Q45 Techs: ohmed injectors at harness...need help

[oxs1]

I just ohmed my injectors from the harness after diag. on car with code 51: injector circuit...I got results from harness from pin order starting with the top left...#1: 28.3#7: 28.3#6: 18.5#4: Possible problem no result. Maybe that is injector circuit.#8: 15.6#3: 15.6#5: 16.4#2: 14.6

Then i only could ohm injectors #1: 12.5 #2 12.6 #8 12.6 #4 No result

Ok now it must be injector #4. What should i do next?

[DAEDALUS]

Wow...Poor readings across the board. But 1, 2 & 8 ohm well directly, so the problem appears to be (at least partially) connection/harness related. If you can do it without removing the plenum, go ahead and replace #4. It ought to help things considerably cause that one is surely completely dead. That's the low-hanging fruit. After that you can see if you need to address the others.Do me a favor and measure #1 and #2 again through the harness. Could be that removing and reconnecting the harness has scraped off some crud on the connectors, and the readings will improve. If so, then work on removing the injector connectors to clean them up.

[DAEDALUS]

Get a reading on #4 directly before removing it. It's possible.

Also, removing it will not be easy, but read Qdog's experience with #6...he was able to replace it without completely removing the plenum. #6 is at least as hard as #4 I bet.

http://www.nicoclub.com/zerothread?id=49246

[Q45tech]

What I do is clamp a current probe around a loop of wire [substituted for injector fuse] and look at each of the 8 injector current rampup waveforms with an oscilloscope.

[Q45tech]

Voltage and current waveforms

[Q45tech]

The little kink or squggle in the middle of the ramp up graph is when the pintle moves open from it's seat .......[common waveform of any solenoid].

Seeing that the peak current and pintle open times are equal in all injectors is better than the exct ohm reading as the VOM typical doesn't provide 13 volts during the test which may punch thru corrosion in the harness/ connectors.

Also the wide range in FSM is to compensate for readings which varry with temperature of coper coil in injector and VOM accurracy........really they should be 12 [+1-0.5] ohm or even tighter.

[oxs1]

Do you guys know anyone who has used injectors within spec for sale just to have my Q running good?

[Jesda]

I just mailed the rest of my injector set (which I got from Evan, thank you!) to Pito. You might wanna ask if he has spares now.