car bucks at constent

[Markovich]

s13 sr20det 7 mount
When driving hard, this car pulls hard! But when driving the speed limit and going a constent speed, the car starts to buck horribly...

help!! Its my dd..

[Pacman]

Check your TPS. You may have a flat spot in the sensor.

[HalveBlue]

Check Codes.

My guess is knock sensor.

[Markovich]

I havent hooked up my new knock sensor would that cause it? would it also cause it too stall when stopped at a light?

thnx

[pbcstylez]

i got the same problem except mine is just a KA24DE, any suggestions?

[Flybert]

Unplug the oxygen sensor and see if that helps out. This helped me when I had a similar problem.

[Markovich]

so that means that you replaced it after you found that was the problem right or you just let your car not know how to set the fuel trim?

thnx for the suggestion though

[HalveBlue]

Yes, having your knock sensor could definitely cause the problem.

No Knock sensor should send a signal to the ECU telling it that your KS isn't working right. The ECU in turn should revert to a fail-safe (rich) fuel map to prevent knocking. Problem is, it's not very effecient so your car will run like crap.

Anyway, check your ECU to see if it's throwing any codes. It's easy, and free, and can tell a lot about what's going on with your car.

[Markovich]

code 55 i put the ks on but it still bucks like shit!!!
it only happens when i hold the throttle just like a 1/4 of an inch so im going to recalibrate it any thing else i should look at

thnk

[gotta240]

check or replace the tps.

also, how is your fuel system? New fuel filter?

[Markovich]

o yeah, new 300zx tt fuel filter and stock fuel pump stock injectors... i works good with wot so idt its the fuel system? but idk cant rule anything out

thnx

[bchslap]

Like a couple have already said, TPS (Throttle Position Sensor)

Mine did the EXACT same thing, and my TPS was out of adjustment. Reset the TPS position and BAM! Good to go!

should be .95v @ idle, and ~4.5v at WOT.. and smooth transition between the two.. 7mm wrench will be needed, as will a DVOM and about 5 minutes.

[redsuns3838]

check timing too... i had that problem when my timing was way off.

[cotbu]

should be .95v @ idle, and ~4.5v at WOT.. and smooth transition between the two.. 7mm wrench will be needed, as will a DVOM and about 5 minutes.

What was it set before?, Where do you idle @?, Did you set timing before or after?
Where did you get the values? Did you pull it out your :mrmeph:?

[bchslap]

cotbu - your post is helpful, and relevant.. how? :keke: :)

http://img219.imageshack.us/img219/9360/capture049sq0.jpg

I rechecked, mine, and actually it is .65 @ idle, [email protected]
It was 0v and 3v. I didn't touch the timing. Via my Nissan Data Scan, the timing was set correctly.I idle at 900. The above picture is where I got my values. You know, the FSM... I guess the FSM is my asshole... ;)

I had also checked my Saab's TPS settings at the same time, and that was
.95 & 4.5, respectively..

[cotbu]

First off if you plug in your tps and it reads 0v replace it. the .65 is ok, but way off from .45 in my book.(throttle closed) Readjust it again! Where does it say .95v then again we have 240's not Saab's (.95v saab?)

OH! the relevance!!? just your values where coming from your asshole!
If he adjust his tps to .95v he would have other problems (around 4500rpm)idk
The proper steps are: check for boost leaks, check plugs, check timing, check everything, don't adjust anything including tps. for all i know he's using 87octane, and thats his problem or clogged injectors or bad mafs or extremely rich or TPS out of whack...

[bchslap]

well, instead of climbing up on a soapbox, and proving how smart you are with your correct steps in checking, AFTER the fact, why didn't you start off your FIRST post by correcting my mistakes, and providing the "correct" steps to check stuff, rather than only question my post, and offering NO ASSISTANCE to the question at hand, originally?

I hope your display of attitude and errogance isn't the norm for zilvia.net
forum members..

And one more thing, my TPS on the SR20DET won't even adjust up to 4.5v, I had said I got the two car's confused.

Enjoy life - it's too short to get all torqued up over little stuff.

[Chrischeezer]

im having this problem now,
but its only after the car is hot and i boost a few times.
im beting its my O2 sensor...

[cotbu]

I'm a skim speed reader. so when something catches my eye like 4.5v instead of .45v, I may or may not catch it. Not seeing more than 4.5 volts WOT is OK
I thought you had a problem as well, with the TPS @.95v
I'm the only true ass @ Zilvia

Chrischeezer, it may, try unplugging it after she's\he's warmed up. or when you notice the problem.

[Markovich]

well I fixed it and thank you for stumping me for like 20 mins till I relized that you are an asshole for telling me false info!!!! so before you try to help some one else make sure you have the numbers right first. ok? well it was my tps it was off but first i set the timing to 14btdc then i checked the tps at the ecu to get the reading the ecu is. i tightened it down check to make sure it didnt move and it runs great now.

[bchslap]

no problem, glad i could be of asshole assistance.. so i guess you fixed it yesterday between 12am and 10am? ;)

bottom line, though, I'm glad you got it straightened out..

edit: for curiosity's sake, was your timing off, as well? If so, how far out?

[Markovich]

Advanced a little bit like 20 something. I had the exhaust cam out because my rocker fell off (long story!) and didnt have a timing light at the time of installation, So I put it in where i thought close and drove it home. On the way home is when I felt the bucking. Now that I have the tps and timing correct it feels like it never felt before.. Finaly :)

peace

[Dream240]

Advanced a little bit like 20 something. I had the exhaust cam out because my rocker fell off (long story!) and didnt have a timing light at the time of installation, So I put it in where i thought close and drove it home. On the way home is when I felt the bucking. Now that I have the tps and timing correct it feels like it never felt before.. Finaly :)

peace

Why o why???

Why didn't you post this info in the beginning??? Could have saved sooooo many posts and time (namely yours)!!!!
I had to read through all these guys telling you to adjust your TPS before I finally saw that your took apart your top end to do some repairs. Next time you remove your dist without a timing light handy just mark it with some white out. That way you know where it was before you took it out.

You could have also set base timing BEFORE you drove it home. I know you were prolly in a rush but that's the safest way. Just try to give more "recent repair info" in the beginning.

Glad you fixed the problem.