Cat 289D 1.5 PSI fuel relief valve

[flipz34]

Working on our 289D, TAW05187. We have several issues but I'm thinking a lot of it is caused by a fuel issue. Currently, when we start the machine, it stumbles as if it was starving for fuel and stalls out within 5-10 seconds. Transfer pump filter and the primary filters were changed as they were pretty bad. I still need to pull the filter head off to make sure that is not causing my issues.

My question at the moment is about the 1.5 psi relief valve. What are the symptoms of a bad relief valve? I'll need to take a look at my pressure gauges to see if mine read that low. I don't think I've seen one that reads that low at the shop. I've read the the HPFP doesn't like too much pressure so that's where the relief valve comes in. We did have an issue several years ago on a 279D and changing the relief valve corrected things. I cannot recall exactly what the issue was on the 279.

My local Cat dealer doesn't really have anyone we can ask questions to about this stuff. The last time I went in for a question, they had someone from OKC call me. All he could do was send me pics from the parts diagram that I already had access to. I was expecting much more from the tech line but it is what it is with some of these dealers now.

Thanks in advance for the assistance

 

[greasynails]

What transfer pump is on it? If it has the old square block pump with a cartridge filter on it, save yourself some time and put a new one on. If it has the newer spin-on filter, deadhead the outlet and see if it's less than 12 psi. You can also flow check it for 1.5 quarts/min. If it fails, check for an obstruction inside the tank, then change. You can also change the old style pump over to the new style spin-on. They're much better but they do still fail.

 

[flipz34]

The thing is, we have good flow out of the filter head. I'm just trying to find out what issues the fuel relief valve can cause.

If the HPFP is getting 12 psi instead of 1.5, what symptoms will be present?

I'm not even sure that I have a fuel problem. We cleaned the dpf because it was past due. I'm was trying to get machine to regen and I can't do that if it won't run.

 

[greasynails]

The thing is, we have good flow out of the filter head.

Did you actually measure it?

I'm just trying to find out what issues the fuel relief valve can cause.

I really dont know. I've never changed one that I can remember. I suppose if it goes completely open then the HPCP could starve for fuel.

If the HPFP is getting 12 psi instead of 1.5, what symptoms will be present?

Shouldn't matter. The HPCP has an internal gerotor transfer pump with a regulating valve prior to the SCV. Final pressure against the SCV is ultimately set by this valve, not anything external.

All I can tell you is that those old square thumper pumps are complete dog ****. I carry 2 of them on my truck because we change so many, and honestly, the new style spin-on isn't much better. My favorite is when the machine runs perfectly fine, then you do a PM, and all the sudden it decides it won't prime up. That's fun to explain to the customer...... "Hey, I know all we did was a 250 hour service, but you're going to need a $500 fuel pump now".

 

[Deimos]

Working on our 289D, TAW05187. We have several issues but I'm thinking a lot of it is caused by a fuel issue. Currently, when we start the machine, it stumbles as if it was starving for fuel and stalls out within 5-10 seconds. Transfer pump filter and the primary filters were changed as they were pretty bad. I still need to pull the filter head off to make sure that is not causing my issues.

My question at the moment is about the 1.5 psi relief valve. What are the symptoms of a bad relief valve? I'll need to take a look at my pressure gauges to see if mine read that low. I don't think I've seen one that reads that low at the shop. I've read the the HPFP doesn't like too much pressure so that's where the relief valve comes in. We did have an issue several years ago on a 279D and changing the relief valve corrected things. I cannot recall exactly what the issue was on the 279.

My local Cat dealer doesn't really have anyone we can ask questions to about this stuff. The last time I went in for a question, they had someone from OKC call me. All he could do was send me pics from the parts diagram that I already had access to. I was expecting much more from the tech line but it is what it is with some of these dealers now.

Thanks in advance for the assistance

Your machine has a C3.3B electronic engine with a common rail fuel system. Have you connected CAT ET to check service codes and to check Fuel Rail Pressure? If not, I strongly recommend you do so. Many problems in the common rail system can only be detected using CAT ET.

Also, the problem with the engine stopping after 10 seconds may be related to a clogged particulate filter, and it is necessary to perform a forced burnout using CAT ET.

 

[flipz34]

Your machine has a C3.3B electronic engine with a common rail fuel system. Have you connected CAT ET to check service codes and to check Fuel Rail Pressure? If not, I strongly recommend you do so. Many problems in the common rail system can only be detected using CAT ET.

ET is the bane of my existance right now. Wouldn't connect for what seemed like all day. Got new drivers loaded and it all fired up. It was end of the day, so figured I'd get back to it next morning. Won't connect again. That was Thursday morning and the guys blew a seal out of a case 580 trans so that has been priority. Once I get more info I'll be back to post it