Engine smokes and rough Idle on start up
 

I have a 2007 ram3500 w/5.9 and 6spd trans with 131000 miles on it. I bought the trk used and for the last couple weeks when the engine is cold and cranked up for the first time, it smokes and runs rough, and it smells like diesel when doing so. when the trk gets warmed up it quits. any ideas on what to look for.

i would do a compression test, min spec is 350psi but an engine in good shape will be around 500psi, if it has a broken ring then its going to be at 150psi or less on that cylinder

if the test shows all good then since you would have the injectors out at that point i would have them flow tested

thanks for the info. I hope not a broken ring, injector would be bad enough. any Idea what the cost would be to do rings on one of these.

Injector time!

1 piston 6 ring sets 12 rod bearings (all genuine cummins parts) and labor +- $1800 as long as it hasnt got into the block enough to require machine work

do you think it could be a broke ring. I think it would smoke continously if it had a broken ring. if it were a injector going out, should I replace all or just the bad. can i check to see if a injector is the problem at hm myself?

injectors there prob over fueling

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its better to replace all 6 and no you will need to take it to a shop

what about: glow plugs and grid heater?

it dosnt have glow plugs

we have had more then one truck that has came in with a similar problem and they all cleared up after the engine was up to operating temp, they would white smoke on start up but as engine temp would rise they would run better and at operating temp they cleared up

it could also be an injector thats overfueling i was just saying that if your going to pull the injectors out i'd run a compressoin test while they are out, it has become standard practice for our shop, only takes about 30min and we dont charge for it, gives the customer peace of mind if they all come back good and if a problem cylinder is caught early enough it can be fixed with the block in the frame

also if i did happen to fail the compression test you would still need to have the injectors tested because an overfueling injector can cause higher cylinder temp in that cylinder and result in the broken ring, so you dont want to fix the symptom and not fix the cause if ya know what i mean

yah, Cummins is not my strong point. sounds like you guys have it under control

thanks
 

thanks for the info I will get it to my regular Diesel mechanic next week to have it ck'd out

If you can swing the cash and are planning on keeping the truck around for a while, I'd generally recommend replacing all of the injectors at the same time. They've got the same miles on them, so they're probably in close to the same condition.

well finally took my truck to my mechanic and he said the injectors are dripping. So now I'm in the market for injectors, i have heard the rebuilt's are a hit and miss so thinking new bosch replacements if I can afford them and try to change them myself. Any tips on doing the change out of the injectors. also who has the best deal for them out there.

how did he figure out that they are "dripping" ?

and please do a compression test when you take them out

dont know how he chkd them, He trust me to drive his 1/2 million dollar plus race car operation 3000 miles round trip so I think I can trust him to work on my truck. lol

he is one of the largest diesel only mechanic shops in my area.

thats cool, i'm not saying hes wrong i was just curious what kind of test he ran without pulling the injectors and putting them on a test bench.

I have no idea how, :humm: I left the truck with him for 6 days while we were at the races, so he may have pulled some ,not sure

I'd say either injectors or fuel. My 05 was giving me some issues replaced the injectors and still had the same problems. Turns out the low sulfur fuel was the problem. A little Keen and myster oil cleared it right up and runs fine now.

we today I pulled all 6 injectors, taking them in the morning for bench testing. 2 of the injectors had fuel pouring out of them when removed and the others stayed dry but had what looked like carbon build up on the tips. I will let you know what the test show.

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well got the injectors bench tested and 2 were bad and a 3rd was borderline, I'm only replacing whats bad now that I know how easy it is to change them

did you do a compression test while they were out? the ones that had the carbon build up on them could be from over fueling or could be from low compressoin

no compression test done, don't have the tools to do it. The trk isn't smoking anymore and running good.

cool good news

mine was doing the same thing with the white smoke and rough idle, now the smoke is gone and the idle is worse, but the rough idle goes away a little if you rev the engine, could this be an injector issue also?

I would think so, thats exactly what mine would do. they are easy to change, you can go to youtube and do a search on how to change them