Do they see 12V pulses at the connectors or they see a continuous 12V signal at the connectors?
are the wires reading good back to the computer? A noid light set would tell you if the computer is signaling the injectors.
Here is a picture of what the pulse should look like for a Porsche Monotronic system. I will assume that the system in a Ferrari is similar. One side of the injector is connected to +12v. The other side is connected to the ECU. When the engine is running the ECU grounds its wire allowing current to flow through the solenoid and opening the injector. The lower figure gives details. However, even if you get the proper pulse it will not rule out the injector. If the injector is clogged and not atomizing the fuel properly it can case a missfire. Image Unavailable, Please Login Image Unavailable, Please Login
Unplugging the injector immediately sets off a CEL, plugging it back in makes it go away, so the computer knows. However, unplugging the injector and then measuring the voltage at the drive pin gives no pulses on the dead Cylinder, same with the good cylinder. I have to figure out a way to put a scope on the connector wires while it is plugged in to be more conclusive.
Or find a way to probe when connected with an adapter. I'm about to replace tubes in a guitar amp and I have a little tool that allows me to remove tube and sandwich tool in between and bias by measuring an installed tube with power on. I guess that might be called some type of breakout
Yes. If you disconnect the connector you should have 12 V on one side and nothing on the other. With the engine running the ECU is just grounding the wire connected to nothing. You need a pig tail with a male EV1 connector on one side and a female on the other (so you can connect the injector to the harness) and then you can tap the wires in the pig tail without messing up the wires in the harness. You could get one each of these and make what you need. Probably get them at NAPA. https://www.amazon.com/MotorWest-Performance-C112-Injector-Connector/dp/B013GPV45U https://www.amazon.com/MotorWest-Performance-C113-Injector-Connector/dp/B013GPV7WK
Noid light will only tell you if the ECU is working. Looking at the wave form will tell you if the injector is functioning as well. But it won't tell you if the injector is dirty/clogged.
One question that hasn't been clearly answered. Is the engine running on 7, or is it an intermittent misfire? And is it at all rpm and load?
Just buy a Mechanic's Stethoscope. I have used it a number of times to listen to injectors: ting-ting-ting (good), funny sounds or no sound, no good. Also, you will impress your neighbours (look, car doctor!). Image Unavailable, Please Login
It will narrow down the problem. If the light flashes then the injector is likely the problem. The next step might be to swap out the injector with another that is known to work. New injectors aren't terribly expensive and I've had mixed results having them cleaned. Is the objective to create a research project or just get the car running again?
Tim, I want the car to run again. Right now it is running on 7 solid cylinders. With a temperature IR gun, I was able to point it to the exhaust port and find that it is 125F while the other seven are 400F so that cylinder is dead. That is also the answer to JohnK question, it is dead all the time.
I have one of those. But the idea is to see what the ECU is putting out in terms of voltage and frequency so that stethoscope will only give you ting ting ting sound and no wave forms.
You may need a attenuator for the scope to read the injector pulses, depending on your scopes specs Here is pico's info page. they have lots good info https://www.picoauto.com/library/automotive-guided-tests/multi-point-voltage
Tim, I fully support the swapping of components as a diagnostic tool although some of the "pro's" seem to often frown upon this. Well, at least that is how they post here anyway..... So, with that said, I think JohnK is offering some good diagnostic advice
I got one of them fancy digital oscilloscope that is good for this signal range. It is made in China from a company I used to do business with.
Swapping two injectors that you already have doesn't cost anything and doesn't take long to do. This is different from "throwing parts at a problem", that can become expensive in a hurry with a Ferrari.
Nice!!!!! I'm jealous I have a cheaply but works hantek ? Anyway pico has a library of lots of waveforms if you need them
Exactly, but I'm not talking about "throwing parts" I stated "swapping" not replacing. I'm specifically referring to SDL issues and swapping of those components. It's a prefect way to diagnose the problem and (often) leads to resolution but some would say (post) otherwise.
No Hantek, that is Korean. Rigol is the brand. The VP of Engr used to be our FAE in China and they bought ADI semiconductor products. I am no longer in that bidness but the connection exists.
Nice I keep looking at scopes but cant see me getting a nice one for as little I use them now. Maybe if I see a 8 chanell on sale LOL They are just such a great tool for cars/bikes
Frankly, swapping injectors doesn't make a lot of sense. If you are going to make the effort to pull out an injector you mine as well just replace it with a new one, reassemble, and be done with it.
I would not replace just one injector with a new one as its flow may not match the flow of the other used ones. I would buy a number of used ones, send all for cleaning and flow measurement and then put together 8 injectors with closest flow.
