Got a Cummins L10 that misses and smokes at idle when cold. I'm going to rebuild the STC valve, but I think it's time to do the injectors. It's got 450,000 miles on it. Who can rebuild them or exchange me decent rebuilds? These are top stop injectors, PT-D I believe.
Check the shift points on the STC first. Also check that the STC tubes aren't leaking at the injector adaptor. If the STC system is not getting oil pressure they will pop and fart on a cold start. Usually the injectors are not at fault.
I dunno. The truck has an obvious miss that brings a cloud of white smoke. It sounds like one, and sometimes two, cylinders are dropping out. The problem goes away when the engine is good and warm. Seems more like an injector issue. Runs great under a load.
"Runs Great warmed Up" tells me the injectors are mostly ok, Check out the STC system first, Been there done that with 855 engines.
With that mileage those top stops are worn out. But like RZ says check the STC system. Truck Shop
Still looking for a source. Or am I going to have to buy new?
Can the injection place behind Altorfer truck shop help you?Forget the name right now but he’s been super helpful to me in the past
Check "Reliance" diesel engine parts.. I think Cummins has those in remans now..
I'll call and find out. He got me some parts for a CAV pump a few years back.
Oregon Fuel Injection in Eugene.
If you need a camshaft you will need to go to Oregon Camshaft they grind one for your locomotive or race car. lol Truck Shop
Don't know if the L series had the same issue as the NTs with oil filled injector push rods, when we had old NTs that missed under load the most common culprit beyond an overhead was the injector push rods filling with oil and deflecting under load RPMs.
I spent the whole day messing with this thing today. I installed a rebuild kit on the STC valve, which consists of new o-rings for the spool valve cartridge and a new spring for the spool. The valve itself is dead simple. Just a spool with fuel pressure on one side and a spring on the other. When fuel pressure reaches 23 psi, the spool opens and allows oil to flow to the injectors. I tested the shift point on the bench and it is perfect. I did some testing of the STC system before removing it, but it's really hard to interpret the results because the only place to check for oil pressure to the injectors is after a check valve, so the pressure goes up, but it obviously never comes down. In my testing I capped off the STC oil line to the injectors and it made no difference in how the truck runs. So, its kind of inconclusive at the point. My hunch is that either there is a blockage in the STC manifold to the injectors, or there is an issue with the injectors. More to come.
You need to check under the rocker cover to see if you have leaks at the injector adaptors. You should have oil pressure at the STC manifold before the fuel pressure hits 23 PSI.
Yep. The cover is off. On the list for tomorrow. I did put air to the STC manifold and did not hear any huge leak, but that was before pulling to cover.
Hate to inform but was informed by a friend still working in STL, Cummins MO now farms out all mechanical pump/injector work from the STL location. Seems they could not get techs qualified to run the pump room so just shut it all down.
I was all set to put the thing back together, but I found that the oil hose from the STC valve to the rocker cover was bad, really bad. I'll have to get one made up tomorrow. I wish I had a hose crimper...
I'm not making much headway here. This is what I know: The STC valve is working correctly. Oil is making it to the injectors Oil pressure should be sufficient. I did the oil blockage test which involves putting compressed are to the STC manifold and looking for air at each injector. It should leak air around each injector link. 1-4 are fine. But I can't get air at 5 and 6. So, I pulled number 6 injector. The manifold is not blocked. But, the passage under the injector link is plugged solid. So, I'm back to the injectors. I went ahead and pulled the cap off the number 6 injector and had a look. Best I can tell it was not machined correctly at the factory and has never been open passage. But, I can't see how that would really hurt much other than oiling the injector link. Anywho, I got a quote from Area Deisel for reman injectors. $250 each. I think that's where we are headed. I tried Reliance, but they can't get the injectors I need.
wes heres another source for what you need ( randy simpson b&d fuel inj. ) in fredericksburg va. 540-368-1626 call him for a quote on the injectors have dealt with b&d for years` never let me down
OK. I'll give them a try. It seems that the only place offering reman of these old injectors is Pro Diesel. All the shops I have found that have them are Pro Diesel dealers.
wes i took randy a cat pump today` i did mention to him your m-11 he said parts should not be a problem
Tried a few other vendors but could not get a call back. So, today I ordered 6 remans from Area Diesel. They will build them up tomorrow and I should have them Friday. About $1,500. While I'm in there I'm going to tackle some other issues. I dropped the pan and checked the bearings. The mains are worn through the babbit layer. I ordered new rods and mains and a pan gasket. About $215 from Reliance (should be Clevite). Cylinders look OK from the bottom, but I guess that doesn't mean much. It has lots of compression. I can barely bar it over. The engine has a lot of oil leaks, but the rocker cover is the worst. It leaks oil onto the exhaust manifold and makes tons of smoke that always finds its way into the cab. I bought a whole top end gasket set. I know the exhaust manifold also leaks. There's a host of other issues. The cab leaks where the lights or air horn are. The exhaust is a mess. Some of the wiring is bad. Hard to know where to stop.
Finished it up this afternoon. The engine runs like a million bucks! No smoking or rough running at idle. Oil pressure is up to 70 psi cold, 45 psi warm at idle. That's twice what I had before. I'm working on the video series I made on this engine. I will post the links when they are finished. Probably old news for most here I guess.
GOOD DEAL.. THANKS FOR THE UPDATE..
If anyone is interested, here are the videos of the process. Part 1 deals with testing the STC system and making the call on the injectors. Part 2 is the fix and fixing some other issues. Probably no new information for the folks here, but maybe helpful to someone. My video on setting the valves and injectors was already posted earlier.
Volvo White? Thought initially Corn Queen but cab does not appear so.
Yes, it's a White-GMC/Volvo WG42 circa 1991.