This thread was saved without dates. "Around Oct 2004" is estimated from neighbouring threads.
I was just wondering, my VG30E engine, i dont know its got some balls until 3000rpm but when it hits 3000 man does it really start to go, is there something wrong with the engine, or is it just the way the engine runs? i was thinking possibly something wrong with air sensor, what is your take on this?
I think something might be wrong. Usually the VG30E in the S12 doesn't start to dramatically lose power until around 5700 rpm. Have you done a diagnostic on your ECU? That's where you should start. There are a few sensors that, when problematic, tend to do that sort of thing. It almost sounds like maybe your timing is not advancing like it should. Might be the crank angle sensor. Or could be MAF, etc. You could also do a compression test to get an idea of the actual condition of the engine internals.
nono i think either i worded it wrong or u didnt understand what i was saying, it doesnt get Alot of power until about 3000rpms before 3000 it has some but after 3000 it seems to get up and go alot faster,VG30E trait?
thats how mine is.. except that mine doesnt start to go till about 3500,.. its like its sluggish before then.. but once it hits about 3500 you can actually feel it kick in a bit and it pulls all the way to 6000 (its like its one of those hemi's where 2 cylinders dont kick in till you really get on it),.. i would really like to get some of that bottem end power back tho
nono i think either i worded it wrong or u didnt understand what i was saying, it doesnt get Alot of power until about 3000rpms before 3000 it has some but after 3000 it seems to get up and go alot faster,VG30E trait?
LOL Nope, I read it wrong. Geez, all that typing for nothing. hehe Anyway, mine is a little sluggish before 3000, but that's because of my mods. Timing can have an influence in your power band. Do you know what your timing is currently set at?
its GOTTA be a trait..but have you noticed its not all the time?? i replaced the clutch on mine..it got way sweet..i had 100% power all the time. then after a week, it ran way back to "normal". I replaced the coil just recently, and had awesome power down low..for a week, then i was back to "normal". i honestly think its the location of the air intake...its sucking hell-hot air..and if it were cold, it would go like mad all the time..but that doesnt explain the every so often get up an go.. :wall:
And you don't get any codes from the ECU? It's gotta be something wrong if you get the power at one point in time, and then lose it at another point. Have you tried resetting your ECU? Just leave the negative battery cable off overnight. It will run a little rough at first because it has to relearn the motor, but sometimes, after mods like an intake, coil, etc., it will help it to recognize them. Give it a try and see what happens.
...gonna try that tonite...
the power loss/gain you had described feels similar to that of a turbo'd motor...right?
yea its almost like its spooling the turbo and at 3000rpm it kicks in, im telling yea first and second gear, from 1-3k rpm its kinda sluggish, then at 3000 it puts ur head back into the seat, weird im telling ya ill try that keepin the negative battery off overnight thing though sounds good. Also when its cold it seems to run better, i think it might have to do with it sucking in hot air like mentioned earlier, is there a way to re-work the air intake so i can get 100 cool air 100% of the time?>
..own a car with more aftermarket support?! i dunno...its a frustrating problem...ive done Darn near everything i can come up with....Wires, plugs, cap & rotor, exhaust, vac. lines, cleaning the intake side (as best i can)...i did come up with something the other night tho...i had raced w/ a celica ST..(new one to me..but the SE prevailed)...and launching at 1800 rpm worked pretty good...took ALOT less to get thru 2nd gear..tried launching at other rpms too..at idle..its slow, at 3000, its tires on fire..lol..if i get something ill pass it along! also..does your exhaust TICK after shut down? i know since ive owned it, my exhust has run pretty hot..the flowmaster and hi-flow cat didnt help that either, loll.
Yeah my exhaust ticks when i turn the car off too. I dont know what you guys are talking about mine pulls from 1800 to 5600 like a motha. bvelow 1800 it has like nothing hell my new clutch will instanly stall it if im not careful. But mine has alot of balls through the whole rev range. But i dont have a bigger TB or cone filter yet.
..maybe thats the problem..i have the bigger TB, and cone filter..?this is prob. where the 300z ECU would help, to know what to do with the extra air?? hmm..
It's definitely not an ECU thing. The S12 ECU can calculate the added air just fine. Also, if you're getting the power sometimes, and then it goes away, that should tell you that something is malfunctioning. That being said, the intake and larger throttle body may sacrifice some torque for higher end horsepower, however, it shouldn't be enough to actually feel a difference.
well..im open to suggestions...as im sure anyone else is, cause this is a bummer..but higher end HP is just fine...its the low-end Torque thats a problem.
So far, I haven't heard anybody say they've done an ECU diagnosis and not gotten any codes. Has anybody done one yet? That's STEP ONE. That being said, there are quite a few sensors that the ECU reads to run the car properly. Any one of those can make the car run a bit out of spec. Faulty o2 sensor, crank angle sensor, fuel temp sensor, MAF, TPS, CHTS, etc. If you don't get any codes from the ECU, try running it in the real time diagnostic mode. I believe it's mode 5. In the past, I've had a faulty crank angle sensor that, for whatever reason, did not throw a code. However, when I ran the car in real time diagnostic mode, it did show me the crank angle sensor code.
...no codes in mode 2, but havent tried mode 5..i do know that on the z31 ecu i get code 34..."load Signal"..or as was told to me by z31forums...Bad ecu!
Do you mean Mode 3? Mode 2 is, I believe, the o2 sensor diagnostic. Unless you have an older Z31 ECU, in which case, there are no modes. I'm using an 88 Z31 ECU, which is exactly like the stock 200SX SE ECU, in terms of diagnostics. Have you tried a different ECU to see if it helps the problem?
..the 86 Z ECU has 2 modes...mode 1..i havent the slightest, mode II is like mode II on the s12..i think....mode 5 on the s12 is RTD.
Bummer, wish I could be more help. Short of going through and checking each sensor's voltage and continuity, which is really hard to do when the problem exists only in certain conditions, I don't know what your options are. Did anyone on Z31 explain what "Load Signal" meant? Never heard of that before. It's so hard to find these nagging little problems. :wall:
Load signal is printed on a sticker, on the z31 ECU. It says if you get a code 34 then check the load signal! code 34 translates to bad ecu according to the z31 guys...but then why wouldnt it say ecu??