truck bouncing at idle and white/blue smoke cold

[thisoldtruck2]

hello, new member, apoligies if this ends up in the wrong place. just picked up a 96 psd 4 wheel extend cab manual, just over 200k on clock, i've had diesels before but bought them new. this is my first used diesel and my first ford. it seems to run and make power good, no smoke or miss on acceleration, it had shut off twice on 100 mile ride home, but with the help here i replaced cam sensor and so far so good, so kinda a two part question, first, the engine seems to idle very smooth warm, but the whole truck bounces when at a light, not the tach needle, the whole truck, maybe this is normal for these trucks, when the weather warms up i plan to check motor mounts, any input would b appreciated. secondly, on cold startup "at around 30 deg F. it sometimes misses a bit the first few seconds and throws some white smoke, enough to make about a ten foot cloud, then smokes a little blue til it warms up, the guy i bought it from said he replaced the fuel heater and all the glow plugs recently, but i am taking his word for it, he told me it allways started fine cold, but he would double cycle the plugs, is it just me or is double cycling pointless since you could just as well wait another ten seconds after the light goes out, since they stay on for awhile anyway, thanks in advance, i really like the truck and am probably worried about nothing.

[jjohns816]

The exhaust back pressure valve (ebpv) will shut when it is cold to help warm the engine then open up. Performance sucks when it is closed and a lot of people unplug it so it stays open. Since you are new to the 7.3 might want to read up on ebpv mods.

[thisoldtruck2]

thanks man, i did read about them sticking, mine seems to work okay, the first time i heard it i though the alternator or idler bearing was goin out, i hear the whisle noise when cold, and it goes away warm, so i assume she's working, but i'll give it a look see

[dr.deere]

With those kinda mile I wouldn't worry about the slight miss and smoke too much my 94 does the same thing but runs like top warmed up and has plenty of power. As for the shaking I would check if it has dual mass flywheel or not when the dmf starts to to bad it makes em shake pretty good it will still shake some even with a smf but a lot less. A smf and a high pressure oil crossover tube will really smooth it out


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[jjohns816]

Originally Posted by thisoldtruck2

thanks man, i did read about them sticking, mine seems to work okay, the first time i heard it i though the alternator or idler bearing was goin out, i hear the whisle noise when cold, and it goes away warm, so i assume she's working, but i'll give it a look see

It is not sticking, the computer is shutting the EBPV to help warm the truck up. That is why a lot of people unplug this so the computer will not shut it. When the truck warms up and the valve opens, unplug it so the computer will not shut it and see if that is better for you.

[thisoldtruck2]

good stuff fellas, to be specific, idleing in nuetral engine warm, it bounces up and down about a quarter inch about 3 times a second clutch in or out, kinda feels like a gasser with a big cam, but it sounds real smooth,the po said it had a recent dual mass installed, but no paperwork to back it, from what i've read the single mass would have been the way to go, i will unplug ebpv when warm to see how it restarts cold. looks like that oil bypass is pretty reaonable, worth a try thanks

[dr.deere]

I would def go with a single
Mass when that dmf starts to get too much play in it if it hasn't already. I can watch my box hop bout 1/4 inch when idling


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[thisoldtruck2]

hello again, i got to thinking about my white smoke, i think i may know whats going on, and i can't believe i didn't think of it before, on my last fillup i added lucas fuel additive, maybe thats a no-no, but anyway i thought it might help. one of it's functions is to remove carbon deposits, and from past experience with seafoam, another carbon remover i've used in other engines, white smoke was a side effect of the burn off. beings this is a diesel my mind went right to unburnt fuel. i'll have to see what happens after i fuel up again