Ok so, in the other thread on this page "Replace Spark Plugs or Not?" Outlines a lot of the problems, but basically the car idles low when the RPM's fall (Going from gear to neutral) and sometimes stalls. When I get on the gas I hear a lot of like bubbling, rasp and shaking and all the way through the power band it makes a really bad sound. Almost a grinding noise.

I took two video's, if anyone can tell me if they've had a similar sound and what they did to fix it, that'd be great. I was also wondering, since my pipes are bent, and there's a possible hole could the resonation/back pressure from this cause problems?

Video 1: From Outside of the car, focusing on my $hitty exhaust situation.



Video 2: From Engine Bay, just listen for the myriad bad sounds.

 

It's a horrible sound... bad accel, etc...

 

ow...that hurts me..oouch. But seriously, it seems like if you're getting "bubling" or sputtering, you might be getting some misfires. That would also account for your crappy idle. It could a number of things (as people have told you in other threads) But, you definetly wanna check the coils, spark plugs and injectors. (provided you already eliminated fuel dirty fuel filter, TB, IACV)

 

I recently replaced the Spark Plugs, and the coils were fine when I did that. I hear clicking which is the sounds of the injectors working, correct?

 

sure, but you wanna listen to each individual injector. There's six of 'em ticking, if there's one that's not ticking the way it's supposed to, you might not notice it.

 

how do I go about checking these? Is there a way to fire each on individually so i can find the bad one? or do I have to like take off the intake manifold and check the resistence or something

 

from what i've read around here, you need like a rubber tube to put against the injector and your ear. Using that method you should listen to each injector to see if anyone of them sounds different from another or makes no sound @ all.

 

haha backyard mechanic work at its best XD I'll give it a shot, couldn't hurt =/

 

yeah, it sux having weird issues with such a great car

 

I hope I don't need new injectors, but if I do would there be any performance gains if I upgrade to some of those higher flowing injectors from deutchse works?

 

not unless you were to run a supercharger/turbo and increase the air flow as well as more fuel.

 

Would it be reasonable to install better injectors, and tune for a NA setup to prepare for a SC/Turbo in the far...far... future?

I'm going with OEM injectors, but I was just curious

 

Not really. If your turbo setup is that far in the future, why would you spend the money now?


Plus, the more time you have until you install your FI setup, the more likely that your plans will change in the meantime. Trust me.

 

True, most likely my max will never be boosted, but it's nice to dream. But, what I'm also wondering is are there any distinct advantages to even slightly larger injectors. For example, even in a NA setup 2.5" exhaust has been proven to provide higher exhaust velocity than a 2.25" (stock) setup. Would the same hold true, and has it been proven in the case of Fuel Injectors?

 

The stock injectors are more than enough to handle any amount of power you could make NA, so the short answer is no.

What some people have been able to do, however, is to install bigger injectors at the same time as an air-fuel controller, like the Apex'i SAFC. The bigger injectors provide more fuel with each pulse than the ECU intends, and the AFC lets you compensate for that by tricking the ECU into thinking it's seeing less air and dialing back the pulses. Long story short, that makes the ECU advance the ignition timing, which leads to more power.

But if you're not doing that, there will be no benefit to bigger injectors no matter what your setup is.

 

i agree with d00d

 

Ah, I understand. Thanks

So as for the problem posted way up above, I just got home and am both happy and pissed. The whole ride home was fine, started great, idled fine no dropping or anything. Only a 5 minute ride home, but once I got here, I couldn't parallel park because the car wouldn't stay on long enough...

It sounded like I had a sputtering muffler under my hood, followed by stalling and a very strong smell of fuel. Sound like injectors to anybody? (Keep in mind Fuel Filter has been replaced with no leaks)

EDIT: Oh and the happy part was my New Y-Pipe was waiting for me on the porch

 

ok, if it sputters and you smell fuel, i'd say that you're just not getting a spark somewhere. Meaning that the fuel is left unburnt and is "evacuated". So.... i'd say that you either have a badly leaking injector OR a bad coil pack/sparky.

 

Hmmm... Ok I replaced the Spark Plugs but it couldn't hurt to just check them. I'll take them out this afternoon and take some pictures of both the spark plugs and coil packs.

Just to be sure, the coil pack is the long black thing you pull out before the plugs right?

 

yah, that's it. What's the mileage on your max? Could be that a coil pack is going out which isn't that big of a deal to replace (not too cheap if you need >1)

 

Yes indeed.

 

Well I replaed the plugs a week or so back, I'm not sure how to check coil packs but they were all in one piece and fairly solid, I was gentle with them mainly because I didn't want to break them. So I'm supposing they are fine.

As for the Injectors, I checked chambers 1, 3, 4, 5, 6 and heard clicking from each. 2 is kind of hard to get to, but would just one injector gone bad cause this massive amount of trouble?

When I get some more time this weekend I'll remove my plugs and coil packs, and if I'm feeling ballsy I'll remove the intake manifold and properly check chambers 1, 2, 3 of my Fuel Injectors. Do I only need to buy new gaskets if I'm replacing the Injectors? Or even if I'm just taking them out to check?

 

You need an electrical tester to check the coil packs. There's a how-to somewhere in the FAQs I think...


Yes, it can.

Also check to see if the clicking sounds about the same on each injector.


You might not have to replace the gaskets after removing the injectors, but you probably should (whether you're replacing the injectors or not).

 

http://forums.maxima.org/showthread.php?t=514567


Credit goes to willard00 for the following:

ide assume so. since if it detects spark, it lights up in the middle, and if theres no spark it doesnt light up

theres also another tester that looks like a spark plug (also called a spark tester) which i prefer over the stick type. all you do is pull the coil out, put it on the tester (like a coil fitting over a plug) and then clip it to a ground. then start the car and look at the tester. if it sparking then the coil is good.

spark plug type tester: http://www.sears.com/sr/javasr/produ...seBVCookie=Yes

'stick' type tester: http://www.sears.com/sr/javasr/produ... eBVCookie=Yes

 

I would give each injector about 180bpm, fairly quick

 

lol, imagine how hard they work @ 5,600 rpm

 

5,600? lol abstract number, but yeah I was checking at idle, crazy

 

..........yah