Lumpy at idle & increasing rpm

[arsenicpants]

Lately my 1.6td has been developing a 'lumpy' idle, that continues through the rpm range until higher rpm (although it may just be too frequent for me to tell)
It's not a knock, it just sounds like... Well, like an old hot rod's motor; a soft 'uneven rotation' feeling
I still have all the power I ever had, it still pulls and is still able to reach the max speed, it just sounds bloody awful
At start up, the engine sounds normal, but it slowly develops as it's been running (15-20 mins after normal driving). It goes away sometimes, but comes back again, and tends to almost completely disappear after running at high RPM on the freeway for a while
It periodically puffs a bit of white smoke at take off or under really heavy acceleration, although not always, and it doesn't smoke at all during normal driving

Are my rings shot? The motor only has 40-50,000 km on a recent rebuild, so I wouldn't think so and I sure as hell hope not

Anyone have any insight?

[maxfax]

My initial though is maybe your getting some air into the fuel system from somewhere..  Hows the filter???

[dodger21]

Did you get your injectors rebuilt also? If not, they would cause a lumpy idle but faster injection pressures would open them up.

[arsenicpants]

hmm, nope, didn't get the injectors rebuilt to my knowledge (previous owner did the rebuilding, not me)
i'll check the fuel lines for bubbles when i have some time this weekend

i thought about buying a can of that 'ring seal' oil additive goop stuff and throwing it in
if it doesn't make the slightest bit of difference, i'll pretty much know i can rule out the rings
my biggest fear right now is that i'll have to tear the stupid thing apart completely

the sound of the engine is similar to when my injector line blew a little while ago
although it was spewing fuel out and had a big loss in power, obviously
just if you've ever had that happen, you'll know what it sounds like (just a little more muffled now)

i'm due for a timing belt change
could the belt be stretching slightly?

[zukgod1]

Sounds like timing to me.

Back in the day when I first started building pumps I had one that had a lopey idle. I think there may be a vid on Youtube still under my user name zukgod1

[blackbird82]

I have a similar thing with my AAZ> Gonna bump up my timing.
Let you know how it goes.

[arsenicpants]

damn, it got SO much worse tonight on my way home
it sounds almost like an exhaust leak now, the engine got like 10x louder
i can't feel any escaping pressure at the exhaust manifold, though

i bought a belt and tensioner and i'll tackle it this weekend
i'll try a few oil additives and see if it does any better as well
i'll also try the 'loosening the injector lines' trick and see if each one makes any difference

looks like i've got a lot of troubleshooting ahead of me

[maxfax]

i'll try a few oil additives and see if it does any better as well

Save your money..  Just about every oil additive I've ever encountered does one of 2 things, or sometimes both..  Those 2 things are thicken the oil, or clean (some variety of detergents)..

However thinking about thicker oil, is this a hydraulic lifter engine??

If it's starting okay and not guzzling oil, chances are the rings are okay..  Start with checking timing and air leaks then go from there..

[arsenicpants]

it's a hydraulic 1.6 TD, and it's running diesel-formulated 15-40

would this possibly have anything to do with my oil pump?
how easy is it to damage them?
say, if my oil pan looks like this?

[R.O.R-2.0]

it's a hydraulic 1.6 TD, and it's running diesel-formulated 15-40

would this possibly have anything to do with my oil pump?
how easy is it to damage them?
say, if my oil pan looks like this?

you gotta bottom out hard to make an oil pan look like that.. trust me, i know exactly how hard it is to get a dent that big.

i doubt you harmed the oil pump tho, its in the half round recess in the oil pan, and that part of the pan appears to be un-crushed.

may have bent the pickup tube, but thats it..

[vanagonturbo]

Umm, if your oil pan looks like that, STOP DRIVING THE CAR!!. In the pic shown, if you know where the oil pump pickup tube is, you can see its outline in the pan. Not good. Restricted oil flow causes all kind of bad things. Dont ask me how I know :banghead:

What kind of car and engine do you have?

[blackbird82]

Restricted oil flow eh? I drove around for a while before changing my pan gasket. and found my pickup screen half clogged with silicone.  Retards that use silicone on engine pans!!!!

agghh!

[arsenicpants]

so yes, the sound was from a lack of oil
i pulled the pan and replaced the oil pump/bent up pickup tube with a high-flow pump, hammered the bend in the pan back out and made it flat on the bottom (to aid in ground clearance)
then put some oil thickener / moly lube type stuff in and it runs great, no more noise, all the same power, no smoke, etc etc
i'm pretty relieved it seems to be okay

tomorrow i'm building a skid plate
this weekend i'm switching the transmission out for one with a proper 5th gear (current transmission has me screaming at 100 km/h)
the motor should be much happier

[nathan_b]

didn't happen to take a peak at a main and/or rod bearing while you were in there??

[arsenicpants]

i didn't look at the bearings themselves, but the cylinder walls weren't worn and everything looks 'good'
i'm using an ABA windage tray, so that may have helped keep the oil that was being pumped through going to the right places