1995 MAXIMA misfire, engine front, most right cylinder.
Identified this location by unplugging injector.
NO ENGINE LIGHT OR CODE SHOWS
Swapped injector to another location, problem did not follow.
Moved Coil pack to another location, problem did not follow.
Compression.... cranking in that no.6 cylinder about 150
PLEASE HELP

 

Do you have a gasoline smell or smoke coming out the tailpipe? How do you know it is a misfire?

 

Runs like it is missing on #6 cylinder. Unplugged front injectors one at a time. Front Furthest Right made no difference in the running rough. The other two it got worse. Also replaced plugs in those three front of car cylinders.
New to Forum... Thanks for replying and offering Help

 

Moving suspect parTs from one cyl to another does help to isolate an issue.

Yet you did not mention moving the spark plug to a different location. Spark plus are generally the first thing to check.

Did the plug look greysh, brownish, or black?

Google : How To Read Spark Plugs.

 

I did just read in my research of forums that some codes may exist without the engine light on. Will have a computer/scan tool later today to see what that may show. I appreciate all advice and direction.

 

I did replace with 3 new ones in the cylinders in front of car. The plugs looked fine that I replaced and the same.

 

These cars do best with NGK plugs.

Which brand did you use?

 

BOSCH was all they had. I did read in other posts people frowning about Bosch or certain types of Bosch. I think I used basic Bosch.

 

Please look up how to read your plugs.

Look at the old ones. Post a picture.

What brand are your old plugs?

 

Our cars dislike Bosch plugs. NGK are best. We will be able to tell you more when you get codes read. Don't panic, this is fixable. Offhand, it sounds like coil pack, plug or injector.

 

AUTOLITE PLUGS, HAVE NGK PLATINUMS TOMORROW MORNING FROM AUTOZONE, Removed from front of car, believe right plug came from right front problem cylinder

 

These plugs look like they have beencountered fouled with fuel.

Does you gas mileage suck?

Has your car been hard to start?

Is your air filter dirty?

Please look at the current post called:

Have fuel and spark, but not starting.

His probable issue is the fuel pressure regulator.

Yours might be too.

 

I have been driving this car. 25mpg on 5 cyl. I drive it 2 hours to work and then back, then fill the tank and calculate the mileage. At 80mph you don't sense the miss....just around town, stops, taking off from stops is sluggish and idling. It starts and drives nice except for the miss.
I thought you would say the problem plug looks slightly wet compared to the other two. I have read in other threads to check the coil and injector harness signals. This could cause a problem and why the injector and coil when moved DID NOT move the misfire to another cylinder.
Thanks for your input.... I am still reading and performing checks and tests. Thank you
How do you test a FUEL PRESSURE REGULATOR? I have a standard fuel pressure guage.
What should the pressure be?

 

All three of the electrodes of the plugs look black.

They should look greyish to brownish.

So all three plus are affected by what is going on.

Fueling is common to all three.

I don't know of hand what the pressure should be.

Look in the Search portion of this forum, or Google it.

Look also at the posting I just gave you. His fuel pressure looks right at first, but drops rapidly.

Do what he did.

 

The furthest right cylinder would be cylinder#6 front row is 2,4,6, backrow 1,3,5, your having 3 plugs that are fouled and using bosh autolites that won't help. Thw car is supposed to use only NGK.

 

I am replacing the front row tomorrow with NGK platinums.... Honestly I hope something so small fixes it. If not I plan to somehow figure out the harnesses signals for the injector #6 and #6 coil. I believe the components to be good because they at separate times were swapped with cyl. #5 and still it was obvious that #6 is the problem cyl.
Thanks for all input and ideas and the clarification on cylinder order and location.
Thank you

 

So the problem continues with the one cylender even though plugs, coils and injectors have been moved around. The compression reading on that cylender is in the acceptable range.

You also mentioned that the problem cyl has a wetter plug than the others.
So it seems that the injector works ok.
But the plug does not fire at all, or is intermittant.
This might be an electrical issue in the wiring leading to the coil. I would start with checking the contacts to that coil for corrosion issues.
There are ground wires bolted to the uim or front head. Remove the bolt to the grounds. 10mm as I recall. Clean the contacts with fine sandpaper, then reinstall.

Your mileage of 25 mpg at 80 , while running on 5 cyl appears reasonable.

Are there starting issues? If so, that and the dark plugs, could indicate fpr leaks.

 

I need to verify correct voltages at the coil and at the injector. 12vdc system I understand but the injector signal varies 12vdc or just on/off?
I did review for hours other posts/threads. I did not see specific info about this test of the signals.
I did buy the NGK platinums this morning and will install cyl's 2, 4, & 6.
Plenum gasket ordered and will do the back later.
What style/name engine code computer is required? Connection type?
Have OBD 2, connector different
Will check FPR hose for gas as stated in other Posts.
Thank you all for responses.

 

To the best of my knowledge, the injectors have a constant voltage. Might be lower than 12v. The amount of gas injected in each pulse varies by how long the injector solinoid stays open. Like not long at idle, quite long when the gas pedal is floored.

There are two code reader ports. The odd looking one you found is for the Nissan dealer "Consult" computer. There is also a normal obd2 port.
On my 96 maxima, the obd2 is on the bottom of the dash, by the left knee. I recall that the consult port I'd in the fuse box.

The locaton of the 95 obd2 connector is somewhere else. I have read that it's somewhere on the passenger side. I'm just recalling what I've read here on the forum in the past.

You are doing just about everything correctly, and are doing your own research. You will find the answer.

 

Just thought of something.

Let's confirm that you have spark on that cyl.

Remove the coil. Leave the spark plug in the engine.

Put a spare plug in to the coil. Connect the trigger wire to the coil. Now ground the tip of the plug to the engine.

Now have someone turn the key. You should see sparks. If not, try another plug.

If neither one sparks, either the coil is bad or the trigger wire is not working. You might try to ground out a known good coil as well.

If the trigger wire does not work, I would do a resistance test between the coil end of the trigger wire and the computer. This would require a wiring chart, such as found in the Haynes manual, and a vom.

 

UPDATE: Still waiting on computer to check codes if available
Installed new NGK plugs, when pulling the Bosch with about 500 highway miles on them, It appeared that No. 4 cyl. bosch had a brown appearance compared to 2 and 6 being white like new. Performed test where I disconnect the coil plug while idling.
Confused but Today cyl. 6 is a noticeable difference when unplugged and cyl. 4 no difference.
Intermittent coil failure... maybe. Still checking .. will perform tests as advised.
Thank you

 

This is very good news! Most excellent.

So now the front most right cyl has a newish white
plug. This indicates that 6 is happy, and functioning properly. It's got proper compression, a good injector, good wiring, and the plug fires properly.

Your problem has now moved to #4.

4 has compression, good wiring, because it functioned before you moved parts around.
It used to fire up a good plug.

So you either have a bad injector, or a bad coil.
I'm going to guess a defective coil.

Now before you run to the parts store, know this:
Dont. These cars like oem coils Hitachi. And another oem brand. Another member like Wizard or CS_AR might tell us soon. The best and cheapest source might be the junkyard. Grab all three front coils from 2 4 6.

Don't bother removing the uim yet.

Do a fuel pressure test when you can.

 

Thank You JvG and others for all the support. Based on everything tried tested and seen I replaced the injector with an AutoZone injector and ITS FIXED for now. Thank you, thank you, Thankyaverrymuuuch!

 

You're welcome.

Congratulations.

Always nice to help a new member solve a problem.

You spent some time doing your own research.

Welcome to the forum!

 

CONGRATULATIONS!!!!! Next time you go to a junkyard, grab some injectors and coil packs for spares and keep them handy. These cars have coil pack failures as their number #1 problem. I have replaced 3 on my car already in 5 years. Not much else has gone wrong on my car.

 

i had the original coils on my engine till i hit 277,000 troo story

 

I'm at 210k miles. I've had the car 110k miles. No problems with the coils.

I had the injectors rebuilt at 180k miles while I had the uim off for other reasons. They still worked, but I figured that one or more would have leaked sooner or later. Old man Murphy would make that one of the ones under the uim I just replaced.

So I sent them out to be ultrasonicly cleaned and rebuilt at RX Injector in Houston. They found bad spray patterns on most of them.

 

If I may get some more direction please. Engine at idle, skips or cuts out for a split second randomly. Codes are po400 and po325. I did some reading... 325 I could test by a 460 ohm resistor being put inplace of knock sensor to test that, could not find much on the EGR 400 code that was valuable. It did say that KS code will come with a problem code meaning the real problem is not the KS but the secondary code which in my case is EGR.


Looking for direction or recommendations please. thanks Please help

 

As I said in your other post, the knock sensor code is not your problem. work on the P0400.