2006 3.0 issue

[joshkeller]

Hey guys, first off, I have a 2006 ranger single cab, xlt, 3.0, 120,000 miles. manual transmission. Everything is stock except for a magnaflow muffler. I have never had an an once of trouble until this weekend.

I got gas, and began climbing the mountain to the hunting cabin pulling the 4 wheeler and trailer. I got up to 4500 rpm and it felt like it was missing - not bucking or jerking, just that It had nothing left - A few seconds later and it would run normal and continue to build rpm. Check engine light came on after I shut it down, ran into wal mart, then started it back up. I thought maybe I had gotten bad gas. Added some isoheat, and ran it down as low as possible. Drained tank by removing fuel connector at the injector rail and jumping fuel pump. Then lowered tank and cleaned. Got two gallons of high grade gas, and flushed it through with the fuel pump. Replaced fuel filter. Topped off tank.

Codes are P0171, and P0174 - lean bank 1 and 2.

The truck still idles fine, and gets up and goes, until you hit that magic 4500 or so mark with a load. The check engine light will stay off after you reset it until you turn the truck off and then back on. This is driving me crazy. Any ideas?

I wouldnt say its bucking, or missing badly - it just feels like it maxes out. You can floor it and it just holds at the rpm until it kicks in, then itll continue to wind out.

 

[RonD]

If you have lean codes on both banks the Long Term Fuel Trims(LTFT) will stay high until problem is fixed for at least a week, you can't "reset" LTFT.

A Lean code does not mean engine is running lean.
It means the computer is having to open the fuel injectors longer than it has calculated because O2 sensors were showing high oxygen content in exhaust.

MAF sensor tells computer how much air the engine is sucking in, computer already knows about how much air that should be because computer is setup for a 3 LITER engine, and computer also has the RPM, so RPM x 3 liters, actually RPM/2 x 3 liters, 4-stroke engine
But MAF sensor fines tunes that, along with throttle position sensor(TPS) and air temp.

Computer has no way to read fuel pressure, it is programmed to expect 65psi, if pressure drops to 30psi computer wouldn't know that, only thing it would know is that it is having to keep fuel injectors open longer to get the right amount of fuel.


From your description the engine is running out of gas under load.
Change fuel filter, $10, EDIT: you already did that

If you still have the problem then either fuel pump is not pumping enough fuel to maintain higher loads or MAF sensor is not registering higher air flow correctly.
Because computer can calculate approx. air flow based on RPM, if MAF sensor was under reporting air flow you would usually get a MAF code, but not always

Test fuel pressure and leave gauge hooked up while you increase RPMs to 3,000 and hold it there for at least 1 minute, the longer the better.
There is a REV limiter so you can't go above 3,000 if not moving.
If pressure is slowly dropping then replace fuel pump if fuel filter is new.
As fuel pressure drops with demand the computer must open fuel injectors longer and longer to maintain correct oxygen levels in exhaust, if open time becomes excessive computer will notify driver with Lean codes.


You could have air intake blockage or exhaust blockage but wouldn't expect Lean codes with those, just lack of power at higher engine loads

 

[joshkeller]

Not sure if its pertinent info or not, but these episodes of power issues are about 2 or 3 seconds in duration. You can floor it, and itll just hold rpm, then after 2 or 3 seconds, itll start climbing again.

 

[delaware74b]

I have no rev limiter on my '04 3.0 with manual. It will wind up all the way to the redline limit.

There is a TSB for Fords and lean bank 1/2. You will need a scantool that will read live data, not just the freeze-frame event to rule out vacuum leaks. I had the P0171/0174 codes. I was driving at 45mph and it stumbled HARD. Check Engine light came on a mile later.

Long story short, I found it was actually the MAF that was contaminated by a piece of fiber from the air filter. It got caught inside, on one of the heated wires deep inside the slot. The computer ran out of adjustment and tripped the codes (it ran out of normal fuel usage based on volume of air measured by MAF). I replaced it with a Hitachi one from rockauto and it fixed the lean code.

 

[adsm08]

If you have lean codes on both banks the Long Term Fuel Trims(LTFT) will stay high until problem is fixed for at least a week, you can't "reset" LTFT.

Ron, I am surprised to see you post that. You don't usually make mistakes like that.

LTFT can be reset, and does not take at least a week to correct itself. Especially not on a 3.0.

A KAM reset will clear the LTFT and set them back to zero.

Also, when dealing with actual lean issues cause by an air leak I would always know I had gotten all the air leak because if I started the engine with the scanner set up to show the long trims without a KAM reset, after it went closed loop those number would drop very quickly off the 25% needed to set a code.

 

[RonD]

That is odd, I will modify further posts but I have seen the opposite using regular OBD2 readers.
Benefit of LTFT is that the computer can run the older engine better in Open Loop with the inevitable dirty MAF, small vacuum leaks and lower fuel pressure that occurs with age, and in Closed Loop to offset for the same reasons.

I know Ford readers can do it, but haven't seen that with the OBD2 readers I have used

 

[adsm08]

Some of the cheaper ones won't because they just clear codes, not reset memory. I know the Ford ones will, my Solus does as well.

And like I said, the way I would test to see if I had fixed all the air leaks was to start the engine without clearing the memory and watch what the LTFT did after the engine went to closed loop. If the leak was fixed that number would start dropping very fast. It might take a week to fully re-write the air/fuel table, but the trim PID should correct to 12% or less in under 2 minutes.

 

[joshkeller]

In a weird development.. ive been babying the truck and was supposed to take it to the shop today. I noticed while merging onto the highway, that the miss was gone. The cel went out and the engine light has stayed off for a day now. Im seriously wondering if perhaps it was somehow related to the fuel i got when the issue initially happened. Too much ethanol maybe? Im stumped. I want to take it in and see what i can find, but its running perfectly now?

 

[RonD]

"Bad gas" means it has a higher water content, ethanol actually helps get rid of that issue.
All gasoline will have some water in it, too much is when it is called "bad gas".

Gasoline can't bond/mix with water, it stays separate, and water of course doesn't "ignite" when it gets to the cylinders, so a high enough water content will cause misfires.
Ethanol does bond/mix with water, and it will still ignite after bonding with the water.

Water is heavier than gasoline or ethanol so will settle to the bottom of the tank as vehicle sits, driving around keeps it mixed but not bonded to the gasoline, so % of water being pulled in by fuel pump(from the bottom of the tank) is less.

Ethanol also prevents fuel line freezing because it bonds with the water and raises the waters freezing point, which is why "winter fuel" has higher ethanol content.

I don't think ethanol content would be your problem, I think newer computers can compensate for 25% ethanol content.
Bad gas issue can usually be solve by using 5-10% ethanol fuel, but water is usually used up after first few days of startup after truck sitting over night, most of water settles to bottom of tank and is sucked up first, so you get the rough running right off the bat and then it gets better as fuel starts to slosh around and water % at fuel pump is reduced.

CEL(check engine light) means more codes will be in memory, you need to get those codes, all of them and write them down.

 

[joshkeller]

The only codes present in the memory were p0171 and p0174. Truck is running perfectly now. Cel has stayed off. Hooked up the boat and did a load test on the engine. 4800 rpm up mointain for 1 mile in 3rd gear and not a single issue. Not sure what to make of it.

 

[RonD]

Well a bad gas issue is one of only a few things that will clear up on it's own after running "good gas" thru the engine, so maybe you are right.

 

[chewy012]

I may be outta my league with RonD and ADSM08 chiming in, but 4500 rpm?

Why are you revving your engine that high? I'd say keep your gear and go slower... I didn't catch if this was a SOHC or OHV but, that seems high for sustained rpm.

Again, may be outta my league, but, I wouldn't put revs in that range. Please shed some light if my thought track is off

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[RonD]

2006 3.0l Vulcan doesn't have best torque until 3,950rpm
Best Horsepower at 4,900rpm

It is considered a high RPM engine design
Specs are here: http://www.therangerstation.com/tech_library/3_0performance.shtml

The 4,500rpm is out of best torque range but still not a high RPM for this engine.


4.0l OHV has best torque at 2,400rpm
4.0l SOHC at 3,000rpm

4cyl SOHC Limas(2.3l/2.5l) had best torque at 2,500-3,000rpm as well

The 4cyl DOHC 2.3l Duratec was also a high RPM engine design, best torque at 4,200rpm

 

[chewy012]

Ah, nice. I don't know much about the 3.0 Vulcan.... all I had to go one was the 4.0s.

Thanks!

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[joshkeller]

Update - still running perfect and cel still off..