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TEO · 08-05-2009, 09:23 AM

Last November I had a problem with my 2002 Journey and CAT 3126. With about 8000 miles on the oil, the engine started to miss, like an ignition problem on a gasser. I checked the fuel filter and found some sediment on the bottom that was not there when I left home, so I assumed it was the filter. Changing that made no difference and I ended up at the CAT center in St. Augustine. Computer code showed fluctuating pressure to the injector actuator. The mechanic said that the oil was very sooty and was probably causing the problem. If not the oil, it could be an actuator problem or an injector problem. Ouch! He changed the oil and the CAT immediately ran fine. My book recommends oil changes at 9000 miles, but the mechanic said that I should probably go to 7000 miles to prevent the problem. OK, here I am at just over 6000 miles and the problem is occurring again. While traveling down the highway, the "check engine" light goes on and the engine runs in a reduced power mode. A few seconds later the light goes out and the engine returns to full power. I'll change the oil and filter this afternoon and I'll send off a sample to be tested. The mechanic said that replacing the actuators would not be a real problem and would not be too expensive (from a CAT mechanic's point of view). I'm wondering if this is something I could do myself or if this should go to CAT?

Paul

smlranger · 08-05-2009, 12:03 PM

I will be interested in the outcome. I now have approx. 68K miles on the CAT and change the oil once annually... mileage on the oil has varied from as little as 6K to as much as 9K. Never had a problem.

Savannah · 08-05-2009, 04:24 PM

Paul, we started having the hit and miss engine not wanting to keep running. Finally it quit outside a campground in SC. We called road service who patched us thru to a tech who managed to get us started over the phone. Sorry I can't remember the sequence of what he had us do. We limped along with the engine trying to die a few more times but never giving us any lights of what was happening. We were headed to Gaffney for our yearly visit with Freightliner so kept plugging along.

We arrived and camped in their lot for the weekend then on Monday before our appointment pulled up to their dump station to dump. After dumping the coach would not start. The tech came out and tried to start it and replaced all filters. No dice, no start, no lights telling anything.

Finally we were towed to Blanchard CAT in Greenville, SC and they diagnosed a problem with an injector. WELL from there they tore into the engine and discovered all the injectors needed to be replaced. The oil was like gooey molasses but since we regularly had had it changed they figured it was just a fluke.

So all the injectors were replaced and they also lashed the valves since they had it all torn apart anyway and a number of other things that could be done again since it was torn apart and easy to get to.

All was covered under the CAT warranty except the valves, thankfully as the final bill was over 5K.

Blanchard did a great job for us and worked us right in since we are full timers. We did spend three nights in a motel since the bedroom was totally torn apart plus they were working on it both day and night.

Our coach is a 2004 Journey 39k CAT C7 and at that time we had around 40k on it.

We started having the problem about two or three months prior to the total die and had the oil and filters changed but the problem did continue off and on. Just not bad enough to make us overly concerned. We figured it was something that could be addressed when we got to Gaffney for our appointment two months later.

TEO · 09-15-2009, 12:05 AM

As an update on this problem, I found some answers on the Caterpillar Forum at Caterpillar Forum - Topix

I paid a personal visit to the shop foreman at my local CAT dealer and it was determined that I have a problem with the actuator oil pressure regulating valve. That valve and a bypass valve will be replaced Thursday to the tune of $300.00

I feel that $300.00 is very reasonable for a job I have no idea how to do. I'll add another update after the work is done.

On the Caterpillar Forum, I noticed that most of the 3126 CATs with this problem had more than 340,000 miles on them. I guess I'm a bit early.

Paul

TEO · 09-19-2009, 01:44 AM

Well, I had my date with Caterpillar on Thursday. They put the engine on the computer and I could see the actuator pressure fluctuating between 2200 and 3500 psi. The regulating valve had to be replaced. In addition, the computer showed a problem with one sensor and that was also replaced. Finally, they replaced the spring in the oil filter bypass system to a stronger spring. The bypass system allows the flow of oil for lubrication when the oil is cold and thick. The mechanic said that the original spring was too weak and allowed unfiltered oil to flow too easily and that would be the cruddy oil that lays accumulates on the outside of the filter element. The total bill was for $461.00 and that included $115.50 in labor. The rest of the money was for the expensive Caterpillar parts.

I now see that I could have done the job myself, but I would have had no way to diagnose the problem with out the system that reads the engine parameters. At this time, I'm happy with the outcome,but I won't really know if it's working until I get several thousand miles on this oil change.

Paul

smlranger · 09-21-2009, 09:53 AM

It would seem that if you can get any CAT service center to put a wrench on one of these things with the engine tucked under the bed and provide some parts for $461, that is a deal.

For those of us who are really into true preventative maintenance, it does make you wonder if it is worth it to have a CAT center plug into the OBD connector and do a diagnostic check to make sure all is well. Wonder if they will do that and what they charge???

TEO · 09-21-2009, 12:44 PM

In reply to smlranger I contacted Ring Power CAT in Brooksville, FL and found that they will do a computer diagnostic on your CAT engine for a 1 hour minimum of $105.00. Some of you may feel that getting a clean bill of health will ease your mind on a long vacation. On my CAT, the fluctuating actuator oil pressure was evident even with the clean oil. Apparently, you can find some problems before they disrupt your travel plans.

Paul