I am getting a rough idle, so I took my car to my local shop for diagnostic. They said my #3 injector was at 24 ohms. The next day I took the car to Infiniti for diagnostic and they said both the #1 and #3 injectors were over 24 ohm and need replacing.
My question is, is my only repair option to replace the injectors, and if it is should I replace all eight? Can a cleaning help the bad injectors?
Any information will be appreciated.
'94 Q Injector Problem-Replace all or none? f
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Professor_Mike
- Posts: 96
- Joined: Wed May 01, 2002 2:19 pm
Professor_Mike wrote:We have replaced 1 or 2 injectors successfully, only the J seems to require all 6. Have had to replace all 6 on 2 different occasions.
Regarding the J30 injectors: Is the replacement of all 6 due to simultaneous failure/degradation or does the failure of one injector affect the other 5?
Since the plenum has to come off for #3, this will be expensive. Injectors are $150 ea. from Scottsdale, so you're cooked anyway you look at it. Plenum off and two injectors would be minimum $1000, probably more like $1200.
So, you've already spent at least $1000. How can we keep this from getting completely out of control?
In for a penny, in for a pound? You'll pay $700 to take the plenum off again when/if the next injector fails. Since your injectors seem to be failing at an alarming rate, you could spend an extra $1000 - $1500 this time and get all-new injectors, gamb|ing that you'll save the $700 plenum off/on a time or two.
My plenum most recently came off for coolant leaks caused by a dealership mechanic replacing the knock sensors, courtesy the previous owner. It might not be long-term smart to disturb the plenum without replacing nearly everything under it that may fail under normal use, including knock sensors. Replace all the under-plenum hoses, too ($200 - $400 ka-ching!) for the same reason. The added resistance problem could be in the injector wiring harness, but you won't find out until the plenum is off.
This all begs the question -- how long do you want to keep the car? Me, I would rather do it right the first time, hold on to the car to "drive" value out of your preventive maintenance investment. It sure beats lease payments.
OR
Word is that you can get to the outboard 4 injectors w/o plenum removal -- I don't have any reason to doubt that, but I've never done it. I think this is originally Fred's suggestion -- you could put your oldest 4 (most likely to fail) injectors in these outboard positions, put 4 new ones under the plenum. That saves $600 this time compared to option 1, and is only $300 - $500 more expensive than replacing just the 2 that are bad today.
Don't fool around with "remanufactured" injectors. When replacing just one injector might be a $1000 adventure, the $100 you might save seems pretty pitiful.
You're in for $1000 minimum. You could easily be in for $3000 to "do it all," but you really would have done a lot. This is of those times when you ask yourself how much more use do you expect to get out of the car. Me, I cut all my bills down by at least half, sometimes 75% by doing it myself. Not for everyone, but it helps me make sense out of keeping the Q.
So, you've already spent at least $1000. How can we keep this from getting completely out of control?
In for a penny, in for a pound? You'll pay $700 to take the plenum off again when/if the next injector fails. Since your injectors seem to be failing at an alarming rate, you could spend an extra $1000 - $1500 this time and get all-new injectors, gamb|ing that you'll save the $700 plenum off/on a time or two.
My plenum most recently came off for coolant leaks caused by a dealership mechanic replacing the knock sensors, courtesy the previous owner. It might not be long-term smart to disturb the plenum without replacing nearly everything under it that may fail under normal use, including knock sensors. Replace all the under-plenum hoses, too ($200 - $400 ka-ching!) for the same reason. The added resistance problem could be in the injector wiring harness, but you won't find out until the plenum is off.
This all begs the question -- how long do you want to keep the car? Me, I would rather do it right the first time, hold on to the car to "drive" value out of your preventive maintenance investment. It sure beats lease payments.
OR
Word is that you can get to the outboard 4 injectors w/o plenum removal -- I don't have any reason to doubt that, but I've never done it. I think this is originally Fred's suggestion -- you could put your oldest 4 (most likely to fail) injectors in these outboard positions, put 4 new ones under the plenum. That saves $600 this time compared to option 1, and is only $300 - $500 more expensive than replacing just the 2 that are bad today.
Don't fool around with "remanufactured" injectors. When replacing just one injector might be a $1000 adventure, the $100 you might save seems pretty pitiful.
You're in for $1000 minimum. You could easily be in for $3000 to "do it all," but you really would have done a lot. This is of those times when you ask yourself how much more use do you expect to get out of the car. Me, I cut all my bills down by at least half, sometimes 75% by doing it myself. Not for everyone, but it helps me make sense out of keeping the Q.
Todd, thanks for the reply. I have a couple more questions. I think I will replace all of the injectors and the other items under the plenum. A local shop, not the dealer is doing the work, will I have to tell them to test the injector wire harness or is it a part of the computer diagnostic? Also, what knock sensors will need to be replaced? Thanks.
Kirk
Kirk
Excellent compromise solution. Great imagination! With a depreciating asset like a car whose main purpose in being is to transport (in this case in stlye), cost containment is paramount especially if maintaining the absolute value of the car as a transportation device is the goal. Great thinking! :thumbuplandtodd wrote:
OR
Word is that you can get to the outboard 4 injectors w/o plenum removal -- I don't have any reason to doubt that, but I've never done it. I think this is originally Fred's suggestion -- you could put your oldest 4 (most likely to fail) injectors in these outboard positions, put 4 new ones under the plenum. That saves $600 this time compared to option 1, and is only $300 - $500 more expensive than replacing just the 2 that are bad today.
Don't fool around with "remanufactured" injectors. When replacing just one injector might be a $1000 adventure, the $100 you might save seems pretty pitiful.
You're in for $1000 minimum. You could easily be in for $3000 to "do it all," but you really would have done a lot. This is of those times when you ask yourself how much more use do you expect to get out of the car. Me, I cut all my bills down by at least half, sometimes 75% by doing it myself. Not for everyone, but it helps me make sense out of keeping the Q.
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Injectors only fail from the gasoline you purchase. Blame that on your state or US EPA. Well you do get blame if you don't flush them regularly and keep the fuel filter changed.
Out of the almost thousand Q we service only 13 have had even a single injector failure. 1.4 percent!I ask the out of towners and this is the bulk of the number.
At least one thing you can't blame Nissan for!Same with Knock sensors mine have functioned for almost 13 years......as have every unit that has not been subjected to a overheat.The plenum hoses [all rubber hoses are only warranted to last 6 years] and that is their life no doubt about it!
Out of the almost thousand Q we service only 13 have had even a single injector failure. 1.4 percent!I ask the out of towners and this is the bulk of the number.
At least one thing you can't blame Nissan for!Same with Knock sensors mine have functioned for almost 13 years......as have every unit that has not been subjected to a overheat.The plenum hoses [all rubber hoses are only warranted to last 6 years] and that is their life no doubt about it!
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Q451990
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- Car: 1990 Q45 - 118K, 2022 Toyota 4 Runner, 2004 Frontier M/T - 108K, 2012 Xterra (Mom's), 2023 Rogue (Inlaws)
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Back in 1997 or 1998 (a month or so after the 100K warranty expired) I pulled the plenum and replaced one bad injector, only to have one more go down a week or two later. At that time I didn't know the ohm test, but the Consult tests showed 0RPM on the offending cylinder. After the second failure I replaced the remaining seven with remanufactured units. The remans had a bleed down problem that flooded the engine (no hydrolock, just hard starting and some black smoke unless the car sat overnight - I guess the gas was leaking down past the rings over time.
So I pulled the plenum a third time - replaced everything with OEM parts and all was well. Remind your shop to lubricate the o-rings to avoid pinching them when they put the new injectors in the rail. I'd go ahead and check the resistance on the knock sensors - if they're in spec and the cases aren't cracking, then they should be fine. I'd still replace the knock sensor harness though - they are very failure prone. If the harness looks really good (no corrosion) you might just tighten the pins a little, pack some dielectric grease in there and hope for the best. Replace ALL of the PCV hoses or you'll get a leak 3 months later after they try to reassemble the brittle ones. Definately replace the cooling hoses that cross from the left and right banks and the one from the filler neck.
You're getting ready to drop some serious cash, but when it's done you should be good under there for another 5 years. Every Q owner goes through this, the only question is how many times...
Good luck!
Heath
So I pulled the plenum a third time - replaced everything with OEM parts and all was well. Remind your shop to lubricate the o-rings to avoid pinching them when they put the new injectors in the rail. I'd go ahead and check the resistance on the knock sensors - if they're in spec and the cases aren't cracking, then they should be fine. I'd still replace the knock sensor harness though - they are very failure prone. If the harness looks really good (no corrosion) you might just tighten the pins a little, pack some dielectric grease in there and hope for the best. Replace ALL of the PCV hoses or you'll get a leak 3 months later after they try to reassemble the brittle ones. Definately replace the cooling hoses that cross from the left and right banks and the one from the filler neck.
You're getting ready to drop some serious cash, but when it's done you should be good under there for another 5 years. Every Q owner goes through this, the only question is how many times...
Good luck!
Heath