1989 348 TURBO, (Norwoods). Stock fuel rails, high flow injectors. I've got a diagnostic indication of an "open injector" by my motec diagnostic screen. The car is missing. My guess is that it's simply a dirty plug. I'll clean the plug to the injector and see if it "goes away". If it doesn't, can anyone tell me if the injectors simply "pull straight out"? Is this akin to removing the cis type injectors? I suppose I'll need to remove the fuel rail first? Can I read the pulses from the end of the harness with my digital multi meter? Who's done this and how tough will it be? I'm guessing an easy fix? Thanks
The injectors should just pull out after the fuel rail is removed. But before removing the injector I would suggest placing an ohm meter across the terminals to see if the injector is faulty. Depending on injector type this should be between 0.5-16 ohms. You can find your injector type in the Motec tuning screen under General Setup->Main Setup-Injector Current (IJCU). If that value is zero you have high impedence injectors (12-16)ohms, other values indicate low impedence injectors (Press F1 for a list of common injectors and resistance values). If the injector appears to be ok then trace place the meter between the wires & plug on the Motec to see which wire is at fault (pin layouts and wiring diagram for the M48 can be found at http://www.motec.com.au/drawings/ecu-m48.pdf )
Also, by chance if the old rail is being used and part of the oild wiring system is being used the inlet side of the injector rail has crappy 348 wiring. You could just have a bad connection which is very likely on stock 348 parts and stock wiring that goes into your new good motec wiring.
Jeff--you can also take an automobile stethescope and put it on the injector while running--you will hear the valve clicking if it is working
On the Motec you can do this by running the Injector test (Diagnostics->Injector Test) without running the motor, but make sure the fuel pump is turned off/disconnected first. The injectors can be activated individually and in my experience are loud enough that you can hear them without a stethescope. The Diagnostics screen should tell you which injector is faulty, if it only occurs when the motor is running then chances are that it's a faulty connector on the injector, especially if it only occurs in a particular rev range.
ok, Thanks for all the posts. It is 3:45 a.m. I just returned home. I'm on my way down to check it out. I'll keep you posted. J
Thanks for the reply. The car has a custom wiring harness done by Norwood, years ago. My guess is a bad connection.
OK, OK. I took a look. I did an injector test. I couldn't really here it clicking or making any sound. I checked some other injectors too; no sounds. Of course I pulled the fuel pump fuses first. I then cleaned thouroughly the pins and plug. I started the car and got the same diagnostic error, "#6 injector open". Next, I removed the fuel rail and swapped #6 injector with #7 injector. Restarted the car. Same error, "#6 injector open". Here's where you lost me, "If the injector appears to be ok then trace place the meter between the wires & plug on the Motec to see which wire is at fault" Could you expand on this? Thanks. Jeff
First you need to know which is injector #6, it may not be the injector on #6 cylinder. It should be the 6th injector to fire, so it depends on firing order.If the wiring loom is done correctly all the injector trigger wires will be a different colour and the common wires, which connect to Battery + (pin 1). will all be the same color, so take a note of the colour of the wire connected to Pin #21 to make sure you've got the right one. Take your ohm meter and connect it between pin #21 at the connector on the Motec and the terminal on the injector clip. If there is no continuity that is the wire with the problem. You can check the common power wire in the same way (pin #1) or you can test for 12v between the wire on the injector clip & earth when the ignition is turned on.
Ok, I ended up chasing down all the wires. continuity was good! It turns out that the 6th injector to fire is cylinder # 8. BUT- Everything checks good with the multimeter! SO, I switched the #8 injector with the #6 injector just to try to see if the "open injector" error would change. Well, it changed all right. Now all cylinders fire correctly. Hmm. I called Motec east. Jay, the manager said, no doubt, this type of probelm is in the harness. I'll be replacing the harness this winter, with a full motec factory produced harness. Hopefully, the car will be close to no issues after the new harness is installed. Many sincere thanks to all that pitched in with the thread. Until next time, I'll be lurking in the shadows..................
