# Scan Guage Saves The Day!!



## Sweathog62 (Jul 28, 2005)

A couple of weeks ago we were pulling the 23rs fully loaded from Oklahoma to Yellowstone. After a brief overnight stay in Ellis, KS we continued on through Denver and up to Cheyenne to I-80 west heading to Rawlings. OK - This was a hill that would never end. OMG.... About 12 miles out of Cheyenne I gave it just a bit too much throttle and it down shifted to 2nd around 55 mph. Suddenly, the engine went into limp mode and quickly died going down(up) the interstate. After securing the vehicle off the road, I checked the scan guage for possible codes. Two registard, 101 and I think 102 (related to lean fuel) Thank goodness we were in I-Phone range and the kids went to work one with each code. Within minutes we started reading stories of this happening after one goes up in altitude. I concluded it was a condition of flooding the engine. About 15 minutes later we restarted and continued on with no further trip disruptions. And I was able to turn off the check engine lite with the Scan Guage.

Anyone else had such a problem with the all mighty gasser? If my wife were to have started sweating I could have gotten a duramx. Ha Haa

Brad

P0101 OBD-II Trouble Code
Technical DescriptionMass Air Flow (MAF) Circuit Range/Performance Problem

What does that mean?Basically this means that there is a problem with the Mass Air Flow (MAF) sensor or circuit. The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4.0 seconds. Other MAF sensor circuit DTC trouble codes are P0100, P0102, P0103, and P0104.

SymptomsYou will likely not notice any serious drivability problems, although there may be symptoms.

Possible SolutionsThe simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures:

Inspect for the following conditions:
An incorrectly routed harness--Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components:
- The secondary ignition wires or coils
- Any solenoids
- Any relays
- Any motors 
A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor. 
A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 230 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system. 
The barometric pressure (BARO) that is used in order to calculate the predicted MAF value is initially based on the MAP sensor at key ON. 
When the engine is running the MAP sensor value is continually updated near WOT. A skewed MAP sensor will cause the calculated MAF value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude. 
A high resistance on the ground circuit of the MAP sensor can cause this DTC to set. 
Any loss of vacuum to the MAP sensor can cause this DTC to set. 
If you suspect the condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Wiring Systems.


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## MJRey (Jan 21, 2005)

These two things from your info caught my eye.

-- The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4.0 seconds

-- The barometric pressure (BARO) that is used in order to calculate the predicted MAF value is initially based on the MAP sensor at key ON.

If the PCM is using a MAF range for fault determination that is based on the barometric altitude when you start the engine it could get way off if you started at a low altitude and then climbed much higher. You would need to know a lot more about the logic to know for sure but it seems more likely than some of the other causes.


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## Carey (Mar 6, 2012)

Ya thats a bad pull. I have heating issues with mine on this hill. But I generally am grossing 23-24000 lbs. so I figure thats a given.

Next time go west on Colorado hwy 14 at Ft. Collins, then head north up 287. Its an easier pull and cuts off a few miles since it brings you out in Laramie.

Carey


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## Sweathog62 (Jul 28, 2005)

Good idea carey. I also lost my alternator on the same hill back in 99.

Be safe.

Brad


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## TN Campers (Jan 31, 2005)

Sweathog62 said:


> Good idea carey. I also lost my alternator on the same hill back in 99.
> 
> Be safe.
> 
> Brad


Not to hijack this thread, but I'm curious about the pulling performance of your 8.1L in general. I went up this same hill about 3 weeks ago with our 270BH (~1300 lbs heavier) and the same tow vehicle as yours but with the 6.0L engine. I could not even maintain 40 MPH going up that beast without kicking into passing gear and was wondering how much difference the larger engine would make.

Van


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## Sweathog62 (Jul 28, 2005)

Hey Van, we were going about 55-60. Thus the reason for accidently hitting second gear at such a high rpm. About 4,000 r's. This caused the engine to swallow hard (for fuel) creating a flood like condition. The altitude got me. The air fuel mix was wrong for the alititude and the only was y to fix it is to turn off the engine and restart. After the re-start I paid more attention and got my act together.

This is what I call the hill that never ends. So, 45 ish may in fact be the best speed for the old gassers anyway. I'd be more concerned with trans and water temp.


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## Nathan (Jan 2, 2007)

So, what grade is this hill?


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## dunn4 (Feb 16, 2008)

I just watched a show on discovery about traveling on the "million dollar highway" in Colorado between Ouray and Silverton. One group of driver's featured was a father and son tank haulers (transporting fuel). They talked about the dangers of pulling up to the higher altitude causing engine failure due to a lack of oxygen. Scary stuff even for a very experienced heavy load hauler. Glad it worked out okay for you getting safely off the road.


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## Nathan (Jan 2, 2007)

dunn4 said:


> I just watched a show on discovery about traveling on the "million dollar highway" in Colorado between Ouray and Silverton. One group of driver's featured was a father and son tank haulers (transporting fuel). They talked about the dangers of pulling up to the higher altitude causing engine failure due to a lack of oxygen. Scary stuff even for a very experienced heavy load hauler. Glad it worked out okay for you getting safely off the road.


That's a great drive, but not for the faint of heart if you have a big rig, much less a Semi.


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## Sweathog62 (Jul 28, 2005)

Nathan said:


> So, what grade is this hill?


I think it was a 6-7% grade toward the top. It's like no other hill... I showed our flameout to have taken place about 12 miles out of Cheyenne, well before the steepest part of the climb. I understand the I-70 west of Denver. You have some big climbs and then it improves, and then you climb again. This hill is like no other. It goes for ever until you hit the divide. I lost an alternator on my '85 burb years ago on the same path, but since those trucks did not have much electrical demands I was able to make it the next day to Coulter Bay for repairs.

See if Carey can speak to the hill more, it is worth the discussion as I have had a co worker tackle the same hill pulling a 23 footer with a half ton Ford some years back.. It about sent him home due to overheating. He had to finish the pull with the a/c off and he had to run his heater to avoid the overheating condition.

Not only do you pull the hill, but you also loose the o2 which changes how quickly your engine will heat up. I agree the Siverton to Durango route is killer, but it's over alot quicker and you are going slower which makes it a nice 2nd gear pull at the perfect rpm range of say 2700-3200. This I-80 route feels like you are on it for a good 45 minutes. It just goes on and on. Your thoughts Carey?? GOT any video of the run????

Google maps show about a 2500 elevation gain. Not that much gain.


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## Carey (Mar 6, 2012)

Its prolly 4-5%. I think its longer than 12 miles. When you leave Cheyenne you start climbing. Its like 40 miles over to Laramie. The drop at the top is only about 10 miles from Laramie. The pull lasts about 30 miles, but yea the last 10-12 is the worst. 
On my truck I start building heat about 10 miles west of Cheyenne. My fan comes on then and never shuts off for the next 1/2 hour. My truck will vary between 210 and 230 engine temp. If I dont watch it it will get even hotter. When it does this I am always at or over the gcvwr for my truck, 23000 lbs. Typically I have a 39 foot Landmark, 40 foot cyclone or 38 foot Bighorn behind me. I generally run 5th gear and drop to 4th a few times to cool the engine back down. In the summer air temps are in the 85-90 degree range. In the winter and if Im pulling a smaller rv I can cruise at 63 or so all the way up and in 6th gear. I slow to about 45mph in summer too.

I see lots of broken down rigs on this hill. Its got to be one of the longest pulls in the country. I feel its comparable to the ones on I40 and I15 in California. But I have seen temps out there in the 115 range and remember seeing 118 once while pulling to the nevada line on I15. Those kind of temps will put you down no matter what rig you have.

Its the altitude on this hill that hurts ya. Laramie sits at around 7000 feet. I bet the top of this hill is in the 8000-8500 feet range. So if its 85 out, its prolly over 100 when comparing altitude. Thinner air doesnt allow as efficient of cooling across the radiator.

Bet there is some sort of guide out there showing the loss of cooling capability in higher altitudes.

Yeah on paper this hill doesnt seem like much, but for some reason it puts the hurts on everyone who is towing.

Carey


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## Carey (Mar 6, 2012)

Ive done that Ouray to Silverton road in a semi. Never mattered how many times I did it. I sure paid attention. Add in a snowstorm and it really gets fun. Been there too. Ive had the heck scared out of me on that hwy.

Carey


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## Nathan (Jan 2, 2007)

Someday I'll have to try that one. I can't say I've been on I80 in that area. Sounds like I might want an Ecoboost first though.









Now Carey, were you speaking of I40 East out of Needles?

Don't remember a big hill on I-15 but maybe I was going in the other direction (or the fact I did both those roads with a Diesel







)

Anyway, sorry for the semi-hijack.

Regarding that hill, I'm guessing you are also pulling into the wind, so you are probably trying to move a lot of air, while climbing? I-70 is shorter, but it's also a little curvy, so you aren't trying to got that fast (or maybe that's just because I'm stuck behind some semi?!?!







).


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## Carey (Mar 6, 2012)

If you leave LA and head for Vegas there are some real big pulls going eastbound.

Same for 40.

I 10 has some big pulls going east too.

Same for I 8 out of San Diego. I think these steep long pulls are prolly the worst in the nation. In the rockies they are steep, but shorter.

Yeah anytime you are in Wyoming one has some wind to deal with.

Carey


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## Collinsfam_WY (Nov 9, 2006)

dunn4 said:


> I just watched a show on discovery about traveling on the "million dollar highway" in Colorado between Ouray and Silverton. One group of driver's featured was a father and son tank haulers (transporting fuel). They talked about the dangers of pulling up to the higher altitude causing engine failure due to a lack of oxygen. Scary stuff even for a very experienced heavy load hauler. Glad it worked out okay for you getting safely off the road.


We just got back from a trip pulling over that road. Our oldest broke out in tears, twice, due to fear. She would look out of her window and could not see road, only straight down. Wife was severely stressed. Not for the faint of heart. A couple of times I chanced a very quick glance to the passenger side convex mirror and saw that the trailer tires were about 2' or so away from the edge. I quit looking and just concentrated on that yellow line. I took Nathan's advice and if a corner said 15mph, I went 14mph. Even that felt too fast at times. Later, I had several locals ask me, as the driver, how I "liked the scenery". When I responded that the only scenery I saw was a yellow line, they chuckled knowing that was the case. We didn't take that road on the way back. Longer? You bet but everyone was happier.

-CC


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## Collinsfam_WY (Nov 9, 2006)

Colorado~DirtBikers said:


> Ive done that Ouray to Silverton road in a semi. Never mattered how many times I did it. I sure paid attention. Add in a snowstorm and it really gets fun. Been there too. Ive had the heck scared out of me on that hwy.
> 
> Carey


You sir have body parts made out of steel. I could not imagine how the rear of a semi would stay on asphalt as sharp as some of those turns are. When we got into Ouray, I parked at the far edge of town and checked everything out. I could not believe how many vehicles went by that had brakes stinking and in one case, smoking. Brakes on the Superduty were fine, the drums on the trailer were very hot. I sat there thinking how grateful I was for the Ford engineers that put engine braking into the Torqshift trans.

-CC


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## Nathan (Jan 2, 2007)

collinsfam_tx said:


> I just watched a show on discovery about traveling on the "million dollar highway" in Colorado between Ouray and Silverton. One group of driver's featured was a father and son tank haulers (transporting fuel). They talked about the dangers of pulling up to the higher altitude causing engine failure due to a lack of oxygen. Scary stuff even for a very experienced heavy load hauler. Glad it worked out okay for you getting safely off the road.


We just got back from a trip pulling over that road. Our oldest broke out in tears, twice, due to fear. She would look out of her window and could not see road, only straight down. Wife was severely stressed. Not for the faint of heart. A couple of times I chanced a very quick glance to the passenger side convex mirror and saw that the trailer tires were about 2' or so away from the edge. I quit looking and just concentrated on that yellow line. I took Nathan's advice and if a corner said 15mph, I went 14mph. Even that felt too fast at times. Later, I had several locals ask me, as the driver, how I "liked the scenery". When I responded that the only scenery I saw was a yellow line, they chuckled knowing that was the case. We didn't take that road on the way back. Longer? You bet but everyone was happier.

-CC
[/quote]

Glad to hear you made it over safely! I bet you can see why pulling that road told me I needed a shorter trailer.









Now that you pulled that, you need to go up and pull over the Beartooths. Then the going to the Sun Highway....









Well, on second thought, maybe you should let the family recover first.....


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