I have a 1990 D5H with a 3304 engine and a scroll fuel injection pump. About 200 engine hours ago I replaced the fuel injection pump and governor with a Cat reman and had a knowledgeable Ag mechanic install it. It ran normal for about 160 engine hours and then the #4 pump O-Ring under the pump bushing started leaking. I ordered correct O-Rings and changed it out but could not get #4 cylinder to make power, a cutout test had no impact when I loosened the line on #4. We set the engine at TDC compression stroke, pinned the pump fuel rail and found I had somehow turned the #4 gear at the bottom of the pump when I had changed the O-Ring. We put is back so that it was 180 degrees from the dowel in the fuel injection pump housing. It ran okay but seemed weak so I had Finning come out and we ended up doing all 4 injectors. It then ran fine for another 20 hours and then I had diesel running down the outside of the timing gear cover and internally into the oil pan. I pulled the pump, sent it to a local diesel shop and they cleaned it up and changed some seals and sent it back to me. I believe I installed it correctly, engine at TDC compression stroke, gear slack removed and it started immediately and sounded normal. After 4 hours of running it started leaking out of the O-Rings under the pump bushing for #1 and #4 pump. I shut down and this time used the pump extractor tool to keep the injector pump down while I backed out the bushing and changed the O-Rings. #4 would not produce power again and I retimed the pump on the fuel rail and confirmed it was installed in the correct orientation. In the end I opened #1,#3 and #4 to confirm orientation and they all matched. Engine would not start, just kept turning over and almost firing. Tried a couple of minutes two times and the last time there was liquid running onto the ground and I had enough fuel in my engine oil it was running out the dipstick. I realize I probably created this mess but why are the ORings starting to leak and why would simply backing out the bushing without changing the pump orientation lead to these problems?
Hum , very strange behaviour... anyhow this CAT pumps seem to be ODD in some cases, at least for EU people used to Bosch systems. Can u post pictures?
It’s common if the orings were aftermarket..(fuel shop).. The 3304 is a sob to just change orings in..even IF u get the pump cyl at the bottom of its stroke, there’s still enough spring force to pop it off the control rack..& the only way to double check the work is to put it on the test stand.. & just because the rack is free, doesn’t mean u got it right.
Shame on the mess. The timing washers, spacers, whatever you call them are super critical and have to be removed and cleaned. Or, even lapped on a marble plate. It’s a metal to metal seal. All surfaces have to be pristine. Sometimes, people don’t realize there is a small and delicate alignment pin, at the bottom that engages the slot in the plunger gear. And that pin gets sheared off. Everything has to be cleaner than you think it should be clean. So many ways to mess this project up. It’s tough to do this job the first time without an experienced guy showing you how to do it.
Okay, really going to show some ignorance here but… when changing these orings, can I leave the whole pump on the Cat, pin the fuel rail, use the pump extraction tool to keep downward force on the individual pump while loosening the bushing. If there is a lot of spring pressure, can I retighten the bushing and roll the engine by hand to move the camshaft lobe under the pump and then remove the bushing with downward pressure on pump again, change ORing and pull pump out of the barrel to confirm we are 180 degrees from the dowel, and then keep downward pressure on the pump as I tighten the bushing? Pull the fuel rail pin and start up? Can I pin the fuel rail and still roll the engine to move the fuel pump camshaft?
Please don’t take this the wrong way.. I’ve seen techs with 20 years experience, miss the gear with the pin.. And as stated previously, the only way to find it is on the stand.. Coaldust is exactly right in everything he said.. I’ve seen this “tried” on the engine.. the only thing that saved the engine is, he was expecting the worst and had plans if it didn’t go as planned.. (loosened the injector line so the fuel wasn’t going to the injector, loosened the fuel feed line and then chocked off the air..)
Thank you for the advice, that is exactly the info I was looking for….can I tackle this on the machine or is my best bet to pull it off and have a pro reset it up on the bench; and you guys answered that for me. I can pull the pump for sure and the little pin is already missing on hole 4 so it is a challenge for sure to drop it in correctly.
Sure, but it helps if you have practiced this repair on a bench a few times before attempting an on-engine repair. Keep in mind, the crankcase fuel is not coming from a leaky o-ring. That leak is from the timing shim under the P&B. The more you hurry, rush and fuss trying to fix this, the more likely you are to really screw something up. I’d put it on the bench at this point and start over. But, you do you, bou. You know, when you buy a reman pump from Caterpillar, the governor settings are not adjusted for your engine. It’s not plug and play. It don’t work like that. You can take the new pump and then pay the dealership to set it up correctly for your engine. It may not even have the correct governor springs, the torque rise spring pack is not correct, FLS, blah, blah. You have to get the TMI for your serial and arrangement. Not the service manual. In emergency situations, I would swap the important stuff from the old governor and put it in the new governor. Like, when the village generator takes a crap in February and everyone starts freezing to death. Or, when the Tender with 80 tons of roe on board starts warming up because the Gen running the reefer is down. We spent years doing this stuff to get competent. Training, swapping pumps, then working in the fuel shop, then going field service to be able to successfully fix this stuff.
Put a fork in it. It’s done, since that pin is broken. It’s time for another reman.
When I ordered the reman from Finning, we used the cat serial number so I had assumed it would come set up for this 3304….and no one at Finning suggested I would need to have the new governor set up, live and learn. Could you explain more about the timing shim under the P&B? I am researching it but more info on it would be great. Thanks in advance!
There are too many arrangement numbers for a dealer to stock every configuration of pump assembly. They have to be set up for your particular engine. There is a ring, washer, shim looking thing under the p&b. It comes out like a washer. They come in different thickness and and can be used to adjust injection timing. When they don’t seal properly, they leak fuel into the crankcase. You can find a copy of the systems operation testing and adjusting book and it will explain it in detail.