View Full Version : Excessive smoke 6.5
Swatravels
03-08-2019, 16:33
Hello. I have a 1993 Chevy 6.5 diesel . This is my first diesel truck ever so I’m looking for guidance to get it working properly
When I start the truck there is excessive white smoke the truck idles perfectly but produces black smoke when accelerating
My question is where do I start everything I find online it’s for 94 and up
Thanks in advance for any help
sctrailrider
03-08-2019, 16:53
Being a 93 it's a manual injection pump motor, no computer. You should start with checking or changing the fuel filter & air filter, the Glow plug system would be next, the lift pump is mounted on the frame rail under the driver side of the cab, with the motor idling, open the filter drain valve, it should be a brass "T" looking thing mounted to the thermostat crossover, if the motor stumbles or quits the lift pump isn't working.
Look it the "stickys" at the top of the forum list, I think their is a list of things to check better than what gave..
Anyway, try these things and report back...
sctrailrider
03-08-2019, 16:55
Lots of info here, it's the tech section....
https://www.thedieselpageforums.com/tdpforum/forumdisplay.php?f=22
Swatravels
03-08-2019, 17:05
Being a 93 it's a manual injection pump motor, no computer. You should start with checking or changing the fuel filter & air filter, the Glow plug system would be next, the lift pump is mounted on the frame rail under the driver side of the cab, with the motor idling, open the filter drain valve, it should be a brass "T" looking thing mounted to the thermostat crossover, if the motor stumbles or quits the lift pump isn't working.
Look it the "stickys" at the top of the forum list, I think their is a list of things to check better than what gave..
Anyway, try these things and report back...
Thank you for this information. The air filter was dirty and was just replaced. Is there anything I need to know about replacing the fuel filter? Or is just pretty straightforward?
Swatravels
03-08-2019, 17:08
Thank you for this information. The air filter was dirty and was just replaced. Is there anything I need to know about replacing the fuel filter? Or is just pretty straightforward?
I also noticed the waste gate actuator does not move at all with the truck on or off
sctrailrider
03-08-2019, 17:16
You will need to prim the fuel system after changing the filter, it might take a few cranks. Their is a priming harness that is plug & play that Kennedy Diesel or myself offer that makes the LP run during key on & a button to make it much easier to prime after a filter change. If your filter has the metal hold down ring used to tighten the filter down don't throw it away, find a AC Delco filter, the cheap aftermarket filters use plastic and aren't as good. It would be a good time to remove the filter housing and clean it, it's probably has junk in the bottom, and inspect the rubber fuel lines while your their, the best way is to remove the intake, it's easy to do just don't drop anything in the runners...
White smoke at startup is unburned fuel. I'd guess you have a few glow plugs burned out or you aren't waiting for them to heat up. It's been a long time, but I think there's a "Wait to Start" light on the panel.
Black smoke under load means too much fuel or too little air. Your air filter, the turbocharger, or a stuck open wastegate could cause that. I've also heard of cases where a plugged fuel filter resulted in black smoke, but can't figure out why that would be.
If you replace the fuel filter you will need to bleed the air out of it. The filter has a black bleeder knob on top. IIRC, if you put the trans in drive and try to start it the fuel pump will run and purge the filter, but I could be wrong about that... (Got rid of the '93 15 years ago...)
If the electric lift pump isn't working you'll also have unusual running problems. Most common failure mode is the oil pressure switch that powers the pump. Kennedy Diesel sells a neat kit to add a fuel pump relay and solve that issue forever.
The wastegate is spring loaded and only moves when maximum boost is reached. You should be able to move it by hand, though, against the spring. The rod pulls out of the canister (unless it's stuck out already.)
sctrailrider
03-08-2019, 17:21
The 93's have a manual wastegate, it may be stuck open so no boost, it would be a good idea to have a boost gauge, but for now, spray some penetrating spray on the locations that move, you should be able to figure it out, work the parts and see if you can free it up without breaking something... A boost gauge will let ya know if the gate is working or not...
Swatravels
03-08-2019, 17:49
White smoke at startup is unburned fuel. I'd guess you have a few glow plugs burned out or you aren't waiting for them to heat up. It's been a long time, but I think there's a "Wait to Start" light on the panel.
Black smoke under load means too much fuel or too little air. Your air filter, the turbocharger, or a stuck open wastegate could cause that. I've also heard of cases where a plugged fuel filter resulted in black smoke, but can't figure out why that would be.
If you replace the fuel filter you will need to bleed the air out of it. The filter has a black bleeder knob on top. IIRC, if you put the trans in drive and try to start it the fuel pump will run and purge the filter, but I could be wrong about that... (Got rid of the '93 15 years ago...)
If the electric lift pump isn't working you'll also have unusual running problems. Most common failure mode is the oil pressure switch that powers the pump. Kennedy Diesel sells a neat kit to add a fuel pump relay and solve that issue forever.
The wastegate is spring loaded and only moves when maximum boost is reached. You should be able to move it by hand, though, against the spring. The rod pulls out of the canister (unless it's stuck out already.)
Thank you for that information. The glow plugs do have a light on the dashboard. I do wait for the light to go out. I’ll try installing a new fuel filter and glow plugs . Hopping that will help
Swatravels
03-08-2019, 17:52
The 93's have a manual wastegate, it may be stuck open so no boost, it would be a good idea to have a boost gauge, but for now, spray some penetrating spray on the locations that move, you should be able to figure it out, work the parts and see if you can free it up without breaking something... A boost gauge will let ya know if the gate is working or not...
Great idea. I’ll do that and see if it helps
Swatravels
03-09-2019, 10:07
4215
4216
Swatravels
03-09-2019, 10:12
4217. When step on it
sctrailrider
03-09-2019, 11:12
Have you had a chance to check the items already listed?
Swatravels
03-09-2019, 11:29
Have you had a chance to check the items already listed?
I’ll be replacing the glow plugs very soon. My question is. When I turn on the Ignition key I’m supposed to hear the lift pump or not? If I go to the junction box on the fire wall and jump the fuel pump fuse I can hear the pump
Swatravels
03-09-2019, 11:42
Have you had a chance to check the items already listed?
I’m checking the T valve at the moment. It’s hard to turn4218
Swatravels
03-09-2019, 11:59
I’m checking the T valve at the moment. It’s hard to turn4218
Got the T valve loose shortly after engine dies
The lift pump must be weak if you heard it when jumping it but the engine dies when you open the T valve.
Sorry about the mad face up top. My daughter did it and I couldn’t figure out how to delete it.
Swatravels
03-09-2019, 14:51
The lift pump must be weak if you heard it when jumping it but the engine dies when you open the T valve.
Sorry about the mad face up top. My daughter did it and I couldn’t figure out how to delete it.
That’s funny . I’m thinking a new lifter pump might be need it
Swatravels
03-09-2019, 15:30
White smoke at startup is unburned fuel. I'd guess you have a few glow plugs burned out or you aren't waiting for them to heat up. It's been a long time, but I think there's a "Wait to Start" light on the panel.
Black smoke under load means too much fuel or too little air. Your air filter, the turbocharger, or a stuck open wastegate could cause that. I've also heard of cases where a plugged fuel filter resulted in black smoke, but can't figure out why that would be.
If you replace the fuel filter you will need to bleed the air out of it. The filter has a black bleeder knob on top. IIRC, if you put the trans in drive and try to start it the fuel pump will run and purge the filter, but I could be wrong about that... (Got rid of the '93 15 years ago...)
If the electric lift pump isn't working you'll also have unusual running problems. Most common failure mode is the oil pressure switch that powers the pump. Kennedy Diesel sells a neat kit to add a fuel pump relay and solve that issue forever.
The wastegate is spring loaded and only moves when maximum boost is reached. You should be able to move it by hand, though, against the spring. The rod pulls out of the canister (unless it's stuck out already.)
I have being messing with the wastegate rod. I can move it towards the firewall about half an inch, i feel it should move more than that am i wrong? If indeed the wastegate is stuck. How do I go about opening it?
sctrailrider
03-09-2019, 15:55
I would disconnect the rod and continue to spray the lube, check the rod and see how much it moves in the canister part, it might need some lube also..
The arm the rod connects to on the housing should move easy by itself, if it's tight some lube might help, if it doesn't it's time to consider a turbo rebuild... while your their, remove the rubber hose on the turbo inlet and see how the blades spin, they also should spin easy, if it doesn't the turbo is ready for a rebuild as it's coked up, the older ones are good at that due to their age...
sctrailrider
03-09-2019, 15:57
And yes, if it dies when you open the t valve the lift pump is not working well, get another, the one for a 93 is the best one as far as psi it puts out...
At some point the lift pump harness would be a good investment...
Swatravels
03-09-2019, 16:05
i would disconnect the rod and continue to spray the lube, check the rod and see how much it moves in the canister part, it might need some lube also..
The arm the rod connects to on the housing should move easy by itself, if it's tight some lube might help, if it doesn't it's time to consider a turbo rebuild... While your their, remove the rubber hose on the turbo inlet and see how the blades spin, they also should spin easy, if it doesn't the turbo is ready for a rebuild as it's coked up, the older ones are good at that due to their age...
I was trying to show how much the rod can travel
4219
4220
sctrailrider
03-09-2019, 16:14
Looks strange from here...
Might disconnect the front canister that the rod is in and move the entire rod and see how easy the flapper moves and also the front portion of the arm... The assembly should move easy but when connected be harder to move, the front of the rod is spring loaded to keep the flapper closed until a certain boost psi is reached then the flap moves...
The arm on the wastegate doesn't move more than 90 degrees. Better if you can measure the manifold pressure, to be sure.
If the lift pump runs when you jump it, then it's probably OK. The lift pump is powered two ways: when the starter is energized and when the engine has oil pressure. If it stalls when you open the "T" valve, try jumping the pump on and repeating the test. If it doesn't stall then, the pump is OK and the oil pressure switch (also the gauge sensor) is not powering the pump. Don't be deceived if there's nothing wrong with the gauge. They're separate circuits in the same sensor.
The black smoke in the photo: was that with no load on the engine?Have you changed the air filter yet? Black smoke means too much fuel for the available air.
No harm in changing all the glow plugs, but some of them can be a real PITA, so you might want to test them before you replace them.
Swatravels
03-09-2019, 18:52
The arm on the wastegate doesn't move more than 90 degrees. Better if you can measure the manifold pressure, to be sure.
If the lift pump runs when you jump it, then it's probably OK. The lift pump is powered two ways: when the starter is energized and when the engine has oil pressure. If it stalls when you open the "T" valve, try jumping the pump on and repeating the test. If it doesn't stall then, the pump is OK and the oil pressure switch (also the gauge sensor) is not powering the pump. Don't be deceived if there's nothing wrong with the gauge. They're separate circuits in the same sensor.
The black smoke in the photo: was that with no load on the engine?Have you changed the air filter yet? Black smoke means too much fuel for the available air.
No harm in changing all the glow plugs, but some of them can be a real PITA, so you might want to test them before you replace them.
On the picture the truck was running. If I step on it it produces a lot of black smoke.
I’m trying to get it working so I can take it over two mountains passes so for now it’s not going anywhere.
The drive it’s pretty intense for a vehicle that it’s not working well
I’ll try testing the pump function tomorrow. Thank you
On the picture the truck was running. If I step on it it produces a lot of black smoke.
OK. sounds like that's no load. The turbo can't produce much boost with no load, so I'd hold off worrying about that until you get everything else taken care of. Do you know if the previous owner tried to make any performance enhancements?
Swatravels
03-10-2019, 10:31
OK. sounds like that's no load. The turbo can't produce much boost with no load, so I'd hold off worrying about that until you get everything else taken care of. Do you know if the previous owner tried to make any performance enhancements?
The truck shows about 084000 miles. The story is that the engine was replace at one point but I have no paperwork of that
The air box it’s stock and somewhat damage where it attaches to the fender. The filter was dirty when I got it. A new filter was install last week,new fuel filter
I’ll say no to the performance enhancements
Engine was pretty dirty since this vehicle used to be driven in country roads. I have cleaned most of the top end using very little solution to avoid damaging
electrical components . When I jumped the pump I was able to hear it running. I’m not sure I have heard the pump run when the truck it’s on. How can I test to see if the pump it’s being activated when the vehicle it’s running? 4222
DmaxMaverick
03-10-2019, 10:45
Is this a P-Chassis, Chassis/Cab, or a pickup conversion (noticed a "box" van in your exhaust pics), and what is the GVWR (sticker on door/post, VIN, and/or RPO code in glove box)? There are subtle differences between them. It won't make much of a difference with the diagnostics, but may help with some component locations, access, and operation, including emission controls if present.
Swatravels
03-10-2019, 11:30
Is this a P-Chassis, Chassis/Cab, or a pickup conversion (noticed a "box" van in your exhaust pics), and what is the GVWR (sticker on door/post, VIN, and/or RPO code in glove box)? There are subtle differences between them. It won't make much of a difference with the diagnostics, but may help with some component locations, access, and operation, including emission controls if present.
This vehicle used to be a rural ambulance then passed on to a swat team to be used for transport
Swatravels
03-10-2019, 12:00
4226
When we first start it.
How can I test to see if the pump it’s being activated when the vehicle it’s running?
You already did. When you open the "T" valve fuel should come out and the engine should keep running. Since it stalled, that indicates the pump is not running. Most likely, the oil pressure switch is bad.
When we first start it.
Take the leads off the glow plugs and test from the terminal (on the plug) to ground with an Ohm meter. Expect a reading around 0.8 Ohms for a good plug.
Swatravels
03-10-2019, 12:27
You already did. When you open the "T" valve fuel should come out and the engine should keep running. Since it stalled, that indicates the pump is not running. Most likely, the oil pressure switch is bad.
Take the leads off the glow plugs and test from the terminal (on the plug) to ground with an Ohm meter. Expect a reading around 0.8 Ohms for a good plug.
Ok. Thank you for all this information,it’s very helpful to me as I’m trying to learn as much as possible
The ironic thing is that my father was in master diesel mechanic of 30+ years and I know nothing about Diesel. Here I’m trying to learn now that he’s not longer with us
Thanks again I’ll check the glow plugs and oil pressure switch
DmaxMaverick
03-10-2019, 14:02
This vehicle used to be a rural ambulance then passed on to a swat team to be used for transport
OK. Can't tell by the pics, but if it has a pickup cab, it's a Cab/Chassis. If it has a van cab, it's a P-chassis. Either way, it's a 3500, NOT a 3500HD, according to the declaration placard. The engine VIN code (8th digit, F) indicates Federal HD emission equipment, which means, no emission equipment (a good thing, unless you're a granola-eater).
Swatravels
03-10-2019, 18:05
New oil pressure sensor install. I was removing the connector and the sensor cap came off so I install a new sensor. Drove it around but still leaves smoke behind when pressing hard on the pedal
Swatravels
03-11-2019, 00:11
4227
OK. Can't tell by the pics, but if it has a pickup cab, it's a Cab/Chassis. If it has a van cab, it's a P-chassis. Either way, it's a 3500, NOT a 3500HD, according to the declaration placard. The engine VIN code (8th digit, F) indicates Federal HD emission equipment, which means, no emission equipment (a good thing, unless you're a granola-eater).
Here is the ride
Swatravels
03-11-2019, 00:58
New oil pressure sensor install. I was removing the connector and the sensor cap came off so I install a new sensor. Drove it around but still leaves smoke behind when pressing hard on the pedal
Just order a new LP harness
It would be helpful to know what you're getting for manifold pressure.
If you're flooring the pedal in neutral, the governor should limit the fuel and prevent smoking.
If the engine is under load, the turbo should be building boost and eliminating most, if not all, of the black smoke.
Lots to read and lots to digest. I just skimmed.
Arveetek just posted about glow plugs.
On the smoke deal those DB2 pumps did tend to get tired/worn and sticky in the advance bore. The tendency was more toward a blue/white smoke coming off idle. Getting the lift pump working is an important first step.
Wastegates on these models tend to stick closed if anything. The fact that it moves at all is a sign that all is well. Boost gauge mandatory for diagnosis.
Yukon6.2
03-11-2019, 09:23
Ok. Thank you for all this information,it’s very helpful to me as I’m trying to learn as much as possible
The ironic thing is that my father was in master diesel mechanic of 30+ years and I know nothing about Diesel. Here I’m trying to learn now that he’s not longer with us
Thanks again I’ll check the glow plugs and oil pressure switch
Not an isolated experience
My Dad baked awesome bread,but would not share the recipe
Now i am trying to recreate it,since he said he would take it to the grave.
Swatravels
03-11-2019, 11:12
It would be helpful to know what you're getting for manifold pressure.
If you're flooring the pedal in neutral, the governor should limit the fuel and prevent smoking.
If the engine is under load, the turbo should be building boost and eliminating most, if not all, of the black smoke.
I’ll search how to check the manifold pressure and report back.
Swatravels
03-11-2019, 11:17
Lots to read and lots to digest. I just skimmed.
Arveetek just posted about glow plugs.
On the smoke deal those DB2 pumps did tend to get tired/worn and sticky in the advance bore. The tendency was more toward a blue/white smoke coming off idle. Getting the lift pump working is an important first step.
Wastegates on these models tend to stick closed if anything. The fact that it moves at all is a sign that all is well. Boost gauge mandatory for diagnosis.
Ok thank you. I just order a new LP harness to see if that gets things moving. I’ll looked in to a boost gauge as well
Swatravels
03-11-2019, 11:20
:D
Not an isolated experience
My Dad baked awesome bread,but would not share the recipe
Now i am trying to recreate it,since he said he would take it to the grave.
That’s funny : )
arveetek
03-11-2019, 12:02
Lots to read and lots to digest. I just skimmed.
Arveetek just posted about glow plugs.
I didn't realize how bad my 6.5L was blowing white smoke upon start up until putting in new glow plugs. It had slowly gotten worse over time without me really noticing, but now there's very little white smoke at startup with the new plugs.
Casey
Swatravels
03-12-2019, 23:12
I didn't realize how bad my 6.5L was blowing white smoke upon start up until putting in new glow plugs. It had slowly gotten worse over time without me really noticing, but now there's very little white smoke at startup with the new plugs.
Casey
Thank you. I’m waiting for my new LP harness and plugs to arrive
Swatravels
03-20-2019, 04:08
I didn't realize how bad my 6.5L was blowing white smoke upon start up until putting in new glow plugs. It had slowly gotten worse over time without me really noticing, but now there's very little white smoke at startup with the new plugs.
4229
4230
Casey
New glow plugs install. White smoke it’s not a problem anymore. The glow plug harness will need replace
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions Inc. All rights reserved.