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Help me with injectors

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Old 12-10-06, 03:53 PM
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Help me with injectors

Whats the easiest way to fix my injector problem? I've searched forever through all the wiring and I haven't found crap. The only thing I've found was a black and green wire cut and a black and red wire cut under the dash. The black and red wire comes from ignition switch and the black and green wire sits right near where the BR is. My wiring diagrams says there should be an interlock switch with those wires, but I don't see any nor do I even know what it does. However I don't think thats the problem, considering the wiring diag's make it seem like it's got nothing to do with the injectors. My car is an 87 t2 that I bought as a project with a blown engine. I replaced the engine with a good one from a good source already and it cranks really strong and has a good spark. I guess knowing exactly which sensors are for the injectors and starting, so I can check them out. I also would like to know if it's worth my time to rewire the injectors to the ecu and skip the harness.
Old 12-10-06, 06:30 PM
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Ok so I checked for voltage at the injectors but the car wouldn't crank. However they were receiving voltage, but I haven't seen anything like this before. The front rotor was getting a little over 12 volts then it would drop drastically to zero over about 20 seconds with the key turned to start (crank) and then left on on. The rear rotor only got 10 volts then dropped the same way the front did. The idiot before me was running high impedence injectors on a low impedence harness with the resistor pack still there. Could this mess up the injectors? I already took out the resistor pack and crossed the wires to make it high impedence. Sooo anyone see something like this before?
Old 12-10-06, 06:57 PM
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alright, more, haha, I figured the interlock switch was what was causing the no crank, so I just rigged that up and it cranks. now, i retested the injector pulse while cranking and they weren't getting nearly enough voltage. My dmm isn't the best but it reads correct voltage off the battery so I figure it's good enough. But I was getting 9.5v and 9.2v pulse at the front and 8.3v and 8.0v at thre rear. Why aren't they seeing a full 12+ volts? Is it because the car is cranking? I have it on a charger so I wouldn't think that would be much of a problem.
Old 12-10-06, 08:52 PM
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So I finished up the night by rewiring the injectors thinking there could be some corrosion or something in between the injectors and ecu. But that was a no go, same thing still. Where are the guru's at??? I'm almost positive it's got to be a sensor now.
Old 12-11-06, 11:08 AM
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I really need some help on this guys. thanks
Old 12-13-06, 01:37 AM
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only a few reasons why you are not getting injector pulse width...

As long as your injectors are within the Resistance reading,(1.5-3 ohms on 1986-87 )**(Non-Turbo)** (12-16 ohms on 1988 models) **(Non-Turbo)** which was what you did first, you need to check the resistance in your crank angle sensor, that will tell you if they are getting the pulse width modulated signal from the PCM(duty cycle)= (on and off time). To test it you need to disconnect and ohm the connector.. **(See picture)**..test continuity from terminal G1-G2 and Ne1 - Ne2...Values should read 110-210 ohms.. now (phew) if that is still ok, you need to check your solenoid resistor..**(see picture again)**1986-87 models..(5-7 ohms)..check continuity between Terminals (A-B or C-D)those can go bad too once you have tested all that you should find your problem. It's all about testing and elminating the good parts in the system, that should lead you to your problem...oh and I almost forgot, make sure that the ignition switch is clicking that main relay on !

good luck...

Dave..
Attached Thumbnails Help me with injectors-main-relay-test.gif   Help me with injectors-crank-angle-sensor-test.gif  
Old 12-13-06, 02:17 PM
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Crank angle sensor checks out ok, 145 ohm's between the ne terminals and 157 between the g terminals. I eliminated the solenoid resitor already since I have high impedence injectors which both check out at 14 ohm's. The main relay was the first thing I tested and it's working fine.
Old 12-13-06, 03:27 PM
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Take the CAS out of the engine then key the car to IGN. Crank the CAS with your finger. Do you hear the injectors clicking? Do you have spark?

Do you have an oscilloscope available?
Old 12-13-06, 04:48 PM
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I didn't hear the injectors clicking but I did hear the coils clicking. And I won't have an oscilloscope available until school is back in session. Should I be able to hear them from the fender or should I get up close and use a screwdriver?
Old 12-13-06, 05:15 PM
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Pull the small, white plugs off the Lead and Trail coil assy's. Then repeat the spinning of the cas. You should be able to hear the injectors clicking as you spin the cas. The coils will be disabled if you pull the small, white plugs off.
Old 12-13-06, 11:02 PM
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This is the same problem I'm having but I have not voltage on the primary at all. Would this work for me too?
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