3126E CAT Starving for Fuel

wayne22ucmt · Nov 9, 2011

I've got a 2003 or 2004 (says one thing on the title from what I think it is) CAT 3126E that started dying on me after we fueled up a few weeks ago. Finally, it completely died and won't start back. We've replaced 2 or 3 sensors and I checked to see if there's
water in filter and none has gotten me anywhere.

I know there are 2 filters on the engine and have been told by a colleague that there's a 3rd and I can't find it anywhere. I've been from one end of the engine to the other. Does anyone know if this engine has 2 or 3 filters?

And I think it may not be starting because of the supply pump but it could be the injector pump. What does anyone out there think? It has about 265,000 miles on it.

davekc · Nov 9, 2011

That engine should have three filters. Two for fuel and one for oil. Some marine engines have a third fuel filter for algae removal. That engine has two speed sensors but should run even with one down. Usually will throw a check engine light.
Do you have a check engine light on?
If not, you can reprime it if it has the manual pump. If not, you can crack a line and try to start it. If fuel comes out, it isn't the pump. Could have a crack or loose connection at the fuel lines or a collapsed fuel filter. If battery is too low, it won't engage the fuel pump which is electric and controlled at the ECM.
If that fails, you will have to put it on a computer to see what is going on with it.

wayne22ucmt · Nov 9, 2011

I checked the fuel pressure at the primer pump filter and it was only 15 PSI and should be 25.

I can only find one fuel filter and can't find the other. I have looked for a diagram of the engine everywhere online and can't find it to find where the second filter would be. The one I replaced was not collapsed.

The check engine light, or any other light is not on and I have already hooked it up to the computer and it's not giving me any codes.

davekc · Nov 9, 2011

That fuel pressure does sound low. As for filters, one is on the side of the engine and the other should be along the frame on the drivers side of the engine. It may have a cover or glass bowl if it is a aftermarket Raycor. Should be another on there somewhere. If unable to locate, take the serial number and call the dealer. That should help locate it if there is a second one.
Fuel pressure or filter problem is the issue. If no codes are thrown, it is not any of the sensors.

Rikk · Nov 9, 2011

I had an fl80, only had one filter. I did have issues with the primary lift pump on that motor. (Went through 2 of them the year before I sold it.

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guido4475 · Nov 9, 2011

No, No, No, No! Lol..there are 2 fuel filters, a spin-on type on the side of the engine, and there is one, it is hard to see and find, because it is an in-line type, wrapped in that black wire loom, under the cab, drivers side,along the frame rail.Believe me, it's there.It doesnt get changed much because many people dont know it's there...I mean, how could you, if you cant see it? I had the same problem, acting like it was running out of fuel, spittering and sputtering kinda,and that is the first thing Caterpillar eliminated, and it ran fine since.It was rusted badly..... A third one is an option, an like Dave KC said, it is on the frame rail, with a glass bowl, otherwise known as a fuel water separator.

Deville · Nov 9, 2011

I had a bad speed sensor & it did not throw any codes. Fond out by accident that it was bad. If you have cruise control, press the set/resume button with the on off switch in the off position. The check engine light will flash, count the number of flashes, when it pauses & restarts count them again. The amount of times the check engine light flashes is a number for a trouble code. Get those numbers & call a cat dealer & see if they can help u get pointed in the right direction.

Have you checked the fuses & relays for the fuel pump? Try shooting some starter fluid into the air intake & try to start it to see if it will run for a second, or maybe create enough of a spark to get it running.

greg334 · Nov 10, 2011

The Davco fuel separator/heater may be the third one he is talking about but I helped a guy with one of these engines a few weeks back and the issue for him was not a problem with the fuel but something else - check your oil level.

There are two other things that come to mind, one is crap in the fuel, the other is asking why is this not in the truck forum.

Tennesseahawk · Nov 25, 2011

I'm having the same problem. Wolverine FL put in new filters, and it ran fine for a couple of fillups. Then, it sputtered and konked out again. Had to add fuel; and now never let it go below 1/2. I'm having the tanks purged, and new filters put in.

Madmaxroi · Dec 29, 2014

Deville said:
I had a bad speed sensor & it did not throw any codes. Fond out by accident that it was bad. If you have cruise control, press the set/resume button with the on off switch in the off position. The check engine light will flash, count the number of flashes, when it pauses & restarts count them again. The amount of times the check engine light flashes is a number for a trouble code. Get those numbers & call a cat dealer & see if they can help u get pointed in the right direction.

Have you checked the fuses & relays for the fuel pump? Try shooting some starter fluid into the air intake & try to start it to see if it will run for a second, or maybe create enough of a spark to get it running.

So if you shoot some starter fluid into the air intake and it ran for a second, what does that mean with reference to your fuses and relay comment?

Deville · Dec 29, 2014

Starter fluid is raw fuel. It can jump start the motor to get it running or it will run for a few seconds and die again. There are fuel pump fuses and relays in the fuse box under the passenger side foot well. It doesn't hurt to check them.