Sprinter Injector Faults
I'm reaching out here to see if anyone can give me a second opinion. If you need anymore info let me know. This vehicle is a crank no start. It immediately sets all 6 injector circuit short to ground faults while cranking. There are no inline connectors between the injectors and the ME. I have verified good cam and crank signals at ME cranking. If someone has a known good as far as timing goes let me know. I have backprobed all powers and grounds at ME while cranking and there is no excessive voltage drop. All injectors have 180k ohms when tested thru loop at ME connector. This is what I would expect on piezo injectors. Let me know if there is a different ohms spec. All injectors pull 2-4 amps when powered with 12 v manually at ME connector. I can hear them clicking/flexing as well. When using an amp clamp on all the injectors none of them are being fired while cranking. No injector control checking voltage either. I had a used ME cloned due too new ME being on backorder and I have the same issue. What am I missing? Maybe I need to start over and see where I went wrong. Thanks all!
When powering the injectors manually from the ME connector you do so both positively and negatively or just positively? Do the same fault codes occur when disconnecting the injectors or do they change to open circuit faults?
No I have not done both ways. I will have to disconnect one and see if the code changes. Thanks for the response.
I understand that you only powered up the injectors with voltage and did not supply a ground. These injectors are supposed to be controlled by the control unit on BOTH circuit legs, positive and negative. If I understood you correctly and the injectors clicked by only supplying voltage they indeed would be permanently grounded. On a side note: I would not expect piezo injectors to do anything…
No, I connected power to the high and ground to the low side at the ME connector.
Hi Caleb, can you please share the codes you are getting?
From the controller connector, have you tried measuring the resistance to ground as described in the flow chart?
Hey Caleb - You need to test the harness and the injectors with a megaohm meter set for the 250 volt range. I use a Fluke 1507. A quick web search will bring up videos with instructions for testing Piezo style injectors. A regular ohm meter will not cut it.
Check the injector harness for a short to ground. If one injector wire shorts the CDI will shut off all injectors and set code. When the code is set the CDI will not fire injectors.
I agree with the other comments regarding a short to ground. The injectors can short internally if the fuel system is contaminated with water or DEF. A megaohm test would be nice. I would check the fuel filter for any signs of water, if you haven't already.
Since all injectors are showing short to ground codes, these codes will relate/interpret as to a no power to injectors issue. Which clearly you indicated you have…Have you tried swapping the engine model relay as a quick test? Confirmed fuses? This year Sprinter is a MBZ/Chrysler Frankenstein vehicle so wiring information can sometimes be incorrect… Can't be sure on this year…but have had some…
Caleb, I second Francisco's request for fault codes (all of them). Next, how did the customer describe the symptom/situation (died while driving, parked and then wouldn't start but it was 32F outside, wouldn't restart after filling with Gas, etc) that ended with a Crank-No Start? What is the rail pressure value? The CDI will not activate the injectors until there is a minimum pressure (From…
Well I missed it big time on this one. I never actually individually checked each injector circuit for short to ground thru ME connector. Found #4 shorted. Unplugged #4 injector. All codes are gone now and vehicle starts and runs. Thanks everyone. First ECM in 12 years I have misdiagnosed. Live and learn I guess.