My 915a1 with big cam 3 400hp cummins that I just picked up in topeka started missing/stumbling today. It sat for 3 yrs in topeka and has just 38k miles on it. It drove home the two hundred miles with no problems and Ive hauled a couple 80k loads with it but today it had a little miss on the way home. I changed the fuel filter thinking maybe that was it but after I loaded corn in it tonight it is still missing. any suggestions? Thanks in advance, Ross/Nebraska
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M915A1/Big cam 3 probs
- Thread starter reb87
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AMGeneral
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Reb87,
Does the miss/stumble clear up on acceleration or progressively get worse? In either case I would run a bottle or 2 of injector flush from a Cummins dealer through it first,the injector(s) may have some carbon buildup on the tips,causing incorrect atimozation of the fuel.
If this doesn't fix the problem,an easy way to determine if it's 1 faulty injector or random(maybe caused by a weak injection pump) is take a infared thermometer and check each exhaust port on the manifold while the engine is warming up from a cold start,the port with the "cold" temp is most likely you faulty injector.
Maybe Will Wagner will chime in on this as well.
Does the miss/stumble clear up on acceleration or progressively get worse? In either case I would run a bottle or 2 of injector flush from a Cummins dealer through it first,the injector(s) may have some carbon buildup on the tips,causing incorrect atimozation of the fuel.
If this doesn't fix the problem,an easy way to determine if it's 1 faulty injector or random(maybe caused by a weak injection pump) is take a infared thermometer and check each exhaust port on the manifold while the engine is warming up from a cold start,the port with the "cold" temp is most likely you faulty injector.
Maybe Will Wagner will chime in on this as well.
It misses from idle to load. I ran it a mile with 80k and it seems to miss all the time. I picked up some lucas injector cleaner and will try putting it directly into the ip and see if that helps. I have a thermometer and will do some digging around. Thanks for the help.
Hammer
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The infrared trick is nice, but a SIMPLE way can often be had by a simple squirt bottle filled with water. Wet down each exhaust leg, and see which ones take longer to 'dry out'.
Btw, for the money spent, QUALITY bio-diesel works as a much better fuel system cleaner. It often works TOO good, causing you to change your fuel filter soon after adding a decent percentage of bio. I have used bio on a number of vehicles, and the results have always been very positive on how well it cleans the fuel system up, and really cleans out injectors (for me personally, it has cleaned up injectors that injector cleaners failed at.)
Also, how do the Jakes work? And do you get a miss while using them?
Btw, for the money spent, QUALITY bio-diesel works as a much better fuel system cleaner. It often works TOO good, causing you to change your fuel filter soon after adding a decent percentage of bio. I have used bio on a number of vehicles, and the results have always been very positive on how well it cleans the fuel system up, and really cleans out injectors (for me personally, it has cleaned up injectors that injector cleaners failed at.)
Also, how do the Jakes work? And do you get a miss while using them?
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Sounds like a dead miss. If there are no unusual noises, i'd rule out a push tube or a cam issue. At cold start, go feel the exhaust manifold. The cold one is the failed cylinder. You'll have about 2 mins to pick it out before the heat radiates through the manifold. It is normal for the two outside cyls to be cooler than the rest. 3 and 4 will get hottest and get there the fastest. If you are unsure, the above idea is good, just spray a bit of tap water on the manifold at the port outlet. The one that takes longest to evaporate is the culpret.
mikepelchy
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If you don't have a temp gun and still want to figure out what cylinder(s) are misfiring, you should be able to unplug the injectors where the wiring passes through the head and listen for your engine to bog down (which would tell you which cylinders are good so no change would obviously indicate a bad cylinder).
Some other things you could look for are a restriction in the air system, a restriction in your fuel system. Even though your truck only has 38k miles on it, it could have done a lot of idling, so it could be as simple as needing a valve adjustment.
And don't rule out your fuel filter just because you changed it, it could still be an issue, just keep it in the back of your mind.
Some other things you could look for are a restriction in the air system, a restriction in your fuel system. Even though your truck only has 38k miles on it, it could have done a lot of idling, so it could be as simple as needing a valve adjustment.
And don't rule out your fuel filter just because you changed it, it could still be an issue, just keep it in the back of your mind.
Ok,
There was some clattering noise and I thought it was emanating from the front head. I pulled the valve cover and found the pushrod on Number 2 cylinder fuel injector was not working. I got a light and found it apparently broken in half under the rockerarm. I had to use a magnet to get it out as it was way in there. I cannot see the rest of it. Where would the other part go? Why did this happen? I am wondering what the clatter was with the pushrod out of its lifter, would the compression from the piston push back on the injector and bump the injector rockerarm around? If so do I need to pull the injector to examine/repair it? I need to fix asap so I can get my corn contracts filled.
Thanks,
Ross
There was some clattering noise and I thought it was emanating from the front head. I pulled the valve cover and found the pushrod on Number 2 cylinder fuel injector was not working. I got a light and found it apparently broken in half under the rockerarm. I had to use a magnet to get it out as it was way in there. I cannot see the rest of it. Where would the other part go? Why did this happen? I am wondering what the clatter was with the pushrod out of its lifter, would the compression from the piston push back on the injector and bump the injector rockerarm around? If so do I need to pull the injector to examine/repair it? I need to fix asap so I can get my corn contracts filled.
Thanks,
Ross
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BCIII is mechanical...no wires.
- 8,539
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It went in the pan. DO not run it any more 'till you drop it and get it out. Baaad things can happen. Look at the cam real good and inspect the follower to make sure the shaft isn't broken. Also, look at the block closely at the rod throw area. The PT usually wraps itself around the crank and wedges itself between the rod and block. That usually happens because someone didn't set the overhead correctly OR the jakes are wrong for the turbo.
mikepelchy
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BCIII is mechanical...no wires.
You are absolutely correct, I was thinking of the N14 which was based off the same engine, my bad on that one.
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One more REMOTE possibility. You say the engine is a BCIII. IF it is an MVT and someone built it with the 100 heads, the push tube cavity is too small and when the MVT advances the timing, the PT hits the head casting. It does this exact thing. It takes a while to do it because the PT only hits the head at idle and low load..<55 psi rail pressure... situations. I'd take the other PT out of the cylinder under the same head and look at it. Don't know wha MVT is? Snap a pic of the fuel pump side of the engine. Got an engine serial number?
I will get the serial number and pic of the fuelpump side tomorrow.
It looks like the heads have been replaced/worked on. I also noticed the pushtubes were numbered with paint like they were taken out and replaced back in the same position, perhaps someone forgot to tighten stuff back down.
It looks like the heads have been replaced/worked on. I also noticed the pushtubes were numbered with paint like they were taken out and replaced back in the same position, perhaps someone forgot to tighten stuff back down.
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The old trick was to check the push rods is to drop them on a steel bench hear a good ting there are OK hear an thud with no ring there on the way out.
also the other end drops down to the cam fouler and can some times rap around the cam shaft or worse.
If you pull the came fouler off make sure that you have an micrometer to measure the gaskets in that came fouler and get the same one back in as it was in stalled be for or you can through your inj timing off along with valve timing. have any questions PM me.
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It is how it left the factory, but it is unknown if incorrect parts may have put on it.
If it were mine, I'd yank all the injector push tubes, roll them to make sure they are straight, give them the drop test...mind you, only a couple inches off the ground... and re set the overhead. Maybe pull the plunger out of the failed cylinder to make sure the crimp didn't break.
PM me if you like and we can chat on the phone.
Will
BASE ENGINE INFORMATIONUpfitOriginalEngine Serial Number11187547Shop Order #SO26063PlantCEP - Columbus Engine PlantBuild Date08 Jun 1984Warranty Start DateCustomer Number8678Customer NameECM CodeNot Available For This EngineFuel Pump Part #https://quickserve.cummins.com/qs2/portal/parts/supersession.html?PN=Fuel Pump Calibration4006Film CardFEngine Config #D093496BX02CPL #CPL531Marketing Model NameNTC-400Service Model NameNH
If it were mine, I'd yank all the injector push tubes, roll them to make sure they are straight, give them the drop test...mind you, only a couple inches off the ground... and re set the overhead. Maybe pull the plunger out of the failed cylinder to make sure the crimp didn't break.
PM me if you like and we can chat on the phone.
Will
laserlee123
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Hi, I just got a 915a1 in Texas any advise in the recovery?
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]Hi, I just got a 915a1 in Texas any advise in the recovery?
HD wrecker to get it off the yard and loaded on a step deck headed back to your neck of the woods.
HD wrecker to get it off the yard and loaded on a step deck headed back to your neck of the woods.