DIY ultrasonic cleaning of injectors

[HJ2]

Dear colleagues,

After replacing almost every sensor on my car, the CO is still a little to high.
Now i want to ultrasonic clean my injectors to see if this brings anything.

For a good clean i need to actuate them during cleaning. Does anyone know at what voltage the injectors open? (5 or 12 volt)?
When i know, i can make some electronics to steer them during cleaning.
Also, what is the nominal operating pressure for the injectors?

My plan is to build a rig that holds 1 injector in the ultrasonic cleaner i have and have a fluid reservoir (with cleaning fluid) connected to the injector and use compressed air to get the right pressure on the fluid.
With the setup i can also make the spray pattern visible to compare the injectors.


Does anyone on LEC has done this before?
All tips are welcome!

[GeoffSmith]

12V nominal with pulse width ~10µs to 20ms from various ES runs.

PL2-320 are equivalent according to the WIki:

http://www.rceng.com/Peak-Hold-Injector ... -P6C5.aspx

http://www.rceng.com/Fuel-Injector-Cleaning-P43C0.aspx

Where do I send mine?

[HJ2]

Thanks!

I don't think that puls width is interesting for cleaning purposes as long as they open and close.
So putting 12V directly from a battery intermittent on the plug is the way forward?

[GeoffSmith]

I agree but you should maybe go for a reasonably high frequency as they dissipate over 50W at 12V.

[HJ2]

I'll take that in account!
BTW: What is the nominal fuel pressure at the fuel rail?

Cheers

[Brit-Car-Nut]

Please consider this carefully as you could damage the injector or yourself!

Our injectors are the Peak and Hold type. The peak current is only applied for a few milliseconds to snap the pindle open before the lower current is used to hold the pindle open.

I considered building an apparatus but since RC Injectors will clean, test and replace the filter and o-rings for $25.00, I sent mine out to them.

The easiest way to control the current is to use an old-fashion 1157 tail light bulb (dual element: brakes and tail). Get a PTC fuse that triggers at a reasonably low current. I thought about 70V 1.85A.
If you can wait for China, ebay: http://www.ebay.co.uk/itm/New-5-x-PolyS ... 0959651405?

Wire the low current (tail light) element in series with the injector, your power source and a push button switch. Place the PTC between the low current element and the high current element (brake light).

When you energise the switch, the high current element turns on for a brief time until the PTC turns off, then the low current element takes over.

Model railroad builders use this technique to keep from melting their layout in the event of a dead short across the tracks.

The Injector is designed for around 35PSI as that is what the fuel pressure regulator is maintaining. The injector works at constant pressure with varying open time controlled by the ECM.

I have seen several suggestions of using a syringe as a pressure source. Here is a youtube video of someone doing it: http://www.youtube.com/watch?v=7aT4S1lIBAY

He doesn't worry about the peak and hold since he is using a newer type injector, so you should still limit the current so you don't damage the windings inside.

Remember, there is a filter basket on the inlet side so his reverse cleaning is pushing the dirt and sludge against the screen. He is also clumsy, so cut him some slack.

I would do a few forward cleanings with the basket installed and if the outlet spray looks good, then just go to the next one. If you want to replace the filter, then eBay and RockAuto have them listed.

A friend, from one of the biggest NASCAR teams, said the early GM injectors stick a lot and they just soak them (standing upright) in WD40 to free up stuck ones (mine were either stuck or sluggish). Then they used a doorbell button and 12V battery to open and close the pindle while spraying WD40 through the injector. Again, they are not using peak and hold injectors, so curernt control is important.

Here are a few hints at what materials to look for:

Injector Service Kit (filters and o-rings): http://www.ebay.com/itm/270914433256?ss ... 1438.l2649
Injector Connectors (6): http://www.ebay.com/itm/300544378709?ss ... 1438.l2649
Injector Connector (1): http://www.ebay.com/itm/EV1-Connector-E ... 0835144215?

Anyway, that is what I found when I was deciding if I wanted to clean myself or send them out.

Ultrasonic fluid may not clean the varnish so you might need to use a petrol based cleaner to get them very clean.

Remember, be careful and be conscious that all of the fluids you are considering are flamable and easily ignitable. Skin grafts are painful and take a long time to heal (experience talking).

[HJ2]

Hohly!

A lot of info and very to the point, thanks John!

This is a project i am not going to finish soon, but whenever i have a couple of spare minutes, i will be working on it

[GeoffSmith]

Looks like the GM ECU use the LM1949 which senses and modifies the drive current.

[GeoffSmith]

I knew I had some information archived somewhere.... Megasquirt have a lot of useful information.