Black Maxima

Okay, I have this check engine light:

I replaced the oxygen sensor and the fuel filter. The oxygen sensor kept the CEL off for two weeks. The CEL turns on and off.

I'm beginning to think it's a blown head gasket. I have heard that it could be. And I am getting the symptoms of it, such as loosing coolant and a rough/bad idle.

What else could it be? Fuel injectors? I was looking through this post and seemed interesting. http://forums.maxima.org/showthread....wn+head+gasket

My dad said bring the car to the dealer to fix the CEL, but I told him I'm not going to spend money.

Time for a 3.5 swap right?

Thanks, Aaron

NmexMAX

iTrader: (22)

If you have the $$ why the f'uck not...


If not, check all these out first.

- Intake air leaks
- Front Oxygen Sensor
- one or more fuel injectors on the front bank
- exhaust gas leaks
- incorrect fuel pressure
- lack of fuel
- Mass Air Flow Sensor

Black Maxima

I think I need help by pointing me in the direction of how to troubleshoot each item.

f550maranello2

iTrader: (2)

bro if its a headgasket you get tons of white puffy smoke out the tail pipe.. i had it blow on my tbird NOT fun... btw check the oil dip stick if its a milky color then you really do need to replace it...

njmodi

iTrader: (4)

Where the coolant going?

It doesn't vanish - it's either leaking onto something hot (so it just vaporizes) and you aren't seeing a leak, or it's a bad head-gasket...

How much coolant are you losing? how often are you having to top it off?

Rough/bad idle can be caused by fuel injectors, plugs or bad coils (among many other things).

Lean codes are typically triggered by bad O2 sensors. Did you replace the O2 sensor closest to the radiator in the y-pipe?

Also listen for each front bank injector to fire.. or since it's the front bank, you can unplug each injector one at a time to see if that changes the way the engine runs... the injector that you unplug that causes no change in the engine note is most likely not firing...

There are PLENTY of ways to start diagnosing the problem... if you don't have the knowledge to do it (and this is not meant in an offending way), it's not a bad idea to shell out the 80-100 bucks to get a concrete diagnosis from either a Nissan dealer or an independent mechanic. It is definitely an option you should consider.

Good luck.

Black Maxima

Thanks for the nice replies guys!

I did replace the one closest to the radiator in the Y-Pipe.

I want to try that fuel injector thing. So your saying I can just unplug a connector on top of the engine?

I understand what you are saying about taking it to a dealer. I also like to learn new things by working on my car.

Let me get back to you on the fuel injectors.

Thanks, Aaron

clive

If you think it's a head gasket, then check it out. Go down to Autozone or wherever and buy yourself a compression tester. The issue will be the extreme distance down to the plug-holes in the Max, I don't know if you will be able to find a comp tester with the right physical parts to do it. Like a very long stem, or one with a remote plug and connecting tube. Maybe someone on the forum knows? Anyway if you can get one, check the comps on each cylinder, they should all be more or less equal. If you find one that's very much down, that's likely to be your problem. You can also use the tester to check the condition of your rings and valves.
Problem with head gasket leaks is that if coolant is 'vanishing' it's probably being drawn into the combustion chamber(s) where it can even cause a hydraulic lockup, (another symptom is that on starting, the motor is reluctant to turn over, goes yow.... ... ... yow yow yow, the first crank taking a lot of effort). At any rate, the antifreeze component will totally b***r up your O2 sensors after a while and is bad for the cat also. So unless you fix it fast, future repairs could be a wallet-ripper.

PAREDLINE

The way I check if a head gasket is making coolant enter the combustion chamber is by taking the coils off the plugs. leave the plugs in place. Disable the fuel injectors. Crank the engine a few times and pull the plugs out as fast as you can. If the plugs are wet, smell them. If they dont smell like fuel chances are it's coolant.


From reading your story I dont think its a head gasket problem. I think you're losing coolant somewhere else.

you basically have too much air. not enough fuel. This means your car is either running lean on fuel, or too much air. Start with the basics, Make sure your air filter is intact. Pull the intake manifold off the car and check/replace the gaskets. Move the back bank fuel injectors to the front bank. See if the code changes. Check and make sure your oil cap is secure, your PCV valve is not stuck, and your valve cover gaskets arent leaking. Do a compression test. if you have a bad head gasket, 2 or more successive cylinders will probably have low compression. If that happens, put some oil in the plug holes and repeat compression tests. If oil makes the compression rise, you probably have bad piston rings. This is highly unlikely unless you never change your oil.

Let us know how you come out

Zach95SE

iTrader: (3)

If you want to check your injectors you can basically hold a screwdriver to one and hold the end to your ear if you hear clicking it is good. If you don't hear a clicking or it is not as strong that could be it. MAF I guess you could swap with someone see if it goes away.

BobK

Just an idea to check the injectors... use an automotive s***hoscope or even a long screw driver and listen to each of the injectors. If you use a screwdriver just put the wooden end right to your ear. Listen to each injector you should hear well defined clicks and each injector should sound similar. If one sounds different than the others it could be clogged.

DR-Max

iTrader: (3)

There's more than one O2 sensors in the Maxima. You should replace the others as well.

As for coolant loss, there's only 3 places (that I know of) where you could be loosing it: radiator/radiator hoses, water pump, and inside the car. Yes, inside the car!!! Coolant circulates into the heater condenser under the front passenger dash. If that unit becomes defective and start to leak coolant, it will end up on the passenger floor of your car. Try this: remove the front passenger side floor mat and feel the floor carpet. Also, feel around the condenser areas and the unit itself. If you feel wet spots, which will be slippery to the touch, you are leaking coolant inside. Time to replace the heater condenser. This has happened to me before! It was a pain in the *** to replace.

suicidalspd99

Yo. What you don't call. Let meknow if you want me to check it out. I hope it is not the headgasket. But let me know. You got my cell. Also. not to be off topic, but you do my switches yet?

Bill

SVI30

Head gasket is pretty easy to check with a compression gauge.

Here is how to check the MAF (post towards the bottom):
http://forums.maxima.org/showthread.php?t=450323

Nissan ask you to check the injector resistance with a DVM, 10-14 ohm at 25 deg C. GM pulse the injector with a half second pulse and measure the fuel rail pressure drop. I built this 1/2 second pulse tester but gave it away after it sat around a few years.

SVI30

Inside the engine also, either white smoke or water in oil. If you can't see where it has gone, check the oil, milky looking.

SVI30

The 3.5 has a number of things the 3.0 doesn't have, VVT, variable intake length. So the ECM and harness are different.

ethnic6

iTrader: (5)

just curious, but how much does a 3.5L swap cost overall?

NmexMAX

iTrader: (22)

Tell me something you think I don't know.

Black Maxima

Okay here's an update. I check all six fuel injectors. I unplugged each one seperatly. Each one I unplugged made the engine becom rough and I guess "knock". The engine didn't seem as strong.

I'm going to try to test the MAF now.

Thanks for all the help guys...

Bill, I will call you later...

Black Maxima

Seems like the MAF is alright. The voltage at idle is like 1.1. I just need someone to rev it up to 2500 for me to be 100% sure the MAF is operating correctly.

How do I check for intake leaks? I do have a hacked air box.

Black Maxima

And how do I check to see if the fuel pump is working correctly?

I don't have any problems strating my car. Turns over fine every day.

SVI30

Hey, this is not to test your knowledge of the car. This is a lot of dough and custom work to make a 3.5L swap. Since you say you know, help the guy.

NmexMAX

iTrader: (22)

http://www.forums.maxima.org/forumdi...sprune=-1&f=79

Some people should leave the 4th gen forum and venture to other forums like the one listed above....

As for "The Guy' He doesn't need help because he knows it has and can be done (3.5 swap) hence that's why he said it.

I did give my help for his issues....

SVI30

There should be a fitting on the fuel rail to fit a pressure gauge. The idling pressure should be 34 PSI. The key off to on, without starting, fuel pressure should be 43 PSI.

GoalieKeg

iTrader: (4)

Alot of dough? How much is alot? Around a grand will get you a ready to drop in vq35. Custom work? Not really...

Go and read away in the all motor forum that nmexmax linked you up to. Lots of good info there.

SVI30

I read it, looked like a long term project. Great if it is a spare car. Also, the numbers looked pretty big, about $3K if everything done right. Giving up the VVT doesn't get you all the power, so it's a catch 22. This is definitely not a backyard project.

May be great if living near one of those guys that will do swaps.

Frankly, I am not a mod guy but a fix it guy and keep my cars for a long time. So I have shop manuals (not Haynes) for pretty much all my cars. Custom made tools too, machanical and electronic.

NmexMAX

iTrader: (22)

They do nothing after 3000RPM, and in the A32 body, there's not much room for more power under that since traction is a major concern, you obviously need a little bit more time around here.

Most people on here did it in there back yard, or garage.... I do not see the big deal.

SVI30

If the A32 body can't handle a VQ35, then just get his VQ30 fixed is fine. Where this guy lives, the only place he can use over 3000RPM is on I84, and there is too much traffic and cops on that to open up any way.

He probably got a foot of snow on the ground right now.

NmexMAX

iTrader: (22)

Did I ever say it couldn't handle it? What I meant was that it's lighter than the body it came in, therefore, is much more apparent(the power).

With a 3.5L you don't need whatever tq the CVTs add..if any.

SVI30

I knowwhat you mean, people arn't worthless just because they haven't been on this site. In any case, where this guy lives, he will be mostly below 3000RPM. I lived in the next town (Southington) before moving to Calif.

Don't go: "I think he should go somewhere else..." just because someone challenge what you said. If you know your stuff, you know your stuff.

By the way, his place is so packed, they have left hand exits. An old lady went on the I84 from one of these left hand exists and drove in the fast lane the other way and wipe out a bunch of people. They are that packed. We can open up and drive fast on I5 to L.A., you can too. This guy can't.

NmexMAX

iTrader: (22)

Someone on this site has a 3.5L 5MT A32 and it snows A LOT there... but it's in his garage....

You made your point, now moving on.

nismology

iTrader: (8)

1. No one said the A32 can't handle anything

2. The fact that the vvt is disabled using the A32 ECU doesn't mean the motor is gutless below 3000 RPM .........

3. The 3.5 swap using the A32 ECU is much easier than you think.

4. It behooves you to come to a new site with an "i don't think....(someone correct me if im wrong)" attitude rather than an "i already know that....." attitude.

Oh yea...welcome to maxima.org

SVI30

Just point out the facts, it is not as simple as just dropping it in, as writrer of the sticky noted. To do it right there are customized work on various pieces also. Without the VVT and intake, what is the HP, 230 instead of 260? Put a switch on the dash and change the intake yourself?

There are a lot of knowledge here. This I30 had been so reliable that I haven't had the need to look around much. Car is my thing, I have shop manuals for most of them.

SVI30

Just thinking about this VQ30 vs VQ35 discussion, there are not 2 choices in doing the conversion to VQ35 but 3:

1. VQ35, engine, A32 ECM, harness
Lose control of the goodies.
2. VQ35, engine, A33 ECM, harness
Some other stuff doesn't work, big money.
3. VQ35 engine, A33 ECM, A32 harness
Compare the connector pinout and function, repin the A32 harnes connectors to A33, add wires for VVT, intake and any new sensors.

Has anybody done number 3 before?

NmexMAX

iTrader: (22)

Did you not get the fact that it doesn't affect peak #'s? Where did the #'s 230 and 260 come from? A33B's were 'rated' at 255, and A34's are rated at 265.


EMU >*

nismology

iTrader: (8)

It's already been done that way already by a few people n00b. And yes, it's relatively simple. People had done it that way even before the write-up was written BTW.
First of all, the variable valve timing system does nothing above 3000 or so RPM. This means that peak numbers are unaffected. Secondly, does the VVT system have to do with the intake??

Just because cars are your thing doesn't mean there's nothing for you to learn.

nismology

iTrader: (8)

Lose control of what goodies? E-throttle is unnecessary and the VVT system would only be missed in driving at low RPM around town but the fact that the 4th gen is much lighter than the A33B somewhat negates this disadvantage. So again, what goodies?

SVI30

The short runners at high RPM or long runners at low RPM, which one would you give up? The A32 ECM expects a long runner, then the engine suffers at high RPM? Put a switch on the dash? Make a RPM based circuit and add it to the car?

Without VVT, are the cam profiles the same for both engines?

Lighter car, more powers are generalities, right? Anybody submitted a dynamo results and compared this engine at different RPM points with A32 and A33 ECM?

I know some of you guy's done it. But as the sticky writer has pointed out, there are a lots of things to look at and. Some modification or fabrication is needed. Without these, you do give up something. Nothing is free.

nismology

iTrader: (8)

If you're talking about the intake manifold, all you have to do is wire up an RPM switch to activate the variable intake. That's easy. But again, what does that have to do with VVT system?
Are you sure cars are your thing?? The variable valve timing system in this case retards the cam timing at lower RPM to reduce valve overlap, which improves torque and emissions, simplified of course. There is no variable valve lift involved.
What do you mean?
The reason that i know that it doesn't do much above 3500 RPM is because i have an official nissan technical document that illustrates the overlaid volumetric efficiency curves of a VQ35DE motor with the CVTC activated with it on and off. Here's the image:



No one's arguing that having the CVTC system wouldn't be better. To think so would be foolish. But when you consider the headache involved just to use the A33B ECU, it doesn't seem worth it anymore.
If you consider the steps outlined in the sticky to be difficult then uhhh...

SVI30

You showed a volumetic efficiency chart. That's pretty good, I am impressed. Does that equate to HP and torque out? The chart does show a big gap at 3K. Are we back to generalities again?

What I asked is the cam profile comparison between the VQ35 (with VVT but disabled) and VQ30 (w/o VVT), are they the same? We are talking using the A32 ECM, right?

The engine in our cars are being used everyday, in all traffic conditions. Not just to be touted, I got a VQ35 in there, and it gives me mucho umph at 5K. VQ30 is a great engine too, even if it only has 190HP.

Stephen Max

iTrader: (59)

VE is a measure of how much air an engine ingests compared to theoretical. So, yes, it does, at least qualitatively.