maxinout93

I have a 93 gxe vg30e engine. I suspect my injectors to have an intermitt failure, as sometimes they work better on some days, and other times they take a little while to kick in without giving the car gas, anyways i recently noticed that while im driving highway speeds of 55- to 70 and above, I feel a slight miss from the engine, i just tuned the car up, new plugs, pcv, and distributor cap and rotor. But i still feel the miss, and was wondering if anyone else had the same problem. Sometimes it idles really rough and I have to put it in neutral to keep the idle speed from dropping. Any help would be great! Thanks

Garf

iTrader: (1)

yes. you probably have one or more injectors on their way out. run some injector/ fuel line cleaner through the car, no harm if it doesn't help. please search about this, or take 2 mins to look through the first page or 2 of 3rd gen threads. start ohm testing all your injectors. they should read 11-14 ohms of resistance. if they don't they are dead/dying. you may also want to try checking for any cracked vacc. lines /potential leaks in the intake.

EDIT: you may also want to check/clean your MAF, just b/c of the idle issue you are having, but it sounds like injectors.

burhan92SE

while engine running unplug each injector turn wise till u see no difference in engine's health and hope u find the satan...plus how about ur spark plugs? how old r they? i used to feel like really bad miss wen i used to zip it to 4000 rpm changed the plugs everything went away....how about maf? did u clean it latley?...how about IACV...cleaned it?...u will find something in those things...i m sure....been through these all already

1993-VG30E-GXE

Yes Maxinout I had the same symptom as you a few months ago. One of the injectors was dying, until finally it died and went rough permanently till I replaced it. I tried the power balance test like burhan suggested as per FSM, but couldn't tell any difference in engine speed or feel. Digital multi-meter did detect a dead injector though, which I did after the power balance test.

DennisMik

iTrader: (2)

I had 3 injectors on my 94 gxe do the jeckle and hyde thing, not work and then work. when I checked the ohms, I had readings in the 60 and 70 ohms.

maxinout93

Well I finially figured out the problem!!! It is a bad injector, and now the problem is very obvious! At first I could not really pinpoint which injector it was as I unpluged each one. There was a drop in engine speed. As of today and yesterday, The idle has gotten worse everytime I come close to a stop! It did it all day today, so im thinking that injector is dead or almost completley dead, as also my gas mileage totally sucks with that miss from that bad injector! I parked the car and looked under the hood, as it was missing and stumbling really badly. I unplugged each injector and listened to see if it affected the engine speed. The three in the rear were ok(for now) the middle one in the front was dead, as it made no difference in the engine idle. I could not check the first one on the front bank, but to be on the safe side, I will most likely replace all three on the front side. Thanks to everyone who responded, It really helped out!!

'92SEJR

But can someone walk me through how to replace a fuel injector on my firewall side. It would be under my intake manifold... farthest on the passenger side, I have the VE motor, has an absolutely terrible idle and have already replaced one injector. This is the last one but I have no idea how i'd get to it without taking my intake manifold off. Help would be MUCH appreciated. Thanks

jakeru

These injectors have copper electrical terminals. Fresh copper is a great conductor. So they work great when new. But dark color/black corroded/patina'ed copper does not conduct electricity at all. Try it with your ohm-tester. Move around on various places on your injector. Then try scratching the dark copper surface clean, until it is bright shiny copper. It will conduct like new again.

I think material selection of the injector electrical connector (copper), torn rubber electrical boots (my maxima has three torn, three in tact), and old age contribute to the problem.

I wonder how many perfectly good injectors we're replacing that all they need are their copper electrical connections scraped/restored, to be maybe good to go for another 10-20 years.

If anyone has a good idea how to clean those copper conductors easier than mine (which is, scraping them with a small sharpened screwdriver.) Let me know. I only scraped a couple of mine (that needed it the most) and still need to do the rest because now I think the others I didn't do yet are acting up again. Preferably with minimal intake manifold disassembly and also leaving the injectors and rails installed in the engine.

I'm thinking some sort of dremel wire brush exists that may do the trick (it's got to fit inside the plastic electrical terminal housing, which is a pretty tight spot), but I haven't located it yet.

jakeru

To answer my own question: I just googled and found some easier, chemical methods of cleaning off copper oxide:
http://cruftbox.com/cruft/docs/cleaningcopper.html

Can Taco Bell hot sauce (or rather, a mixture of vinegar+salt) really help our maxima get rid of their misses? :O Maybe I'll guinea pig!

1993-VG30E-GXE

Maybe a fine carbide tip abrasive tool that goes on the end of a die grinder?

jakeru

The small carbide tip is not a bad idea! It's probably what I'd do if I hadn't discovered hot sauce. Because there may not be any dremel wire brush tip available small enough to get in between plastic housing and electrical connector.

I tried the hot sauce on a penny trick. It worked! I think it should work to clean corrosion off copper electrical terminals too. Hot sauce is cheap, should be easy to apply, and easy to clean up (I'll just squirt it away with water after it's done it's job.) I'm going to try it to get rid of my miss!

jakeru

As an update - I tried using chemical cleaning methods on my maxima's injector connectors: first brake parts cleaner (to clean any grease), then baking soda+water (to neutralize any acid salts), then hot sauce (to eliminate any copper oxide) and anyway I found there was some "layer" over the connector that prevented it from working. What was effective in removing it down to bare copper was, scraping the terminal with a jewelry/micro-sized, flathead screwdriver.

Unfortunately, cleaning the terminals didn't repair two injectors which were reading in the kiloohm area (rather than the expected ~ 12 ohm area), so oh joy, I get to replace some injectors again.

I was surprised I got the high ohm readings on two, because usually the engine fired on all six, it only intermittently dropped down to five or four cylinders and usually running it a while cleared it up.

I am imaginging heat causes the electrical circuit inside the injector to be connected, or go disconnected somewhere and stop the injector from working.