TonyJr

I believe I have a bent valve. I'm only driving on 5 cylinder instead of 6. It's drives ok with 5. I'm wondering if it's bad if I keep driving like this for awhile until I get the funds to repair this problem? Also which gasket should I buy in order to replace a bent valve? And the problem is on the firewall side. Thanks anything would help.

TonyJr

Ooooo yea it's a 1992 Nissan maxima se 5 speed

2brosgixxer

Way off topic, but how are you able to post new threads and only have 3 posts? I'm confused so am I missing something about the "15 Post" rule to post new threads?

LvR

Well - lets get to the bottom of this all ................ how exactly did you manage to figure you have a single bent valve?

Kountz430

was wondering the same thing

TonyJr

I checked the compression.

TonyJr

A local machanic said that could be the problem. He also said he would have to opened it up in order to see if it's only a bent valve. What sucks is this is my only ride. If they open it up then I'm carless for awhile.

James92SE

iTrader: (31)

If the car still drives adequately, and you can't afford to be car-less for a while - I think you've answered your own question.

LvR

I am sorry but I don't see how a simple compression test and even an experienced mechanic's diagnosis could possibly get you to the point to believe that you have a single bent valve.

Valves just don't "bend" by them-self ............... either there is more to this story ito other previous mechanical mishaps or you are going to be wasting your money and time pulling the head.

Why did you, based on your compression test eg not conclude that you have a broken ring or a burnt valve - why the "bent valve" diagnosis immediately?

What are the individual cylinder compression values?

maxinout93

I can understand the possibility of a burnt valve, but a bent valve, and the car is still driveable???? My car wont even start because tbelt skipped or slipped and I bent several valves. When the car was running and it felt like it was running on 5 cylinders, mechanics told me it was a burnt valve. But i did my own research and found out it was a fuel injector going bad. That may be your problem hopefully. After the injector was replaced it ran great, up until now.(replacing motor) now im carless.

ShocknAwe

iTrader: (3)

If you had a bent valve and have been driving it your engine would have had catastrophic failure. It has got to be a broken ring if its still drivable AT ALL. I would fix it immediately if I were you. A lot of shops are struggling right now and if you call and say "hey I need this to be fixed in one day is that possible?" they should be able to get to it. Just might take one of your vacation days to do it though

LvR

FWIW - its actually quite possible to drive with a bent valve - it all depends on the severity and position/location of the bend in the stem and how much of the valve lift is taken up by the bend - if its only slightly bent and eg it only remains open about 2mm from a fully closed position, then the motor will undoubtedly run. Question still remains though how the valve got bent at all .................... imo the fix is not the correct answer - the tracing of the cause is the correct action else it will undoubtedly happen again.

TonyJr

Well I checked spark plug and its ok, I switch coil n it's ok. At first I though it wasn't getting power to the coil n that's ok. When a person unplugs a coil from the harness u should feel the motor stumble a little likes it's lost power. Well when I unplug the top left plug nothing happens. Should I post a video of it for u guys can understand better?

LvR

Sure sounds like the common failed injector issue to me - I would definitely NOT start stripping heads and replacing perfectly straight valves at all.

Stickies and forums are full of injector fault-finding and replacement info and threads.

shiloh51933

iTrader: (5)

+1

Bring it to another Technician before you get ripped off.

Laevateinn

iTrader: (3)

You might wanna be sure. Have 'em do a dry and wet compression test to isolate the rings from the valves.

TonyJr

I'll check the injectors . I keep u posted

inhalation2

I second that always get 2-3 mechanics to verify what the frist mechanic says.

TonyJr

I bought a injector today n I'm going to replace the one that I believe is bad. Which is the underneath the coil that doesn't not seem to function right.

maximagician

how many miles is on the car and motor?

TonyJr

Well I bought the car with about 223,000 for $700. The owner of the car said he swap the original motor. It's still a ve30de , it's a very clean motor and u can tell it's has new gaskets and the head been rebuilt before installing motor. The only problem it has is the hesitation. Which I'm really thinking it's the injectors. Right now I'm just making sure I have the right tools and parts to install one injector lol. Correct me if I'm wrong but all I have to do is disconnect very thing on the upper intake manifold and disconnect the old injector and put in the new one. Right!!

LvR

In theory its all that is required yes - in practice you are bound to find that the old injector and O-rings have sorta mated with the rails and they are often a female dog to separate. Patience is the answer (read the many threads on injector replacement) and make sure you fit new O-rings else you will be doing it again

TonyJr

Lol yep I heard about how they can be a ( female dog) to take out.

maximo018

iTrader: (6)

Read the FSM on how to do it. Done it several times already. If the original screws are on the pinnacle caps then you will require a impact driver to remove those. DO NOT (I repeat) DO NOT TRY TO REMOVE WITH SCREW DRIVER! You will F.U.B.A.R. them up and make it even harder if possible to remove with impact driver. Once caps are removed grab injector from top and twist from left to right while wiggling and tugging up. In time (usually 2-5 mins ) the injector should free itself from fuel rail. Don't use a screw driver to pry it out. You will mess up the port for the o-rings. You can you a flat head to assist when the top lip of the injector unseats from the fuel rail to lift it up and out. GL Your fingers/ thumbs will be sore.

TonyJr

I got the fsm from auto parts store going to do it today but should I buy a new upper intake gasket

TonyJr

http://www.youtube.com/watch?v=4AZgZgS3JBo&sns=em


Here a video of the problem. It sounds like a chripping sound. Maybe it sounds familiar to you guys.

TonyJr

Here another video

http://www.youtube.com/watch?v=LHRG-WW5oVo&sns=em

LvR

At a loss atm ................ did you replace the injector you found to be faulty?

Didn't make any difference? - to either the "5 cylinder" or the "hesitation" thing?

From those 2 videos I am not able to say anything other than it seems to pull fine and that you probably have a non-OEM intake filter set-up.

TonyJr

Lol yes it aftermarket intake. I didn't have time to install the new injector. Like I said it drive great but has that minor hesitate

LvR

There you go then - that already could explain both the sound and the hesitation thing ...................... often top-end performance (what most after-market intakes are about) is gained at the expense of "drive-ablilty" at lower engine speeds

TonyJr

That hesitation n chripping sound is only when I'm on gear and driving. But when idle it fine.

TonyJr

It's was doing it before I installed the aftermarket intake filter. And I'm starting to think it's the maf sensor because of the problem only happening when I'm driving. I'm still going to change the injector since I already bought it.


Ok my ? Is why when I unplug the connection to the top left coil nothing happens. When I unplug any other that I unplug reacts to it

LvR

The chirping thing is most likeley due to funky airflow characteristics as I said and running without the OEM intake plumbing - at idle there is minimal airflow so it obviously will not whistle/chirp ................... its only when you start chasing hordes of air through the tubing that things start resonating.

"IT" being the noise or the hesitation?

If "IT" was the hesitation then you have the answer already - fix the cylinder you KNOW is not working properly ALREADY and start from there afresh. Misfiring cylinders screw the O2 feedback loop and the whole mixture control so you are chasing your tail speculating about anything else till you have fixed what you know for a fact is wrong.

So I take it you have not read any of the injector fault-finding guides/threads here then? ..................... that is the classic symptom of either a funky coil/injector/ECU/wiring. You sodding off and buying an injector solely on my guess based on experience is probably right so fitting it will not hurt anything, but then again just as with the "bent valve" theory you started with here, you may be wasting your money without proper analysis.

maximo018

iTrader: (6)

Yes. You could have got the FSM for free on here.

maximo018

iTrader: (6)

Wow where did you get that 90s wood trim? Lol. Anywayz check to see if you got a vac leak while your at it.

TonyJr

Wood trim came with the car. Well finally I have time to work on the car and my plans is to buy a 470 ohm resistor for the knock sensor and change the injector that I believe is bad( the coil that has no action taken when I unplug it n no it not the coil or the spark plug, I switch it to another cylinder n it work fine) and hopefully I will solve this hesitate problem. But I will post another video right before I start to work on it of the engine bay

TonyJr

I just check the compression on the cylinder and it's good. I just don't get it. It has spark on coil ,it has good compression, there gas on the tip of the spark plug. I bought the injector for nothing. I can't figure it out. Can the injector be bad and still shot out gas through it? Or can the injector be clog and not be working 100%

LvR

If there is proper compression, correct fuel and spark at the right time on that cylinder there is no way it can be misfiring.

Is the new injector installed properly? ................... especially wrt the use of new seals? Screwed-up seals will flood that cylinder (and the motor eventually too) guaranteed.

Well - I did warn you to do the fault-finding properly

At least you have confirmed (?) that the original bent valve theory was indeed funky as suspected




Erm hang-on.

Initially when I asked you how you figured that you have a bent valve you saidSo lets start again:

You now say you checked compression and its fine WTF!

Is the compression correct or not? ........................ post the compression values for all 6 individual cylinders because somebody is wasting time and money here and its not me.

jordan101

yes it is bad. dont drive it.

TonyJr

compression is good. im changing the injector on monday so ill keep u posted.