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cummins bad injector?

Posted By: bigblockbryan

cummins bad injector? - 10/06/14 04:35 AM

okay guys i have a 1995 cummins 12 valve 5.9 i think it may have a bad injector it starts really hard. Like i have to floor it or pump it to get it started weather its cold or warm and smokes slightly white untill it warms up its got a p pump on it too
Posted By: rumblebee4232

Re: cummins bad injector? - 10/06/14 10:24 PM

Does it start hard every time you try to start it or just after it has sat for a while?? If it is just after it has sat for a while did you change or have the fuel filter changed just prior to this happening?? The reason I ask is I had a 95 that would take forever to start and it began after I changed the fuel filter.. There is a Disc that the fuel filter seals against, sometimes when you remove the filter this Disc will turn a little( it has an O ring on top to seal it) when you put the filter back on it tightens the disc back up and can damage the O-ring.. Pull the filter back off them remove the disc above it and replace the O-ring ,, sometimes it is a real pain to remove the disc
Posted By: 71yelladustr

Re: cummins bad injector? - 10/08/14 05:17 AM

Don't sound like an injector problem to me. It is very rare to have injector issues on a 12 valve truck FWIW. You could have several issues resulting in a hard start. Idle speed is critical to a P pumped truck for easy starting. If it is too low, it will require you to push the throttle to make the engine start easily. The truck should idle around 780 rpms when warm (in gear if an auto). The white smoke when cold is usually due to slow injection pump timing. The pumps are not keyed and are only held in place buy a tapered gear and shaft. It is common for the timing to slip and cause smoking and hard starting. I would advise advancing the pump timing to 16* anyways for better performance and mileage. There could also be air entering the low side full system causing hard starts and white smoke. Common areas are rotted rubber fuel lines on rear of the engine, melted or warped fuel heater element, leaking fuel filter or WIF sensor, and rusted fuel lines on top of the fuel tank module. I should add that some of these issues could be hard to find and not necessarily be leaking fuel enough to leak on the ground.
Posted By: Savoy1964

Re: cummins bad injector? - 10/08/14 11:47 AM

Could also be a fuel pump going. Friend had hard starting and a miss from number one cylinder he changed injectors and the miss was still there so he replaced pump and truck now runs like new.
Posted By: bigblockbryan

Re: cummins bad injector? - 10/08/14 05:44 PM

it has good fuel pressure according to my fuel pressure gauge it runs about the same as it always did and dosnt miss when when running idles perfect I will check out the fuel lines maybe its getting air in it some were I never changed the fuel filter on it yet could it be possible that my batterys are getting weak too this is in my Frankenstein truck the chevy dodge its all dodge drive line with chevy cab

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