tilt

Hey guys. This is a bit lengthy but please take a moment to bare with me and my '92 maxima gxe.

I took my car to the mechanics to have my #5 fuel injector replaced (it wasn't firing at all ). I noticed when I got home that my car was making a puttering sound, and especially if I was parked. When I'm idle, whenever the car putters (it feels like it's about to stall but never does) the tach falls about 100 rpm but then goes back up. When I rev the engine it makes a pop sound every now and then... though it's not loud like a backfire. This never happened before my #5 fuel injector went out. When I drive my car around the puttering goes away almost completely... it's still there but almost unnoticeable, but as soon as I put my car back in park the puttering and poping comes back.

I checked all of the injectors and they are ticking but my guess is one of the injectors is missing every now and then. I replaced my spark plugs and cleaned out the throttle body but neither helped the situation. I had my spark plug wires and distributor replaced before the fuel injector was replaced so I dont believe those are the problem either.

The mechanics said they couldnt help me until I fix my rear downpipe (a broken stud), because they said it affects the o2 sensor. But it has been like that for some time now and hasnt ever affected my car in this way prior to having my injector replaced.

If anyone can help me out or has any suggestions, please let me know! thanks.

tilt

follow-up... hey guys I just realized that when my distributor was replaced, cylinder 5 wasnt working. Sorry, I'm not too familiar with this area but, would the mechanic need the #5 cylinder functioning to have the distributor working properly? does he even need to adjust timings at all?

Turbo Todd

Take it somewhere and get the codes read and see what is showing up. Then have the codes cleared and see if it gets better. then check codes again and see if a new one shows up. That will tell you where to look next.

Check all the spark plug wires nad make sure there is not a loose one on the distributor or on a plug. The distributor swap should not matter if all the injectors are working or not. but if there was work performed in that area it would be best to look there for something that was not done correctly.

tilt

follow up... ok i just realized that whenever the knocking, puttering happens there is white smoke that comes out of the exhaust. does anyone have any ideas what it is buring? would that happen if one of the cylinders is missing?

Also after I cleaned the throttle body, whenever I start the car or after I've been driving for a while and then place it in park, the tach will jump to 2000 rpm then slowly die down to 700-1000 idle. This has never happened before... so maybe it's worth a mention.

I checked the distributor cap. all the wires are snug. I might try a resistance test on them, or swap the cables with my old ones since I know they work.

As for the codes, I will have to try that out next.

eric93SE

iTrader: (1)

when they replaced the distributer they could have put the wires in the wrong sequence into the dis. just a thought but check to make sure that the distributer wires are going to the correct spark plug.

davis4004

If white smoke is coming out that probably means unburnt gas, so one of your cylinders is misfiring. I think I heard one time you can figure out which one is misfiring by removing the spak plug wires and seeing if it changes the way it runs. If it runs the same as before then you found the bad cylinder. As far as the mechanic telling you that the 02 sensor is affected by the broken manifold stud, I don't know how those could relate unlesse pressure affects the sensor.

nuthut957

Tilt!

Your mechanic botched the job! One or more of the lower injector O-ring is pinched and leaking!!! You mentioned changing the plugs, if one of the spark plugs is more carbonized (blackened) that cylinder's injector is your cuplrit.

I just got done replacing ALL the injectors on my '92 GXE. Did the job once - twice and had the same problem. Finally got smart and pulled the fuel rail and pressure tested. Bubbles around the injector o-ring (another sign is black residue around the injector port on the manifold). Unfortunately, just wetting the O-rings with gas isn't enough lubrication to keep them from pinching and ripping when installing as the manual suggests - - use an extremely light coat of grease.

Have him pressure test the fuel system through the fuel rail, if he can, or else fire his *** and sue him in small claims court for the follow-up job. Pep Boys does the work for 2 hours labor ($150 in Denver).

Also, be sure that all the injectors are the same type.

INJECTOR COLOR CODING: There are TWO type of injectors for the 92 GXE a BLUE (better) and a BLACK (eh), labeled by paint marks on the side of the connector. NO! They are not interchangeable! i.e. ALL one type or the other no substitutions (per a Nissan Mechanic). Mixing them leads to performance and possible computer problems.

I had one replaced in May last year and found that the Mechanic had replace a blue with a black... so I decided to do the job myself. Not so bad, get the Haynes manual, took about 4 methodical hours. If you're mechanically inclined you can remove an injector plug and ident the injectors yourself without a major hassle -- slip out the metal clip with a pair of needle nose pliers then slide the connector off, don't do like some dork greaser mechanics and grab the wires and rip them off -- tears the insulation boot and possible permanent damage. You'll see either a blotch of paint (aftermarket) or a colored spot (Nissan) on the side of the injector electrical connection*. To replace: reinstall the metal clip into the connector first; spread from the inside and slide in place, then you can snap the connector back on.

*If you want, use a multimeter and check each injector resistance, I found the norm is 11-14 Ohms, though the spec is 10. Anything higher the injector is probably doomed.


SIDENOTE - PRICING: I found in my travels that NEW Nissan Injectors even being more expensive are a better investment than the aftermarket (rebuilds). The dealer commented that the rebuilds tend to have "leak-down" problems and a shorter life. Yeah, you can source them through other places, I found the aftermarket Black injectors for as cheap as $45... reliability... ? I later found out there is a national recall on Nissan injectors of that era, so this might be one good investment from the dealer.

Found mechanics that would do the work if I brought them the parts. Anyway there's no exchange involved and this gives you a set of used backup injectors if you need them.

If you need an even-longer winded reply drop me note:

nuthut957@hotmail.com

ToM ;-)

Ps: Yes some of the studs broke on the rear exhaust manifold too. Damn they are a ***** to fix, had to helicoil a new stud in place. Still leaks on occasion, one of the few (only) bad designs of the Max.

tilt

nuthut957 and davis4004, I think you guys are right on the money. The resistance on the injectors are right around 12 ohms so I know they are electrically ok. It's looking more and more like it's leaking fuel because of the O-rings. I'll have a word with the mechanics. Thanks guys.

Turbo Todd

I changed injectors on a mustang once and had an o-ring that got pinched on the top of the injector. When the ignition was turned on it looked like a sprinkler under there spraying in all directions. This is bad!
Not sure why I didn't think of that myself. that is probably going to be the issue. Good luck!

Bill Doran

Did you ever solve the high idle, I cleaned my throttle body and have been getting idle periodically shooting up to 1200 rpms?

tilt

Ok guys... before I was going to take my car back to the mechanics, I wanted to see if I could fix the problem myself... and thanks to nuthut, I took a better look at my injectors and the color of the new injector is Blue but all the other injectors are Black. I called up the mechanic and he said, "the colors used to matter, but now the color doesn't matter anymore." ??? Is he BSing? why would the injector still have a color if it doesnt matter anymore? can anyone explain?

I've went ahead and decided to try to fix the problem myself. I've removed the intake collector and am down to the fuel injector rail. This is where I'm a bit confused... Do I have to remove the whole fuel rail for one side? or can I just remove one injector?

tilt

Bill Doran... no, I'm not sure why but it still shoots up to 2000rpm.

Bill Doran

I carefully pry up the injector using 2 small screwdrivers after removing the retainer clamp. The plastic caps are soft so be careful.
Once the injectors are a little loose you can pull them out. Be sure to change both O-rings when you replace injector. Your mechanic is BS the injectors should all match in color, all black or all blue. I'm pretty sure you will find the lower injector was pinched causing the miss.

CDoja

I just hope this dosent happen to me....

tilt

thanks man, I just got it out. I'm gonna go get an injector from nissan and lube up new O-rings and see if it fixes everything. What kind of lubricant do you think I should use? I heard that Vasoline works... can anyone confirm this?

nuthut957

tilt:

If you're at that point. The best thing to do is remove the complete fuel rails (injectors and metal fuel line and rubber connecting lines) the job removing an injector is alot easier. Lemme 'splain. Originally when I replaced the injectors I used a pliers (not good) and ripped 'em out, I didn't care, I was going to replace them all. Alot of damage because they're sealed in there pretty tight after compressing the o-rings and all. But when I was having problems EXACTLY as you have had, I needed to remove/inspect the new replacement injectors. That's when I found I had ripped the new bottom (and a top) o-rings on the replacement installation.

ONE NOTE; Before removing the fuel rail, be sure to plug the intake ports with paper towel or rags, so none of the insulating rings or washers that hold the fuel rail in place fall down in there. There's only 4 socket head cap bolts that hold the fuel rails in place, the hardest thing is removing the inlet and return fuel lines (be sure to release the fuel line pressure and disconnect the battery). Other than the bolts/insulators/washers the whole assembly lifts out, the injectors may be stuck to the manifold insulators (rubber seals), no need to disconnect the lines between the rails.

Same problem with removing replacement injector's; they're in there for good, but I found after removing the whole fuel rail assembly, I could use a socket and push them out from the bottom up. Find a deep-socket that fits over the injector head and inside the housing (I think a 7/16" worked -- not sure?). Just be sure your not pressing on the injector head but rather the bottom of the injector/lower o-ring. It takes a good bit of force holding the rail in both hands and with two thumbs on the socket press the injector back through the housing. Of course, remove the injector caps, be careful not to loose the little washer/spacer that goes between the cap and the top of the injector. One note, removing it this way is like launching a champagne cork from a bottle, so wrap the thing in a rag to catch the injector a keep it from bouncing across the floor (did that once, doh).

You're "mechanic" is a greaser, fire his butt.

If you have access to a air compressor: I plugged the fuel inlet and made up a quick connection so I could pressurize the assembly from the tank return line. Then I sprayed some WD-40 around the O-rings to detect leaks. The fuel line pressure is rated at 36-44 psi, but I think it must peak higher than that, anyway my assembly sealed with 80 psi (I wouldn't go any higher). A good shop may be able to do this for you, plus check the injector spray pattern, call around for a fuel rail pressure check etc. if you bring them the assembly. You'll gain new respect. Most shops test them this way.

Good luck and congrats on taking the leap into knowing your Max to the max.

Ps: Don't over-torque the intake manifold bolts, etc. only to specification -- steel bolts into aluminum equals easy strip! Replace the upper and lower plenum gaskets (if your mechanic charged you for these but didn't replace them - - there's your answer to his honesty).

Double check your vacuum lines for old rubber cracks etc. replace a/r.

Call your local Nissan dealer and ask the service tech. about the color coding on the injectors.

nuthut957

Just posted a note but notice you got the injector removed. I used good old moly grease. Vasoline should work also 'cuz it's petroleum base. Most any grease will easily dissolve in fuel (especially today's fuels). Just use a super-light coat.

Good job.

Ps: Don't overtorque the intake manifold bolts, etc. only to specification -- steel bolts into aluminum equals easy strip! Replace the upper and lower plenum gaskets (if your mechanic charged you for these but didn't replace them - - there's your answer to his honesty).

Double check your vacuum lines for old rubber cracks etc. replace a/r.

Call your local Nissan dealer and ask the service tech about the color coding on the injectors.

tilt

thanks to you guys, my car is fixed! Like you guys said, turned out the o-ring was pinched. I called up my local nissan parts dealer and he says the colors should all match and that it isnt a good idea to mix injector colors. I had to put the blue injector back in because the dealer was out of stock of black ones... I'll be putting the right one in as soon as they get the order in. Oh yeah, my idle is back down to normal as well. Once again, thanks a million to those that helped me solve this problem. Cheers

maxinout93

IVe got a 93 gxe and my injectors are all green dot. I have a few pink dot that I am installing. Will see how it works out