How many Volts to trigger an injector ?

[E Sully]

The DME's occasionaly have to be repaired, mine was bad when I bought it, but seem to survive for the most part. I don't want to hijack, should return thread to Prebordao.

[ChrisBennet]

I open injectors briefly for testing using a 9v - I just tap the battery terminals and listen for the click. I have injectors get stuck after that sit when they come back from being professionally cleaned a time or two so I always test them before I put them in a motor.

Here are some data points.

Injectors use a solenoid i.e. a coil of wire around some metal that sucks the metal into the coil when current is applied to the coil.

A coil of wire (aka "inductor") has very little resistance except for the brief moment when current is first applied - after that it becomes a short circuit pretty much.

A short circuit get pretty hot.

In a peak hold injector, the current is reduced after the initial surge of current but not so much that the injector closes.

[timmy2]

Originally Posted by HawgRyder

How about putting a resistor in series with the injector?
It would limit the current..but not the voltage.
And...arrange for a pulsed supply to open them.
Bob

Sounds like an easy project to build a variable voltage pulse circuit with a 555 timer, a potentiometer and a few resistors and capacitors. May have to dig out the old 555 timer projects book I saw somewhere recently.

In high school (when IC's were new ) we built led flashers with 555 timers, just have to remember how to do the RC time constant math again...

How many pulses per minute would be adequate?

[theiceman]

the reason for the magic smoke with a car battery is because there is no current limiting circuitry. as pointed out 12 v on a 2 ohm resistance injector is a 6 amp fry job.

thats why the 9 v is way safer or even an old cube converter from some other device. i have tonnes of those in boxes from old electronic equipment.

[prebordao]

Thanks for the tips. I'll start low.

[E Sully]

It seems you started this thread to look into alternative injectors. I don't know how it turned into a good voltage to hold open the injectors for cleaning and such, as that is a different matter. All the 9v posts are well and good for their intended purpose, but the system is still a 12v input with a duty cycle that works at that voltage.
To get it onto the alternative injector subject again I will post some links to that topic.
Alternative Fuel Injectors
Buick Fuel Injectors in 3.2
Another Buick Fuel Injector story.

[prebordao]

Wow, great info on those threads.
In fact i'm looking at replacing the WUR with an electronic alternative. I'll keep you posted.

[E Sully]

I'm confused now. From motronic injectors to 1974S with cis. The recommended replacement for the original wur is 0 438 140 129. I was lucky enough to find a used one cheap in the Used Parts Forum.
Check for PM.

[Tippy]

Not sure if anyone has mentioned but it's very easy to burn up the coil inside an injector by hooking up directly to a battery source.

They are triggered in the milliseconds. Even tapping wire to a battery and releasing fast as you can is MANY times longer than they are supposed to be triggered causing overheating.

I've read tons of people burning up injectors on the Internet doing a DIY reverse flow cleaning job.

[prebordao]

I'm confused now. From motronic injectors to 1974S with cis. The recommended replacement for the original wur is 0 438 140 129. I was lucky enough to find a used one cheap in the Used Parts Forum.

Check for PM.

It's CIS but i'm looking to replace the wur with a home made electronic one involving an injector. My 001 is working perfectly. It's all in the interests of science.