1994 Nissan Maxima Repeated Fuel Injector Problems

Tiny
DYLANG
  • MEMBER
  • 1994 NISSAN MAXIMA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 202,000 MILES
I drive a 1994 nissan maxima, with the 3.0L VG30DE SOHC V-6 engine. About 15,000 miles ago, I had to replace one of the fuel injectors (the injector circuit was open). Then about 10,000 miles ago, the same problem occured, but with a different injector. Since it is so much work to get to the injectors to replace them, I replaced all remaining injectors at the same time. Today, (10,000 miles later) the same problem occured: an open circuit in the #5 cylinder injector. From what my maintenance manual says, the injector resistance should be between 10-14 ohms. The rest test within this range.
Why would I be having so many problems with the injectors? Is there something wrong the the PCU that keeps creating this problem? Would a clogged injector (caused by not changing fuel filter often enough) cause an injector to read open on a resistance check?
This is getting frusterating, and I would like to get to the root of the problem before I change injectors again.
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Tuesday, March 24th, 2009 AT 1:13 PM

7 Replies

Tiny
RACEFAN966
  • EXPERT
OK fiirs off we will need to do a test on the voltage supply and go from there ok.
First disconnect injector harnesses 1,3,5. Then disconnect the sub harnes connector for injectors 2,4,6. Now check the voltage from term a to ground at each point should read battery voltage. Here is a pic to help. Let me know what you find if all it good then we will check continuity.


http://www.2carpros.com/forum/automotive_pictures/249564_Graphic_53.jpg

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Tuesday, March 24th, 2009 AT 9:15 PM
Tiny
DYLANG
  • MEMBER
I tested like you said, and I have battery voltage at all points specified on the harness.
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Wednesday, March 25th, 2009 AT 3:30 PM
Tiny
RACEFAN966
  • EXPERT
Great that means they are getting the power needed now we need to check for coninuity but before I get that info for you I need you to read you hood sticker and see if has california or federal emissions. Please do not guess as the tests are very different. Thanks and get back to me with the needed info so I can get you the test needed.
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Thursday, March 26th, 2009 AT 10:23 AM
Tiny
DYLANG
  • MEMBER
All is says on the emissions sticker is that it complies with EPA emmisions standars applicable for the year of manufacure: 1994. I dont think its got california emmisions.
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Thursday, March 26th, 2009 AT 11:00 AM
Tiny
RACEFAN966
  • EXPERT
Ok here is what is next. You will need to set you meter or ohms and make sure that there is continuity between each injector and the computer. So with key off unplug the computer harness and then you will unplug one injector at a time. Start with injector 1 Red/black wire (red wire with black stripe) I will refure to each wire that way ok. pin 101 at the computer harness (pic included below of harness). If that one has continuity then move to the next. If any don't have continuity then there is a break in that wire ok.
Injector 2 red/white wire to term 110 on ecm harness.
Injector 3 red/yellow wire to term 102 on ecm harness.
Injector 4 red/blue wire to term 112 on ecm harness.
Injector 5 white/red wire to term 105 on ecm harness.
Injector 6 blue/red wire to term 114 on ecm harness.
If all have continuity then we will check the ecm next.

Here is the term identification chart


http://www.2carpros.com/forum/automotive_pictures/249564_Graphic_57.jpg

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Friday, March 27th, 2009 AT 11:04 AM
Tiny
DYLANG
  • MEMBER
I did the continuity check and everything looks like it should. What test do I do on the ECU?
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Monday, March 30th, 2009 AT 3:56 PM
Tiny
RACEFAN966
  • EXPERT
Ok with the tests that have been done and if all the wiring to the ECM are good then this leads to one thing if there is no codes in the computer that is is not good. I have saying that a computer is not working correctly as it isn't real common but in this case the test done lead to that being the only problem. Now you can get one from a wrecking or salvage yard just be sure they will give you an exchange warranty so that if you get a bad one they will allow you to bring it back to exchange it for another on. Let me know how it goes.
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Tuesday, March 31st, 2009 AT 10:27 AM

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