2L-T Smoky start (1 Viewer)

[Funksolid]

My friend has a Prado. 2L-T And bought it with a new/upgraded head.

Brand new injectors and glow plugs. Has some pretty bad white smoke @ startup (5 seconds or so, smoke cloud is about the size of the vehicle), and then run perfect. Good power, MPG ECT clean exhaust...

What could be the issue?



Thank You

 

[roscoFJ73]

My friend has a Prado. 2L-T And bought it with a new/upgraded head.

Brand new injectors and glow plugs. Has some pretty bad white smoke @ startup (5 seconds or so, smoke cloud is about the size of the vehicle), and then run perfect. Good power, MPG ECT clean exhaust...

What could be the issue?



Thank You

My guess it is air in the system. The white smoke is from moisture particles in the air. If it doesnt smell of coolant its almost certainly air leaking in from somewhere.
Look closely around any joints or seals disturbed during the head replacement.

They always get a quick 1/2 second puff of white from a cold combustion chamber.

 

[Funksolid]

Thank you

 

[gbcruiser]

Water in the fuel or low quality diesel? Not sure if Prados have water traps in the fuel lines, but might be something in there if they do...

Is your friend running bio? Often even B5 has a higher moisture level than regular diesel and in winter it becomes more noticeable with cold starts.

 

[Funksolid]

Nope the smoke is consistent, and he has bought Diesel from multiple places. And also ran Stanadyne for a few weeks. And no Bio diesel, just the straight stuff.

I'm gonna look into the Air idea.

 

[Rosters]

I know this is an old post but did you ever find the problem. I have the same (only worse in terms of smoke quantity) issue with my 91 2LTE after changing out the diesel pump, plugs, and injectors

 

[GTSSportCoupe]

I know this is an old post but did you ever find the problem. I have the same (only worse in terms of smoke quantity) issue with my 91 2LTE after changing out the diesel pump, plugs, and injectors

This is probably one of the most common questions regarding these motors. Start-up diesel smoke is from one of three things in my experience. Glow system not working (just changing plugs may not fix the actual problem), air in lines (all those old rubber hoses leak easy as they get older, as does the primer), or low compression. It's a process of elimination. I've written how to do it countless times, but can write again if you don't know what to do.

One last thing that can cause the problem but is less common is the emissions system not working right, and starving the motor of air. There is a small vacuum actuated butterfly valve in the throttle body. This should be open at start-up, but if there are problems (no vacuum for example), it can cause a difficult and smokey start. Hard to burn diesel with no air!

 

[Rosters]

will follow the emissions route for now, btw also looking at the pump and ECM again.
Hopefully the low compression is the last resort.
appreciate your feedback
thanks

 

[GTSSportCoupe]

will follow the emissions route for now, btw also looking at the pump and ECM again.
Hopefully the low compression is the last resort.
appreciate your feedback
thanks

I do recommend just removing the whole system. Many of us have removed all the EGR piping and installed block off plates. We've also removed the two butterfly plates in the throttle body, and the various vacuum switches and actuators. This gives the motor all the air it could want, and keeps the intake manifold from getting coked up with soot. There are some great LJ78 build threads here that show how this is done with pictures.

I sort of doubt that this is what is causing your problem though. Most likely it's air getting into the fuel lines, or your glow system not working right.

Testing the glow system is easy. When the engine is cold (first thing in the morning), use a volt meter to measure the voltage on the glow rail. Have an assistant turn the key to the 'on' position. You should measure 11V for about 7 seconds. This should then decrease to 6V for another 30sec-1minute or so. If this is not happening, let me know and I can help you troubleshoot. You should hear the first relay open after the 7seconds. Normally this is when you should start your engine (don't go by the little glow light in the vehicle - it doesn't stay on the right amount of time)!

Eliminating air in the lines is a matter of checking all the rubber fuel lines, and putting new hose clamps on the ends. I also recommend completely swapping out the fuel primer. If it's original, it's probably leaking. The Ebay knock off ones are cheap and work fine. Finally, check the torque on the fuel return rail (bolts onto the injectors). Also the little hose that connects it back to the injection pump. I've had leaks at one time or another in ALL of these spots.

 

[Rosters]

I going retest the glow right away. Would be great if it was a simple oversight. will let you know
thanks much

 

[GTSSportCoupe]

I going retest the glow right away. Would be great if it was a simple oversight. will let you know
thanks much

I was just looking at your other post too where you were taking about your compression numbers. I had low compression on one cylinder in my original 2LTE short block. It would always smoke and misfire for the first few seconds after startup. It was obvious it was running on 3 cylinders; and I could see the pulses of smoke coming out the exhaust from the one bad cylinder. Once the motor warmed a bit it ran on all 4. Doesn't sound like this is what is happening to yours though.

 

[roscoFJ73]

I have the same (only worse in terms of smoke quantity) issue

Its all about the colour of the smoke. And other details like mileage, oil usage work done by yourself or shop

 

[Rosters]

I was just looking at your other post too where you were taking about your compression numbers. I had low compression on one cylinder in my original 2LTE short block. It would always smoke and misfire for the first few seconds after startup. It was obvious it was running on 3 cylinders; and I could see the pulses of smoke coming out the exhaust from the one bad cylinder. Once the motor warmed a bit it ran on all 4. Doesn't sound like this is what is happening to yours though.

 

[Rosters]

Truck is at my mechanics as its beyond my tech ability, regardless he checked the glows yesterday. All good. Also ran clean diesel from a 5gal nurse tank directly to the pump. no change in smoke issue. bypassing the EGR today to see if that is contributing. will let you know
thanks

 

[Rosters]

Its all about the colour of the smoke. And other details like mileage, oil usage work done by yourself or shop

 

[Rosters]

Will try and post a couple of cold start videos (having difficulty). 66K miles. new head. Cold start (say 40F air temp) 10 seconds of black smoke then almost exclusively white smoke with slight diesel smell. consistent large volume for up to 4 minutes if its parked. After 1 minute of driving at low speed the smoke drops dramatically. After 3 mins of driving its totally normal. Restart engine at 55 degrees, very little smoke. Restart with thermostat at operating temp, no smoke. little or no smoke (slight grey) at acceleration. Little oil usage. Clean oil, no coolant.

 

[roscoFJ73]

10 seconds of black smoke says there is most likely something wrong with the injection system. I would get the injectors checked, I know you had them done, but it shouldn't be making black smoke if it was done properly.
Come back and tell us what your mechanic wants to do.

 

[Rosters]

Its all about the colour of the smoke. And other details like mileage, oil usage work done by yourself or shop

 

[Rosters]

hopefully you can view this video
cold start smoking

 

[Rosters]

10 seconds of black smoke says there is most likely something wrong with the injection system. I would get the injectors checked, I know you had them done, but it shouldn't be making black smoke if it was done properly.
Come back and tell us what your mechanic wants to do.