Community Forums

afens94 · 01-07-2019, 07:46 AM

Hi there,

Newbie to the forum. I have a 2000 Cat 3126 that is in a rig I just purchased and picked up over the weekend. Drove it just fine 175ish miles home without missing a beat, and basically when I pulled it in the farm yard it started "loping" when idling in neutral. Sounds just like it has a lope tune in it. RPM bounces up and down until you give it just a smidge of throttle and then everything is smooth. It also momentarily shut of for a split second like you flipped the switch off and on. Thought it was running out of fuel but there was still plenty of fuel in the tank. Let it sit for a few hours and cool down, fires up and runs like a champ. Any ideas? Thanks in advance!

JNSNWT · 01-07-2019, 10:11 AM

First thing that comes to mind and easiest to do is change fuel filters

Second has the rig been sitting for a while? I would suggest you unplug and re-connect every pigtail connection you can find two or three times to re-establish connectivity and maybe displace rust and corrosion

afens94 · 01-07-2019, 10:17 AM

Quote:

Originally Posted by JNSNWT

First thing that comes to mind and easiest to do is change fuel filters

Second has the rig been sitting for a while? I would suggest you unplug and re-connect every pigtail connection you can find two or three times to re-establish connectivity and maybe displace rust and corrosion

Unit had seen very little run time in the last year or so, I think about 300 miles total. I am planning a full service anyway so I will start there. And I will run through electrical connections and grounds. Battery connections were pretty cruddy so I have cleaned them up already. Thanks for the advice.

2 Stroker · 01-07-2019, 11:01 AM

Does your fuel system have a line cut off so the fuel does run back to the tank? Does it have a fuel priming system? Can be a killer if you try and start with no fuel. If you pre-fill your filters, fill only through the small holes with clean fuel.

I always start my motor and run for a few minutes to warm it up that way it starts better after filter change. Use only Cat Advanced filters. Keep the fuel tank full when setting to keep down condensation in the tank.
2 stroker

afens94 · 01-07-2019, 12:41 PM

Quote:

Originally Posted by 2 Stroker

Does your fuel system have a line cut off so the fuel does run back to the tank? Does it have a fuel priming system? Can be a killer if you try and start with no fuel. If you pre-fill your filters, fill only through the small holes with clean fuel.

I always start my motor and run for a few minutes to warm it up that way it starts better after filter change. Use only Cat Advanced filters. Keep the fuel tank full when setting to keep down condensation in the tank.
2 stroker

I will have to check into the fuel cut off and priming system. After I got it home Saturday I had to hop in the car with the wife and drive 3 hours to go meet our new baby nephew, so I haven't had a chance to get back to it. Hoping to get the rig in the shop in the next day or two to start looking it over. This is actually a Freightliner FL60 toyhauler that I bought so please don't banish me for not being a true "RV" haha. I also noticed my dual tanks are not equalizing on their own, so I need to look at that too.

Gaspumpcity · 01-07-2019, 01:18 PM

Did you experience check engine light?

afens94 · 01-07-2019, 01:27 PM

Quote:

Originally Posted by Gaspumpcity

Did you experience check engine light?

No check engine light.

I90Tom · 01-07-2019, 10:16 PM

I also have a Cat 3126E in my 2000 Dutch Star. If it starts easy when cold and idles fine until warmed up, but "lopes" when warm, it could the HEUI actuation valve. As my condition worsened, I had to tickle the throttle at red lights so it wouldn't die. We discovered it had to cool off about 2 hours before it would restart. I limped into a shop late one Saturday afternoon where they hooked up their computer and the preliminary diagnosis was a failed HEUI pump & maybe 6 new injectors. We parked it there overnight. When it started right up and idled normally Sunday morning, a seasoned Cat mechanic suspected the actuation valve. The valve itself was fairly cheap but we ran up repair bill of about $550.00.

afens94 · 01-08-2019, 02:52 PM

Quote:

Originally Posted by I90Tom

I also have a Cat 3126E in my 2000 Dutch Star. If it starts easy when cold and idles fine until warmed up, but "lopes" when warm, it could the HEUI actuation valve. As my condition worsened, I had to tickle the throttle at red lights so it wouldn't die. We discovered it had to cool off about 2 hours before it would restart. I limped into a shop late one Saturday afternoon where they hooked up their computer and the preliminary diagnosis was a failed HEUI pump & maybe 6 new injectors. We parked it there overnight. When it started right up and idled normally Sunday morning, a seasoned Cat mechanic suspected the actuation valve. The valve itself was fairly cheap but we ran up repair bill of about $550.00.

That is exactly what it was doing. Was loping and sounding like it was trying to cut out. I feathered the throttle to get RPMs higher and it smoothed out. Let off throttle and it would start loping again. Like I mentioned too, it briefly cut off and back on as well. I will need to look into the IAP sensor and the valve.

Golfer Guy · 01-08-2019, 07:03 PM

I suspect you may be getting air in your fuel line too.

Another issue with the 3126, C7, and C9 Huie pump system Cat's is the need for a 24V electric fuel pump to keep a constant flow of fuel from that tank 30ft away from the engine. CAT would like the fuel source to be no more than 6' from the Huie pump.
I added the CAT 24Vfuel pump and it fixed the problem of looping at low rpms and improved the general performance of my C9.

Take a look at this article on the issue. http://beaveramb.org/acadp_listings/c9-rough-idle/

CountryB · 01-10-2019, 07:58 AM

Quote:

Originally Posted by Golfer Guy

Take a look at this article on the issue. C9 Rough Idle | Beaver Ambassador Club

Golfer Guy,
It may not be my place to speak on this (I've done it too) but the Beaver Ambassador administrators (and club rules) say we should not post links to the Beaver stuff (which is provided only for "paid members").

Golfer Guy · 01-10-2019, 10:03 AM

Did not know that, I stand corrected. Tried to delete the reference to the BAC but was unable to do so. Thanks for the input Mike.

boyland · 01-16-2019, 06:12 AM

It may state that but the article he listed is indexed by google. I simply did a search of "C9 Rough Idle beaver ambassadar" in google and guess what it pops up.

So you are not in any violation of their club rules because it is public content. If they do not want it public then i suggest they hire a professional in the IT industry to secure their content.

CountryB · 01-17-2019, 07:53 AM

Quote:

Originally Posted by boyland

It may state that but the article he listed is indexed by google. I simply did a search of "C9 Rough Idle beaver ambassadar" in google and guess what it pops up.

So you are not in any violation of their club rules because it is public content. If they do not want it public then i suggest they hire a professional in the IT industry to secure their content.

Thanks Blaine, I'm just repeating what I was told when I did it. Maybe we (Golfer Guy and I) should just provide our links to the Google link rather than to the club site directly, so we stay out of trouble.