VERY Rough Running

[StevenPH]

Hi all, i was hoping to get some diagnostic opinions before i start pulling the engine apart.

My 89 1.6d Jetta started running incredibly rough towards the end of a 2 hour drive yesterday. There was a moderately loud metallic tapping coming from the engine area, the speed of which increased with higher rpm's. It occured whether or not the car was in gear or not, stopped or moving.

I stopped the engine, and tried to restart. It did not want to start up, the starter moved very slow, but playing with the fuel pedal i got it going again. Lots of smoke out of the tailpipe, and the same rough running and tapping sound.

Nothing looks visibly wrong inside, other than the timing belt, of which the passenger side was sheared away about 1mm.

Thinking the timing belt had slipped, i changed the belt and reset the timing. Everything looked fine, and i was able to turn the crankshaft freely, to confirm nothing was binding inside. From what i could tell there was nothing too far off with the timing or the belt, and after the replacement it started up the same way and ran terribly. The tapping was kind of a clanging by now (though probably just louder as the hood was up). Lots of smoke, wanted to stall out at low rpm's.

Some helpful background -

20,000 miles ago i took the head off and replaced all of the valves, guides, and anything else in the my guy recommended. I did an in-chassis rebuild of the block, replacing the rings and main bearings (i had been having significant blow-by). It's ran great since then, with significant improvement in fuel economy and power. At that time i also had the transmission pulled and a new clutch and push rod bearing put in.

In the past 600 miles or so i've noticed a decrease in fuel economy (from 47 to about 40 or 42), but attributed it to driving in the hills and traffic of Seattle, where i just moved. Performance has stayed consistent.

The only other thing in the engine that is showing signs of wear is the vacuum pump. It the newer style that's supposed to last a long time, but i don't know how old it is. Yesterday i noticed a small amount of oil around the base of it, and it's always been weeping very small amount of oil from the connection tube at the top.

Could a failed vacuum pump cause these symptoms? Or does it sound like an internal issue, like a rod or a valve?

Thanks, and sorry for the lengthy post.

Steve

[Prairieview]

Sounds like a stuck injector. Did the starter/battery/ground work well prior to the noise? The slow starter may not be related.

If the engine truly rotates and does not bind with a valve or precup problem, you could fire it up, don protective eye wear and leather gloves and loosen the injector lines one at a time on the top of the injectors and see if loosening one of them does not seem to make a difference in how it runs.

You are going to have to put a little more effort into determining where the sound is coming from. A generalized "metallic sound from the area of the engine" is not all that helpful.

You are also going to have to determine why your belt is not tracking properly. It is probably a matter of how the pump's mounting bracket was tightened down on the face of the block. You are lucky it is not tracking worse than it is.

Did you replace the hydro. lifters? Do you know what a sticking lifter sounds like? Is the sound worse when cold?

Bear in mind that the vacuum pump rotates the oil pump for the engine. The pump has an o-ring in it's base which can be replaced to help with weeping. It is naturally a metric size but is pretty easy to locate at a seal shop. Did the oil light come on at any time? Is the 13 mm-head bolt which holds the pump in place tight?

[82vdub]

Over the years, there's been several people with sudden problems that you've experienced. It's typically related to timing and/or fueling. You messed with the timing when you changed the belt. I would probably try to advance the IP towards the head to see if that helps at all. If it does not and you still have smoke pouring out the exhaust, that's a sign of poor combustion. Some have had the Tbelt slip on the crank pully. Verify that it's all set per the Bentley and then advance the IP towards the head if it still runs poor.

I would then try to rig up a bottle feed with a filter in it and bypass the entire fuel system and see how it runs. I've had it where you got lots of water in the fuel filter, and it runs horrible until you change the filter, and even has a pinging noise too. If it runs horrible with the timing advanced (and are you sure it's set fairly properly) and the fuel system bypassed, then it's probably injector pump or injector related. However, doing the timing/fuel test isolates systems and removes them from the list of potential problems.

[StevenPH]

Now that i you mention it - the rattle/clanging/pinging i'm hearing could be similar to what i've heard before when loosening injector lines to bleed air. I haven't ever replaced or pump tested my injectors (50k miles of ownership), so they could be a prime suspect. I'll go through them and see if one is faulty.

I can't remember if the lifters were replaced, though i know he inspected all components and replaced everything he thought necessary. I know next to nothing about what happens inside the head, and don't know what a sticking lifter sounds like. I don't even know what the hydro lifter does...

I didn't run the engine long enough to get more specific on the sound, i was concerned i was doing severe internal damage by letting it run.

If i can rotate the engine by hand, and the timing is accurate per bentley, is there a big risk in continuing to start it up and let it run rough while trying to diagnose? The clanging/pinging just scares me.

I probably haven't drained the FF in a while - i'll replace it and see if it helps.

Unfortunately the car is about 100 miles away, but i'm having it towed back tomorrow and will see what i can find.

Thanks for the help - i'm happy to hear the cause could possibly be a fuel/timing issue and not an internal engine problem. I'm not too inclined to pull the head again this soon.

[bscutt]

Also check for possible sources of air getting into the fuel system. I have had two occurrences on my 82 where it started a horrendous banging similar to a rod knock on a gasser engine but apparently it was air or a stuck injector which cleared itself both times. The second time was on the way to work at 5:30 n the morning which was pretty disconcerting in the dark. However, I didn't really experience any loss of power, just the nasty banging noise but if you are sucking in air somewhere that would definitely affect performance.

[StevenPH]

Ill inspect fuel line unions. How did the injectors clear themselves? Did you just run it for a period of time? Maybe loosening the injector lines one by one to purge any existing air?

[StevenPH]

I just found your old thread from when this occurred - my symptoms sound identical. I'll go up tomorrow and run at idle for a while to see if it can't work itself out, while also loosening the injector lines to see what they tell me.

Thanks for the help so far, this is all much better news than i was expecting to hear.

[bscutt]

Good luck. Mine usually clears in a few minutes but if there's really something stuck in an injector nozzle it may not clear itself. If you can locate the offending injector you may be able to take it apart and clean it out with brake cleaner or some good solvent.

[82vdub]

As long as you have good oil pressure and there's not piston/valve interferrence, it probably doesn't hurt anything to keep it running while it's making noise. The diesels just clatter a lot more when they have poor fuel or timing issues. I personally wouldn't just let it run and run thinking that it's going to be an injector and fix itself. Work to eliminate items that could cause the issue a piece at a time.

[Fatmobile]

I stopped the engine, and tried to restart. It did not want to start up, the starter moved very slow, but playing with the fuel pedal i got it going again. Lots of smoke out of the tailpipe, and the same rough running and tapping sound.

white smoke?

Nothing looks visibly wrong inside, other than the timing belt, of which the passenger side was sheared away about 1mm.

Is the belt still running off the edge of the sprocket? That can let air in around the mainshaft if the mainshaft bushing is bad. Do you have clear fuel lines to and from the pump?

Thinking the timing belt had slipped, i changed the belt and reset the timing. Everything looked fine, and i was able to turn the crankshaft freely, to confirm nothing was binding inside. From what i could tell there was nothing too far off with the timing or the belt, and after the replacement it started up the same way and ran terribly. The tapping was kind of a clanging by now (though probably just louder as the hood was up). Lots of smoke, wanted to stall out at low rpm's.
Did you check/reset the cam/crank timing? How did you check the injection pump timing? What color smoke? I had an injector so bad it sounded like a rod,.. started a thread called knock knock

[StevenPH]

So I got it up and running, and the knocking is intermittent. I can okay with the throttle and it'll go away, then if I give it lots of throttle the knocking returns.

I check the injector lines - they all seem about the same. When I loosen each one the idle lowers and rattles more, consistent with times in the past I've done it.

I advanced the timing (rotated pump top towards the head) a small amount, and the rattling continued but there is now noticeably less white smoke.

I checked the cam/crank timing yesterday, it was spot on. The pump timing also seemed accurate. Though I use the timing dial which doesn't always give me the most accurate readings.

Fuel line to the pump looks clear, and I drained the fuel pump.

Next steps? I'm thinking I may advance the timing slightly more, and if that doesn't help then have it towed home to do further diagnostics.

[StevenPH]

I just took a closer look at the fuel line into the pump and saw small air bubbles rising up...

While running there were bubbles flowing pretty consistently towards the pump.

Could the cause be at the fuel Filter? Clogged, and if so it there a way to unclog it? If not i imagine its a fuel line issue, which I'd need to tow it home to tackle.

[82vdub]

Any question with fuel or a blockage, change the fuel filter. I've gotten in the habbit of changing mine every spring, no matter what. They are so cheap that it's not really worth it to try to milk one for longer use. The air in the line can cause poor running, and the white smoke you have. Timing and fuel. Advance the pump more and see what happens with the white smoke. I've timed my last 2 timing belts by the dial gauge, and redid each one two more times after that. Now, I will only time them by ear and leave the dial tool in the toolbox. Each engine is different as the pumps wear, that's why I don't use the dial gauge anymore.

[StevenPH]

Any roadside filter cleaning ideas? I have three hours before the tow truck shows up.

I removing the air plug entirely and the drain spout cap entirely and was able to get another 1/4 cup water out. There don't seem to be anymore bubbles in the fuel line, but it's still running the same.

I checked the injector lines again and #3 doesn't seem to effect engine performance much when loosened. Could be that one.

[Quantum-man]

Post a sound track. We can then see if it's single cylinder based.