Hello everyone. First, a little of my history, for the last several years I have been working on how to properly tune a diesel engine for alternative fuels and blends of these fuels.......the principals of "super tuning" are the same for #2 diesel as any other fuel. I have a pop off tester and a pulse timing light, but I rely on the glow plugs to tell me the final results...............

As I have just purchased a 1989 Super Duty 7.3 IDI Rollback that I will be using this method of "super tuning" on, I thought maybe there would be some interest from others on how to do this and we all could learn something from the experience..............(it smokes like hell now and the fuel mileage is horrible.............that will soon change )

At this point the only tool required is a multimeter that will display a milli volt scale..................

If there is interest, please chim in and we will get started...........

regards,
crossbones

 

Please note that I am a newbie and do not have email privileges yet, so I can not return emails to answer any questions at this time................I will post answers on the forum.................

So far, it has been brought up about different meters and different brand glow plugs giving different results.............this is possible..............but not a real problem............we are more so looking for a relationship of Your readings and will most likely given enough input from members we will develop a "window" of the readings.......................

If you want to get started collecting information: connect the positive lead of the multimeter to the glow plug system (at a single glow plug or at the relay) and the negative to the Block ................after the engine is hot (no voltage going to the glow plugs)....extend the leads so that you can put the meter inside the cab so you can see them as you drive.............turn the meter to the millivolt scale and at this point just make mental notes to the readings and your driving conditions such as on level ground, a hill, loaded or not loaded, what they are at idle......................now I can tell you what you will see, but I much prefer for you to tell me what relationships you see.......................

regards,
crossbones

 

I will see if I can get to this in the next couple of days, may have to wait for the weekend. I think I will connect to the glow plugs at the relay, as this would give an average of all of them, as they are all in parallel. I figure the average is better for what you are trying to do...

 

If I remember my electrical correctly what you are doing is using the glow plug as a thermocouple by measuring the amount of millivolts coming from the glow plug as temperature increases. Correct me if I'm wrong but this one has my interest as well. I may end up installing a wire harness permanently into the cab so I can just plug it into my meter.

 

Brimmstone, you are exactly correct on the thermocouple effect (Seebeck effect)..........what you will not believe until you try it,,,,,,is just how accurate it is

crossbones

 

what are you going to do with this info? my multimeter is close at hand.

 

xjvince, at this point, the actual readings that you get is not the issue, I want people to see the relationship of how the readings change under real driving conditions........I want people to see just how sensitive the readings are for Their engine and Their driving conditions.........I want people to "think" why the readings change with going up a grade or down a grade, ambient temperature, pulling a load or empty,even changing the air pressure in the tires.............we are going to use the most powerful computer in the world to Super Tune Your Engine............your brain.......to instantly look at the readings and understand all of the conditions that are effecting the way Your engine is performing................

The biggest thing at this point, is seeing "real live information" and as you start applying logical thought to what you "see".....you will begin to understand the "secrets of Super tuning a Diesel engine".............they are so simple, that you will only believe them if you "see" them with your glow plug readings............but we have to "program the most powerful computer in the world first"
crossbones

 

Hello. As people start collecting information on their readings, please post them........try to include as many "conditions" as you can think of.........I hope you will include "why" you think the readings are changing...........

crossbones

 

I find this whole concept facinating as well. A couple of questions though. You can't just connect this to a glow plug that is still connected to the harness, can you? Wouldn't all the wiring of the harness - which is connected to the relay contacts and 7 other glow plugs - have a major effect on your readings?

I haven't got time to actually give this a try right now - too busy trying to get my truck, camper, and Jeep ready for a week-long camping trip to Moab Utah April 1st - 8th. However, I would like to make a prediction on what I would expect to see. Since you're essentially installing an in-cylinder thermocouple, I would expect it to track the readings you would get from a properly installed pyrometer thermocouple pretty closely.

In other words, when your pyrometer shows your EGTs going up, the readings on the meter attached to the glowplug should also be going up - though probably a bit sooner and faster since the in-cylinder thermocouple will read the conditions at the point of combustion instead of at the point of exhaust.

My big question is what do you DO in response to the data? Say your cylinder/exhaust gas temps are getting too high under load, but not while lightly loaded, about all you can do is adjust the IP fuel delivery screw and/or IP timing, right? The problem is that they are both STATIC settings that you can't adjust dynamically. You can only "super-tune" them to the ideal setting for one condition or the other (high load or light load). I suppose you could use the data to fiddle with those two adjustments to get the best compromise performance between the two, but since you can't make either one of them adjust dynamically in response to the conditions, you can't "super-tune" it for BOTH conditions. The perfect settings of these parameters for one condition isn't the same as it is for the other, so the best you can do is a compromise.

Or is there some other adjustable parameter - or something else - that I'm missing here?

 

Well I'm sure glad to see that I'm not the only one of us "old farts" who doesn't quite see where this is going. Given your knowledge level and experience, Malcom, the fact that you don't quite "get" it makes me feel a little better about my state of cluelessness...

 

Looks like we are all in the same boat together .

I have read through this thread several times and I'm a bit lost at where this data compilation is going. I mean, if you are using the glow plug system as a sort of thermocouple in each cylinder, then wouldn't it have to do more with heat than timing per say? Sure a timing adjustment would alter the heat reading but all you are doing is putting the glow plug system to work as a cheap pyrometer...How could you gauge adjustments in each variation if there are so many different variables? I'm not scrutinizing your thoughts as to this matter, I would just like to know where this is headed and how these readings will in all time super tune our engines...Personally, I would love to get the timing adjusted (planning to turbocharge) but all the stories about how hard it can be to get it right on the money has caused me to shy away from the thought. Even local shops can't do it right just makes it seem out of reach. Although, If this process should prevail, I would be more than willing to try doing this tune...

 

Hello. The average person and most shops does not have the equipment that I have for injectors and setting the timing on a diesel...............Even if they do have the equipment, ask them what your timing should be at 2500,3000, 3600 or any other rpm besides the factory speck which is for one rpm only................and the proper timing changes through out the rpm range.........I am trying to give everyone a simple tool (a multimeter) that you not only can tell things about the engine dynamically at any rpm, but many more things, such as which glow plug is bad or going bad, which cylinder has a injector problem (with out cracking a line).....................there are several more things that I can tell with the readings and would only confuse people at this point...................

What we are measuring is the final results from many things with a representative scale of temperature inside the cylinder...................so if you change one thing at the time, you now have a scale to compare if the change was a "good or bad " change under real driving conditions..................

all of these things and more change the temperature in the cylinder.............
injector timing.........(advancing the timing decreases the temperature until you have auto ignition before TDC)
injector pop settings ( weak pop off increases the time the injector is open and increases the amount of fuel at the wrong time)
leaking injectors (increases temperature)
water jacket temperature........(until the block is heat soaked, increased cylinder temperature)
ambient air temperature (real cold intake air increases cylinder temperature)

Increased cylinder temperature is a sign of wasted fuel and there is no power gain with wasted fuel..............the big Secret is turning the heat into power and efficiency of fuel burn.................not what you have been lead to believe, is it........................

Now, tjc has reported a Increased reading to 5 millivolt going up a hill.................do you usually use more or less fuel going up grades??????........now being fair to tjc.....that is a fair reading, but it can be improved................What was the reading at idle after the engine was hot.......what is your fuel mileage...........do you consider the engine to run ok, great or excellent............

Just as a comparison.............

there is no telling how many miles is on my truck (its a 89 Super Duty rollback)...as I stated earlier it smokes like hell in the mornings and the fuel mileage is 10 MPG unloaded.....at this point the lowest reading I have had is about 7 millivolts on level ground at 55 MPH with a high of about 14 millivolts on some small grades and this is with a brand new set of Beru glow plugs installed.............now I cheated a little and have check the injector timing and its set at 1° BTDC at 2000 RPM's (but, I did not change it simply because I would have to set it again when I clean and set up the injectors).........now I can also tell by the color of the smoke in the mornings that the injectors are dripping or leaking down over night..........if they leak at night, they are leaking when the engine is running.................

Dave7.3........it does not matter if its N/A, turbo or super charged..........same tool and the same principle used.............................

crossbones

 

Power stroke rattle with advance on, no rattle with advance off, optimum timing IMO.
Fuel screw, limited by EGT when pulling a load! Pop test of injectors is recommended every 60K miles, if not in limits replace, injectors new or rebuilt inexpensive in the big picture, what else is there, Other than that you can't independantly adjust each cyclinder, so WTF, Get er done RAM air and BIGGER exhaust, maybe a TURBO if you want to blow up your motor once in a while and haul 17000lbs down the road. I really like the KISS prinicple, so get to the point with this post about what PRACTICAL point you are getting to. Give it up- most of us aren't as stupid as your lack of revealling the ultimate outcome of this may bring! PS I have a several very good mulitimeters and a Pyrometer, and I know how to use all the scales!

 

Kevin...............I can adjust the temperature in each cylinder .....several ways...........please do not call what you are not informed about stupid............this is not new......it has been used by very professional diesel people for at least 80 years.......even the glow plug manufactures and diesel engine manufactures are using a version of this method on the engines coming in the future.................

If you can not see the Practical point of this, then Do Not Use It.........
And for me, I can spend my time doing something else.............

crossbones

 

Crossbones2 - I do understand what your talking about- In simple terms-short and sweet- the voltage drop or resistance of each glow plug varies with temperature as measured in mililvolts, you can adjust each cyclinder somewhat by varing the pop pressure- higher means closer to TDC (advanced) lower means earlier fuel release or (retarded) timing. So in essence if you tell us the big secret about how this works we can fine tune each cyclinder if we have all the right equipment and enough of a variety of shims to adjust each injector. In my tikering I found that .002 shim changes the pop pressure by 100 psi, so when people get on here an tell me that each injector should be within 5psi I tend to think they are full of crap- how can you adjust that fine when .002 changes things by 100 lbs- were talking practical real world here- not theorectical- but I am willing to conceed that if there is a better way thats do-able, I'm willing to hear it out, but lets here it. What is pissing me off here is that this forum is all about sharing helpful information. This is an 80 year old way of doing things then get typing and spell it out. By the way the factory timing using the pulse method, which is completely different than the luminocity probe method calls for 8.5 BTC @ 2000 RPM, if yours is set with a pulse method @ 1 @ 2000 your way retarded, and with leaky injectors its no wonder your truck smokes like hell. Get rebuilt injectors installed, (cleaning is a waist of time if you know yours already leak- bein there done that), get your timing set up, then do all the fancy voltage measurment stuff and let us know what you find out. Everyone here- is here because we like these trucks, working on them, and sharing information. Give us something practical we can use. Sorry if I come across as a little PO'd, nothing pesronal but you seem like you have a big secrert you won't divulge unless we beg for it. So how about it lets move forward from here.