[Critterman]

Okay my head is now official reeling, I have read all 18 pages on this site and the same on several other sites. Looks like I am going to have to do the relocate as well.

A little history, I bought an 01 Frontier SC in 03 used 23k on it. I have had it ever since. At 49k I got a CEL, took it to the dealer and a new supercharger, knock sensor and 2 O2 sensors later I got the truck back. Luckly for me it was still under warrantee.

Since then I get 16mph regardless. 15.6 to 16.4, in town, on the highway, combination, heavy foot or driving with an egg under my right foot, it never changes. last week I got a CEL (87k) so I plugged my scanner in and I had a P440 code (Evaporative Emission Control System Malfunction) and a P0325 code (Knock Sensor Circuit Malfunction) Cleared the codes, removed and replaced the gas cap and went on my merry way. Two tanks later and the CEL is back. Check again and I have two P0440 and a P0325 codes again. Go to the dealer and buy a genuine Nissan Gas cap after reading about avoiding after market caps.

I cleared the cells again and drove back to work. P0325 when I checked at work. Cleared and later drove home. P0325, cleared started the truck, read the codes (P0325).

Truck has 87k on it, stock with the exception of a K&N CAI and a magnaflow (55 I think) muffler, better flow no real noise I run nothing but top tier 93 Octane in the tank. Truck has never been tuned so I am going to start there:

new plugs - What kind?
New plug wires - Suggestions?
Distributer cap - OEM or aftermarket?
Anything else?

After that I am going to clean all my connections to the KS. Then run the truck and see if I get a code, if I do I will start getting what I need for the relocation. Truck has not seemed to have lost any power, it will spin the tires at will from a dig, SC still screams through the K&N but I have no way of reading the outputs.

So my next question: For my little toy I have HPTuners to keep track of everything and modify as needed. Is there something simular that I can use on the Frontier, and also my Xterra which probably has the same problem with the KS?

Thanks in advance. John

 

[ksdtoday]

Shoot I did the relocate and it didnt help me, I think the only way to fix mine is unplug the cel and sell the POS. Then go do what I should have done in the first place, BUY A TOYOTA!!

 

[TwoBills]

I'd forget about the 325 code if you've got plenty of power and your gas mileage is around 16. I'm in the process of installing head gaskets on my '01 sc and after aprox. 18 hours of disassembly I reached the KS. I probably won't even replace the thing, just pull it out of there and wire tie it to a harness somewhere, maybe bypass the circuit w/a resistor. I've been setting the code for years now and it never seemed to bother anything.
If that gas cap fixed your 440 code then you're good to go, but just for the hell of it crawl under the truck and look on the side of your gas tank, driveshaft side, for a gas stain. This is an indication of the sending unit O ring going bad. You'll smell gas after a fill up, on a hot day, if this is part of the problem.
I'd go w/oem parts for the plugs, wires, etc. Start thinking about the timing belt, but if you don't have any coolant leaks the belt should be good to 120K. Suspect the t-stat housing if you're losing coolant, especially around the base, where the gooseneck bolts to the block. Reseal this with the timing belt change.

 

[Critterman]

No coolant leaks, no gas smell, I am going to stick a boost gauge on it to make sure I'm getting full boost (between 4-5 lbs right?) Don't know if the gas cap fixed my problem yet as it has to go through several key cycles if I remember correctly. Since the 325 doesn't pop a light I don't know how long I have been throwing the code, Unless it won't pass inspection with that code, and it passed the last time I took it in.

 

[joefrontier2]

No coolant leaks, no gas smell, I am going to stick a boost gauge on it to make sure I'm getting full boost (between 4-5 lbs right?) Don't know if the gas cap fixed my problem yet as it has to go through several key cycles if I remember correctly. Since the 325 doesn't pop a light I don't know how long I have been throwing the code, Unless it won't pass inspection with that code, and it passed the last time I took it in.

There has been a number of people with the SC that say that you loose boost when the KS is dead. Putting a boost gauge on it will let you know for sure.

 

[jammintrey]

How hard it it to replace the sending unit oring?

 

[chainsaw]

Do the relocate and call it good.

 

[Critterman]

Funny I picked up a gauge on the way home, will install it this weekend and see. The P0440 is back, so I need to take care of that as well. Will have to download the manual from home as the site is blocked from here.

I will probably put my little car back together first, since I have all the parts for that, and then I can start on the Frontier.

As for the P0325 code, I don't know how long I have had it, I don't feel any difference in power, but then I am seldom in full boost as it really isn't needed. I did drive to OC and back, about 100 miles each way on just under a half tank which is normal for me right around 16 mpg. I did notice on the way home and one the way to work this morning that my tach is at 2.5k at 70 with the stock tires and wheels on it. From what I have been reading here when the KS goes it takes more rpm to maintain the same speed?

 

[TwoBills]

How hard it it to replace the sending unit oring?

Haven't done it yet, but from what I've read you've either got to drop the gas tank or remove the cargo bed. Heard it was easier to remove the bed.

 

[TwoBills]

, I am going to stick a boost gauge on it to make sure I'm getting full boost (between 4-5 lbs right?)

Should be closer to 7lbs. But there's other things that can cause loss of boost. Let us know if you see boost only before the engine warms up and lose it at operating temp. Common problem. If you havn't bought your guage yet, I'd recommend a combo guage w/vacuum.

 

[fusionfronty99]

Shoot I did the relocate and it didnt help me, I think the only way to fix mine is unplug the cel and sell the POS. Then go do what I should have done in the first place, BUY A TOYOTA!!

this was the most informative post ive seen on this forum

thank you for wasting my time... take your toyota loving-ness to a toyota oriented forum

 

[shakedownstreet]

hey i'd buy a toyota, but the resale value on used models is just too damn high

 

[Critterman]

Okay, todays update.

Sprayed the connection for the knock sensor, no more p0325
Crawled under the truck, there is a discoloration along the center of the tank, it doesn't smell like gas but what else could it be?

Installed a boost gauge, 20 inches of vacumn at idle, 7 lbs boost at WOT. So for the moment everything is fine.

Attempted to do a tune up, after spending an hour trying to get the first plug on the drivers side out, I gave up before I broke the plug. so for the moment my plans are to keet the truck until I need to go for emmission inspection again, then I will trade the truck in for a newer Nissan, maybe even brand new.

 

[TwoBills]

Did you spray the connection right at the ks or the one on the main harness?

The stain is probably caused by a leaking o ring. I wouldn't worry about it until you start to smell gas fumes after you fill up, on a hot day. You'll also set a "gross emissions leak" or something like that. I forget the number.

That's #6 you're trying to get out. It's a bugger. You'll need a couple of extentions and a knuckle to get to it. Gotta hug the engine a bit also. Be careful of the distributor cap. You'll need to loosen your blower intake to get to #4 also.

I'd read a lot of the posts on here before I made the decision to buy a generation 2. Different problems, but just as many.

Keep an eye on that vacuum guage. It's a good early warning guage. Never w/o one on all my vehicles.

 

[Critterman]

Sprayed the connector on top of the passanger side valve cover. The #6 plug is at the front of the engine? That looked like the easiest one on the driver's side, don't even want to think about trying to get the back one. well I only put >10k a year on the truck so I should have until the next emmissions test to figure out what I'm going to do.

 

[TwoBills]

Oops, must've misread. That's #2 you're talking about. That should be pretty easy. If it's in there real tight you might have a coolant leak causing a chemical weld. Good luck w/that. Get some anti-seize on it when you get it out.

 

[Critterman]

Looks like I am going to have to bite the bullet on this one, both codes are back and 'yes Virginia" the knock sensor does limit boost big time. You get 2-3 lbs max. But I cannot complain I have had this truck since early 2003. In that time I have spent money on the following:

4 new wheels and tires for winter driving
2 OEM replacement tires
K&N sorta cold/warm/hot air intake
8 oil changes and filters (once a year Mobil 1 extended life)
2 sets of brake pads
3 alignments (pay once align as needed)

and that's it, I feel kinda bad about *****ing about it now that I think about what it has actually needed. So I will probably take it somewhere and get it fixed. New OEM knock sensor, and emmissions leak fixed as well. Figure around 2-3k or so to get it done. Any one know a good stealership or private mechanic in the greater Baltimore/Washington area?

with 87k I should probably go ahead and change all the fluids as well, and get it tuned, as I can't seem to get the plugs out That should give me another 4 years before I need to start worring about the knock sensor and timing belt.

 

[TwoBills]

When you lose your boost does your vacuum guage drop a little? Is boost dropping after the vehicle reaches operating temperature?

 

[joefrontier2]

Two things - For the SC there are more problems than standard V6. Also relocating the KS to the Upper Intake has been proven bad as the KS picks up the SC noise.

So you need to replace your KS to gain boost or I've read some are guys have overridden the KS by manually hooking up something up to the vacuum (I'm not 100% how this works). I still wonder why the SC boost is tied to the KS when the KS goes bad.

Still - 1st gen Frontiers are fun to drive so get those gremlins fixed.

 

[Critterman]

twobills, Yes it does, I show 18" at an idle instead of 20"

Joefrontier2 - I'm just guess here since I don't believe we have a smart computer, but it is probably coded into the software. Once the knock sensor starts pulling timming, it has a point where it also opens the boost bypass, venting to the air so you do not damage the engine with pre detonation.