A few weeks ago I was pulling my 5th wheel and truck didn’t have any power and kept downshifting. Limped it home and took to the dealer. I didn’t have a check engine light or wrench come up but truck was very limited on power. Ford said fuel cooler was air locked.They manned pump on and it ran but fuel temps were high. They bled air out and truck appeared ok afterwards.

I towed my 5th wheel about 15 miles and truck was in Regen on the way to RV storage. Offloaded trailer and was heading home and truck made zero boost and would barely move. Took forever to get up to 20 mph. Had to let of gas to get truck to **** to try and gain speed.

Anyine have any ideas? Truck doesn’t have any check engine light. Though about driving some more to try and make it come on but scary making left hand turns and can’t keep up with traffic when taking off.

Intercooler boots popped off

dpf is clogged

ebp system is clogged

intercooler boots are good. Beginning to wonder about DPF. Had an EGT sensor go bad and truck shut off when slowed down to 5 mph. Wouldn’t restart for one hour. Sensor thought temps were 1900. Then few days later DPF sensor melted.

What ever it is it is causing the truck to de-rate and not make any power. Prob wait to see what response I get from here before taking back to dealer. Don’t want to take it in and they don’t do anything because there are no codes

1900 is real hot...you need to do compression test

a bad #3 would cuase iit not to start ....but high heat would put it in reduced power mode

if you in reduced power mode your display would tell you that

overfilled with oil due to fuel dilution would cuase no power as well

are you running a tuner ?

No tuner and oil changed two weeks ago and checked oil level yesterday. I will check oil level again today. Truck starts up and idles perfectly fine. No reduced power message on display or wrench.

Sensor read 1900 but others were within range, The bad sensor was replaced 1 1/2 years ago. Asked a Ford if there was an update to make truck read two sensors before shutting down while pulling trailer uphill. Ford said no. Think newer truck take an average Incase a sensor goes bad. Displaynsaid pull over now and once truck saw 5 mph, it shut off. Had an EGR sensor go bad about 3 years ago and truck would barely go 60 pulling trailer.

Ford said fuel fuel cooler was air locked and fuel temps were too hot causing truck to de rate. Injectors sounded different and rattled more if you gave it more pedal trying to accelerate last time I took it in. This time it seems like it even has less power and struggles to get up to 20 mph. I try taking it for another drive now thst it has cooled off and see how it acts.

is coolsnt pump working

Not sure if pump is coming on and do t know how to verify. Here is what Ford tech said last month when I took it it

FOR THE NO POWER CONCERN THE TECH SAID:

INSPECTED AND VIEWED THE CUSTOMER SUPPLIED VIDEO TO VERIFY THAT INTERMITTENTLY THE ENGINE WILL DE RATE. HOOKED UP IDS AND PERFORMED PCM KOEO SELF TEST, PASS, CMDTCS, PASS. PERFORMED DIAG BY SYMPTOM WITH NO CODES PRESENT. USED DATALOGGER TO MONITOR FUEL, AND EXHAUST TEMPS. FOUND THAT THE FUEL TEMP IS HOTTER THAN LIKE UNITS. INSPECTED SECONDARY COOLING SYSTEM, APPEARS FULL OF COOLANT. USED IDS ACTIVE COMMANDS TO TURN ON THE FUEL COOLER WATER PUMP AND FOUND THAT THE PUMP DOES RUN, BUT DOES NOT PUMP ANY COOLANT. APPEARS TO BE VAPOR LOCKED. USED VACUUM COOLING SYSTEM PUMP TO EVACUATE ALL THE SECONDARY COOLING SYSTEM. AFTER THAT RECHECKED SECONDARY COOLING SYSTEM OPERATION WITH THE PUMP COMMANDED ON AND VERIFIED THAT THERE IS NOW COOLANT FLOW. ROAD TEST 6 MILES AND THEN HAD THE SHOP FORMAN ROAD TEST ABOUT 30 MILES, NO FURTHER CONCERNS WERE NOTED, OKAY.

Appreciate your input and filling me in on things to look for

I would disconnect the hose on the girl cooler on the same side where the shreader valve is and see if coolant is being pumped and if not replace the pump.

Took truck back into Ford this am and it ran great and made full boost. Guess we will see what they find. Had to pay $50 deductible for AC anyways. I will post the outcome

Well truck has been at Ford for a week and they can’t duplicate problem and there were no codes stored. They have driven it 50 miles and runs like a champ. I asked them if they could put a recorder on it so it can capture what’s going on next time it acts up. Supposed to head to California next week with trailer and don’t have a warm fuzzy. Might try hooking up to trailer this week and see if I can get it to act up.

Anyone know any tricks I can try if it goes into limp mode? Don’t want to get stranded in California. Key off, key on, disconnect batteries, let it cool down, etc. I understand it might clear computer if I disconnect batteries but I don’t want to be stuck on the side of the road. Appreciate any feedback

I carry a code scanner that can clear codes.

Disconnecting ng the battery may or may not work

Shoot I won’t be able to clear codes if they have data recorder on it. Guess all I can do is chance it and try recording. If it goes into limp mode try shutting key off and letting truck cool down and try restarting again. Only time I have had problems is when towing 5th wheel.

My my buddy has an 08 and his would go into limp mode after pulling or in regen and when he stopped. He couldn’t remember if Ford replaced fuel temp sensor or fuel pressure sensor. Thanks for all your input speakerfritz

A very common cuase of limp mode on 08’s when towing is the #3 egt sensor. An improved sensor became avail in later year models. The differences is the tip...the problem one is straight and the new version has a tear drop on the tip.

a failed #3 for example can’t be code cleared to get out of limp mode.


towing with a dpf is problematic . The pressure sensor will trigger the regen process if the pressure is high for more than 1 minute.

I had one of my sensors go bad before when towing. Got a message on display that said pull over now. Truck backed off on power and once it saw I was at 5mph it shut off. No power steering or brakes of course going uphill over single lane bridge. Then the truck wouldn’t restart. Had a guy pull in in an old Cummins and and said I will pull you up he hill. Freakin Cummins was a beast, pulled truck and 40 ft toy hauler up the hill so I could get off the road.

I unhooked trailer and hour later truck started. Drove to Ford dealership an hour away and they said EGT sensor was bad. Not sure which one. I know it was on the DPF because they broke the sensor off and tried using an easy out and broke easy out off. Tried removing easy out and ended up removing bung and welding a new one on. trying to get it out. Then on way home truck kept going into regen and losing power. Unhooked trailer and made it home. Took it to Ford and DPF Pressure sensor was melted. Truck has 83,000 miles now. I should probably replace all the EGT sensors for piece of mind.

The cost of deleting is cheaper than replacing all the egt parts on the 6.4 going into regen an additional 7/8 worth of fuel is injected creating enormous heat. Once I deleted fuel economy skyrocketed!