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ISM Cummins boost problems??????????????????? Jump to page : 1 Now viewing page 1 [50 messages per page] | View previous thread :: View next thread |
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tooth and nail |
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I have an ISM Cummins (11 liter) that has erratic boost pressure. It will only build 10psi until 1400 rpm then will usually go to 30-35 psi. However it sometimes will not hold a steady psi , it jumps about 5psi. you can feel the engine surging. Some time it will hold steady for a long time/hill. EGT's max at 720 where it used to max at 940 , I know it's not getting the fuel it used to. When pulling down under a load , as soon as it hits 1400 rpm , boost will fall to 10 psi again. Also only 10 psi boost until temp is 180 degrees , Cummins says that is NOT part of the ECM program Cummins can't seem to figure out the problem, doesn't throw a code on the ECM. I have changed the filter several times , the turbo was starting to throw some oil , new one, they were SURE that was the problem. Checked the inter cooler for leaks , air filter is pretty clean , they were also SURE that was the problem, until I took them for a test ride with it removed. I'm pretty sure it's in the ECM that's de rating the fuel for some reason , just can't figure out why it won't throw a code IF that's the problem. They want to put a TEST ECM on then change it to a new one if that fixes it , I say try the new one first to save me the labor. ANY IDEAS??????????? | |||
sdan27 |
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A new ECM is like over a grand I think, I'd test it to make sure it works first. We had an IH with an ISM that was always surging/running rough and I adjusted the injectors/valves and that helped out a lot. | |||
tooth and nail |
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ECM is $1400.00 , they keep 2 in stock so it must be a common problem , however , I don't want to throw parts at it until something sticks :( | |||
scott nelsen |
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Leeds, North Dakota | Matt, does this have a egr? air to air hoses and clamps are fine? does turbo have a aneriod on side of turbo? possible fuel pressure sensor, not working, not familar with these engines, throwing my two cents out for what its worth, Scott. | ||
tommyw-5088 |
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south Texas , York Rife Freemason | There is a turbo sensor ,try that | ||
Bern |
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Mount Vernon, WA | What year is this engine? I'm going to assume from your comments that it is not new enough to be ECM controlled (variable geometry). It likely then has a wastegate. I would be taking a close look at that. You can test it with regulated shop air pressure to see if it's opening when it should. | ||
tooth and nail |
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It's a 03 , no EGR , no waste gate , no boost/intake leaks . Replaced mass air flow , and manifold pressure sensors , the "cheap" stuff with no good way to test. Could be a fuel presure prob, but I think that should throw a code???????? My thoughts are the ECM is de rating the fuel/HP for some reason that doesn't throw a code, don't know enough about them , or where to start when the "BRAINS" of the engine won't tell you what's wrong. THANKS for the ideas, keep em comming!! | |||
scott nelsen |
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Leeds, North Dakota | Matt, you have answerd my questions, now more for you, would look at wiring, wouldering about rack, how many miles, has rack been set? if its beening derated, Cummins should be able to hook computer up and see it, have they? It does it all the time? if so Cummins know what they are doing? shouldn't be that hard, you changed sensors I was thinking of, they will sometimetimes not throw a code, how long has problem been, fuel system possible, system is not gelling is it? just throwing some things at ya, give me more info,serial number of truck and eight digit on engine, will do some checking, Scott. | ||
Bern |
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Mount Vernon, WA | Are you SURE there is no wastegate? I am surprised something that new has none. Also, if it's an '03, it should have EGR. Something is not adding up here. Low/erratic fuel pressure will not necessarily throw a code. Most engines don't even use a fuel pressure sensor. Send me the engine serial number so I can do some research on Cummins QuickServe and see if this thing even has one. If in fact this thing is de-rating itself, it should be at least turning on a check engine light at the same time. In addition, it should also log a code that anyone with Cummins Insite should be able to retrieve. | ||
tooth and nail |
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250x,xxx miles, I've put about 3x,xxx of them on , don't know if anything's been done to engine. Seems to get worse/better on rough roads , pointing toward wiring short, I've checked/cleaned most connections I can find. 2 different Cummins shops have checked it , neither suggested a road test with diag. computer hooked up , I asked for that and am getting it done in next several days Has done the low boost on cold engine since I bought it 1.5 yr ago , got to this point about 3 weeks ago Actually runs better the colder it is , got 37psi boost Fri when -3 , could get 37 any time before. Even though max boost is lower than before ,5-8psi, it's the 5-10psi under 1400 rpm that's killing me now. I thought about bad fuel , however , I never fill up ,usually get 60-100 gal. at a time for MAX payload ;) | |||
bollpuller |
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Grandfield, Ok. | Check the wiring real GOOD!!!!!! Could be a rubber strao or frito floating in the fuel tank , both will cause similar symptoms. Rcheck the wiring especially the grounds. as this is the source of most ecm problems. | ||
bwire |
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Rock County, MN | I've the same issue and it doesn't throw a code but change the turbo boost sensor and bullseye, about $110. I replaced with one from recycler for $35 and is doing okay | ||
mafrif |
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NC Iowa | How do you know what the boost pressures and EGT's are? | ||
tooth and nail |
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Gauges Grounds are 1 thing I haven't checked Edited by tooth and nail 1/23/2011 17:18 | |||
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