Home Made Fuel Injector Cleaning Machine

[ollopa]

Naw, it's really quite basic stuff to an electronics guy. Double entry accounting and ERP are a mystery to me, but I'm sure your typical MBA could talk my ear off all day in business jargon.

I don't think Radio Shack still has repair technicians. None of the employees at the last 5 Radio Shacks I visited knew the difference between a resistor and a diode. They're just pushy cell phone salespeople now. In typical form, one girl insisted on helping me find a part and then asked me "how do you spell 'resistor?'" I doubt any of the people there are going to be able to help you. They probably couldn't even point you to the right books that would help you.

But I think Hoys can fill in the gaps I left. Try an IRF510 and 1N4001 for the driver. Heat sink the IRF510 and you can probably drive 4 injectors off the same MOSFET.

What I'm putting together has a continuous mode where it's free-running and you can turn a knob to control the frequency. I did away with variable duty-cycle, though, and fixed it at 50%. I've yet to see any utility in varying the duty-cycle for this application. It's the pulse-width that matters. Anyway, it can be reconfigured in software if we later discover a need for it.

Still waiting for my cylinders to come in. I never got a tracking number or shipping confirmation and my inquiry to the company has gone unanswered. Assuming they were shipped, I'm expecting arrival some time this week. I just painted some rusty headers. I don't have a sandblaster so I used electrolysis to clean the rust. I'd recommend giving that method a try to anyone with rusted parts. Check it out over here: http://www.instructables.com/id/Elec...val-aka-Magic/ I got the best results with an overnight soak in the bucket. The rust mostly flakes off. What's left turns to a soft black residue that can be rubbed off with soapy water and a scotch brite pad. Kinda fits with our theme of mixing electricity and chemistry to clean car parts

What I wouldn't give for a 48-hour day or the ability to survive comfortably on only 2 hours sleep....

[60dgrzbelow0]

Jesus Palomino! What I would not give to possess a clone of just one lobe from your brain that understands all of this. This is pretty clever detective work, Rick. Okay... so now that you have broken down all of the performance values into discreet circuits... is this anything like you intend to eventually build? If not... would the average radio Shack repair technician be able to hold the hand of an idiot like me and show us how to make one that works from off-the shelf parts? This is fairly exciting stuff to me...even though I don't really understand any of it from looking at your circuit images. I just can't WAIT to see what comes of this!

[ollopa]

After reading the tech sheets for the LMD 18400, his hand written diagrams, and pictures he took, I'm pretty sure I know what he is doing with the second controller board.

You can see in the pictures that he brings all four inputs to the driver out to a screw terminal but only has the one white wire connected. The other screw terminals must be jumpered to the single input from the 555+LM393 board. Not much of anything going on with the driver board. It's plug and play.

The way he adds a comparator to the 555 in order to control pulse-width is interesting. He has a circuit that's basically like this one to set the frequency:


But he takes the output from the top of the capacitor at pin 2 of the 555 instead of the square wave at pin 3. He calls the waveform a sawtooth but it actually resembles a distorted triangle wave (exponential rise and exponential fall whereas a sawtooth would have a linear rise and an abrupt vertical drop). This he feeds into one input of a comparator in the LM393. The other input would be connected to the wiper of a potentiometer that just acts as a voltage divider and sets the pulse-width. Like this:


The output of that comparator then goes to all four inputs of the LMD18400. But for about half as much as that part costs, you could duplicate the following circuit for each injector and tie the inputs in parallel. Use a 12V supply to power the comparator so its outputs are high enough to fully turn on the MOSFETs:


I'd suggest a 10 to 100 Ohm resistor between each MOSFET gate and comparator output, though, to reduce parasitic oscillations. See how each parallel MOSFET is connected here (just look at the MOSFETs and ignore the left and right ends of the circuit):


There's a pulldown to ground to ensure they aren't turned on by static electricity and to discharge the gate capacitance so they don't get stuck on, and then each one is driven through a 10 Ohm resistor.

Combine all of these circuits and calculate the potentiometer and capacitor values for the frequency range you want for the 555.

[HOYS]

After reading the tech sheets for the LMD 18400, his hand written diagrams, and pictures he took, I'm pretty sure I know what he is doing with the second controller board.

[60dgrzbelow0]

In lieu of using glass or Pyrex... these are identical to the ones I'm using on "The FrankInjector Machine" for Flow Balance Tests and are 50ml graduated polypropylene cylinders...

http://cgi.ebay.com/LOT-24-MEASURING...item518d733901

Those EFI connectors are the lowest priced ones I've seen yet... Great Find!

[ollopa]

The 555 and all its imitations have been around forever. Circuit cookbooks and the Internet are littered with example schematics that you could use. It's an analog IC that relies on an RC time constant for timing, so it's not very accurate but it would get the job done for simple cleaning. The 555 datasheet from many manufacturers has example circuits for creating saw, triangle, and square waves as well as the equations to calculate duty cycle and frequency. It's a piece of cake to make a square wave generator with variable frequency and duty cycle and use that as input to the power electronics that drive the injectors. You can not drive the injectors directly from the 555, though.

The guy linked previously is using an LMD18400 quad high-side driver to drive the injectors. It's a bit expensive and hard to source. Digikey currently has some for $12.25. It drives 4 outputs. You could make the same thing for a lot cheaper with MOSFETs (minus the digital feedback which he isn't using anyway).

He is surely driving them simultaneously and not in any kind of sequence since his circuit has only 1 output. Google "555 pwm motor speed controller" and there are several circuits you could use to start with. Find a circuit with both a transistor output and a free-wheeling diode (reverse-biased diode across the motor/injector/relay/etc.). It's more useful to vary frequency than duty cycle. A fixed duty cycle of 50% would work great. Fuel delivery isn't metered by duty-cycle, it's metered by pulse-width. Duty cycle calculations are useful for determining if your injectors are undersized for a particular application.

What I'm building is a lot more precise (and repeatable) and drives 8 injectors. My goal is not only to see if the fluid levels are even but to make flow measurements in order to characterize injectors before/after and under different simulated conditions.

I just got back from a short trip and now I'm back to juggling my projects. I've been waiting for my graduated cylinders to arrive so I can measure their height and finish building my machine. The cheapest ones I found are Here and Here I also just received some injector connectors from This Guy for about $2 each. They have rubber seals and a metal spring clip. The quality is nothing to rave about but they were the cheapest I could find and I have no complaints.

[60dgrzbelow0]

This is exactly what I need for a wet flow bench and injector tester.

Ben...

When I stumbled on to this site looking for the electronic "How-To" for this project... it occurred to me that you...and John (Forced Firebird) as well as CNCGuy might want to look this place over.... assuming of course that all of you are not already members there... It looks like a very interesting place for a machinist to enjoy.

http://www.practicalmachinist.com/vb...e-brew-158732/

[HOYS]

Okay...so far...so good on the basic capabilities of the "555" Chip as a switching tool... but in looking at "MARKS" "MARKSInjector"... it appears that he has three major segments to his controller hardware:

(1) A Power Supply that looks like it comes out of something related to aviation/avionics.
(2) The breadboard that has the variability adjuster on it.
(3) Another breadboard that fires the EFIs.

I might be wrong here...but when watching the video(s) of the machine in action... it appears that he is firing all four injectors Ford Escort EFIs in an oscillating pattern, rather than firing all four EFIs at once... either very rapidly or slowly as a group. If that is the case... wouldn't it place less demands on the need for a big and bulky power supply since only one injector at a time is receiving the power surges and amperage demands for the varied durations?

I can almost guarantee that for this phase of the project... I'm useless in trying to climb whatever learning curve is necessary, then grab-bag the required parts and pieces to build something workable that can be plugged into an injector harness. But if somebody else can build one and show me exactly what to do... then I would be able to "Monkey-See Monkey Do" one together on my own.

The power supply should be easy, rig a cheap computer power supply to turn on when you want, and take a 12v line into your circuit, the first controller we have discussed and should be fine. I'm trying to figure out how he drives the injectors from the other board, ill have to do more reading. I believe the injectors fire all at once.

[SappySE107]

This is exactly what I need for a wet flow bench and injector tester.

[60dgrzbelow0]

Okay...so far...so good on the basic capabilities of the "555" Chip as a switching tool... but in looking at "MARKS" "MARKSInjector"... it appears that he has three major segments to his controller hardware:

(1) A Power Supply that looks like it comes out of something related to aviation/avionics.
(2) The breadboard that has the variability adjuster on it.
(3) Another breadboard that fires the EFIs.

I might be wrong here...but when watching the video(s) of the machine in action... it appears that he is firing all four Ford Escort EFIs in an oscillating pattern, rather than firing all four EFIs at once... either very rapidly or slowly as a group. If that is the case... wouldn't it place less demands on the need for a big and bulky power supply since only one injector at a time is receiving the power surges and amperage demands for the varied durations?

I can almost guarantee that for this phase of the project... I'm useless in trying to climb whatever learning curve is necessary, then grab-bag the required parts and pieces to build something workable that can be plugged into an injector harness. But if somebody else can build one and show me exactly what to do... then I would be able to "Monkey-See Monkey Do" one together on my own.

[HOYS]

"Monostable mode: in this mode, the 555 functions as a "one-shot". Applications include timers, missing pulse detection, bouncefree switches, touch switches, frequency divider, capacitance measurement, pulse-width modulation (PWM) etc

Astable - free running mode: the 555 can operate as an oscillator. Uses include LED and lamp flashers, pulse generation, logic clocks, tone generation, security alarms, pulse position modulation, etc."

seems it can have multiple uses in auto environments.....

Shouldn't have to go that deep into the IC...just have to make the circuit...if you must know it would be running in astable mode as an oscillator...

[robertisaar]

"Monostable mode: in this mode, the 555 functions as a "one-shot". Applications include timers, missing pulse detection, bouncefree switches, touch switches, frequency divider, capacitance measurement, pulse-width modulation (PWM) etc

Astable - free running mode: the 555 can operate as an oscillator. Uses include LED and lamp flashers, pulse generation, logic clocks, tone generation, security alarms, pulse position modulation, etc."

seems it can have multiple uses in auto environments.....

[HOYS]

A few things before my battery dies:

555 is a very common type of IC. A good read:

http://en.wikipedia.org/wiki/Integrated_circuit

http://en.wikipedia.org/wiki/555_timer_IC

Yes, the 555 has its own wikipedia page. Essentially a 555 IC acts as a variable timer to control a circuit. In the videos you posted of the epic injector cleaner, it functions as the "RPM" knob. It regulates the power going to the solenoids in the fuel injectors depending on what you turn the dial to. It sends the little blips of energy faster or slower depending on how you turn the knob.

What other questions? I'd be willing to spend a few bucks and solder this together for you if you needed it.

[60dgrzbelow0]

I will have to read this thread for more details on what your trying to get the circuit to do, but thay circuit is very easy to make, I'm pretty sure radioshack stocks 555 ics, but I'm not sure. PM me if you need electronics help.

Welcome to the thread, HOYS... and thanks for the offer of help. This Epic Post is peppered throughout with many suggestions on how the EFI controller might be made...but no plans have solidified to date. The problem which I have been facing all along since posing the "Q" on this subject is that I may know my way around a workbench in many odd and sundry ways... but when it comes to anything electronic that involves anything more than plugging things in... I wouldn't know a Bull's Ass ...from a Bass Fiddle... So the numbers "555" do not register a solution in my electronically dyslexic lexicon. The help I need is for someone...anyone with enough understanding of these things to just build a controller similar to the one shown in the recent videos done by "MARKS" and then take enough close up images of it that somebody like me can get the parts you might suggest from "The Shack" or as Robert suggested...another vendor...and plug the necessary parts into a breadboard...solder them in well and truly...hook it up to "The FrankInjector Machine" and just turn it on... and watch the magic happen...

[robertisaar]

radioshack does indeed have 555s.

http://www.radioshack.com/product/in...ductId=2062595

http://www.radioshack.com/product/in...ductId=2062597

i grab electronics stuff in quantities that would be bad for radioshack though.....

http://www.taydaelectronics.com/servlet/the-92/555-DIP8-HAM-IC/Detail

good company, if you can wait on shipping.