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914World.com _ 914World Garage _ Injectors clicking
Posted by: JPA914 Jun 23 2016, 07:37 PM
My '74 2.0 is running rough and I'm trying to rule out as many causes as I can. The car was running fine, but started idling low and acting like it was running on three cylinders a few minutes after being started. Now it acts this way right at startup. In trying to rule out the fuel system (I'm also looking into the ignition and injection, but that's a different thread), the following has been done:
Confirmed the fuel pressure is good at 29.5 psi
The injectors were just tested and cleaned
All new SS and rubber fuel lines (no kinks, no leaks)
Cleaned fuel tank, brand new sock.
If I stick a stethoscope on each injector while the engine's (barely) idling I can hear them all click at a regular rate. All click at the same volume without any dead spots in the sound. Can I rule out my trigger contacts because of this? I would imagine if the trigger contacts were a problem, I wouldn't hear certain injectors click at all, or perhaps there might be erratic clicking. Anybody know if that's the case?
Posted by: JPA914 Jun 24 2016, 12:12 PM
Nobody knows?
Posted by: G e o r g e Jun 24 2016, 12:49 PM
you list what has been done, is this since the problem started or before?
have you pulled 1 wire at a time to figure out what cylinder is not firing?
Posted by: Mueller Jun 24 2016, 12:59 PM
How is your battery voltage?
You can also see if your alternator is going out, perhaps too much AC ripple in the system?
Posted by: mgp4591 Jun 24 2016, 01:11 PM
you list what has been done, is this since the problem started or before?
have you pulled 1 wire at a time to figure out what cylinder is not firing?
Have you pulled one injector connection at a time to see if one is weak? The pintels on the injectors should sound the same most of the time but if you've got a bad connection because of an intermittent short in the connector it can cause the same issue.
Posted by: JPA914 Jun 24 2016, 07:05 PM
The car sat for years and I did everything I listed to the fuel system before I attempted to start it. I've also gone through the ignition and FI components as well, but since my question was fuel system related, I wanted to keep the focus there for this thread.
When first started, it would run fine both at idle and higher RPM for a few minutes, then start to run rough throughout the rev range. Now it runs rough right from a cold start and doesn't improve after warmup.
So does anybody know if the repeated, equal volume/tempo clicks I hear from each injector are an indication that the trigger contacts are working properly and I can rule them out as a cause?
Posted by: 914_teener Jun 24 2016, 07:48 PM
The car sat for years and I did everything I listed to the fuel system before I attempted to start it. I've also gone through the ignition and FI components as well, but since my question was fuel system related, I wanted to keep the focus there for this thread.
When first started, it would run fine both at idle and higher RPM for a few minutes, then start to run rough throughout the rev range. Now it runs rough right from a cold start and doesn't improve after warmup.
So does anybody know if the repeated, equal volume/tempo clicks I hear from each injector are an indication that the trigger contacts are working properly and I can rule them out as a cause?
The car works as a system.
So you believe you have checked to fuel system.......so is the correct amount of fuel getting to the injectors?
Trigger points are part of the FI system and not fuel delivery. Do one at a time.
Posted by: 914_teener Jun 24 2016, 07:49 PM
So....pull an injector at test each output.
Forget about regular clicks for now.
Posted by: Mueller Jun 24 2016, 08:19 PM
The injectors fire in pairs, so each trigger event 2 of them should be going off, never on the same side however, diagonal to each other.
The are a solenoid and will make a clicking sound when operating so that is normal.
Posted by: JPA914 Jun 24 2016, 09:09 PM
The injectors fire in pairs, so each trigger event 2 of them should be going off, never on the same side however, diagonal to each other.
The are a solenoid and will make a clicking sound when operating so that is normal.
Ok, so the fact that I can hear (with a stethoscope) the solenoid clicking at idle at a regular, constant rate in all the injectors (all sound identical) indicates that the trigger contacts are functioning normally?
Posted by: Mueller Jun 24 2016, 09:12 PM
The injectors fire in pairs, so each trigger event 2 of them should be going off, never on the same side however, diagonal to each other.
The are a solenoid and will make a clicking sound when operating so that is normal.
Ok, so the fact that I can hear (with a stethoscope) the solenoid clicking at idle at a regular, constant rate in all the injectors (all sound identical) indicates that the trigger contacts are functioning normally?
I would say yes, unless it is valve train noise you are hearing instead.
Posted by: Mueller Jun 24 2016, 09:14 PM
To confirm you can use a noid light...pro version here, but if you google it you can make one similar for less than $5
http://www.engine-misfire.com/how-to-check-fuel-injector-pulse-using-a-noid-light/
Posted by: JPA914 Jun 25 2016, 12:27 AM
The injectors fire in pairs, so each trigger event 2 of them should be going off, never on the same side however, diagonal to each other.
The are a solenoid and will make a clicking sound when operating so that is normal.
Ok, so the fact that I can hear (with a stethoscope) the solenoid clicking at idle at a regular, constant rate in all the injectors (all sound identical) indicates that the trigger contacts are functioning normally?
I would say yes, unless it is valve train noise you are hearing instead.
Thanks for the response. Positive it is the injector solenoids and not valve train as I moved the stethoscope around and the click sounds disappeared even a very short distance from the injectors.
I guess I can scratch the trigger contacts off my list then.
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