91 q45 missfire

[1991q45]

whats up, luv the site.has alot of useful info on the q45.

i recently bought a 91 q45 with 154k miles, body is mint! but she needs a couple bugs worked out on her.

first one is the missfire.she has a missfire at all revs.the exhaust smells kinda rich so i'm assuming it's an coil on plug.

i already looked on the fsm on how to test the coil but i hav'nt seen anything on it.

plus i searched here before posting same thing here.

also the key release stopped working.

the buton to release the key is already pushed in and on top of that the steering wheel doesnt lock (with the key out already).

theonly way for me to get the key out is if i i mess with the little metal tab.

so beside's these two issues she rides good, everything thing works...too damn well at that for the price i paid for her.

so if you can please help me out so so i can drive her asap!

thanks in advance!

[Infinitiguy19]

Please read the owners manual to see how to release the key, if you don't have one I can sell you one.

Please test you injectors to see which are good and bad and while your at it test the knock sensors too: http://q45.org/ohminjectors.html

Welcome to NICO.

[qship96]

Dont waste one dime on the old sled until you confirm the chain guides have been updated. If not, the first $ 1500 goes there, before you even drive it down the driveway again.

[Q451990]

Your miss is probably a dead injector... the coils are pretty much bulletproof on the early Q45. Welcome to NICO!

There are some posts about the stuck key too... but I can't remember where they are.

Welcome to NICO!

Heath

[1991q45]

the chain guides i already read up on.thats the first thing i did. because i assumed this engine came with a timing belt.but thats all good.

ugghh on the fuel injector. i did one on my 92 maxima and that wasnt really fun.

thanks for the advice.as for the key i checked the manual for that too.it's weird the owners manual for my maxima has a way to bypass it but the q45 manual doesnt.but i was able to get the key out.

it unlocks the glove box, trunk, doors with no problem.goes in the ignition and tunrs with no problems it's the getting it out of the ignition i'm having trouble with.

[qship96]

Are you saying you have replaced the chain guides?

[1991q45]

no. but there's dealer documentation which has been done.

now i know you guys are pros or gurus when it comes down to the vh45.but comparing the misfire once the q is warmed up.i smell the exhaust and it has the rich mixture smell.i know the smell of a lean running engine. thats the smell my maxima produces when the injector is acting up.

plus i drove to a gas station then drover her around for a bit (and i know its wrong but i wanted to see all the big talk was bout the vh45) so i gunned her and man she took off quick...too damn quick at that!lol!


Modified by 1991q45 at 6:05 PM 2/23/2009

[Q451990]

The Q will run rich while warming up - or if the thermostat is bad and it won't heat up to operating temperature. Your next step should be to ohm test the injectors.

http://www.q45.org/ohminjectors.html

Heath

[1991q45]

okay i'll do just that.thanks again, i know i'm probably coming off stuborn to you guys.thanks again!

[Haitian_King]

no. but there's dealer documentation which has been done.

now i know you guys are pros or gurus when it comes down to the vh45.but comparing the misfire once the q is warmed up.i smell the exhaust and it has the rich mixture smell.i know the smell of a lean running engine. thats the smell my maxima produces when the injector is acting up.

plus i drove to a gas station then drover her around for a bit (and i know its wrong but i wanted to see all the big talk was bout the vh45) so i gunned her and man she took off quick...too damn quick at that!lol!

Modified by 1991q45 at 6:05 PM 2/23/2009

I had a similar experience with a misfire that was confirmed with 2 power balance tests. The first one checked out fine as the engine was still cold. The second one showed the #7 injector as the culprit. I had some spare injectors and was getting ready to replace it, and then it went away.

From time to time it'll pop up at idle, but then will be smooth as silk for a long while after that.

If you're smelling fuel in the cabin while cold, the problem could also be your fuel lines if they haven't been replaced. I saw an article on the board about a pesky line near the firewall that can be fixed by tightening the clamp. The lines develop small cracks and leak while the car is warming up but generally seal themselves when the lines expand after warming up.

[1991q45]

okay i did the injector test.

all is fine but # 7 and #2.#7 is 18ohms and # 2 shows nothing?

shouldnt it show something but really high?

[goody90q45]

It's an infinite resistance reading. She's dead. If in doubt about #2, remove the center shroud covering injector #1 and #2 and measure the resistance directly on the injector pins.

#2 is probably the cause of your miss. You can live with #7 at 18 ohms but it will be going dead soon. #2 injector is an easy changeout.

[1991q45]

THANKYOU SOO MUCH!~!

well according to the link paul wall (lol) and q451990 sent me.

it stated that the readings will be bout 1 or 2 ohms off.checking the readings from the harness.so i'll live with that and #7 (if i looked at it right) looks easy to change also.

now i guess you can consider this as a dumb*** question.but i have a few 89-94 maxima vg30(sohc) fuel injectors that are excellent.

are those the same as the vh45 or will i have to get vh45 fuel injectors?

[goody90q45]

The odd injectors are on the driver's side, evens are on the passenger side. #1, #2 and #8 can be changed without removing the plenum. FI #7 is covered tighter than a spent nuclear fuel rod and you'll need to remove the plenum to replace it or grind on a couple of the plenum intakes to get a better angle for your tools. Remove the plenum to replace the injector, it's not that difficult.

[jmorasch]

just changed #7 myself,sounds like youve changed injectors before so it shouldnt be a problem.Id change them both at the same time.

dont for get to have the proper hoses,while you pull the intake the odds are your gonna need to change them.

welcome to NICO.

[Q451990]

now i guess you can consider this as a dumb*** question.but i have a few 89-94 maxima vg30(sohc) fuel injectors that are excellent.

are those the same as the vh45 or will i have to get vh45 fuel injectors?

I don't think they're the same... may look similar, but I would bet that the flow rates are different.

Heath

[Infinitiguy19]

If you haven't already figured out how to remove the key see this old topic: zerothread/149729

You ignition cylinder might be worn or your key might be worn, Show us picture of you key if you don't mind.

Or see if your key has rounded off groves.

[1991q45]

lol. yea i've changed them on my maxima.as for the keys...yea they look kinda worn.so for now i'm gonna do what the other member did.wedge something between it and leave it like that till next week to have the keys redone from nissan.

where do you guys recondmend buying from...besides the dealer?and no i wont be doin autozone either
Modified by 1991q45 at 2:51 PM 2/25/2009

[Infinitiguy19]

There was another old thread about that too but I am not at my laptop, But basically it says to not use anything but a dealer key for everday use, And if you have to use the aftermarket spare key rarely because you will ware out the lock cylinder.

Wes said in that thread that all 6 lock cylinders go for $1000 installed.

So dealer only = everday use.

After market key = rare use like if you get locked out.

[1991q45]

okay i fixed the key issue.so she's good in that area.i hav'nt taken off the ornament cover to check the injector.

at least i know that it's either the wire for the injector or the injector itself.

i do have another lil issue.i did'nt know that the vh45 had vtc problems also.

because when i start her up i hear the noise at first i thought it was the hla's, or the top chain tensioner/guide(that was the last thing considering it's been replaced).

but the noise is coming from the top in front right in the same area as the vtcs.

the driver side goes away once she warms up but the pass. side still does it.

i was either gonna get some engine restore or use a 1/2 of a small cup of transmission fuid.

[maxnix]

Ouch!

Much better to determine what is causing the problem. Start with connectors.

Why do people think something in a can will cure mechanical problems?

[1991q45]

because i had a 92 ve30de that had the dreaded vtc clatter.and a 1/2 cup of transmission fluid solved the problem bout 75%.then corroded connectors fixed the rest.it's not bad because i've heard worse.

but your right.as far as a inkow it could be a 10w40 in there.could be build-up.or the vtc solenoids...

[Q451990]

I have never heard of one VTC failure... well one, but it was damaged during a catastrophic timing chain guide failure. Apparently it took the dealership tech. over a week to diagnose, and included multiple calls to his tech. support line to figure it out.

Heath

[1991q45]

I have never heard of one VTC failure... well one, but it was damaged during a catastrophic timing chain guide failure. Apparently it took the dealership tech. over a week to diagnose, and included multiple calls to his tech. support line to figure it out.

Heath

oh...hmm.well if it's so uncommon for the vh45 think it's gotta be oil crud or something like that.

i'll just pour a lil bit of transmission fluid in the day before the oil change drive for a few minutes then change the oil.

in the mean time i got a few other things fixed.checking her out all over and stumbled apon a full service manual!

[maxnix]

well if it's so uncommon for the vh45 think it's gotta be oil crud or something like that.

If you have "oil crud or something like that", you have much larger problems.

Dont drive the car hard of rev over 2500 rpm until you change your oil and filter.

[1991q45]

okay well i have'nt driven her today (maxima was jelous. lol) but did check the injector itself and you guys was right it does look very easy once youo take off the fancy cover.

but got 0 so that injector is getting replaced for sure.

when she was cold no vtc noise, then once she was luke warm you can hear it but not as much. then once she's fully warm...nothing.

but it's not as bad as when i first got the car.so the more she's driven the more it goes away it seems like.

but yea thursday im gonna change the oil and use the synthetic too.

but i'm glad i'm finding out all of the issues (thanks from you guys) i'm having with this car not as hard or exspensive.

[1991q45]

okay here's an update.did the oil change (5w30 castrol senthetic) the tapping is there a lil bit.but goes away more once the car is fully warmed.

but i went to the junkyard to get the injectors so on top of it raining hard, me sick, the 2 q45's i seen there last week are now gone.

so before i bite the bullet and buy it brand new does anyone know if the use the same injectors in like a j30 or 300z??

if not does anyone here a a copuple for sale?

[Infinitiguy19]

TT 300ZX and SR20DET injectors are all the same as the Q45 ones, I don't know when the other models changed there pintle style though.

[1991q45]

damn! i think i would have a better chance in the 300tt...ehh...okay now my next question is will the car be fine with this one bad injector till next week?

[Q451990]

I think you'll be fine for a week. If you're buying used, might as well buy a fully cleaned and tested one from our sponser... http://www.deatschwerks.com

Heath