Hey guys, been touched on around the world millions of times but can't find what I'm looking for. I picked up this n/a auto non turbo z32 last week, I have a built Turno engine and gearbox to go in but for now I'm going to roll with the de. Now , it's running rough as guts and I did the old coilpack pull and narrowed it down to an injector, or three. I'm pretty sure it's 1,2,3 injectors that army firing, checked them with the screwdriver. I checked voltage and both wires run voltage and all teted with 13.9 ohm, so within spec. So I'm stuffed now , could this be 3 really clogged injectors that they can't fire??
It maybe the injector connectors..... If you remove the suspect injector connector look inside them and if they are green then it is the connectors. I had 3 such corroded connectors and if I move the wiring near the connector the car would run very rough and move them again and it would rune smooth. I ended up replacing all the connectors with new connectors which came with wires attached and crimped already. All I did was cut existing connector off and joined to the new connector to existing wiring. If this is your problem there is more to replacing the connectors than I have detailed. I will elaborate if this was your problem. Good luck. MichaelZ
Remove the CAS. Turn on the ignition. Slowly rotate the CAS shaft. You should hear the injectors "click".
Thanks guys, I will try all the above, the plugs on there now are green as shit but I have better ones on my other loom so I might chop and change and give it a go
Not necessarily the injectors! A noid light is a rough verification the wiring circuitry is intact up to the injectors if it pulses. It doesn't check injectors.
I take it that you didn't put a noid light on it.... ...if you don't have these you could always try put a DMM in either pin on the connector side, set to peak hold and crank the motor. You should see some voltage as the ECU earths the injector during the firing sequence. Keep in mind that one side of the plug is positive and one is negative, and that the injectors have constant power and switching earth. With this in mind I would start by earthing the meter to the body of the car to verify that you have power on one side of the harness, and then earth via the plug as above to verify that the injector is being fired by the ECU. If you don't have a Digital Multi Meter head out to Jaycar and buy a cheapie that does voltage, ohms, current, has a continuity buzzer and a peak hold function. This small investment (approx $50) will be significantly cheaper than ad hoc changing out parts in search of a diagnosis. Assuming that things are OK on the harness side that would point to a fault with the injectors themselves. Good luck.
An abbreviated excerpt from: Get the most from your multimeter [www.autoserviceprofessional.com] Testing fuel injector solenoids The truth be known, fuel injectors don't really inject anything. What is called a fuel injector is a really a valve with a spray head that opens in response to a computer signal. Behind the valve is fuel held at a pressure created by the fuel pump and regulated by a bypass valve. The amount of fuel dispensed depends on the size of the valve opening, the amount of pressure and the amount of time the fuel is allowed to flow. The DMM can be used in a couple of ways to check the performance of the fuel injector. One measurement that can be made is the DC resistance of the fuel injector's solenoid coil. A common failure mode for injectors is that one or two turns of the coil may have shorted due to overheating. The DC resistance of the coil may show the drop in resistance caused by the shorted turns. Since the two or three shorted turns don't amount to much in the way of resistance, you will need an especially accurate resistance measurement. What will improve the accuracy of your measurement is to "zero" the meter. Often when the probes are connected together, the display will show some tenths of an ohm of resistance. This is caused by resistance in the leads and in the connections to the meter. What will help you make a more accurate measurement is to remove this "error offset". The way to do is to cross the meter leads (short them to each other) and then hit the "rel" button to cancel out the resistance in the leads and make the meter read zero. Now when you measure across the two terminals of the fuel injector, the value you read will reflect the true resistance of the injector's solenoid. Using the pulse width measuring feature Not all meters have a pulse width measuring capability. If your meter does, it can be quite useful in measuring devices that use pulse width modulation (PWM). These devices use electronics to control the amount of time the device is on as a way of controlling how much it is on. PWM devices include fuel injectors, idle air control, and some DC motors like the one used for the fuel pump. For fuel injectors, the way to do this is to use your back probe accessory probes by slipping them in along the sides of the wire entering the back of the wire harness connector that goes to the injector. You will need to configure your particular meter to the pulse width mode. On some meters this means selecting the DC voltage range and then pushing the Hz range until "Pulse width" is displayed on the screen. It is not the easiest feature to select, but the value is that you can see the amount of time the injector is open as a pulse width time measurement. If you tip the throttle you will see the computer modify the pulse width to enrich the mixture and then lean it back. Your DMM owner's manual will tell you how to configure your particular meter for measuring pulse width. Idle air control motors often work on the PWM principle. Using the back probes, configure your meter for the pulse width measurement. You should be able to watch as the ECM varies the pulse width to change the idle speed. Since idle speed problems are often the result of vacuum leaks, you can watch the pulse width as you wiggle vacuum lines to try to make the possible leaks worse. You'll be able to see the ECM try to adjust the pulse width to compensate for the increase or decrease in the vacuum leak. Other devices such as actuators and solenoids also use PWM techniques and can be tested similarly. User convenience features The "hold" feature is somewhat similar to the min/max average function. Its main advantage is for the convenience of the technician using it. When this feature is activated, it is possible for the tech to devote his or her attention to getting the probe on to the terminal or test point that is wanted without having to watch the meter readout from the corner of your eye. When the "hold" feature is activated, whatever value the probe detects will be held on the screen until you remove it. You can touch the test point and then look over to the meter to see what was read.
Cheers for the info, I don't have a mood light but I did put the multimeter on , it has constant 12v on both wires when ignition is on. Haven't tested while cranking yet will do that later on.
+12vdc.... ....will be on both wires, even with the ignition OFF! :nono: So, how do you know there is NO PULSE? How did you test it? The PULSE is going to be about 2 to 3ms in duration, you're going to need a good meter to catch it. :rolleyes2: 1 millisecond is 1000th of a second. I don't have a mood light either!
So you think too fast to catch with a meter on hold? I've never tried it but seemed like it might just work..
The ECU grounds one of the injector wires.... To see the pulse firstly there must be +12volts present on one of the injector wires. Do this with the injector plug removed for the injector. If you see +12v on both wires when the connector is removed then the CAS or ECU is faulty. See the Factory Service Manual Online (See the tech section on this forum to find it) EF&EC -13. The ECCS grounds each injector in resonse to the cAS signal and the ECCS electronics. Both need to be functioning for the Injector signal to be present. This assumes that the Fusable link near the battery (on the diagram) is intact. MichaelZ
What is the chance of three injectors failing at once? Um ...... its not likely to ever happen in anyone's lifetime, ever! If you had a dual fed rail then it could be a fuel blockage in one rail but if "mood lighting" is anything to go by in experience, then its unlikely you have a dual rail. This means that you should be looking for a short circuit/ open circuit/ broken circuit in the wiring from the injector bank wiring main harness through to the CAS/ PTU/ ECU. Noid lights will do nothing for you here that a multimeter can't do at this stage (except provide mood lighting) Do the CAS Injector test first - that will narrow it down to confirm the problem then test with a multimeter back through the injector harness wiring until you find the electrical problem (possibly at the CAS itself as banks of wires join here) - either way - you will know where to go from the CAS test first! Stop chasing rainbows and go straight to the problem Good luck Jamie
Well I have bit the bullet an pulled the plenum, ill replace te 3 injectors cost me 40$ so no biggy, hopefully that does it, I have a feeling they are clogged shut coz they were sitting for 12 months no start and the car took 30 cranks to fire so maybe the other 3 popped and started working and 3 didn't, who knows. If that doesn't work ill go to the CAS .
Funny thing is its not a bank that's not firing it's the front left and two on te pass side front so...
If it looks the same then it is, there was a different socket on the later models. Mr Anti started a thread on it.
All sorted, was the injectors. Swapped them out and she runs on all 6, think a couple are a little dirty but almost 100%, thanks for all the info lads
