Infiniti 1994
Our car has recently starting a little shake like it is going to stall. We've given it a tune up changing the spark plugs and fuel filter added a seafoam and it stopped. After at least 5 weeks, the car has started with the shakes again.
We did go for a diagnostic and it pointed to the fuel injectors.
Any pointers on fuel injector replacements?
Fuel Injectors
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gr8scott72
- Posts: 1220
- Joined: Thu Feb 16, 2006 1:37 pm
- Car: 1994 Infiniti J30t
Re: Fuel Injectors (sanchezd3)
Bookmark this site. It's full of helpful stuff.sanchezd3 wrote:Infiniti 1994
Our car has recently starting a little shake like it is going to stall. We've given it a tune up changing the spark plugs and fuel filter added a seafoam and it stopped. After at least 5 weeks, the car has started with the shakes again.
We did go for a diagnostic and it pointed to the fuel injectors.
Any pointers on fuel injector replacements?
http://fuzzycats.com/
I recently replaced injector #6 on my car and the injector was $99.50 including tax at Auto Zone and it took several hours of grinding. Better than paying a shop thousands as they think you have to remove the intake manifold which involves about 15 hours of labor.
Re: Fuel Injectors (gr8scott72)
You were right -gosh that was a life saver. Not taking out the whole thing apart for just one injector.
Thanks for the input, wisdom, experience. . . . you know what I mean, eh.
Thanks for the input, wisdom, experience. . . . you know what I mean, eh.
Re:Fuel Injectors - Spark plugs - or coil packs? It is easier looking back!
These are some things I will do a bit different next time in fixing my rough idle.
1) I bought the 1993 J30 with a 160K, so when it idled a bit rough, I guessed it had an occasional misfire. This engine, which is the same as the 300ZX, runs so well on 5 cylinders, I would have never guessed it was a fuel injector that would not fire at all. My first incorrect guess was a spark plug on its way out. Not knowing when the spark plugs were replaced, I got a new set of NGK PFR5G-11 (2647), which is the OEM application so commonly recommended, at O’Reillys for $10 each. They were $24 at AutoZone. I would have used the iridium NGK upgrade #7994 which has an iridium center electrode and a platinum pad on the ground electrode; the cheaper iridium NGK ones do not have this pad which is the same effect as the so called double platinum ones I bought. I visited with an NGK tech who said both have exactly the same heat range and performance properties; the improvement is that it lasts longer (90k vs 80K as I recall) and iridium has less resistance. He indicated the smaller resistance was not especially significant; however, we speculated it could be factor as my coil packs continue to age. Removing the coil packs is easy on all but one cylinder and using a vacuum hose on the end of the spark plug makes it easy to lower it into its hole and get it started without fear of stripping the threads. By the way, do yourself a favor and check by removing the wiring harness to each individually as the engine is running; there will be a noticeable change except at the dead cylinder. Swapping the coil pack with one from another cylinder and then maybe a spark plug would have forced me to recognize I could have unplugged the suspected injector and tested it. Even a cheap ohm meter would have shown mine did not even move the needle. The injector was obviously defective.
2) Before removing the injector, be sure to pull the fuel pump fuse (under the hood on my 1993 J30) while the engine is running so the fuel rail will not be as pressurized; also, have the gas cap off. I removed the fuse and waited for it to stall but did not have the gas cap off. Little did I realize but the cylinder filled with fuel and although it could be related to removing the fuel lines in the way around injector #4, I think it maybe was the gas cap causing the problem.
3) I could have been more aggressive with the Dremel tool on the flange of the plenum to make removal of the screw and installing the new one easier; it was not necessary to break the screw loose initially. I was able to get the old screw broken loose by removing the easy one and them moving the metal cap back and forth with a Phillips screwdriver on the screw at an angle which made the seemingly impossible angle of the challenging one easy. There was no way I was going to get a Phillips head screwdriver squarely on the partially hidden screw. By the way reinstallation was easy with a magnet on the ball-shaped hex wrench allows the new bolt to go in easily after positioning the metal cap over the injector.
4) I used plenty of PB Blaster overnight and it still takes effort and finesse to remove an injector. Twisting and pulling finally did it. I would use a CV Boot Pliers from AutoZone or a rope with a noose around the injector instead of regular pliers. Another option is a flat-blade screwdriver to pry it out with a twisting motion. This would not have been such an ordeal if I had seen an injector before removing it. I would have waited to remove the injector until I had the new one. Be sure to keep the rubber spacer with its affixed metal washer that goes between the injector and the metal cap; my new one did not have this part.
5) Before installing the new injector use a flashlight to look in the hole to be sure fuel has not accumulated in the cylinder; it could have been a huge problem if I had not checked and siphoned it out!
6) Installing the new injector was more challenging than I expected and it did not have to be. I mistakenly used PVC pipe that was I inch (inside diameter) that was nearly a perfect match around the lip of the injector after notching it out. It would not go in even with Vaseline. The lip is more brittle than one might suspect and I broke part of it off when tapping this bigger pipe with a rubber mallet. Fortunately, Plastic Welder (epoxy) made by Devcon, selling for less than $5 worked well. It is far better to use ½ inch (ID) PVC pipe about a foot long notched-out. Installing the new injector takes finesse and hand-force only. A twisting and hand-pressure motion snapped it in much more easily. I tried tapping it with a big flat head screwdriver; however, even with enough force to leave a divot from the screwdriver did not do it. The twisting and pushing provided uniform pressure and snapped it in within a minute. Putting the cap on with the rubber bushings metal side toward the injector is easy if you just look at it for a minute and position it without the new hex head screws. The magnet on the 4mm ball-type hex head (Allen) wrench made it easy.
I probably would have tried this place that offers a lifetime warranty on injectors for about $45 http://www.directautomotivepro....html. 800-611-6730. There is a $12 core charge so be careful in removing the old one as mentioned above.
Experience is an incredible teacher, especially when we make mistakes. This forum and the 300ZX would have made it so much easier.
1) I bought the 1993 J30 with a 160K, so when it idled a bit rough, I guessed it had an occasional misfire. This engine, which is the same as the 300ZX, runs so well on 5 cylinders, I would have never guessed it was a fuel injector that would not fire at all. My first incorrect guess was a spark plug on its way out. Not knowing when the spark plugs were replaced, I got a new set of NGK PFR5G-11 (2647), which is the OEM application so commonly recommended, at O’Reillys for $10 each. They were $24 at AutoZone. I would have used the iridium NGK upgrade #7994 which has an iridium center electrode and a platinum pad on the ground electrode; the cheaper iridium NGK ones do not have this pad which is the same effect as the so called double platinum ones I bought. I visited with an NGK tech who said both have exactly the same heat range and performance properties; the improvement is that it lasts longer (90k vs 80K as I recall) and iridium has less resistance. He indicated the smaller resistance was not especially significant; however, we speculated it could be factor as my coil packs continue to age. Removing the coil packs is easy on all but one cylinder and using a vacuum hose on the end of the spark plug makes it easy to lower it into its hole and get it started without fear of stripping the threads. By the way, do yourself a favor and check by removing the wiring harness to each individually as the engine is running; there will be a noticeable change except at the dead cylinder. Swapping the coil pack with one from another cylinder and then maybe a spark plug would have forced me to recognize I could have unplugged the suspected injector and tested it. Even a cheap ohm meter would have shown mine did not even move the needle. The injector was obviously defective.
2) Before removing the injector, be sure to pull the fuel pump fuse (under the hood on my 1993 J30) while the engine is running so the fuel rail will not be as pressurized; also, have the gas cap off. I removed the fuse and waited for it to stall but did not have the gas cap off. Little did I realize but the cylinder filled with fuel and although it could be related to removing the fuel lines in the way around injector #4, I think it maybe was the gas cap causing the problem.
3) I could have been more aggressive with the Dremel tool on the flange of the plenum to make removal of the screw and installing the new one easier; it was not necessary to break the screw loose initially. I was able to get the old screw broken loose by removing the easy one and them moving the metal cap back and forth with a Phillips screwdriver on the screw at an angle which made the seemingly impossible angle of the challenging one easy. There was no way I was going to get a Phillips head screwdriver squarely on the partially hidden screw. By the way reinstallation was easy with a magnet on the ball-shaped hex wrench allows the new bolt to go in easily after positioning the metal cap over the injector.
4) I used plenty of PB Blaster overnight and it still takes effort and finesse to remove an injector. Twisting and pulling finally did it. I would use a CV Boot Pliers from AutoZone or a rope with a noose around the injector instead of regular pliers. Another option is a flat-blade screwdriver to pry it out with a twisting motion. This would not have been such an ordeal if I had seen an injector before removing it. I would have waited to remove the injector until I had the new one. Be sure to keep the rubber spacer with its affixed metal washer that goes between the injector and the metal cap; my new one did not have this part.
5) Before installing the new injector use a flashlight to look in the hole to be sure fuel has not accumulated in the cylinder; it could have been a huge problem if I had not checked and siphoned it out!
6) Installing the new injector was more challenging than I expected and it did not have to be. I mistakenly used PVC pipe that was I inch (inside diameter) that was nearly a perfect match around the lip of the injector after notching it out. It would not go in even with Vaseline. The lip is more brittle than one might suspect and I broke part of it off when tapping this bigger pipe with a rubber mallet. Fortunately, Plastic Welder (epoxy) made by Devcon, selling for less than $5 worked well. It is far better to use ½ inch (ID) PVC pipe about a foot long notched-out. Installing the new injector takes finesse and hand-force only. A twisting and hand-pressure motion snapped it in much more easily. I tried tapping it with a big flat head screwdriver; however, even with enough force to leave a divot from the screwdriver did not do it. The twisting and pushing provided uniform pressure and snapped it in within a minute. Putting the cap on with the rubber bushings metal side toward the injector is easy if you just look at it for a minute and position it without the new hex head screws. The magnet on the 4mm ball-type hex head (Allen) wrench made it easy.
I probably would have tried this place that offers a lifetime warranty on injectors for about $45 http://www.directautomotivepro....html. 800-611-6730. There is a $12 core charge so be careful in removing the old one as mentioned above.
Experience is an incredible teacher, especially when we make mistakes. This forum and the 300ZX would have made it so much easier.
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yodawill2000
- Posts: 3888
- Joined: Thu Mar 24, 2005 4:10 pm
- Car: 94 Infiniti J30
- Location: Grand Prairie TEXAS