Fuel starvation problems going uphill?

[Native]

It really would be cool if that is the problem. Fingers crossed!

[Lherrlinger]

I had to have the socks in my fuel tank cleaned out! It only bogged at high rpms/ uphill

[Dirtdoctor]

Rock filter. Clean it and check your fuelPickup tube in the tank. I’ve had my International 4900 have fuel
Issues. Finally after having to keep full
Tanks it dawned on me. Pulled the tube and there were cracks sucking air. Had a machine shop build new ones. No more problems.
Cheers

[musigenesis]

Originally Posted by Lherrlinger

I had to have the socks in my fuel tank cleaned out! It only bogged at high rpms/ uphill

That sounds like me for sure.

[musigenesis]

Originally Posted by Dirtdoctor

Finally after having to keep full
Tanks it dawned on me.

This also sounds like me.

[musigenesis]

Well, my hand primer showed up and I replaced the one in my engine. It seems that the old one alternated between easy to push down and foamy or hard to push with regular fuel coming out; with the new one it was medium-hard to push each time, and I worked it a bunch without anything seeming to change. Started up the engine and I heard a little bit of the clacking and irregular idle but after about a minute it seemed to smooth out and sound like normal.

I decided not to drive it and wait until tomorrow when I'm going to try to get it the few miles to the shop. I think it's far more likely to be cracks in the fuel lines or junk in the filters than this hand primer, but at least I have brand a new hand primer and I can claim to have actually done something mechanical on my bus now. I'll have the mechanic check out the things you guys have suggested and hopefully they won't charge me ten grand to fix it.

[Native]

Check the prime pump in the morning before you take off. If it is still hard to pump, you may have found the problem. A few cackles right after starting up (after replacing the prime pump) could be the system working out any left-over air in the fuel.

[lemmeskoolu]

Originally Posted by musigenesis

I'm having a problem recently with my bus. When I start to climb a steep hill, the transmission will downshift and the RPMs will go up, but the engine will pretty much lose most of its power. Or else it kind of chugs where the power will cut in and out. I ease off the pedal and then it downshifts and I can get up the hill, just slower than usual. This seems to happen at about 1800 RPM or higher, if it's lower than that the engine seems to be fine. And this only happens on an uphill, on flats or downhill I can rev higher and the engine has power like normal.

It was suggested that it sounds like a fuel filter problem, so I researched changing them and then took my bus to the shop last week. The mechanic sort of dismissed this power problem as possibly just air bubbles in the fuel line, but it's been happening consistently for the last five or six trips. My fuel filters were changed in May 2019 and I've only driven 700 or 800 miles since then, so he didn't think it was likely to be a fuel filter problem.

Any ideas on what might be happening? There's no check engine light coming on, no unusual smoke out the back end or anything. I have to take the bus back this week to have other things done (new front brake drums and a new exhaust, gulp) and I'm going to re-emphasize this problem to him.

I had the same issue and it turned out my transmission fluid was low!!!

[musigenesis]

Luckily my transmission fluid is fine, although I did wonder initially if that's what was going on. I was feeling the same loss of power even when I revved it in neutral, though.

[JodyandRenee]

Originally Posted by musigenesis

Welp, I think I may have blown or damaged my engine because of this. I picked it up this morning and was driving it home, but on the first (relatively small) hill the power cut out and then stayed cut out. I was barely able to limp to the top and then turn around, and while trying to limp up a hill going back the engine warning light came on. I stopped and shut the engine off and then turned it back on (the engine warning light did not come back on, at least) and then limped back to my lot.

I popped the hood and pushed the primer pump a few times. It was easy to press in and a frothy foam came out. After maybe 10 pumps it stiffened up and then pure fuel (no air bubbles) started coming out. I tried the engine again and it has a strange sound in idle now.

I found the data plug on my bus so I'm going to try plugging in my new Bluefire and seeing what I can see.

I had the same problem on my powerstroke truck. I don't know if your bus is the same way, but I had algea in my tank and the filter socks on the fuel lines were clogged. The easiest way to check to see if its a fuel delivery problem is to put a pressure gage on the lift pump coming from the tank TO the injection pump. Its not monitored by the computer so it won't generate trouble codes. Most diesels need about 7 psi of pressure to the injection pump from the tank. I had to drop my tank, clean it out completely, and replace the filter screen pickup assembly. Might be worth a look.

[musigenesis]

Well, I was at least able to make the four miles to the shop this morning. Weirdly, the bus wouldn't start this morning (first time since my new starter that it hasn't fired right up). I hit the hand primer some more but now I'm not even sure it's working correctly - I just keep pushing with the same amount of light resistance and it never gets harder to push. Anyway, the engine started up after doing that and I was able to limp up the couple of hills I had to go over, although again the power was cutting out if I got over 1500 RPM or so. The WARN ENGINE light came again during the second hill.

After the hills there's a two-mile straight run and it seemed like the problem cleared itself again and I was able to rev over 2100 and still get normal power.

Anyhoo, it's in the mechanic's hands now so hopefully this won't be too grisly in terms of wallet damage.

[BamaBus]

Originally Posted by musigenesis

I hit the hand primer some more but now I'm not even sure it's working correctly - I just keep pushing with the same amount of light resistance and it never gets harder to push.

A few days ago I went out and tested the primers of couple of DT's and they were easy to push but no fuel leaked out. As always, , the buses started without issue. I looked at another candidate today and the primer leaked badly. It wouldn't start but I think it was because the fuel smelled like an oil based paint, not diesel.

[musigenesis]

Shop has diagnosed my problem as a failed high-pressure oil pump, which fits with the 333 code that was thrown. They're waiting to get a quote on the cost of the part.

[CHEESE_WAGON]

Originally Posted by musigenesis

Shop has diagnosed my problem as a failed high-pressure oil pump, which fits with the 333 code that was thrown. They're waiting to get a quote on the cost of the part.

[musigenesis]

Originally Posted by CHEESE_WAGON

Attachment 49643

Uh, how many dollar signs are we talking here?

[CHEESE_WAGON]

Originally Posted by musigenesis

Uh, how many dollar signs are we talking here?

The pump itself is $1202.58 from the local dealer, with about $100 in miscellaneous parts recommended as part of the job (grommets, some pipe connecting back to the engine was also recommended -- a $75 part dealer price).

If you can't do it yourself, dealer labor $160-$180 an hour and estimated about 3 hrs labor.

The upshot is that these don't fail frequently on the same vehicle as long as it is maintained. However, I imagine regular oil service is critical on these HEUI / HPOP systems just as it is on VVT gasoline engines.

[musigenesis]

Originally Posted by CHEESE_WAGON

The pump itself is $1202.58 from the local dealer, with about $100 in miscellaneous parts recommended as part of the job (grommets, some pipe connecting back to the engine was also recommended -- a $75 part dealer price).

If you can't do it yourself, dealer labor $160-$180 an hour and estimated about 3 hrs labor.

The upshot is that these don't fail frequently on the same vehicle as long as it is maintained. However, I imagine regular oil service is critical on these HEUI / HPOP systems just as it is on VVT gasoline engines.

Ah well, that's actually not as bad as I thought it might be.

I had my oil and filters changed in May of 2019 and I've driven maybe 700 or 800 miles since then (and the level was fine and the oil looked good). Is this likely to happen if the oil isn't changed after a year, even if the miles are low?

[CHEESE_WAGON]

Originally Posted by musigenesis

Ah well, that's actually not as bad as I thought it might be.

I had my oil and filters changed in May of 2019 and I've driven maybe 700 or 800 miles since then (and the level was fine and the oil looked good). Is this likely to happen if the oil isn't changed after a year, even if the miles are low?

Oil can get oxidized over time regardless of mileage, so yes, it is possible. Typical intervals on oil changes for commercial diesels are usually anywhere from 15k-50k, but you have to account for most of these running anywhere from 150-600 miles a day. Mileage is much more of a factor than time in that situation. I would say the time factor really comes down to what is recommended for a particular oil or by the engine manufacturer. Just off the cuff, I'd say every 6-12 months regardless of mileage, but check with Navistar about this.

That being said, I hardly think one overdue oil change will kill an HPOP, but it's not a habit you want to get into with a high-mileage diesel, especially with a HEUI system, which I believe HPOP precludes.

[musigenesis]

Originally Posted by CHEESE_WAGON

Oil can get oxidized over time regardless of mileage, so yes, it is possible. Typical intervals on oil changes for commercial diesels are usually anywhere from 15k-50k, but you have to account for most of these running anywhere from 150-600 miles a day. Mileage is much more of a factor than time in that situation. I would say the time factor really comes down to what is recommended for a particular oil or by the engine manufacturer. Just off the cuff, I'd say every 6-12 months regardless of mileage, but check with Navistar about this.

That being said, I hardly think one overdue oil change will kill an HPOP, but it's not a habit you want to get into with a high-mileage diesel, especially with a HEUI system, which I believe HPOP precludes.

Thanks man, I appreciate your information as always. I wish I lived closer to you so I could trade some work for your expertise.

[cadillackid]

I do 6k milkes for oil and 3k miles for filter on my diesels.. so one filter change in the middle between oil changes...