: Failed/stuck EPR control, EBP fault, EPR circuit
P0478 Exhaust pressure control valve high input
Causes: Plugged sensor line, stuck butterfly, restricted exhaust

All these codes except P0470 and P0476 have footnote b, which says "MIL (OBDII) illuminates after second consecutive fault." MIL = Malfunction Indicator Lamp (aka Check Engine Light)

 

So back to my question, would a bad sensor read anything? Is it safe to say I need a new one based on the reading being completely off from everyone else's.

 

Yes. MAP and EBP should be within a few tenths of each other at KOEO and at idle. You need a new EBP sensor.

 

yes, X2....

Here are some pics I posted in a previous thread........

These are my readings prior to the new EBPS at KOEO. I was getting poor MPG's (10 or 11) and for a while I just thought it was the combination of winter fuel, #1 diesel and extended winter idles. Had no engine codes......



The readings after the new EBPS



Mpg's seem to be doing much better - fuel gauge reading between 1/2 & 3/4 at 179 miles. Much better considering she idles about an hour a day.

 

Short box with the smaller tank?

I have the long box with the bigger tank.

 

Rich, this ones the Excursion - 48 gallon tank? The did the hutch & harpoon mods on this but it doesn't stay on the full mark for 120 miles like My F-250 does.

 

Hmmm.... you may have an issue.

 

I've got a few if them On this tank at least :

1. 1/2 tank of #1 diesel - so lower mpg's
2. @ 80 miles in a 20 mph crosswind driving at 75-80 mph (10-15 lbs of boost)
3. Pulled a 5k trailer a bit - some of it through the snow
4. Idling 40-60 minutes a day (it's been 0F to -16F mornings this week.)

I didn't really notice anything until I checked last months fuel bills......I was wondering why I spent more - then the EBPS thread caught my eye. I hadn't checked the tube or the sensor in @ 2 years. Need to put it back on the yearly maintenance schedule.

 

Well ordered a new EBP sensor from Riff Raff and got it the next day, turns out they are right down the road from me (small world). Replaced the sensor and my EBP is reading the same as the MAP now. Thanks to everyone's input, you guys are great!