Pre-ignition ping

[newnico]

my 2003 Nissan frontier has had a rattle for a few months now I've brought it to a Nissan dealer and they told me the engine needs to be rebuilt and I need a new mass airflow sensor. I wanted a second opinion and hopefully someone can tell me a cheaper fix than rebuilding it. has anyone ever had this problem before? it sounds like a fork is being rattled around in a metal cup and the rattle speeds up when I accelerate

[ezb57e]

What exactly did they tell you was the problem?
Rod knock?
Bearing?
Something else?
How is the noise related to you needing a MAFS?

[newnico]

all they told me is that the computer was sending off a code for the mass air flow sensor. also it was reading a "pre-ignition" combustion. they said that the mass air flow is sending back the wrong information so the fuel to gas ratio is all thrown off causing it to bog down and rattle. when in a higher gear or under a load.

[ezb57e]

So, your check engine light is on?
If so they probably found a DTC for the MAFS. That's a long way from an engine rebuild. I suppose if it was causing a very lean condition some ping could occur.
They feel this has damaged the engine?
They probably also found a knock sensor code which may have been there a long time as that will store a code, but not turn on the check engine light.
Pre-ignition sounds occur at a different frequency then mechanical engine knocks and rattles, and should not set knock sensor codes in themselves.
Get the MAFS issue fixed first then re-evaluate the health of the engine.
How many miles on this truck?

[newnico]

there are 77,000 on the truck and the dealership told me it wasn't hurting the engine at all but it sounds as if the darn thing will explode if I push it any harder when it rattles.

[Desert Rat]

have you tried running a tank of premium gas through it to see if it improves? If that does help, but doesn't solve it completely, you could try backing the engine timing off just a little.

[BRubble]

I'm thinking along the line's of DR.

Get a Reputable Professional to check the Timeing.

In the mean time,, pour in a bottle of Chevron Techron Injector cleaner and Water remover in the Tank. Injector's can make Crazy Sound's Too.

Is the Engine Useing Any Oil? Did they run a compression Test to see if the Cylinder's were loseing too much pressure?

77K mile's seem's way too early for an Engine Build,, unless it was Abused in OffRoad Activitie's. Was the Truck Abused in Rock Climbing, Mudd Playing, Water Crossing Above the Axle's, or High RPM Full Throttle in Lower Gear's, which can cause severe damage to Top end and Engine.

When they said Engine Rebuild,, maybe they meant Top End. The Valve Train,, can also make or Cause Racket, if way out of Adjustment or Damaged.

[newnico]

no here was no offroading done in this truck it is a 2wd xe. I have run multiple tanks of premium through the vehicle and the rattle is a lot quieter with premium rather than regular gas. they have turned the check engine light off and when the truck reaches about 50mph the light comes back on if that is a clue to something with the timing or what I'm not sure. Thanks for the advice!!

[newnico]

also I don't know if its related but when I am running the engine for a while, like driving on the interstate for about 30 minutes when I exit onto regular streets the engine revs a lot longer than usual to get through the gears. when I'm just starting off in the morning the reaction time is normal but when it gets warmed up it loosens up and rattles louder

[BRubble]

When is the last time the Fuel Filter was changed?

At some point after the recommended thing's have been done,, I would want to take the Valve Cover off,, and take a look at the Valve Train, to see if any problem's could be spotted.

[ezb57e]

Fix what is turning on the check engine light and go from there.
You are wasting time.

[Adverse Effects]

Fix what is turning on the check engine light and go from there.

agreed i would also back the timing off a bunch to see if it fixes the problem

if it dose then you know its something to do timing wise

[BRubble]

It might also help us to know which engine you have 2.4L or 3.3L. Timeing Belt or Chain. SuperCharger?

Sure hope you don't need a Top End Overhaul, with only 77k Mile's. I would be wanting to know What is Worn Out or Damaged and why so soon.

I had a '93 2.4 L Timeing Chain Engine with 176K and it was purring like a Kitty when I sold it last year, after I got a '13 Frontier.

I'm sort of Guessing that you have a V6 3.3L with Timeing Belt.

[newnico]

its a 2.4L 4 cylinder

[BRubble]

Thanks,

Well that illiminate's a Timeing Belt, cause your's has a Chain.

If you've done all of the Maintenance Item's listed, then the prudent approach seem's to me,, would be to start with the Engine Light,, and any other Trouble Code's that are indicated.

I want to suspect that something happened to cause this. Which is the main reason that I alway's change out the Gas Cap with one that Lock's.

Sure hope you get it straightened out, and We hope you'll keep us in the Loop to let us know what the problem was.

Good Luck

[Desert Rat]

That's the same motor I have in my Frontier. Backing off the timing takes literally 30 seconds. Loosen the adjustment screw at the base of the distirbutor and turn counterclockwise a little bit, reset, and go for a drive and see if you have any noticeable difference. If the premium helps, then it probably is detonation. If the timing is too far advanced, the SES light might be due to a lean misfire or something along those lines if the timing is too far advanced.

Before you reset the SES light, get a parts store to pull the codes and post them up.

[newnico]

I had advanced auto parts do a scan on it a couple weeks ago and the code was. "lean running engine" he told me this could be due to the pre-detonation or the mass airflow or a whole list of things. based on what I have told you about the truck would a logical answer be just the pre-detonation or a mixture of many different problems?

[Adverse Effects]

just retard the timing some and try it see if there is a improvement

[Desert Rat]

things that can cause lean condition - MAF, clogged fuel filter, weak fuel pump, and enging timing.