got_max

iTrader: (5)

Hey Guys, I just need a little Imput.

Latley (well for the past couple of months) My Max has been bogging. (only word I thought of to describe) When you give it about half throttle it will just seem as if its pumping harder, sounds louder, but doesnt advance timing or accelerate.

I was just wondering if theres any easy fix or what causes this. I noticed it when I drove a friends 96 auto and it pulled and drove much different

*My Max is a 96 auto

ROCKART

iTrader: (23)

typical knock sensor symptoms
i had the same thing

bkmax98

iTrader: (4)

Sounds like knock sensor to me also

ROCKART

iTrader: (23)

easy fix is debatable. most of the people here say you can just do it by sticking your hand or ratchet + extention down into the engine valley (under the manifold) and loosening it. that would cost you 75 bux roughly plus a half hour of your time and a lot of lost skin.
then theres a few people and your average local mechanic that say you should remove the entire manifold to get the proper torque when tightening the bolt (i think its like 15-19 ft lbs). plus that would also allow you to sand the grounding points. it probably seems like a safer way to do it, but you are looking at like 300+ dollars for all of that labor.
unless you could remove the manifold by yourself, but that is a huge job and would take more than a day.

got_max

iTrader: (5)

I will probably get Chris to help me out. I have a new knock sensor in my wrecked maxima. thanks for the help guys

andrei3333

scan the ecu or use the screw method and see if you got the ghost KS code before doing anything

Double E

I would remove & clean the throttle body ...before the KS gets replaced. The cost is minimal and the KS is such a pain to get to, I would glady have cavities filled first before replacing mine again.

Keep in mind though...you're probably on borrowed time for replacing it.

It's very easy. First remove the MAF, then 4 bolts around the TB, a couple of electrical connectors and a vaccum line or two and last, ...the throttle cables. Clean the back end of the TB too (intake side) & you'll probably see why you're slow off the line. Use TB cleaner, rag & a toothbrush & toothpicks. You'll be best served by purchasing a replacement gasket for the TB. (The old one will probably crumble when the TB is pulled from the intake.) Ask me how I know.

Don't drop anything inside the intake or drop any parts on the ground & reassemble in reverse order.

There's an OK write up on Motorvate, but they don't discuss taking off the TB to clean it really well.

You'll come away with more skin and in half the time of the KS replacement. At this point, if you're feeling wild & crazy, do the IAC mentioned in the Motorvate site too.

Concerning the KS, for now I would just remove the wires that connect to the KS (mounted by a single bolt at the front of the valve cover I think) and clean/brighten the contact ponts really well. Use the Motorvate site again to locate the exact bolt location that "grounds" the contacts.

Once clean and reassembled, you should see an improvement as long as you're also using 93 octane. If still no improvement, I would then do the KS.

dgeesaman

iTrader: (10)

Two other things to think about: plugs and fuel filter. They're both maintenance items, so I would do them first since they should be done anyway.

Dave

ROCKART

iTrader: (23)

i just bought a car with 41,800 on it from original owner. i had bought the PFG-11 double platinum plugs and 300zxTT fuel filter for my 96, but never got a chance to install them before the car got wrecked.

so obviously i want to install them, but the car i just bought has such low miles, do you think i should throw them both in now, or wait a bit to get the last remaining life outta the stock items (i gotta say the OEM fuel filter in the new car looks pretty clean)

andrei3333

clean from the outside you mean ? hahah dont you live in florida? there is no salt there and no winter too of couse its gona look clean, its the inside that gets clogged with use - yes replace everything, since you got the parts just do it man, its fun working on cars

KRRZ350

iTrader: (29)

and make sure you're running premium as well.............

heynow

iTrader: (1)

yep...+1

heynow

iTrader: (1)

most definetly!!

hot_wax_tree

Yeah i had that problem so I replaced my fuel filter cause my michanic buddy said that was the problem. I did and the problem went away for the most part. but I still have a bad O2 sensor that is setting off my knock every once in a while so I have sluggish accel it feels like I have a couple miss fires. I am replacing the O2 soon.

got_max

iTrader: (5)

Im not getting any ghost codes, ive had a few knock sensor codes in the past, but i just figured they were just an ecu fault. I am due for cleaning the TB my idle is very very messed up so i do need to clean the IAC as well. the plugs are bosch platinum 4's. very new, the fuel filter looks like a jumky fram, ill be sticking in either the stock one or a 300zx stock filter again.

ROCKART

iTrader: (23)

make sure you get the 300zx TT (twin turbo) fuelfilter. 12.95 plus shipping from courtesynissan.com

Cheeshead

I've done all of the above and:
-checked all coils
-replaced all plugs
-checked all fuel injectors
-replaced the MAF

and I have similar issues....I also have a stutter when at idle. Next on the list to replace is the TPS and the fuel pressure regulator. I have no codes at all

ROCKART

iTrader: (23)

cleaned the throttle body too? how many miles are on the car?

the fuel pressure regulator would trip the CEL if it was malfunctioning.
unless your CEL has been cut by some shadeball dealership.
you see it when the key is in ACC right?

andrei3333

THE KS ghost does come up WITH OTHER codes sometimes when the KS itself is perfectly fine - IF you WERE getting the KS ghost by itself before then its your KS - why would the KS ghost code be just some random ECU fault ?

Sorry to say but you got probly some of the worst plugs out there the "+4" tips dont really work the way you think, i suggest you switch to the proper heat range of ANY NGK plugs be it copper plat or whatever (NGK is the OEM choice)

Fuel filter is not the problem here i think, even if its a fram i would still swap it for a 300zx filter ANYTIME (no point in getting the smaller oem max filter) if i were you, OEM is the better filter in this case

When was the last time you scanned the car for codes ? (regardless of the randon KS code in the past)

KRRZ350

iTrader: (29)

The KS code doesn't really come up with other codes, it's just that alot of people think that because they never knew it was there the whole time. As for the ECU issue, HIGHLY unlikely. You're probably experiencing knock, from running low-octane or a variety of other problems, see sig. The KS circuit is somewhat simple. If the ohm goes out of the specified range, which happens from a bad sensor OR actually knock/pinging, than the ecu trips a knock sensor code and the timing is retarded.

Cheeshead

I have cleaned the throttle body, and the IACV. The CEL does work..it has approx 310,000 kms

goldmax

You've done everything except the one thing that might fix your problem. You could have a bad spot on your TPS that wouldn't be throwing a code or anything. You should check the voltage per the FSM to make sure the voltage is linear. Remember...the TPS is the one sensor that gets a physical workout every time you drive the car, so it will eventually have problems. Make sure you adjust the new TPS if you get one so the throttle position switch portion of it reads the "throttle closed" (idle) and "WOT" positions. Yours may be just so far out of whack that it's sending the wrong signal to the computer at the wrong throttle opening.

heynow

iTrader: (1)

yes, do check your TPS. I know mine's outta whack. It's reads over 1.1 KOhms @ closed throttle. I'm trying to have my mech change it while he's going for the rear valve cover again.