S1cTech

I can't really pinpoint what it is, but the car has an extremely rough idle for the first 10-15 mins of driving and constant misfiring when I am driving, its been like this for like 2 months now, I just tried to live with it, but I can't do it anymore, epepeally when I am now starting to hear a knock from all the unburnt fuel. My MPG isn't great but still the same it has always been.

Did a complete tune up and everything under the sun last summer besides taking out the injectors and cleaning them physically and changing the coils. The only thing I can think of is the MAF? and it runs fine after it is warm because of the hotwire?

Maxima 97 SE

Bad fuel injectors. You will have to find out which one and replace the ones that are bad. Go to a junkyard or go on ebay and by a used fuel rail that comes with all 6 injectors which will be cheaper and replace them. The misfiring and the unburnt fuel is all becuase of that and if you keep driving like that your engine will soon be bad and wont be running like it should. Since your engine has been knocking do to the bad fuel injectors I insist that dont turn on or drive it until you get it fixed. By the way your maf seems good I would not touch it.

S1cTech

ok so if you are so sure it is them? Why is this problem gone after like 20mins of driving? You think them getting warm makes them better? The only thing I can think of, is the warmness is changing their impedance somehow.

JoshG

would be nice if u show a video of u driving the car and showing examples.

Maxima 97 SE

Im sure because i had the same problem and it was bad fuel injectors and the reason why its gone after 20 minutes is becuase the fuel ratio decrease when its warm and puts out less fuel when engine is warm and what causes a bad fuel injectors sometimes is a broken pintle cap. Everybody thats had raw fuel coming out of their exhaust has turned out to be the fuel injectors and if their impedance is changing then they have got to be bad its not supposed to change. Just trying to help here from experience as i would not like to give anyone false information have them waste any money. click on this post below thats underlined as it will explain everything and it really similar to your situation. http://forums.maxima.org/4th-generat...ite-smoke.html

S1cTech

hmm okay makes sense lol. I will run to the junk yard. How much you think we talking ?

Maxima 97 SE

I went to pick n pull and it was 6.99 for one injector.

asand1

iTrader: (1)

Sounds more like ECTS.

njmaxseltd

iTrader: (19)

Would be the first thing to check.

Nismo_Pilot

iTrader: (1)

^^^ Coolant temp sensor is responsible for determining target mixture. Cold engine = more fuel, hot engine = less fuel. Provided you do not have one or more injectors that are working improperly (common-ish), CTS is where id go first. Fail-safe for this sensor will cause it to dump fuel like a sumo after a trip to golden corral on cold starts.

S1cTech

I doubt it is the ECTS but thanks for the tip. I will check it out, I really have some awful misfiring and while. I have't had a bad start up, it is a very rough short, sometimes even a misfire on the final stroke of the piston as it starts up it, and it is rough for a fair about of time, almost 15 to 30 mins, but after that the car seems fine when warm, idle is noticeable rough even when warm but I've never had a great idea in this car ever since I start to mod it or when my 02 sensors went maybe. IACV has been cleaned and gaskets replaced twice now, but idle is not my man concern, I learned to live with it, I just want to make sure this gets fixed before it causes an issue with my engine, and I am getting some knock.

Crusher103

iTrader: (10)

It can't be the Maf, mafs are not effected by engine temp. Maf would be a constant problem not an engine temp problem.

dwapenyi

iTrader: (3)

If you are uncertain as to the issue but are willing to make some changes, I would suggest that you do the least significant changes first.

If you've never changed the FPR, do that one. Then try the ECTS. I would leave the injectors for last. Actually, do ECTS first since it's the cheapest, then FPR.

On a 16 year old car, no maintenance items, like the FPR, become maintenance items

S1cTech

Car is having issues starting, sometimes almost 8 cranks. SO ECTS sensor now? Exactly. I knew it wasn't that haha

asand1

iTrader: (1)

You are a fool.

ECTS tells the ECU what temp your engine is. If the ECU thinks its 32* degrees outside you're not gonna start, or you are going to run like ****. Try closing the choke on anything with a carb, and and see how it starts and runs in warm temps.

If you don't want to take advice from more experienced people (Former dealer tech and MANY years working independently) then why are you here?

Nismo_Pilot

iTrader: (1)

Exactly. The second this dude asked for help and then started bashing the people helping him, I lost all interest in helping him. Been following the thread to see how long it takes this genius to figure out the problem that he seems to know the answer to already.

Maxima 97 SE

Your car will still start without ects disconnected and it will run and drive without it but you will have a high idle and the fans running all the time. I listened to you guys who we're saying ects and lost a lot of money about 120.00. I first went to the junk yard and got a new one and it didnt fix my starting problem. Then you guys suggested go buy a new one and that didn't work either. The problem turned out to be bad fuel injector o-rings and pintle caps which stop the fuel from leaking when the car is off and hold the pressure. Not everybody has bad ects. What your car needs to run is fuel, air and spark and if one them is disturbed you will get problems like hard start, no start and misfires. Our cars are notorious for hard start problems and mainly it's because of the fpr that will fail overtime and because of the fuel injectors. Always check those two things first for hard start and cranking problems and then move on to the next thing.

asand1

iTrader: (1)

And a bad ECTS will cause the wrong amount of fuel.

I'm not saying this is his problem, but it is a very likely cause. It should not be dismissed, and buying a new part form rockauto.com for $13.00 will be cheaper than tearing the upper intake off and replacing injector caps, o-rings, and plenum gasket.

theWalkinator

I would check vacuum leaks first.

CMax03

iTrader: (3)

ECTS or Water temp sensor controls the A/F mixture when the engine is cold or during warm up (Open Loop).....Once the proper water temp or cylinder head temp is achieved (Closed Loop) the A/F mixture is controlled by the O2 sensor and MAF....

Nismo_Pilot

iTrader: (1)

I agree with you here. It could possibly not be the ECTS. And the car will start without one. But the OP stated originally that is was a rough idle/rich condition after startup, which could also be fuel injectors. I think the issue most are taking is the fact that this dude asked for help, and then dismissed quality suggestions without trying them. Why ask for help and then turn around and act ungrateful?

As for your car, we (at least I) said nothing about your car. Getting cranky with the responders in this thread for following advice given to another member with a different car isn't exactly fair.

S1cTech

lmao that is a bunch of crock *hit. I been working on cars for 15 years and trained for 5, and an ETCS sensor would NOT cause a car to not start if it was faulty. Don't throw that crap at me. It may tell the ECU what temp the engine is, but it won't take "longer" to start if it was cold. So if the engine is that cold and -32 degrees out, the ECU will just let the engine crank over 20 times and help ware down parts while the oil is far to viscous to actually move through the engine and have the right PSI(usually 8-14 pounds right? of oil to spread through the engine. So don't give me that. "oh I worked at a dealer so I know so much more than you, I know fairly amount about cars kid.

I've never replaced one on other cars or ever in school and they always been talked about as just a temp sensor, some car use it for diagnostics some use it for A/F but as for "telling" the ECU to "take" longer to start, that is so ridiculous, not to mention a very rough start shouldn't be telling the ECU that either.

S1cTech

Annnnnnnnnnnnnnnnnnnnd I rest my case. So much for these "dealer experienced PROS"

asand1

iTrader: (1)

And now I'm blocking you becuase you dont deserve help.

dwapenyi

iTrader: (3)

Since you seem to be leaning towards the injectors, I would do the FPR 1st, especially if you've never changed it before.

Nismo_Pilot

iTrader: (1)

Got it fixed yet smart guy? This "dealer experienced pro" wouldve had the car back on the road by now. I gave you two things to check, did you even bother trying? Given that you don't understand how a MAF or ECTS works, I am excited to hear your final diagnosis.

S1cTech

My car is on the road. Mr. Experienced Dealer pro. it just runs ****ty, and I know it has something to do with the fuel rail, and I know how a MAF works. I replaced my MAF last year, Yes, it could be that, but I doubt it due to the very hard start up. IT is something I have considered though. It just isn't the cooling sensor. I know it for a fact.

Maxima 97 SE

Why don't you just replace the front three injectors with new good working used ones and see if that helps because if you still have fuel leaking out of the exhaust it will destroy your cat. Replace the front injectors because there the easiest compared to where u have to take the manifold off.

Nismo_Pilot

iTrader: (1)

I said that provided you don’t have an injector issue, move to the ECTS. So you're telling me that you've checked the injectors and found nothing wrong, and then tested the ECTS and found nothing wrong? If that's the case then we need to move down the diag tree. However, something tells me you've done neither. If you want help from someone who fixes weird problems with only nissan products everyday, ditch the attitude, get out in the garage and do the tests that several members here have told you to do. Check the injectors for leaks and impedance, check the o-rings, measure fuel pressure after you shut the ign off to give you an idea if you are leaking fuel, itll be a slow leak if its injectors, possibly over 6-7 hours. Test the ECTS and harness, its free, takes 5 mins and CAN CAUSE YOUR INITIAL PROBLEM (not a no-start which you added later) Then check the impedance and condition of all of your ignition coils, then manifold vacuum leaks, then check cam and crank sensors. If you make it through all that and it still runs like crap come back. Not a word until then, or I will block you and you will be dead to me.

P.S: The only reason I did any of this was for your car, I find your personality..... off-putting. But I can't take it out on a car, its not her fault.

CS_AR

+1 for this and other similar posts in this thread. I usually try to rule out the easiest to change and lowest replacement cost items first. I figure since I'm saving a bundle of $$$ on a DIY project, why not include some preventative maintenance items along the way.

My recent experience with something like this turned out to be from a combination of items that snowballed into a "perfect storm" of hard to diagnose problems. Those issues converged within a couple of weeks to produce one big hard to diagnose problem with cooked/clogged up cats. I suspect the cooked/clogged up cat problem was caused by a couple of broken injector pintile caps and a malfunctioning ECTS that created flooding and a "way too rich" fuel mixture problem. Yep, one problem seems to lead to another.