new truck has some issues

[copracr]

I just got my first diesel truck and it some some minor issues, as weel as some big ones. I'm not new to diesels (i was a tech at a shop backin the 90's) but i am a little green. Love the truck overall and i got it for a steal at 5k, but i knew it had some issues. BTW, it's a 99 250 w/ 6spd, full 4" exhaust, CAI, and a power programmer of some sort (it has a 5 position switch under the steering colomn).

First issue is the clutch. It fully disengages when the pedal is fully depressed, starts to engage normally when the pedal is maybe 10% of the way up, but then it fully engages rather fast at maybe 20% up. the top 80% or so of the pedal travel really does nothing. it's noticable but not real bad when its on stock power level, but is very noticable at 75hp level. I thought i might need a clutch but is this normal? It's hard to drive smoothly, but otherwise is functional.

Second issue, which i thought would be the pricey one, is the rough idle. From idle to about 1600 rpm its got a lot of vibration, like a miss. It's engine related and not speed related. It does clean up and run smoother after 1600 or so. Does this sound like a bad injector? Any ideas what to do with this?

Thanks for looking, Merry X-mas

 

[Zookie400]

the miss sounds exactly like the miss i have right now, and mine is an injector. its actually not missing completely, but it is very weak. you can unplug one injector at a time with the engine running to see who is the weakling. check out our site sponsors for really good prices on upgrades or replacement injectors.

clutch.....sounds normal for an empty truck, but its been a while since i have driven a standard superduty.

 

[JRJ04]

i just had 3 injectors replaced and now have it not running smooth. can you unplug each injector without removing the valve cover? this might be something i want to try. i find it hard to believe that it would start running like crap with just replacing 3 new injectors. what else could it be?

 

[Zookie400]

you need to removed the valve covers, unless you can find someone with a break-out box type diagnostic tool. i want to make a bunch and sell them, but i havent yet so....

-remove the valve cover (one side at a time)
-start the engine
-unplug one at a time and listen to the change in sound/rpm/roughness

its really not that bad, keep your fingers clear of the rockers, and throw some sawdust or cardboard under to catch the minimal oil spillage.

it may be a little more difficult to find the bad ones when you have say 3 bad ones, because firing order and the placement of bad injectors can complicate things. if you have a dead injector there will be no change at all, a weak one will have some change so you may need to go through the cutout test several times to pinpoint a bad one.

the snap-on scan tool cutout tests are junk IMO, i havent had one work yet. my ear hasnt failed me so far if you find a scan tool that allows you to do each cylinder manually that would be the easiest.

also, it could be uvch's or the vc gaskets that are causing your skip, so make sure before you go buy parts to swap the injector into a known good hole, and see if the skip follows it.

 

[BJS]

Jourdan,

go ahead and replace the rest of the injectors, what you're likely doing is finding the weakest of the weak and then when you put a new injector in then you're making the difference between the best and worse larger. If you have 3 injectors that are significantly better than the others then it will run very similar to 3 bad injectors.

 

[copracr]

I've heard on the new 6.0's the injectors get clogged and can be remedied by some oil additives. Is this something that can be applied to the 7.3's also?

 

[BJS]

it all depends on what is clogging the injectors and if you run good fuel filters then you don't have any problem with clogging injectors. If you are running a sooty program and never get the cylinders good and hot then you might have blocked/clogged injector tips from carbon buildup but that's a bit of a stretch.

 

[copracr]

OK, so far i've only done a little maintenance (oil change, airfilter, fuel filter, and some tires) and now i'm ready to fix this truck up.

Is there any thing i could check or clean that doesn't involve pulling valve covers to check the rough idle? It's not a random misfiring, it's more of a loping regular miss (chug chug chug ish). Kind of like half the motor is firing weak.

Still sound like a bad injector?

 

[BIG JOE]

OK, so far i've only done a little maintenance (oil change, airfilter, fuel filter, and some tires) and now i'm ready to fix this truck up.

Is there any thing i could check or clean that doesn't involve pulling valve covers to check the rough idle? It's not a random misfiring, it's more of a loping regular miss (chug chug chug ish). Kind of like half the motor is firing weak.

Still sound like a bad injector?

Does it run any better after 25 or so miles on a FULL tank ? If Yes.. you could be getting Air infused into the fuel system from some questionable fittings in the Tank and on the inlet to the fuel pump. Rough noisy Idle.

Also could be caused by unequal HPOP oil pressure between the left & right bank oil rails.

Two of the above are fixable for less than $75.00, with NO major tear downs. One would involve dropping the fuel tank and another $100 bucks or so.

Start Simple (and Cheap) is my Moto.

 

[copracr]

i like your moto big joe, but i did fill it up twice and i havent let it get below half a tank since then. there was no improvement. i also drove it 6 hours across ohio and back in 2 days, so it was definetly good and warmed up. no improvment, but i can say it runs strong above 2000 rpm where its noticebly smoother.

should i check the hpop and how do i do that?