wdornbach

Hey folks

My 1999 maxima 5 speed has 240+ k miles. I need to replace the knock sensor, and I'm going to take off the intake manifold because it's a California emissions car and there is all kinds of hardware related to the swirl chamber thing, can't can a wrench under the intake manifold to remove the knock sensor.

So anyway, I figured I should service the injectors while the manifold is off. They are original with 245,000 miles. So any opinions? should I just get new injectors? or should I send them out? Does anyone have a recommendation for a reputable place to send them for rebuilding?

Thanks!

JvG

I had to remove the intake manifold on my car for other reasons when my car had 180k on it.

Since our injectors are known to start leaking at any time now, I decided to have them rebuilt.

I sent them to Injector RX in Houston, Texas.
They clean, rebuild, and flow test them.
They charge 18 dollars per injector.
Check out their website.

I sent them by USPS Priority mail.
Their turn around time is one day.
They send them back very quickly.
The total time was less than one week.

I was very happy with their service.

My car ran much better, and I no longer need to worry about a rear injector leaking at a bad time like the middle of winter.

wdornbach

JvG,

Thank you! Glad to hear someone has actually done this! Awesome too that you noticed a performance improvement.

JvG

I noticed that the car ran smoother.

But I also need to mention that I cleaned out the egr port, and the door handle. You should too. It's much easier to do while the uim is off.

I also cleaned the iacv and the throttle body.

All of those things help to make the car run as it should. This is an opportunity to do deferred maintaince.

All this work was done when my car had 180k on it.
It's at 220k now. I've had no issues since then

I'm talking about miles, not kilometers.

Turbobink

iTrader: (2)

If the injectors you’re wanting/needing to replace or rebuild are the OE injectors.

Have them rebuilt.

Not really a question ... in my mind anyway.

wdornbach

Thanks JvG

Yea, I was planning to do the egr port, but What is the "door handle" you mentioned? and what is the "iacv" ? Thanks

JvG

The intake air control valve is next to the throttle body. It's also attached to the intake manifold.

The door handle is a metal tube which carrys exhaust fumes to the egr from the exhaust manifold. The tube looks like a door handle. It tends to clog with carbon deposits. It will cause a check engine light for an egr code. It's easy to get to when the intake manifold is off.

You might want to examine the knock sensor for cracks. Again, it's super easy to get to while the uim is off, but difficult to do when it's on.

I'm mentioning all of this because all of these items cause problems sooner or later. Most of them are difficult to impossible to do while the upper intake manifold is on the engine. The intake manifold is not something you want to take off again any time soon.

wdornbach

JvG, thanks again for the info!

Actually, the knock sensor is the primary reason why I'm taking the intake manifold off. It's a California emmisions vehilce, so there are some extra swirl chamber components on the trans side of the intake manifold. Makes it absolutely impossible to get in there to change the knock sensor. I had another maxima, it was a 98 w/auto trans. (sold it earlier this year). It was a federal emmisions vehicle, and there was enough room to change the knock sensor on that car without removing the manifold.

But yea anyway on my 99 I'll be sure to get the injectors rebuilt & i'll address the other items you mentioned too. Prolly going to change the valve cover gaskets too. I watched this video, Pretty good R&R. He recommends deleting the coolant loop to the throttle body. I may do this.
Overall my 99 is in pretty good condition for 240k miles. it's a 5 speed, but the clutch is slipping a bit. I have a south bend stage 2 clutch kit ready, I'll install that next.

KP11520

Knock sensor, PCV Valve and supporting Grommet all while you're under there.

If you want to buy rebuilt original OEM fuel injectors that are flow matched and not have to wait, motor man fuel injectors has an offering for $129.95. Use "Maxima.org" for a promo code discount. It used to work when they were $139.95. Maybe still: https://www.motormanfuelinjection.co...ssan/5G60.html

Also buy the 6 new Grommets that support these injectors, and the 6 insulators that go on top under the caps and a JIS Philips #2 screwdriver to remove the screws without stripping them. JIS is a what the Japanese use and don't cam out with high torque, like US Philips does. Vessel on Amazon is very reasonable. Grommets can be bought at Rock Auto but the top insulators should be OEM. Insulator part number: Nissan 16635-53J0A. Grommets: Fel-Pro 71045

While you're in there, I'd also replace the Fuel Pressure Regulator. Standard Motor/Intermotor PR59. Replace the fuel lines and clamps connecting the rails and out to the gas lines and returns and new fuel filter. And you'll hopefully be done under there.

And of course the associated gasket kits. This would be the time to do valve cover gasket kits if any leakage is indicated.

JvG

I didn't replace the valve cover gaskets when I did all that work originally.

So I had to remove the uim this spring because they started leaking. Not fun.