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Cat 446B poor start

Bermudian

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Joined
Jul 1, 2020
Messages
15
Location
Guatemala
What is the problem with a CAT 446B backhoe with the 3114 engine that starts hard? A little history...When I got the machine, it started very well but had no power and smoked black like a freight train. The injector rack was worn bad so I put a new CAT one in. I also put Cat reman injectors in and had the CAT dealer do all the injector adjustments. I also installed a CAT reman turbo. This gave the machine a lot more power and it does not smoke unless under load at low rpms. It still lacks power especially at low rpms. Now the machine needs to crank over for a while and hardly starts if it has not been running for an hour. (When it is shut off it starts just fine right away and will start instantly with ether when cold) I have looked over the fuel system very well and it seems the one way valves are all functioning well. What am I missing? Why did it start very well before changing the injector rack and injectors but now starts very poorly?
 

thepumpguysc

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Mar 18, 2010
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Sunny South Carolina
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Master Inj.Pump rebuilder
If it has a hand primer in the system, pump it up BEFORE trying to start it..
If it fires up better than before. U have either a bleed back problem or a supply problem..
The 2 go hand in hand most times.
The bleed back is usually caused from the valves not seating in the supply pump..
Give it a try..
 

Bermudian

Member
Joined
Jul 1, 2020
Messages
15
Location
Guatemala
I have done that and it does not seem to help much. The fuel pressure comes up rather quickly. It started like a charm before in 2 seconds before I changed the injectors. Now I need to crank it for 10 seconds before it begins to fire and then it seems to fire on just a couple cylinders for another 10 seconds till it finally gets going. The governor is adjusting the rack for max fuel when trying to start as well. Are the CAT reman injectors the culprits? The engine is missing the tag on the valve cover so we did not know the injector height spec but the CAT technician put them at 65. Could injector height affect the starting?
 

Nige

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G..G..G..Granville.........!! Fetch your cloth.
There has been plenty of anecdotal evidence on HEF over the years that Cat Reman injectors have a signficant failure rate right out of the box. I have experienced it myself, not with 3114 injectors though.

The engine is missing the tag on the valve cover so we did not know the injector height spec
You have the machine Serial Number I'm sure. I wonder why the Cat tech did not use that to pull up the engine S/N in the online system and get the data that way.? Post the machine S/N, I'll tell you what the engine S/N should be.
 

emmett518

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Mar 24, 2021
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USA
Do all diesel engines have a hand prime? I had no idea such a thing existed on big engines. Does my Deere 310 L have this?
 

Nige

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Do all diesel engines have a hand prime? I had no idea such a thing existed on big engines. Does my Deere 310 L have this?
A lot do. Amongst other things it's to assist with priming the fuel filters after replacement.

The question whether your engine has a hand primer will probably be answered after a short search in the engine bay.
 

emmett518

Senior Member
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Mar 24, 2021
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What do I look for? A bulb like on a leaf blower? Or an outboard motor on a boat?
 

emmett518

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When I changed my 2 fuel filters, I didn’t have any problem starting right up, even though there was no manual priming.
 

Bermudian

Member
Joined
Jul 1, 2020
Messages
15
Location
Guatemala
The serial number for the CAT 446 B is 05BL00385. I tightened the injector adjustment down another 3/4 turn advancing the timing and now it starts a little better but still smokes a lot at low rpms and lacks power as well.
 

Coaldust

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May 9, 2011
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Cargo Tanks, ULSD, RUG, Methanol, LPG
That’s a bummer. What catches my attention is you paid premium for a dealer tech to do it right. Whom has access to all the product support information. Doesn’t know how to look up TMI info. I wouldn’t trust that tune at all.
 

Cmark

Senior Member
Joined
Jan 2, 2009
Messages
3,176
Location
Australia
When you replaced the injectors, did you do anything to make sure the sealing surface between the injector tip and sleeve was good? I sounds like you may have an air leak into the fuel gallery.
 

Bermudian

Member
Joined
Jul 1, 2020
Messages
15
Location
Guatemala
I just made sure it was good and clean and installed new Cat orings. Is there more you can do other than change the cups?
 

Bermudian

Member
Joined
Jul 1, 2020
Messages
15
Location
Guatemala
Thanks Cmark! You highlighted the problem. I had read a little about seating the injectors but thought that was only needed after installing new cups. After reading the thread and some other forums on the problem of compression entering the fuel and causing hard starts and lots of smoke, I knew that had to be the problem. So I put a clear hose on the return and the bubbles just flow out of the engine...! Now I hope that reaming the cups and seating the injectors gives me relief from those issues.
 

Cmark

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Jan 2, 2009
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3,176
Location
Australia
Be cautious with cutting the sleeves. Unless you are fully prepared, you can end up making things worse and having to replace them. I suggest giving the seat a good polish with scotchbrite© and carrying out the coining procedure first. If that doesn't work then think about cutting or replacing the sleeves.
 
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