Testing the injectors, any tips? Options

[swl]

Well we have the fuel system all back together, we've lubed up the engine, checked the spark and now are ready to attempt to flash her up. The car was running well when it went into the coma 20 years ago so I'm trusting that the timing and dwell are all good. If it doesn't cough immediately the next logical place to look will be the injectors - they could well be suffering from old fuel as well. I've heard advise here about pulling the injectors and checking them by turning over the engine and having them squirt into a jar. By the looks of things you would need to do this two at a time by removing both injectors which would allow the fuel rails to pull up. Sound about right? Any advise to keep me from buggering something up? I have new seals at the ready.

[SLITS]

You are not only checking volume, you are checking the spray pattern as well. If they do not exhibit a fine mist cone spray...they need to be "rebuilt" as the internal passages and pintle are prolly gummed up.

I don't remember if PBander's site has info on the volume of the injector....so many cc's per minute.

Trigger points could be a problem source too. Cleaning an lubing them might help.

4 glass jars would be nice.............

[Oled]

Easy way to check injector action. Hook a long hose onto your fuel rail side of the fuel pressure regulator. Its best to have a gauge on the hose to make sure the pressure is at specification. Make a doohicky to activate the injectors. I used a battery box that held two D cells. Put a "push on" switch in the line.

Get your car outside. To test, get a graduated cylinder. Hook an injector to the end of the hose. Turn on the injector for a known interval and you can figure out the amount of flow through each injector. Look at the spray pattern. If a pintle doe not operate, soak the injector in injector cleaner and it should free itself up

ed

[swl]

Thanks guys. It did not start. No big surprise there but it was worth a shot. We pulled the injectors out and they were just spitting - on drop per fire and just a tiny one at that. We soaked them in injector cleaner for while then tried again. Now none of them are doing anything. One step forward two steps back. I figure one of two things have happened

There was crap in the injector hoses that are now in the injectors themselves causing a complete blockage. gotta wonder about all 4

I've disturbed some brittle wiring and lost connection to the injectors. I had to do some pretty rough pulling over on the passenger side to get around the pressure sensor so the wiring thing is a distinct possiblility.

Question. can you detect the firing pulse for the fuel injector with a multi meter? I have it done on the most sensitive scale (.3V full scale) and I'm not seeing anything. Mind you it could be that I'm not making good contact inside that connector.

Anyone successfully used a meter to check the firing pulse?

[TravisNeff]

Go to a FLAPS and spend 3 bucks on a "noid" light. Attach it to your injector wiring, it lights up showing the pulses as they occur.

Have an air compressor, if so blow the injectors out from the tip, back out the inlet, that will remove the shit in the screen and hopefully out of the pintle. I haven't tried this before, just read it here somehwere, YMMV

[swl]

Noid light sounds useful - I'll see if crappy tire has one in the morning. I was able to blow through the injectors both ways but you need the solenoid activated. Ed I used your setup without fuel pressure to test basic funtionality - thanks. I was surprised that it worked at only 3 volts but it did indeed work.

I've cleaned and tested two of the injectors but still no luck. Tomorrow I'll use Ed's setup with the fuel pump running just to check the injectors one more time and see if we get a nice spray pattern. Then start hunting back the missing signals.

[Chromatech]

swl:

I'm another newbie from Brockville. A friend of mine in Prescott just finished restoring his and has all the Bosch FI manuals and test equipment. He has resurrected a a number of injectors by putting them in a sonicating bath.

If you do a search for freezing14, PM or e-mail him for advice.

good luck and cheers (IMG:http://www.914world.com/bbs2/html/emoticons/beerchug.gif)

Todd

[swl]

QUOTE (Travis Neff @ Sep 10 2005, 12:14 PM)

Go to a FLAPS and spend 3 bucks on a "noid" light.

geeze - crappy tire is willing to order me a 'set' at $70Cdn - sounds like highway robbery if individuals are that cheap south of the border. given that they come in sets is there a spec for one that works with our d-jet?

[McMark]

You should be able to feel the injector fire if you're holding it in your hand. If I were in your situation I'd take them off the car, soak them in some injector cleaner for a few days. Make the D cell push button tester mentioned above (wire them in series so you get 1.5V). Blow air backwards through them while cycling the injector on and off repeatedly with the tester. In the mean time, check to make sure your fuel pump is putting out the correct amount of fuel. And make sure your fuel pressure regulator is working correctly.

Oh, and you can buy and ultrasonic jewlery cleaner, put some injector cleaner in it and let it run for a few days. It'll get even more crap out.

[GWN7]

Here is a good article about having them cleaned......

[swl]

QUOTE (McMark @ Sep 11 2005, 09:27 AM)

You should be able to feel the injector fire if you're holding it in your hand. If I were in your situation I'd take them off the car, soak them in some injector cleaner for a few days. Make the D cell push button tester mentioned above (wire them in series so you get 1.5V). Blow air backwards through them while cycling the injector on and off repeatedly with the tester. In the mean time, check to make sure your fuel pump is putting out the correct amount of fuel. And make sure your fuel pressure regulator is working correctly.It'll get even more crap out.

yep. That's pretty much what we are doing. I'm pretty confident that we will get them cleaned up. I'm just concerned that I'm not getting a firing pulse.

Went out and got a fuel pressure guage to test that that pump that mark found for me is performing up to snub. I'll get that hooked up a little later. I've got the injectors for #3 and 4 soaking now.

Do the injectors have a duty cycle? By that I mean can you do them harm by having them fire for a few seconds at a time to do the blow through?

[JeffBowlsby]

The D-jet injectors need 2.3V as I recall. You might consider sending them to www.cruzinperformance.com for cleaning and even rebuilding if they need it. Its not expensive and I have heard they do great work.

[swl]

Bruce and Jeff,
Thanks for the heads up about Cruzin. Looks like a great service and reasonably priced ($12 per injector). I would probably spend twice that in shipping and border clearance charges but I'll keep it in mind if we strike out. Perhaps there is someone in Toronto/Montreal offering the same service - I'll have to give Google a try.

With respect to voltage. The wiring diagram suggests that the 1.7 runs at full 12V. Tech Tips 700 says the 1.8 uses a ballast resistor to drop the voltage but doesn't say by how much. It makes sense to keep the voltage to a minimum when messing around like this - less heat to dissipate so less chance of doing something dumb to the unit. Ed uses 3v, I've tried 6v (lantern battery - no messing around with 2 cells). In another thread Mark (marksaircoooled) says he uses 9v. They all work but I think Ed's is the safest.

[swl]

woo hoo! Found a guy with a ASNU machine 20 minutes from my office. Like my daddy used to say - if it worth doing it's worth doing right!

Fuel Injector Service Belleville Ontario

[tracks914]

I just took all the injectors out and tested them with a 12V battery. You can just tap the contacts and feel the injector clicking inside.
I had one that wouldn't fire at all but I just kept puttin the power to it a couple dozen times then I came free. It worked in order to get the car started but I quickly realized that it had dried out and one of the seals were now leaking. It was garbage after all.
So I took it apart to see what's inside and here is what I found.

[tracks914]

I bought 2 new injectors and next I followed the right procedure and tested them in the car with 4 test tubes.
It's been running great ever since.

[swl]

Damn Doug - I love dirty pictures of naked parts. I take it that was strictly a one way dissassembly.

By the looks of it the electro magnet just draws back the plunger and away she goes. Spring and fuel pressure closes it when the pulse is done. Pretty simple device.

[swl]

injectors are back all nice and clean. Cost $25cdn and a couple of bucks in Diesel. The service was not nearly as professional as cruzin - no written report - just a verbal. Fired them by hand and they work beautifully. Still no luck though with the getting a firing pulse.

I've been working off line with freezing914 and he suggests looking at the injector points in the dizzy. Do you have to pull the dizzy to clean them? If not does anyone have pics? I really don't want to disturb the timing until I have her fired up.

Second question. Aren't the injectors supposed to fire once during the 3 second key-on fuel pump buzz? George H refers to that in his troubleshooting guide. That fire would be independant of the points - suggesting the problem is elsewhere. Cleaning or replacing the points are probably a good 'while you are in there' thing to do anyway but may not solve the problem.