89 6.2 Diesel is geared to smoke point, need smoke detector :)

[rmay635703]

I need a simple way to monitor my A/F or simpler whether I am "smoking" on my 6.2 diesel. I believe I need to turn down the ip a bit (never would smoke before upgrade) but even with that turning 500-1200rpms at times will mean I am riding the edge for smoke. I am geared so the motor outputs just enough to keep it moving on the flat, no more no less this drives like an old 3 on the tree except I have two overdrives after that.

I am wondering what the cheapest way to monitor this would be?

I am thinking one of those $9.99 see in the dark security camera jobbers aimed at the exhaust might work but I haven't seen any good deals in over a year.

Otherwise I may need to install a wideband to keep the A/F around 16:1 or higher.

Its way too easy to give it too much fuel so I need something to get me into proper throttle and shifting points. But the power boost going to MT has been quite amazing.

And I have sucessfully driven 600rpm @ 30mph without smoke, just a fethers touch is all, doesn't help the throttle is sloppy and hard to accurately control though.

Any ideas?

[JohnAh]

Sorry, I´m not sure I hava a clever solution but I´m interested in diesels and like to learn how they work in detail.

If I understand it right, you are running on very low rpm to minimise losses in the engine. To get maximum torque the IP have to be set as close as possible to the smoking point? Is there a non-linear function between injected ammount of fuel for each piston stroke and the engine speed? With a turbo I can immagine that to be the case but is it also valid for a suction engine?

I read somewhere that many average diesels may have around 50% more air than is needed for smokeless combustion. If the IP can be made to increase the ammount of fuel the power will increase up to the smoking point.

I guess a turbo conversion of a suction diesel can easily result in heavy smoking at lowrpm if the IP can´t be made to compensate for the lack of boost pressure.

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Concerning the problem to see when the engine begins to smoke, how about an optic system like infrared smoke-alarms? I´m not sure how they work but I guess they have an LED and a photo-sensor in the open air, a identical setup in a closed chamber as reference and a bridge-circuit sencing the slightest difference.

My idea here is to arrange the LED and photodiode with lenses in such a way that the distance between them can be more at least a few inches. The reference should be placed in exactly the same way close to the meassuring device to get the same temperature. There must be total darkness offcourse, and a clever solution to keep soot away from the surface of the optical components. Perhaps injection of a clean airstream around the sensor and LED can be arranged? The speed of the exhaust gases may take care of this air injection.

[rmay635703]

My truck being pollution controlled (C-code) and being a NON-turbo diesel was tuned from the factory (with a regular transmission and RPMs) to never smoke significantly. This meant loosing about 20% of the max power but also better FE and much better emissions.

However because I have opened the intake and now can take off at much lower than normal RPMs the IP does not quite compensate correctly and allows it to smoke which a non-turbo diesel should not do if you want the best MPGs.
The manual IP is capable of keeping proper tune over the entire operating range but near the extremes it is not very accurate which is why now that I can drive in the extremes it lets a little smoke out when it shouldn't.

Also as a driver my throttle is sloppy and chunky (hard to control) The throttle was always that way but after the transplant has become much more so. This makes it hard for me to add a small amount of throttle without racing, not sure how to fix this.

In my case I need an aide so I can learn how to drive the truck all over again so I keep it burning clean and efficient. I am tempted to alter the IP pressure but then my top end will suffer significantly (I can't make it smoke above 1500rpms) so it is a matter of me becoming aware of what the truck can and can't do efficiently, my best solution is to downshift but the trouble is that the motor is very efficient (surprizingly so over a large RPM band) but only right near the point that it smokes which is hard to find.

Cheers
Ryan

[lowglider]

Why don`t you just turn down the fueling a little and then you can floor it without worrying about smoking on WOT?
Just try it, if it doesn`t work you can go always go back to more fuel. On a diesel you can`t screw up the engine with wrong fueling like you can on a gasser.

Are you running it on biodiesel or pure dinosaur juice? The bioD tends to smoke less.

[2000mc]

put a throttle cable on it?
i had a '91 with over 300k, took both ends loose and moved it around, wasnt perfect, but not too bad either. didnt really think it was my problem, but i think the cable was only like $15, so i figured i'd give it a shot. new cable made a huge difference.

[thomason2wheels]

What is the ip reference referring to. I am diesel ignorant but trying to learn.

[rmay635703]

Originally Posted by thomason2wheels

What is the ip reference referring to. I am diesel ignorant but trying to learn.

The injection pump if I tear apart part of the top end has a tiny hole that if aligned perfectly allows me to turn a screw that controls the IP pressure which refers to how much fuel it can give. It also has static timing which I should probably touch because of how I intend to use the truck.

[Phantom]

IP= Injection Pump (fuel pump)

Are you able to adjust the injection timing on that truck? If so increase the timing a degree or two, switching to Bio-D chemically increases the timing I do not know the specifics on that but it has been discussed on TDIclub. So if you have access to Bio give it a try up to maybe 20% and see if it changes the smoke.

[thomason2wheels]

Originally Posted by rmay635703

The injection pump if I tear apart part of the top end has a tiny hole that if aligned perfectly allows me to turn a screw that controls the IP pressure which refers to how much fuel it can give. It also has static timing which I should probably touch because of how I intend to use the truck.

Injection pump....should have figured that myself but was probably brain dead due to the hour.

[stillsearching]

Off topic but what kind of mileage are you getting by lugging the hell out of the engine like this? And what are you supposed to be getting stock?

What gearing change did you did to make it run like this?