Code?

[Silverwolf]

Have a code or ECU warning, cant clear it, not sure why its happenin. Its on a Volvo VNL , trucks and 06, but engine is the ISX400 from 08. I notice no performance loss or anything wrong other than the check ECU comes up every time I start up. Checked the code, it says fuel pressure high, 3 times. Can't clear it, wont go away. Cant figure out how or why fuel pressure would be high. Changed all the filters on the truck, (4), and poured 2 bottles of Duralube fuel treatment into the fuel filters. Code still there, still can't clear it . Doesn't say when or if it still has high pressure, but code cant be cleared. The check ECU at next stop first came up after I climbed a big long hill. I was only towing about 28k pounds, 9th gear, about 1300 rpm, steep enough I couldn't catch 10th gear without bogging out. Got to the top, as I came to a stop at a light, the ECU message came up. As said, no noticeable performance loss so far. Changed oil as well, old oil was dirty but good no fuel or anything abnormal. Didn't have much mileage on the old oil, but changed anyway, added 2 bottles Duralube Heavy Diesel oil treatment. Any Ideas whats causing the code? Bad fuel sensor? Pump pooched? Gel in fuel some how? 80 degrees here, summer. Regularly use fuel additives to prevent that. Any help would be appreciated. Would like to fix it before it breaks for good.

 

[Hammer166]

Two distinct possibilities come to mind. First is simply a bad fuel pressure sensor. The other is something wrong in the pressure regulating circuit, but I'm not familiar enough with how that works in those engines to guess beyond that.

 

[Silverwolf]

Thanks for that, I'm trying to uncode that code , hoping it tells me more, like which of what you said it may be.

 

[Silverwolf]

So found the code description, but it appears to not exist? Meaning I found the whole list, and the FMI code is what tells you what failed, and the list starts at 1, and all of them are LOW pressure codes. This clearly says high pressure, and the "0" FMI does not exist?

 

[Silverwolf]

Found some interweb posts on the high pressure code. One specifically was a good match, it was caused by the guy hauling a load up a steep hill, sucked up the sludge from the bottom of the tank. Since mine seems ok, I'm thinking it did the same, and the filter change and cleaners cleared it up. It did idle and run a lot smoother after the oil and total filter change. BUT! I can't clear the code??? How do you do that ? The regular clear all option were you have to enter your password, does not clear it. Also, turned on key this morning to listen to the pump. It sounded as it did before, buzzes for about 2 minutes and shuts off, repeats if you cycle the key on and off. So figure it survived the goo gobble. I did pour an entire bottle of fuel treatment and octane booster combo into the 3/4 full tank. It treats 2000 liters of fuel, so it was almost a triple dose. Should dissolve any goo left in the tank I hope. Figure the bottle of duralube fuel system treatment in each fuel filter probably cleaned up the pump pretty good, since its in between the filters, and they treat 1000 liters each, so Kabaam! Super cleaned. Now if I could only clear the code to see if it comes back?????

 

[Silverwolf]

Update, fired her up. Wow, its a lot quieter than before. Injectors were pretty clacky when cold before, real smooth and quiet now. All that cleaner seems to have helped more than just the pump. Alot of Km on this truck. Bought it with the 08, 2nd motor in it, so not sure of the motor mileage, but the truck has a bundle. Those injectors must be pretty happy with the super clean and lube. Hahaha

 

[Silverwolf]

Went for a good drive non loaded. Runs like a dream, real smooth after the cleanup. Never tossed any codes, but still can' t clear the existing code. Don't know why it won't accept the delete command, even after entering my password. Does anyone know how to clear that code?

 

[Electric Chicken]

Maybe it's code that goes away on its own after it runs without that issue for a certain number of miles.

 

[Silverwolf]

Well, its still there because its an active code, meaning it still happens. I can't find anything wrong, runs fantastic. But has this Too High fuel pressure code, happened 4 time now, so 1 time yesterday when I went for a long drive. Didn't even notice until I checked the code. What would cause the pressure to go too high? Didn't think the pump could go too high?

 

[Ontario Outlaw]

Did you try using Powerspec or Insite to clear it?

Disconnect the batteries? Unplug the ECM?

What scan tool are you using?

 

[Silverwolf]

Using the cpu in the truck to pull the codes. It wont clear because its reoccurring. I need to find why its reading over pressure, or actually over pressuring. And fix that. As dchawk says, once its not reoccurring it will be able to be cleared. I will try unplugging the batteries, but I'm pretty sure its going to reappear as soon as it throws the code again. Following the fuel lines I don't see any sensors, then it all disappears under the engine cpu. So any sensors are under the valve covers from what I can see. I don't see how a fuel pump can over pressurize, even if totally dead headed. So it must be a sensor. Trying to find an engine drawing to find the sensors. IF not to pricey I'll just toss sensors at it until its happy. lol

 

[Ontario Outlaw]

Using a scan tool you’d be able to clear it, assuming at the time it’s an inactive code.

What controls the fuel pressure on that mill? The ECM or the fuel solenoids?

 

[Silverwolf]

That I do no know. I see solenoids there by the fuel pump, two look pretty new, two look original. THought there would be 6 since there were 6 cylinders. The lift pump turns on fine when you key on no start and it runs for about 2min then shuts off. Steady buzz, seems ok. Trying to find the drawing in the service manual I downloaded. A lot of info. Once I identify all the parts I should be able to find the issue. Do you think it could be those two ancient solenoids?

 

[Silverwolf]

Code still there, odd it doesn't seem to affect performance. Getting lots of work this week, haven't had time to research possible causes of high fuel pressure. Cant find a drawing in the manual I got. Seems to only cover the volvo motors. I will have to buy a cummins manual to figure this out.

 

[Silverwolf]

Well, unplugging batteries did not clear code, because its active. SO , have not found a source for a service manual for this motor, so trying to figure out what I can until then. As said, it is running very smooth, Idles great. Starts good too. BUT. I tested it before unloaded, and it seemed improved other than the code. But today I had a chance to pull a full load, on the hwy, and up some good hills. It is running at about half power. It still goes, but takes along time to get there, and wont hold gears on the hills like it used too. Its weak. But running great. How odd. I figured out that the fuel over pressure happens once only, every time I start the truck. Then nothing until I start it again. So it does not happen driving. With the low power I'm thinking the lift pump is pooched and can't supply enough fuel to get power? But why would it over pressure on start? Shouldn't it throw the low pressure code? Maybe I'll try blowing out the pick up line from the pump back with an air compressor. Then put an exterior pump on it to see if its drawing good fuel. Might put a pump in it , will have to price that out. I have two fuel filters , so can't see anything plugging the pump or past the pump to cause high pressure. Could the power loss be a "Limp mode" being caused by the pressure being high and the cpu cutting power? Or most likely a fuel pump issue. Those solenoids ohm out ok and after the drive they were all warm to the touch, but the same warm, no abnormal ones. Hopefully the pump is cheap like the alternator was. lol.

 

[Silverwolf]

found some good help on a truckers forum. they all figure its first the fuel pressure sensor, and then the two regulators. So off to the parts store to toss some parts at this girl. Two regulators and a sensor. Cross your fingers.

 

[ironpony]

found some good help on a truckers forum. they all figure its first the fuel pressure sensor, and then the two regulators. So off to the parts store to toss some parts at this girl. Two regulators and a sensor. Cross your fingers.

Start with the sensor... it's probably the cheapest option.

 

[Silverwolf]

Yup, it was the sensor. I got all three, sensor and regulators. put the sensor in first. started up and the code vanished right away. Went for a drive and honestly it feels like it has way more power than before. The one that came out was huge, quite a bit larger than the new one. Cummins said it was the original. 1.1 million miles on that sensor. Total bill was 650 bucks, but they let me return the regulators so ended up at about 200. Thanks for the help guys. Back to work now. lol

 

[Ontario Outlaw]

Yup, it was the sensor. I got all three, sensor and regulators. put the sensor in first. started up and the code vanished right away. Went for a drive and honestly it feels like it has way more power than before. The one that came out was huge, quite a bit larger than the new one. Cummins said it was the original. 1.1 million miles on that sensor. Total bill was 650 bucks, but they let me return the regulators so ended up at about 200. Thanks for the help guys. Back to work now. lol

Pics of said sensor?

Good job getting it fixed

 

[Silverwolf]

Sensors looked the same. The original was a 1 1/4 socket, new one was 1 1/16 socket. Quite a difference. Guess technology keeps making things smaller. If I can figure out how to first get the pics from my phone to my laptop, then how to post them, which to date I have never successfully done on any site. Lol. I would post pics. My sons over tomorrow. He'll know how to do it. Computers and phones are not my friends.