#6 cylinder misfire

[zfan]

Hi everyone I have searched and read everything i can find and there has been alot of discussion on this topic.But my case is a little different
I parked this car 18-20 months ago with 113K miles and it was running fine. Now it has a rough low rev(not smooth when reved) and running a little rich check engine light on at first it popped a coolant sensor code which i fixed then it popped a code 51(fuel and filter has been changed)# 6 injector was a little quiet so I tapped on it and it started working properly and is as loud as the others and i also swapped coils and spark plugs but Im still having the same problem except the exhaust is not rich smelling and when I disconnect the coil there's no change in idle.I know it could be a bad injector but before i delve into a major lob like that i need to make sure.I tried to checked the OHMs but I got no reading at all,is that possible? and what does it mean.Also could it be a bad connection on the cas and where is this cas located.....Thanks in advance any help would be great! Oh and the car is a 91 n/a

[t.mcginley.jr]

First, are your fuel injectors stock or have they been replaced before? If they're stock, they are either frozen or they just went bad.

There should be some kind of ohm reading on each injector, usually when they go bad the reading is above what it should be, not under (although I guess it's possible). No reading at all would be weird, are you sure you touched both terminals?

The CAS is the round aluminum sensor located on the driver's side timing belt cover. Here's a pic:

[zfan]

The fuel injectors are original,I dont understand why I cant get a reading from the injector because one of the other ones I got 12.8 so my meter is working I even tried putting clips on the prongs but still no reading and I even tried checking it through the top of the injector plug. but its operating because I can hear the clicking.Thanks to this forum I found out about the PTU recall and had it replaced and the nissan mechanic said it had a injector stuck open for the code 51.So before I tear the dang thing apart I just wanted to at least check the cas so thanks for the info and if you can think of anything else its much appreciated!

[zfan]

I just disconnected the plug from the injector and started the motor and no change in the way it runs but it still clicks like the rest of the injectors I dont get it but it seems I have a completely dead injector which I have never encountered before especially from just sitting.
Should I try checking the voltage on the injector plug and what should the voltage be.Would the cas have anything to do with it

[t.mcginley.jr]

If it's only one or two injectors, then it isn't the CAS. Usually a bad CAS will give you problems with all the injectors (like not starting) and will also throw a code 11. A bad injector can still make a clicking noise, AND still ohm out correctly and still be bad. Those tests usually work, but aren't always 100% conclusive.

As for the injectors, the old style are prone to failure because of the ethanol in the gas we get today. It basically ruins the injector from the inside, which is probably what happened to yours. Honestly your best bet is to upgrade to new style injectors so that this doesn't happen and you don't have to worry about injectors for another 10-15 years. The adapter kit is ~$120 and a set of sonic cleaned new style injectors is about $120-130 too. You can get brand new injectors but they're like $400+ for 6 I think.

[zfan]

Thanks for your reply I will have to figure out what I should do because I was just trying to get the car ready for sale,so I guess I will try to find injectors at the price you quoted.

[t.mcginley.jr]

Just looked on ebay, I might have gotten a little confused. It's $140 for a set of reman'd new style injectors. The older style set is $280. If you really just want it running then try finding someone selling a set of good used old-style ones, it will be much cheaper than $280

[t.mcginley.jr]

Here are the links just for reference:

http://www.ebay.com/itm/Nissan-1990-93- ... 257ce0f0ee

http://www.ebay.com/itm/Infiniti-1993-9 ... 6e&vxp=mtr

[zfan]

The car i s running great,Unfortunately I did take the short cut and dremeled away the plenum and replaced the one injector which i got from ebay $63.I got what i wanted with little trouble the best thing is that the car runs smooth once again, thank you for your guidance.
P.S The old injector was stuck wide open.

[t.mcginley.jr]

Awesome! Glad to hear you got it worked out. Many people dremel their plenum so it's pretty acceptable. If any more fail, dremel those out as well