A NISSAN Dealership diagnosed a bad #4 injector in my car...how can I know that it is definitely a bad injector and not bad electrical contacts or other less expensive problems?

 

Accuracy of the Nissan Consult is very good. Accuracy of the 3rd grade Nissan mechanic's evaluation of the problem is questionable. There is a difference.

You could examine the connector yourself or just clean it to see if it improves the situation.

 

I wish I had the consult tool. It will tell the mechanic whether the injector is blown, leaking, or clogged. If its clogged, that means the injector has been running hot for a while and will probably fail, if it's really bad then injector cleaner probably wont do much. If its leaking it could mean the body of the injector is cracked, or an o-ring is leaking.

The consult tool reads out this information in the form of engine rpm, or actually each cylinders contribution to the over all idle rpm (very cool). Above average idle means leaking. below average means clogged. no idle contribution means blown injector.

Two simple test that can be performed by the DIY'er is an Ohm test and also a current load test.


Ask the mech. whether it was leaking or clogged. If it was just clogged then I would say try using injector cleaner w/each gas fill up and do this for four consecutive fill ups. (try a different brand each time, that way a different solvent will be used to dissolve the deposits.)

A leaking injector give you poor fuel economy. But when you consider the cost of replacing an injector....thats another story.

 

Can you read codes from the computer without the consult tool. Like the check engine light or an LED on the computer?

 

Yup....but the consult does alot more.

 

Yeah the mechanic used CONSULT to diagnose the problem, and after asking him specificly what was wrong with the injector, he said that it is not electrically firing properly, and so injector itself has an electrical problem, and needs replaced. That's a pretty specific diagnosis...would be nice to just pop that tool in at home whenever u feel like it!

...Also, is it possible to tell whether my car has blue or black fuel injectors without physically looking at them? Thanks

 

Dude the answer that he gave you was very vague. He could just be saying that to you b/c either he does not feel like tell you exactly what went wrong or he thinks your stupid and would not understand or he is studpid and does not know how to explain. I'd go with the third . Is the injector totally dead? did he say that b/c to say there is somthing wrong with it electrically would mean its not firing at all.

 

No its definitely not totally dead, it works the majority of the time, though it seems it has been increasingly acting up lately. The dude at Nissan said that the injector was sending out of range electrical signals or something. I have no experience with injectors, so I don't know what to take from that.

 

You should try cleaning all the connector like Jeff said. It's not that hard and it's not that easy, but its simple. Whats tuff is getting inside the connector (both sides) with a extremely thin file or sand paper, you can also try contact cleaner (from an electronics store). Then after the corosion is removed get a small tube of dielectric grease on spread some onto the metal contacts that you cleaned.

My father filed down a small file to make it incredibly thin and narrow so that it could be slid in between the female side of the connector.

I guess the easy way would be to go with a can of contact cleaner and spray into all the terminals. Just be carful and do it when the engine is cold. The cleaner sprays use alcohol's which are very flamable also you will want to use a large rag to prevent overspraying onto other engine components.