Author Topic: Smoking and running rough (Read 7109 times)

mtnsammy · « **on:** January 13, 2008, 04:17:23 pm »

I am once again lost. Here are the symptoms and what I have done.

White or gray smoke from fire up to running warm.
Full throttle = more smoke but if I turn up power screw it definitely adds black smoke to the exhaust.
Motor will not start unless I preheat block.
Cold start has little to no effect after motor is running.
Cracking one injector at a time has no change but good spray from joint.
Bypassing filter shows no change, and disconnecting fuel line shows good flow from tank pump.
I have checked and rechecked the timing with no change. No adjustment needed each time I check for skipped belt or wrong pump setting. I am aiming for 99 on the pump.

The smoke is very thick but has little to no odor different from the normal exhaust. There is no sign of water in oil or exhaust gas in water. No water losses either. If anything motor is still running too cold. The temps are in the 40's here. The injectors were changed with glow plugs 500 miles ago.

Any help is appreciated as well as recommendations of a great diesel shop near Victorville California. Many out here charge High dollar and give bad service. They seem not to know what they are doing and just change everything out until it runs. The IP out here averages at $750 and it is the first thing they want to change. I do not think it would go belly up over night.

vanagonturbo · « **Reply #1 on:** January 13, 2008, 06:03:48 pm »

compression test?

mtnsammy · « **Reply #2 on:** January 13, 2008, 06:09:13 pm »

385... before the rebuild I was closer to 500 but they said that was too high. It has been steady at 385 since then.

If someoe can tell mehow to insert pics I can post a couple small photos[/img]

vanagonturbo · « **Reply #3 on:** January 13, 2008, 06:11:04 pm »

Umm did you just say that you were told that 500 psi is too high and that after the rebuild the compression is at 385?/?

mtnsammy · « **Reply #4 on:** January 13, 2008, 07:42:53 pm »

Never agreed with them but it has been smoking more and more since the rebuild. I plan to pull the head and check to see what gasket they used as soon as it runs smooth. The compression is steady and the powere was OK at first.

I read anothers thread and I think I may have an air leak at the back of the IP from setting the timing so many times. I never thought of changing the gasket for the bolt. I know there are no air leaks up to the IP so maybe the bolt is leaking air into the IP??

Factory compression is 415-500psi. I know what it should be but I do not have any quality machine shops nearby. It ran and I didn't have time to mess with it. I'll buy a new gasket for the IP and repost tomorrow.

Vincent Waldon · « **Reply #5 on:** January 13, 2008, 08:28:11 pm »

Quote from: "mtnsammy"

Never agreed with them but it has been smoking more and more since the rebuild. I plan to pull the head and check to see what gasket they used as soon as it runs smooth.

You should be able to see the "notches" or holes in the gasket without removing it... it's on a tab that sits outside the engine to the left of the main oil gallery.

Don't have a picture handy, but if you search around a bit you should find one.

Any idea what gasket you have before the rebuild ?

mtnsammy · « **Reply #6 on:** January 14, 2008, 07:26:36 pm »

3 notch on first assembly. The tab has been cut off or modified. I tried to see what they used right after I found the compression was 385.

The new gasket did not change anything. THe smoke is through out the powere band naturally worse at high RPM with the extra air flow. There is no difference with any single injector so I kinda doubt it is the injectors. I just would hate to spend $500 on a rebuilt IP and still have the same problem. The shop wants to rebuild the IP (500) replace injectors (300 ) and time the motor too (150 labor ) That 950 will give me the custom axle parts I wanted on my next upgrade. I wish I could find a shop to test run the IP for me without the high shop costs. Even if I deliver it they want $100 just to flow check it.

burn_your_money · « **Reply #7 on:** January 14, 2008, 07:50:42 pm »

Is your engine heating up properly?

385 is low but once it warms up it should not be smoking

Quantum TD · « **Reply #8 on:** January 14, 2008, 08:27:15 pm »

Quote from: "burn_your_money"

Is your engine heating up properly?

385 is low but once it warms up it should not be smoking

Indeed. It sounds like your car is not warming up properly. Is your T-stat stuck open or missing altogether? White/gray/bluish smoke on startup is normal, but it should clear up after about 1-3 minutes of running

If you have a Rabbit (older than 1984), and your IP is timed properly (i.e. at 1.00 mm of static timing), then the cold start lever will do absolutely nothing at all. You'll only really notice a difference if the timing is slightly (or greatly) retarded.

Did you set your static IP timing with the lever all the way in? If the lever is out, it affects the timing. From the symptoms you describe, it sounds like you did the IP adjustment properly.

Once the car warms up, that white smoke should dissappear. The fuel screw adjustment makes black smoke, as there is more unburned fuel. So, the fuel screw setting is likely fine.

I'd check the t-stat. As burn-your-money notes, 385 is a bit low for compression (near the wear limit), and starting may be a bit harder, but that should not create plumes of smoke that last longer than about 1-2 min. My old rabbit had about the same compression. While it was a bit hard to start in cold weather, it always started and did put out a puff of white/blue smoke.

There is one thing that catches my eye in your descripton: the fact that it won't start without preheat. By preheat, you mean plugging it in with a block heater, or preheating with the glow plugs? If you have to use a block heater, then there is definitely something wrong with your glow system. Check the fuse, check to see that the connections are clean and tight, and check for power at the glow plug buss. The glow plug dash light will come on, even if there is no power going to the buss/fuse/plugs. If by preheat, you mean 'glow the plugs', then that is normal.

Another cause of white smoke is buring oil. If your valve seals are bad, you'll see white smoke on start-up and when accelerating after a stop. If you have bad rings, you'll see white smoke at all times.

Either way, the compression is a bit low, but probably not the cause of the problem. The only internal problem I could forsee is bad oil-scraper rings or valve seals.

Let us know.

subsonic · « **Reply #9 on:** January 14, 2008, 08:37:14 pm »

They want 300 to redue the injectors :shock: That is straight up robbery.
Sounds like you are getting dry reamed.

mtnsammy · « **Reply #10 on:** January 14, 2008, 09:02:19 pm »

THe block heater is used to preheat. It is 30-40 outside now and even my ugly Ford needs some pre-heat.

I am going to redo the compression check and try it with a spoonful of oil. The motor is a 1.6TD from a Jetta installed in a Samurai. I must admit my luck has been far from good so far with this motor but when it runs nothing beats it.

Glow plugs tested at 35 ohms so I assume they are good.

Motor ran great at 385 compression for a few months until the smoking started. At first it was just a little but it gets more and more as time goes by.

Again I wish there was a way to home check the flow test on an IP. If anyone has a home bench setup I am a great fabricator. All I need are the IP specs and a good picture. This week I am going to try the local COllege to see if a kid needs a project IP for the shop. I thought I saw a bench from the 70's or 80's in there. If the flow check is off I will probably hook up with Giles for a new one. I just hate the idea of 500-750 for a part I do not know is bad.

I am building the injector stand off another thread here with a 2 ton jack. Way too simple now that I have seen the photos.

THe way I see it it can only be IP timing, Injectors, IP, compression, fuel supply or return. The timing I have checked and rechecked with many looking over my shoulder.

the injectors are new but when I crack open the lines there is no difference with anyone injector.

The IP has never been worked on other than when I tweeked it by the book off this forum. THe star wheel was turned 1/4 turn, power screw up 1/4to 1/2, the pin turned to allow full movement for acceleration. But none of these cause white or grey smoke. They all make a lot of black smoke if done wrong.

Has anyone had IP leaks allowing air in the fuel stream? POssibly an internal air leak? Heck I just want to isolate the problem before dumping money where I do not need to.

Vincent Waldon · « **Reply #11 on:** January 14, 2008, 09:28:31 pm »

Quote from: "mtnsammy"

.

I am going to redo the compression check and try it with a spoonful of oil. The motor is a 1.6TD from a Jetta installed in a Samurai. I must admit my luck has been far from good so far with this motor but when it runs nothing beats it.

Glow plugs tested at 35 ohms so I assume they are good.

A couple of random thoughts here:

- adding oil during a compression test on a diesel is highly 'not recommended"... because of the high compression the oil can easily ignite and lead to a a flying compression gauge or worse.

- 35 ohms seems pretty high for the glow plugs... iirc they should be an ohm or less each, since they draw in the neighborhood of 12 A at 12 volts.

Quantum TD · « **Reply #12 on:** January 14, 2008, 09:38:09 pm »

Quote from: "mtnsammy"

THe block heater is used to preheat. It is 30-40 outside now and even my ugly Ford needs some pre-heat.

40 degrees is not that cold. Both of your vehicles should start up fine in those temps. With fair compression, and a properly functioning glow system, your car should fire right up. My old Rabbit with about 375-390 compression on all cylinders, would fire up (after a few cranks) every time, even at temps below zero (32 F). I never got stuck, even when it hit 12 degrees.

That your car will not start without the (electric) preglow, and it smokes white for a while really makes me think that the glow system is worth investigating. What year car do you have? There are some differences between the Turbo glow plugs and the NA plugs. From what I understand, the Turbo plugs are supposed to be SLOW GLOW, and need to have the correct relay. The NA are FAST glow, and need their appropriate relay. If the wrong relay is used with the plugs, then it can cause premature failure. Now, probably not 500 mile failure, but investigating it won't cost any money.

As far as testing the glow plugs, a simple test light will work fine, but you will need to remove the buss. But I'd assume the plugs are fine, but checking for power at the buss is a really good idea. I've heard stories of people buying used car's that wouldn't start. They cleaned the glow fuse contacts, and the cars started right up.

I'd venture to say that the IP is probably the last thing to look at, since they rarely go bad (unless leaking, and you'd see the leaks when it's running), and they're the most expensive part to replace.

As far as air leaks go, if you have a pre 1985-car, I'd say buy a new clear line from the fuel filter to the IP. You can buy new ones for cheap: Her's the PN: 068 130 309. Or, you can hold a flashlight behind the clear input line, and look for bubbles when the car is running, or bubbles heading back to the filter after it's stopped running. I'll doubt that you'll see any. If you do, then check all the filter/IP fittings, return lines, and make sure the filter is screwed on tight.

Quantum TD · « **Reply #13 on:** January 14, 2008, 09:50:19 pm »

Quote from: "Vincent Waldon"

A couple of random thoughts here:

- adding oil during a compression test on a diesel is highly 'not recommended"... because of the high compression the oil can easily ignite and lead to a a flying compression gauge or worse.

- 35 ohms seems pretty high for the glow plugs... iirc they should be an ohm or less each, since they draw in the neighborhood of 12 A at 12 volts.

Indeed, the newer TDI's test at about 6-11 ohms, and they're basically the same thing. Here's a link about testing those (Make sure your multitester is setup right too):

http://forums.tdiclub.com/showthread.php?p=483553

I just checked some 1.6 NA loosies laying around the shop, and the resistance is that same as the TDI ones: about 8-11 ohms.

mtnsammy · « **Reply #14 on:** January 15, 2008, 05:34:06 pm »

When adding the readings it totaled 35 ohms. My bad. The glow Plugs are great and do heat up well. All plugs individually measure between 8-9 ohms. Again they are new and should read like that. The relay is also new. I have never had any problems with the plugs but changed them out while I had things clear last time.

The white or gray smoke is continuos and never goes away even after the motor is hot. The compression test with oil is directly from the VW service shop manual. I know it can ignite and some folks even tell about how they blew their motors up doing it. VW has been using this as a test for over 20 years now so I can feel confident with reason I will be OK. The point of the oil is to seal the rings with liquid that is thick and will not slide away as the piston cycles. I normally use 40-50 weight iol as it takes a lot to ignite. WD 40 or penetrating oil would be a bad idea. The compression test done wet locates the leak as the rings or valve guides by noting a high rise in pressure for the rings bad or a small rise in pressure for the guides. With all four injectors out and oil with compression only on one cylinder I am not too worried even if it does fire off. The gage is rated at 1000PSI and so are the hoses and fittings. That is why we use Diesel testers not gassers.

Thanks for the help. Again I hope to get the time quick to run the compression test and check for more leaks. I will video the test just incase it blows up. If it is exciting I will send Waldon the video so he has something to laugh at.