I have a frieghtliner with a 3126. It just started shuting down at low idle in 1st or 2nd gear. I took fuel filter off and it was half full. I filled it up and it started. About an hour later it died again. I Did same thing and it started. Is it fuel filter or something else?
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Cat 3126
- Thread starter dan7
- Start date
simonsrplant
Senior Member
Perhaps someone else would chime in here... I believe the on road application 3126 motors have pressure regulator trouble... Could have my wires crossed tho.
Shimmy1
Senior Member
Just so they have the info (they are all going to ask for it) truck VIN, Engine Serial, Arrangement number, I think there is one more but drawing a blank right now. I would guess you're going to have to snap a gauge on and see what the pressure is doing when it dies. Without a pressure reading we're just throwing darts.
Cutterjohn
Active Member
Without the engine serial number I'm going to take a wild guess and say it could be the fuel return valve at the rear of the cylinder head. See attached, highlighted area's. 
GregsHD
Senior Member
Need more info! I've found when the fuel pressure regulator leaks it will cause hard starting after sitting overnight and slight loss of power, at low idle it doesn't need to be much fuel pressure to run it would just have no power. I've had lift pumps fail and seen almost 0psi in the fuel rail and it was still running, although it didn't have enough power to move the truck in 1st gear! If it's an electronic 3126B I'm leaning towards engine wiring harness rubbed through behind the HEUI pump on the corner of the intake manifold, seen that many times shutting engine down for no apparent reason. If it is electronic are you getting any trouble codes/engine light?
Cutterjohn
Active Member
This looks like an OEM# (Freightliner) the engine serial# should start with something like this, 1WM, the CAT prefix is usually a number followed by two letters. Call your Freightliner dealer and have him get you the build listing the installed engine, hopefully that will have the engine serial#
Nige
Senior Member
For the engine Serial Number you need to be looking either for a stamped data plate on the LH side of the cylinder block just forward of the flywheel housing. This plate will contain details of the engine model, the Serial Number, & the Arrangement Number.
Alternatively look for a stick-on film on top of the valve cover. That will contain the same information as the plate on the block but additionally will have information regarding engine power, fuel settings, max. operating altitude, etc, etc.
The Serial Number in total is eight characters. The first three can be letters or a combination of letters and digits. This is known as the Serial Number prefix which identifies the engine "family". Examples of the prefix for different models of 3126 engine would be 1WM, BKD, or G3E.
Each of the last five characters will be digits (0-9) and is the engine Serial Number within the family.
Alternatively look for a stick-on film on top of the valve cover. That will contain the same information as the plate on the block but additionally will have information regarding engine power, fuel settings, max. operating altitude, etc, etc.
The Serial Number in total is eight characters. The first three can be letters or a combination of letters and digits. This is known as the Serial Number prefix which identifies the engine "family". Examples of the prefix for different models of 3126 engine would be 1WM, BKD, or G3E.
Each of the last five characters will be digits (0-9) and is the engine Serial Number within the family.
Birken Vogt
Charter Member
To further complicate matters you found the "engine family number" which near as I can tell is used for government emissions purposes.
http://www.arb.ca.gov/msprog/onroad/cert/mdehdehdv/2000/caterpillar_mhdd_a0130132_7d2_4d0-0d10.pdf
Some interesting info found in those publications such as available power and torque levels but nothing that can help your project.
http://www.arb.ca.gov/msprog/onroad/cert/mdehdehdv/2000/caterpillar_mhdd_a0130132_7d2_4d0-0d10.pdf
Some interesting info found in those publications such as available power and torque levels but nothing that can help your project.
GregsHD
Senior Member
I have seen many primary fuel filters only "half full" when you pull them, especially if they are mounted up high, we don't even know what filter he pulled. Not enough info. I have never seen a 3126 just shut down if it sucks air without stumbling and knocking.
I got all the numbers. Thanks for all the help. Serial -8yl92142. Ar-197-1131. Core ar-173-1332. Oem-c01-00023-309. Famliy-Ycpxh0442hrk. Also the filter I pulled was the only filter and it is up high mid way back on the engine.
Nige
Senior Member
8YL92142 is a 3126B rated at 230BHP @ 2200RPM for Freightliner usage. It was built in November 2000. This is what the fuel pressure regulator looks like on this particular engine. Same place on the engine but a slightly different Part Number in this case.
Mobiltech
Senior Member
Are you 100% sure there is no other filter. I know there were a lot of these freightliners without a primary filter but I've seen some where they have been added. I have even seen an inline style replaceable filter under the cab on some.