DIY Injector cleaning PCM Free tip!!!

perfectchoicemotorsports · 10-10-2001, 09:41 AM

1. Pull injectors out of car
2. cut a length of fuel hose aprox 12" long
3. hose clamp one end to the injector.
4. hold hose straight up and fill with carb cleaner.
5. hose clamp other end to air compressor blow gun.
6. regulate air compressor to 45-60 psi
7. take a battery charger that has a 2 amp charger setting.
8. turn on the air and touch the battery charger + and - across the 2 electrical terminals of the injector. ON AND OFF!!!!!!

"DO NOT HOLD THE BATTERY CHARGER TO THE TERMINALS PULSE THE INJECTOR JUST LIKE IT WOULD BE DONE IF IT WERE IN THE CAR"

refill the hose as many times as you like.

If you are real anal!!

You can build your own injector manifold to hold all 4 of your injectors using hose and brass T fittings from Lowes or home depot. Snag a 4 cylinder wiring harness from a salvage yard and test the spray pattern of your injectors, by visually comparing one injector to the other.

And if you are Really Really ANAL!!!

You can measure the amount of carb cleaner you put into the manifold and put 4 beekers to catch the carb cleaner as it passes through the injectors and measure the difference of each injector. YOU HAVE JUST NOW BALANCED YOUR INJECTORS OR YOU KNOW IF THEY ARE OR ARE NOT BALANCED.

Kevin
PCM Injection

Hope this can help someone!!

Ehab · 10-10-2001, 11:39 AM

Cool, you should submit this to the 944 garage to be listed under the shop manual ..
You get to have your name there ...
E

ribs · ribs's Garage

This will definitely be an addition to my list of things to do once I tear my car to pieces in the near future.

------------------
ribs, 86' 951
My gallery

Richard Foy · 10-10-2001, 01:32 PM

Sounds great.
Have you used the injectors after this cleaning?
Could you see them clear out as it was cleaning? I just spent half a morning on the phone, and driving around town, trying to find a shop that would do, just as you are describing.
My only concern would be electrically damaging the injectors. Where these injectors for 951 or 944na? Mine only have 2.5 ohms or so, and when in the car, they are only turned on for a limited amount of time...so I would be afraid it might easily blow them if left on for very many milliseconds.

perfectchoicemotorsports · 10-10-2001, 04:41 PM

Follow up answers to the questions:

1. It will not hurt the injectors, if you pulse it on and off quickly.
2. Yes we have used them after this procedure. As a matter of fact we have used 42 lbs injectors on a Turbo Rabbit, that had been sitting in a junk yard in a throttle body for years.
3. Injector size, impedance, manufacturer does not matter.
4. You will be able to tell a clog one from one that is not clogged, just how cloged only a set of beekers will tell you.

P.S. Probally just pissed every injector cleaning business off!!!!
At their defense: They do spend $2.49 per injector for new orings and hats!!

Kevin
PCM Injection

Richard Foy · 10-10-2001, 06:33 PM

You are right, it works. It's not the safest thing I've ever done, but it does make the injector squirt, and it was a lot of fun, seeing the unsee-able. Reminds me of a cow I used to milk ......

I expected the spray pattern to exit at a pretty wide angle, but they didn't, except when the cleaner in the line was nearly gone and air was mixing with cleaner...it was more of a mist and a wider angle. All 4 injectors had a spray was only about 2/3s the diameter of the injector cap diameter at a point 4 inches out the injector, and stayed that way.

For fun, I did like I'd done with the cow a long time ago, and let it squirt acrossed the garage...it went about 6-8 feet before it arched back to the floor...in a fairly focused pattern...again much like the cow …

Is that what I should expect? ...or should it be more like the pattern when is was partly air..???
Suggestions:
For anyone trying this, be very careful. I used two long Radio Shack alligator clips between the battery charger and the injector. An I scratched the positive connector at the charger, which was setting as far from the injectors (and the cleaner) as I could be, because it sparks each time you fire the injector. Probably should use some kind of momentary switch, or better some transistor firing for 50mil sec or so.

Thanks for sharing this idea with us, it’s a pretty good one, we just need to refine the details a bit

mlue · 10-10-2001, 07:32 PM

One of my friends told me about a system like you've described that the dealers use to clean the injectors while in the cars. I believe he called it Motor vac or something like that. They start by removing the fuse to the fuel pump then crank the engine to depressurize the system. They disconnect the fuel line from the rail and a container with a 50:50 mixture of gas and a cleaner is connected to the fuel rail. The container is attached to a compressor to supply the fuel pressure. The car is started and allowed to idle until the mixture runs out. They reconnect the fuel rail and fuel line and replace the fuse.

Thanks for sharing your knowledge with us, you setup is similar to what the dealers use but may yield better results as we get a chance to replace the o-rings and hats on the injectors.

Is carburator cleaner the best to use or could we use the stuff that the dealers use? I believe Ford sells theirs for under $10.

Mark
'86 944NA

perfectchoicemotorsports · 10-10-2001, 09:22 PM

Mark we just use the carb cleaner B-12 Chemtool. Its economical and easy to find at any parts store.

Good point! It is flammable so caution should be used. I always leave out the most important stuff.

Kevin
PCM Injection

perfectchoicemotorsports · 10-10-2001, 09:26 PM

One other thing you can turn down the pressure to 15-20 psi and back flush the filter in the injector. Just by hose clamping the discharge end of the injector.

Kevin

PCM Injection

Tom Swift · 10-11-2001, 09:28 AM

On my 924 I just get a hippie to buy me a gallon of Tolulene and fill the tank to one half (6.3 gals) and run it hard till the gas is used up. We had dinner on the valves they were so clean.....