white smoke running rough at over 1500 rpm

[Idaho Mike]

2006 Navistar 4300 with DT466 box truck starts and idles perfect, take it up to 15-2000 rpms and starts missing, blowing white smoke, let it go back to idle and it runs fine. I get the PID94 FMI 1 code which is a lack of fuel pressure... What I have done, replaced cannister check valve, new fuel filter, cleaned strainer, changed fuel line grommets, new fuel pump. This started while going down hill and decelerating, when at the bottom of the hill thats when it starts to smoke real bad then clear up and run fine, this continually got worse to where I can't run it and broke down on the side of the road outside of Laramie Wyoming. I checked the coolant level and it's fine, no fuel or coolant in the oil either. Fuel pressure on analyzer 48psi

 

[Slapdash]

Just a stab here, but if the white smoke smells like maple syrup, could be a head gasket. My wife's car, very different engine, etc., had a head gasket leak, but it was between cylinders, so no coolant leaked out. Took a long time for me to diagnose. Sure enough though, when I took it apart, there were two fail points on the gasket between cylinders.

Also, maybe, water in the fuel?

Either way, good luck!

 

[Idaho Mike]

I'm not losing coolant at all. If it was head gasket there would be coolant lose. I have a fuel pressure issue. Wondering if a bad HPOP would cause this. Only thing is it starts fine cranks a couple times then fires right up

 

[ewo1]

Does your bus have a lift pump in the fuel tank ???

 

[Idaho Mike]

Negative

 

[ewo1]

PID94 FMI 1 code is listed along side DTC 372 in the EGES-270-1 Diagnostic/troubleshooting manual.

Here is what is listed on document page 408

DTC 372
EFP is below normal operating range

• DTC 372 is set by ECM when measured fuel
pressure is less than expected pressure by 103
kPa (15 psi) for more than 30 seconds.

• DTC 372 can be set due to dirty fuel filter element,
fuel inlet restriction, debris in fuel tank, debris in
fuel regulator valve, failed fuel regulator valve,
failed fuel pump, bias low circuit, or failed EFP
sensor. See “Fuel Pressure and Aerated Fuel” –
Section 6.

• When DTC 372 is active the amber FUEL FILTER
lamp is illuminated.

 

[Idaho Mike]

PID94 FMI 1 code is listed along side DTC 372 in the EGES-270-1 Diagnostic/troubleshooting manual.

Here is what is listed on document page 408

DTC 372
EFP is below normal operating range

• DTC 372 is set by ECM when measured fuel
pressure is less than expected pressure by 103
kPa (15 psi) for more than 30 seconds.

• DTC 372 can be set due to dirty fuel filter element,
fuel inlet restriction, debris in fuel tank, debris in
fuel regulator valve, failed fuel regulator valve,
failed fuel pump, bias low circuit, or failed EFP
sensor. See “Fuel Pressure and Aerated Fuel” –
Section 6.

• When DTC 372 is active the amber FUEL FILTER
lamp is illuminated.

Thanks ewo1,
I'm leaning towards the IPR, does the IPR affect the fuel pressure?? I have the original in it now and think it may be worn out, the magnet getting weak and not opening the valve, long story on how I got to this Hate to fork out the bux for an OEM but don't want to roll the dice on the aftermarket cheap chinese. The not so funny part is the OEM's are mad in china as well...

 

[Idaho Mike]

could a faulty throttle position sensor cause this? If I press on the pedal fast it starts sputtering and smoking white real bad, If I press it slow it works fine all the way up to 2500 rpms and holds steady

 

[ewo1]

Yeah, OEM IPR is around $400= bux!

I'm guessing you don't have servicemaxx available? You could see the IPR numbers and get a better idea...and check for DTC's.

My experience with IPR, mine just went dead, overnight. Put in a knock off, gott errors...put in an OEM and problem solved for me.

I can't give you an answer on the IPR or TPS.... My limited knowledge doesn't go that deep...yet...

The TPS should be good or no good. It is nothing but a simple potentiometer and a hall effect sensor in one package. You could try swapping it out from another truck/bus just to see if there are any changes but those guys are costly to at the stealership.

I think your simple test just might be a result of a no load on the engine test. Driving under a load I would be surprised to see the same pedal response results.

If you have access to a fuel pressure gauge, not an app but an actual gauge I would check fuel pressure as you were also stepping down on the pedal, see if there is a pressure regulation problem, maybe a problem with your pressure regulator ???

I'm guessing here.....

 

[Idaho Mike]

I do not have the SM adapter. I was thinking the same thing about the TPS, it either works or it don't, was just a thought.
Would a bad IPR cause the smoking and misfiring?
I do have a pressure gauge, I'll put it on this morning.
I have an analyzer that reads the fuel pressure, it idles at 40 and goes down to 35 when I give it throttle. I replaced the fuel pump twice, gonna check the pressure regulator inside the cannister this morning, it's brand new.
I have a wix filter in there now as the parts store did not have an OEM so we did a cross reference could the wix filter be the problem??

 

[ewo1]

could the wix filter be the problem??

Potentially, yes...It is not unheard of that a poor quality filter can obstruct fuel flow...

 

[Idaho Mike]

Replaced the IPR and the wix filter with OEM, runs like a top, could not be happier. The OEM filter was less expensive than the wix but the IPR was 600 bux, OUCH

 

[Idaho Mike]

Update:
Finally made it back to Boise the other day, what a trip. First broke down in Wellington Colo. for a couple days trying to figure out what the ****. After replacing the IPR and filter on the road we went, again....
2 hours from Boise on our 7 day trip that should have taken 5 again white smoke started billowing out on an incline of course, luckily there was a nice place with enough room to pull over..
First thing I did was drain the filter canister then pull the cap, when I pulled the cap I noticed sh!t ton of fine metal filings, not good, I pulled the filter, it was plugged, looked in the bottom and full of filings. To make a long story short it ended up being the cheap a$$ chinese fuel pump that let go. I just happened to have a spare used one and put it in, fired and mad home at 70 mph the whole way...
Moral of the story, don't use crap from china, spend your money on parts made here otherwise you'll end up on the side of the road in the middle of no where....It's not worth saving a few bux...

 

[ewo1]

What a trip!!! hopefully that fuel filter caught all the fine metal shavings!