SES / Max Boost?

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May 17, 2011 | 11:14 PM

#16

Forest

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From: Tulsa, OK

Quote:

Originally Posted by cheezit

guys if your reading map and trimg to get what boost readings are your gonna have a hard time.
the calc for it is easy though.
MAP-BARO=MGP (mgp is boost)

Yes. Correct. I am "rounding" the BARO to 15 and mentally subtracting it when I drive. At one time, I glanced down and watched the MAP jump from about 36 to "4.6". I assumed the "jump" occurred at 40 psia, giving 44.6 minus the 15 for BARO, gives about 29.6 psig boost.

From one of these posts about the ScanGauge, it may be that it "starts over" at 37 psia instead of 40 psia. This would mean a "4.6" may be 37 + 4.6 - 15 = 26.6. Still very high, but maybe not a real problem.

The last time I towed our trailer back in March, I had the SES come on. I had the code read at an auto parts store and it returned a code for "under boost".

In either case, it sounds like I have issues with the turbocharger. Truck seems to be running pretty well. Does this seem like a show-stopper or can I wait until after this 1500 mile towing trip to refurbish the turbo?

May 17, 2011 | 11:40 PM

#17

Forest

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From: Tulsa, OK

Quote:

Originally Posted by BLADE35

you need to reprogram your scangauge
the map gauge it comes with tops out at I think 37 psi absolute witch turbo charged diesels have no problem doing

read this thread
https://www.ford-trucks.com/forums/1...injectors.html

lots of great info here^^^^ you can program a x-gauge that will fix this and dial in your boost gauge its all in this thread

Wow. Thanks every body. I will program to get boost directly with an assumed BARO pressure (say 14.7). This will definitely help me to watch it...

May 17, 2011 | 11:51 PM

#18

3000 FPS

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From: S CAL

Quote:

Originally Posted by Forest

I have driven my truck from S Calif to Cheynne Wyoming with the exact same problem. When you need to be really careful is when you are pulling up a hill and the transmission downshifts and the engine RPM's go up, that is when the over boost will occur and mean over 40 PSI of boost. All I did was back out of the throttle and it came down. The down side is you cannot pull the hills as fast. I have a boost gauge coming off the intake so it is easy for me to monitor. Running 40 PSI is enough to blow head gaskets and blow the boots off the turbo so just keep that in mind. I just took my turbo off last week end and cleaned because of the vains sticking and plus I am getting ready for another trip the Cheyenne. Good luck.

May 18, 2011 | 08:24 AM

#19

Forest

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From: Tulsa, OK

Quote:

Originally Posted by 3000 FPS

Thanks for the advice and the vote of confidence--that it can be done if I am careful. We are pulling through Eastern Oklahoma and Texas, so the hills are relatively short. They can be definitely be significant, however. Even as bad are the potential headwinds.

I have learned from many of these great posters that I can program my ScanGaugeII to calculate and display boost directly. I'm going to go program the SG2 to do that and then watch the ultimate boost level. So far, I think the highest level I have seen (dragging the trailer around Tulsa while under hard acceleration) was a "5.2", which I think was about 5.2+37-15 = 27.2 psig boost.

May 18, 2011 | 09:54 PM

#20

cheezit

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From: N. Fort Worth, tx

the dash gauge is pretty close to accurate.

May 18, 2011 | 10:29 PM

#21

3000 FPS

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From: S CAL

Quote:

Originally Posted by cheezit

the dash gauge is pretty close to accurate.

Yes it is I have compared it to my boost gauge coming off of the intake and it looks right on the money.

May 18, 2011 | 11:39 PM

#22

Forest

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From: Tulsa, OK

I drove the Excursion around town today unloaded as we prepared for the trip. I did manage to get "BST" (boost) programmed into the SG2. Very convenient to observe it now.

Oddly enough, the SES light went out of its own accord. Truck is running great and I cannot make the boost exceed 26 psig even when I floor it going up hill. Tomorrow we begin a headwind pull down to Lufkin, Texas.

May 26, 2011 | 10:51 AM

#23

Forest

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From: Tulsa, OK

Thanks to all for advice before we departed. I was able to program SGII to give me boost directly (I input assumed barometric pressure of 14.9 psia).

The SES light came on every day that I towed, and went out when unhitched. I do not know what it is as my SGII cannot seem to display the 2 codes that are there. I may have to go to someone else.

Having said all that, even with the SES light on, the Excursion ran and towed well. Fuel economy seems a bit down, but not too surprising with headwinds.