Brown smoke, rev up and down at idle after lots of troublsho

Discuss (and cuss) the Nissan LD-series OHC Six diesel engine, popularly available in the US in 1981-83 Datsun/Nissan Maxima Sedans & Wagons.

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SirSmeez
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Location: Ashland, OR

Brown smoke, rev up and down at idle after lots of troublsho

#1

Post by SirSmeez »

1982 LD28 sedan with 140,000 miles. When I bought this car it didn't run, broken timing belt cog. Had an extremely competent mechanic put on the new cog and time the belt. He timed the belt with information from this forum. Car started right up but smoked brown...a lot. It keeps an idle but the idle isn't consistant, revs up and then back down up and down up and down.

Doesn't seem to be symptomatic of of early or late timing as there is no white or black smoke. Car had been sitting for two years when I bought it so I flushed the fuel system, drained and replaced the old diesel and changed the oil. The smoke still didn't go away and idle was the same.

The mechanic doesn't think that it's a blown head gasket because the temp stays fine even after idling for 2 plus hours. Also runs fine with radiator cap off. Maintains good temp after idling for a long time but the smoke doesn't clear up, the idle does smooth out after an hour of idling.

He said his next guess would be clogged injectors or defective cold start device. I just took the injectors off and apart to soak them and then blow them out with compressed air. When I took the injectors out there was what looked like motor oil around the tips of two or three of them. Is there supposed to be motor oil here and if not what is this symptomatic of? Also, does the rev at idle and smoke sound symptomatic of a failure in the CSD? If so how can I render the CSD inoperative and get this smoke to clear up? Any other ideas on troubleshooting the smoke or or the rev at idle?

I didn't know these cars existed until recently and they are so cool! I really want to drive it. Also thanks for all your posts and this forum, it has been extremely helpful already!
diesel-man
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Location: Elkton, MD

#2

Post by diesel-man »

I can't say that I have ever seen brown smoke come out of a car, so bear with us as we poke and prod the "patient".

I assume you have never heard another LD28 run besides the one you have, so in asking if the engine feels lazy or has too much "diesel" knock would that be hard to guage?

Last month I started a Maxi diesel that sat near my back steps for 6 years since the last time I pumped my septic tank. It honestly started and ran as if I had shut it off the day before.

Twenty cogs on the injection pump belt is 7 1/8". I timed one up almost 15 years ago, and had it off by a tooth, and it was pretty "ragged".

What happens when you take it out on the street? I had a car that was in a salvage yard that took 15 miles to get it heated up to burn the sludge, crud or whatever out of the rings, valves, combustion chamber, etc. Any how the end result is the car ran great after 20 miles, most likely from a lot of idling, bad thermostat, short distances, etc. from before I ever got the car.

How does it run when you speed it up above idle? Will the engine hold a steady speed (in neutral or park)? When you jazz the accelerator will it blow black smoke and race right up in speed? What about when you take the air filter out? The cold start has no bearing on the situation once it is running. Does the thermostat work so that the coolant guage comes up to 1/3 or 1/2?

What part of the country are you in?
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asavage
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#3

Post by asavage »

Hello:

Please update your Profile (click on "Profile" at the top of any page) and fill in your Location, and maybe add your vehicle info to your Signature. It will save a LOT of repetive Qs later.

A wild, but fairly educated guess, would be that either the IP belt is off one tooth (it will run, but very poorly), or the wrong timing mark on the IP sprocket was used. It's disturbingly easy to do either of those.

I have finally gotten pictures and taken notes to do a step-by-step of the IP belt and IP shaft seal replacement. I just lack the time to write it up and edit the photos. Hopefully, by the end of the year. Meanwhile, member diesel-man owns or has owned more of these LD28s than any two other people I know. Listen to him.

(Though I don't know as I'd try to drive an LD28 with the IP belt of one tooth. That could be damaging.)
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
SirSmeez
Posts: 2
Joined: 16 years ago
Location: Ashland, OR

#4

Post by SirSmeez »

Unfortunately, I have never heard another LD28 run but I do own other diesels and feel that I have a fairly good understanding of what a healthy diesel sounds like. My LD28 sounds pretty good and doesn't knock.

I haven't measured the injection pump belt since I got it back from the mechanic but he told me that at first he had the timing off and it was smoking white so he adjusted it back one tooth. he may have even timed it three times, anyhow. When adjusting the timing, is the 7 1/8" spec measured along the top of the belt?

I haven't run it for 15 miles, maybe 5 at the max. The engine does hold a steady speed when when sped above idle but blows excessive dark smoke in both neutral and park. When I am driving the car runs smooth but slow, can't really get above 35. But yes, when I jazz the accelerator it does pick up to speed and blow black smoke. I have taken the air filter out but this doesn't seem to affect the cars performance. I can't remember the reading on the coolant gauge when it was running before I pulled the injectors. I will read it when I put the injectors back in and start her up today.

I updated my profile but I live in Ashland Oregon, southern Oregon about 15 miles above the California border. Also I own a biodiesel production company here that produces biodiesel from both WVO and virgin feedstock. This is the third diesel vehicle I've owned and it's a dream on wheels, once it stops smoking that is. Thanks for all your help guys!
1982 Maxima LD28
1983 Chev Blazer 6.2L Diesel
1976 Mercedes 240D
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asavage
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#5

Post by asavage »

You might want to read most of the entire FAQ on the Maxima and LD28, and specifically the section on Intake Manifold Grunge. You may have an extreme example of plugged intake.

If the EGR was stuck wide open, that might explain the idle, but not the lack of power. With the coolant temp up, the air filter throttle opens off idle and even with the EGR stuck wide open, there is insufficient delta pressure to push enough exhaust to the intake to affect the power that much.

Can you borrow a pulse adapter setup, like a Snap-On MT257(a), or a Kent-Moore Tach-N-Time (I rent them)? If so, you can use a std gasser timing light and double-check that your IP timing is in the ballpark -- mine runs about 8° BTDC when measured this way, at idle and for quite a ways above idle.

AT or MT? If AT, vacuum modulator check? Sucking ATF will sometimes give odd colored smoke. (You might put your trans. type in your Signature in your Profile.) Wagons with the LD28 didn't come with the MT, but your Sedan was available either way.

The CSD (Cold Start Device) only advances the base timing a couple of degrees, and then only for a certain low-RPM band. It is unlikely to be contributing to your current woes.

We just lost our local retail B100 distribution: after five years, we were no longer "under the radar" of the LAHJ and they shut the operation down until proper permitting, zoning, licensing, secondary containment, and insurance were in place. That pretty much ended our 600 member operation, and I can't say it is a bad thing because I'd been lobbying for years to get that all squared away.

Now I'm looking for a tote, pump, hose, nozzle, and I think I'll just have to put the tote in our warehouse and feed only my own vehicles. Been running B99 in my '82 Wagon for 16k miles -- ASTM D-6751 spec. BD, that is (until the last batch out of the totes). Been running BD for several years in various diesels here.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
diesel-man
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Posts: 150
Joined: 18 years ago
Location: Elkton, MD

#6

Post by diesel-man »

Pouring out black smoke tells us that there is plenty of fuel available, but the low power tells us it is not timed correctly.

7 1/8" is 20 cogs on the timing belt. Pictures on this thread: http://nissandiesel.dyndns.org/viewtopi ... =9618#9618

It is so easy to get mixed up on the timing marks, easier to get it wrong than right since it has two sets of marks on the pump gear.

Also check the "throttle" plate in the air filter box that it is open above idle...highly unlikely that it is stuck shut, but I look for an odd solution when having an odd problem.

I believe you will find that the injection timing is a tooth off.

AL: Automatic trans fluid is only an issue in a gasser, the vacuum on a diesel doesn't enter into or originate from the intake.
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asavage
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#7

Post by asavage »

diesel-man wrote:I believe you will find that the injection timing is a tooth off.
That's what I think as well.
AL: Automatic trans fluid is only an issue in a gasser, the vacuum on a diesel doesn't enter into or originate from the intake.
I forgot that the Nissan pumps pump air into the crankcase. I was thinking MB/VW vacuum pump -- lazy thinking.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
glenlloyd
Posts: 640
Joined: 18 years ago
Location: Des Moines, Iowa

#8

Post by glenlloyd »

You might listen to this clip I have of my car idling in the driveway and see how that compares to your vehicle.

http://www.youtube.com/watch?v=pwHocrYt4_k
97 Jetta TDI, 86 VW Golf D
89 VW Fox diesel, 92 MB 300SD W140

gir - won't the sploding hurt?
zim - silence!
RacnJsn95
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Location: Central Point, OR
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#9

Post by RacnJsn95 »

I bought this car today, and will be bringing it home hopefully before this weekend so I can start playing with it...
diesel-man wrote:It is so easy to get mixed up on the timing marks, easier to get it wrong than right since it has two sets of marks on the pump gear.
I did a little research, and it looks like one set of marks is the the LD20, and one is for the LD28... My question to that is, if somehow the mechanic that worked on it, got the marks mistaken, would the car even run like that?
82 Maxima Diesel, Auto 164k
77 620 k/c 4x4, 4spd, L20b (wishes it was an LD20)
RacnJsn95
Posts: 37
Joined: 16 years ago
Location: Central Point, OR
Contact:

#10

Post by RacnJsn95 »

I bought this car today, but haven't really had a chance to play with it. Hopefully I'll be picking it up before this weekend.
diesel-man wrote:It is so easy to get mixed up on the timing marks, easier to get it wrong than right since it has two sets of marks on the pump gear.
I did some research, and I see that one set of marks is for the LD20 engine, and the other is for the LD28... If by chance the mechanic that did the work on the car went with the wrong marks, would the car even run?
82 Maxima Diesel, Auto 164k
77 620 k/c 4x4, 4spd, L20b (wishes it was an LD20)
goglio704
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Joined: 18 years ago
Location: East Tennessee

#11

Post by goglio704 »

Yes, they'll fire even when the timing is badly off.

http://nissandiesel.dyndns.org/viewtopic.php?t=1105


Since this story continues here:

http://nissandiesel.dyndns.org/viewtopic.php?t=1681

I am going to lock this thread.
Matt B.

83 Maxima Sedan, LD28, 5 speed, white, 130k miles. My original Maxima.
83 Maxima Sedan converted from gasser, LD28, 5 speed, 2 tone blue, 230k miles
82 Maxima Sedan, LD28, 3 speed auto, 2 tone Gray/Silver, 140k miles
81 810 Sedan, LD28, 3 speed auto, rust, rust, and more rust!

2005 Jeep Liberty CRD
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