Need advice for smoking problem. (long post)

[gmc64sub]

I have a 1985 J NA 6.2L engine transplanted into an older suburban. I have had an ongoing problem with kinda-hard cold starting (new batteries, glow plugs and starter) and white smoke on startup.
Had the Chevy dealer set IP timing. Then the IP started leaking at the bottom. Sent the IP to Tim at Accurate Diesel for rebuild. Also ordered new injectors at the same time.
When I put the rebuilt pump on (new fuel filter, too), I set the marks the same as the dealer had set. Got the engine going again, but again had lots of white smoke, and now it keeps smoking after warmup (air cleaner on or off). I talked to Tim, and have experimented with new IP timing settings, including advanced about 3/16" (IP notch moved towards the drivers side as far as I could get it). The white smoke seemed darker, but was still excessive.
Checked the cold advance and idle speed by pulling the connectors off when running while cold. The idle speed definately works, and I do hear a slight difference in engine sound when I pull the cold advance off as well. I put a clear tube on the IP return line, and also on the return from both banks of injectors. The IP return fills up and runs clear (I can feel the pulses when I squeeze it). The injector returns barely seep fuel back, and are full of air for the most part (Tim at Accurate said this is normal, especially on new injectors).
So now I've run out of things to check and try after reading many posts in this forum and using the troubleshooting guide. Oh yeah, I had the compression checked before the swap, and every cylinder was around 400 psi.
Any advice would certainly be appreciated. I'd really like to fix this myself if possible!

[john8662]

I wonder what the quality of fuel is in the tank. Perhaps some fresh fuel could help this situation.

Great compression
Rebuilt IP
Fresh injectors.

You should be top.

Sounds like the IP is running air-free once it's going, the pulses are normal too.

White smoke at idle all the time?

How thick is the smoke?

Just a little, or very obvious (during the day at idle).

Does it ever warm up and stop?

[gmc64sub]

Well, the fuel has been in there since mid December- two months or so. It's B99, by the way. It now smokes noticably after warmup. It didn't on the same fuel two months ago. I've been too embarrassed to drive it very far- thats how smoky it is. I did notice that it seems to miss and make a racket when I'm trying to give it power while driving. Maybe not firing on all cylinders, so to speak. I might try loosening each injector one at a time to burp any more air out. I started to do this but the injector itself started to unscrew...I guess I need a 30mm open end wrench to back them up.

[Robyn]

HMMMM
If you have a miss you need to check your injector lines and make sure
you dont have two that are swaped.This has been known to happen.

The firing order is 1-8-7-2-6-5-4-3 The two top lines on the pump are 8 on the drivers side of center and 7 to the pass side. The firing order runs clokckwise around the pump looking from the drivers seat.

Trace out all the lines and be sure they go where they need to.
Drivers side cyl's are 1357 front to back and pass side is 2468 front to back.
There is a diagram here at TDP that shows the line routing.

Give it a look see

Robyn

[john8662]

Maybe not firing on all cylinders, so to speak. I might try loosening each injector one at a time to burp any more air out. I started to do this but the injector itself started to unscrew...I guess I need a 30mm open end wrench to back them up.

Let's step back a little.

The injectors need to be good and tight in the heads.

Sounds like they're not.

They should all be torqued in with the 30MM socket to 50 ft. lbs.

I've witnessed what you're seeing when loosening lines and the injector turns. You'll need some kind of open end wrench now to get the lines off, cause it'll try twisting your lines now.

Get all the injectors secured in the head properly and try again.

The hint above by Robyn is probably on target, check your injection line routing to make sure they're going to the appropriate cylinders, two of the lines can become swapped.

[Mikeandwendy74]

I have the same smoking problem. I removed all 8 injectors figured what the heck cant hurt to rebuild them or at least have them checked. I took one and opened it up. UH OH look at the broken piece inside the injector! 7 out of 8 were broken internally.I would imagine this could cause some smoking problems :(. Half of the nozzle tips wouldn't even come out of the nozzles without a vise and vise grips. I'm replacing all 8 nozzles and little internal metal washers with factory spec pieces. This weekend I will be done and let ya know how I make out. By the way, I think the dude who owned this truck before me advanced the pump 100% as far as it will turn, thats what the marks on the pump look like to try to get rid of the smoke.That can't be a good thing.So new nozzles, tips, washers, copper washers, return fuel hose kit, and set timing I shoud be good.

[Robyn]

In your first post you said you ordered new injectors, did you install the new ones in the engine ???

[gmc64sub]

Yes, the injectors are rebuilt. They came packaged with plastic sealed over white cardboard backing. They had 6.2L stamped on them. I did torque the injectors with a torque wrench, but I don't remember taking them to 50 lbs. I might have tightened the tubing nuts too tight, since I didn't use the torque wrench on those. I'll check out the tube routing this weekend, and retorque the injectors.
Hopefully I can get to the bottom of this smoking problem. Thanks for the suggestions. It's great to be able to discuss these things with people that know diesels. My friends around here are all spark plug types.

Richard S.
Ukiah, CA

[gmc64sub]

Well,
I have checked the injection tube routing, and it is correct. I also checked the torque of the injectors into the heads, and it seems that I got that right as well, at least according to my torque wrench. 50 foot pounds doesn't seem like that much with the long handle on the torque wrench! Anyway, I probably overtightened the injection tubing nuts on a few injectors trying to make sure I have no leaks. I had to buy a wide jaw crescent wrench with a short handle to back up the injectors to loosen the tubes. My next step is to put some fresh fuel into the tank, and try loosening each injector tube -one at a time with the engine running- to see if I notice any cylinder not firing. If I find a cylinder not firing, then I guess I might have a bad injector? Not sure what to do after that. I'm trying to avoid towing this rig to the nearest diesel injection shop - 60 miles away in Santa Rosa, CA.

Richard S.
Ukiah, CA

[moondoggie]

Good Day!

[FONT=Verdana]A 6.2 with 400 PSI compression should start real easy when cold, & instantly when at full operating temperature. Even a cold start at ambient > 20

[gmc64sub]

I finally got the chance to check each injector by loosening the injector tubing connection one at a time while the engine is running. Each time the engine started to sputter and drop RPM. So I think its safe to assume all cylinders are firing normally.
The next thing I'll check is the fuel pickup in the tank. When I transplanted this engine, I modified the existing 1964 fuel pickup in the suburban tank by adding a return tube thru a hole I drilled in the cover plate. My fuel sender isn't working for some reason, so I need to drop the tank and check it out anyway.
Once I do that, I'll take Moondoggy's suggestion and fill up with some good quality fuel.
I'll let you know how that goes!

Richard S.

[gmc64sub]

Next Chapter:

I dropped the tank out and dumped most of the fuel into a five gallon bucket. The B99 looked fine- with a brownish tint, but very clear. Then I pulled the sending unit- found the copper float had a miniscule crack which flooded the float. The nylon (?) pickup sock looks fine- no debris to speak of. I was wondering if the B99 might have attacked this material but it didn't.
Checked the sending unit with a VOM. Read 3.5 ohms at the bottom, rolled up to about 34 ohms at the top. This should work correctly with the autometer gauge in the dash board.
No local auto parts store I tried carries a fuel tank sender float, but I did find one on the web at www.quantaproducts.com. Cost is $10.00 and UPS ground shipping is $13.19.
Now I await the float so I can put this back together and try it with fresh fuel.

[john8662]

Good work dropping the tank, doesn't sound as though anything was out of whack there, well, except the float being bad (gauge problems not running problems).

Be interested to see how the fresh Dino Diesel runs when you get it back together.

J

[gmc64sub]

Got the tank back in and now I have a working fuel gauge. Filled up (10 gallons) with fresh fuel. The smoking problem is still there. I set the timing marks to line up. The engine starts right up, idles nicely, RPM drops as the temp switch opens. Garage fills with smoke. The smoke must be unburned fuel. You can almost see the little droplets of fuel hanging in the air. Took it out on the road (at night so I don't get pulled over for gross pollution) and drove around for a while. The truck has a lot more power than before the new IP and injectors. The whitish-grey smoke clouds are still following me around. I also noticed a clicking/tapping noise at higher RPM that wasn't there before. I wonder if this noise could be coming from the IP?
Very frustrating...
Richard S.

[gmctd]

Try pulling the return line hose to the tank from the 'tee', blow it out towards the tank with shop air

Remove the fuel cap, first.

[gmc64sub]

Are you thinking that the return line is blocked? I'll definetely check this out.

[gmctd]

That's another part of the system that requires proving - go or no-go.

If it is plugged, it will greatly reduce advance

[gmc64sub]

Return tubing checked out OK. I had my wife listen at the tank filler while I blew air into the return line. She could hear it bubbling and sturting inside the tank. I guess I'll try another new filter to see if that makes any difference. Anyone know if the fuel heater could cause this smoking problem? I don't have it hooked up at this point. I've never seen any info on this forum about the heater that's located in the filter assembly.
Thanks, Richard S.

[gmctd]

That warms the fuel at temps below 40deg - if it's broke, you wouldn't be getting much fuel at 17deg due to the paraffin.

And, any water in the fuel would also be frozen.

[gmc64sub]

I've got an appointment in town with a local diesel repair shop. I will have him check the IP timing, the HPCA effect on the timing (temp & pressure) and check the compression. Anything else I'm missing?

Thanks,
Richard S.

[gmc64sub]

Got the call from the diesel shop. He said at least 5 of the injectors were bad. One of them had apparently failed to seat and was leaking into the cylinder continuously. The others were doing the same thing to a lesser extent. The exhaust still gives off a big puff of white smoke on a cold start, and the smoke gradually diminishes in a few minutes to invisible. Later in the day, it hardly smokes at all. The truck sounds and runs much better now.

I wonder if it is possible to get a bad batch of injectors? These were presumably rebuild and tested. They came sealed in plastic on cardboard. Is it possible that I was guilty of contaminating the injectors on original installation? I was very careful to keep things clean.

I didn't keep the bad (but new) ones because it would have cost $8 each for core charge. I guess I'll call the place I got them from, but I doubt they'll refund anything without the cores.

Thanks for everybodys help in trying to figure this out!

Richard S.

[Robyn]

There are many outfits out there selling "rebuilt" stuff online thats junk.
Stick with a local supplier or the folks that advertise here at TDP and you wont do bad.

The engine should toss a little white to blue smoke just as it starts but should clear out almost immediately.
Is your IP in good shape??

If its been a long time since it was reworked it would be a great idea to get it freshened up.

[82blazer]

did you say b99? I have read that bio-diesel starts to degrade in about 20 to 30 days. I'm tring to remember where I saw that. But I would try new fuel based on readings and it should be a simple test. :)

[gmc64sub]

Well I'm not sure if B-99 starts to degrade after a while, but I've been using it a long time without any bad results. You may not want to let a vehicle sit around too long with B-99 in tank. I don't seem to have that problem.

Richard S.