Author Topic: 2.4 flat spot!!!!! (Read 7509 times)

pete05 · « **on:** Dec 7, 2003, 07:03PM »

Hi all , have just bought a 1990 trx with 190000 kays on the clock and i have a problem i was hoping someone could help me with.
The car is in excellent condition except for this prob, it seems that between 2500 and 3000rpm the engine hits like a wall where it doesnt want to rev smoothly then when it finally gets to 3000 it take off like a rocket?
It has all new filters ,leads and plugs,the motor run quitely and doesnt blow any smoke.

CAN SOMEONE PLEASE HELP!!! ( ITS DRIVIN ME NUTS)

Insu · « **Reply #1 on:** Dec 7, 2003, 07:19PM »

Well, if you searched these forums you'd probably find that we all suffer the same sort of problems, there is a flat spot in U12 2.4ltre pintara's just as you have stated.
If its really driving you nuts, i suggest you invest in a chip for your computer, run a search on antrx or team nse chips or just ask noss.

Xnissman · « **Reply #2 on:** Dec 7, 2003, 09:36PM »

I know everyone says that the ka24 has a flat spot but i have to say that my pinnyT has never shown any sign of having one. it has always run smoothly up to the 6k redline

[JET-20T] · « **Reply #3 on:** Dec 7, 2003, 10:23PM »

My old trx was smooth power throughout the rev range.. thats why my flat spots is shitting me up aswell..

My previous car wasn't modified.. the only thing i could notice was a cover in front of the extractors was gooooone... other than that stock from factory..

noss · « **Reply #4 on:** Dec 8, 2003, 07:33AM »

i guess the more mods you do the more you will notice the flatspot.. the fuel map of the stock chip gets suddenly rich around this area which is the reason the flat spot is there.. once the engine gets to the point that the air fuel mixtures even out again thats when the car takes off.

an easy solution to fix this is to advance your timing, however if you do then you have to make sure you dont advance it too much so that it will cause pinging in the higher end of the rev range..

and yes, most performance chips will overcome this.

pete05 · « **Reply #5 on:** Dec 8, 2003, 06:09PM »

Cheers guys im goin to get a chip when available

[JET-20T] · « **Reply #6 on:** Dec 9, 2003, 08:50PM »

Apart from modifications causing this flat spot, or rich period, could a faulty lambda sensor be blamed on this aswell?

I noticed my car runs rich from all the black soot around the inside of the tip. and the puff of black smoke wen u put the foot down..

noss · « **Reply #7 on:** Dec 9, 2003, 09:06PM »

yeah that is also why you get the chip, it leans it out to a much more optimal mixture.. and you also get performance

[JET-20T] · « **Reply #8 on:** Dec 9, 2003, 09:08PM »

But if the lambda sensor was replaced, would that terminate the flat spot??

SSS · « **Reply #9 on:** Dec 9, 2003, 09:10PM »

Nope. You have to modify the fuel maps in the ECU to remove it.

FLOGTARA · « **Reply #10 on:** Dec 22, 2003, 02:34PM »

I emailed a guys from "Powerchip" and asked him a few questions. He said that the timing of the engine has to be stock timing, thus not advanced. He said the chip advances the timing. I find this a bit contradictory because the spark timing runs off the distributor right??

Also, the power figures quoted are therefore made on stock timing of the engine, and if 13kw are quoted for the best chip a fair bit of that power quoted is made from the timing advancement right??

Therefore really all the chip does is a few tiny kw here and there and moves flat spots. I don't see a chip as a great power improvement if your car doesnt really have a big flat spot.

If a chip is what your after for a nice power improvement i'm thinking its not the best way to spend your power improvement money if your engine is pretty good..... $:-\$

What do we reckon about that NOSS SSSGTR

WantaTRX · « **Reply #11 on:** Dec 23, 2003, 11:19PM »

Just to add my little bit to the topic, my friends TRX also has the flat spot probelm, especially when the aircon is on, but for the one test drive i have gone in my TRX , i didnt notice any flat spots, it was nice a toey all the way through, (i pick her up on boxing day by the way! IM SO EXCITED!)

Shawn

[JET-20T] · « **Reply #12 on:** Dec 27, 2003, 09:38AM »

ok this morning i filled her up with jizz.... oops wrong lady...

wat it should be is, i filled up my car with an octane booster + premium unleaded and the flat spot that has been making my hairs white had almost disappeared, well not quite disappeared but it helped. i tried this under load too and the car seemed happier under the 2750rpm...

We'll see how this goes for the next week or so and ill get back to this thread.

WantaTRX · « **Reply #13 on:** Dec 27, 2003, 10:58PM »

Is it any better with the air-con off, like, does the aircon suck alot of power?

noss · « **Reply #14 on:** Dec 28, 2003, 01:12PM »

yeah guys look dont waste your money on a powerchip branded chip.. its a shame that its a grey area & probably cant be bought to the attention of the ACCC. powerchip is definately a dodgy company.

noss · « **Reply #15 on:** Dec 28, 2003, 01:13PM »

oh by the way timing can be advanced on the ka24e with the chip.. not sure about the ca20e though

H · « **Reply #16 on:** Sep 18, 2005, 10:43PM »

remove & clean injectors with ultrasonic bath fit new seals & filters this will get rid off 70-80% of it

SSS · « **Reply #17 on:** Sep 18, 2005, 11:00PM »

H, if you read this, you are an absolute fucking idiot. You just have no clue whatsoever do you? Trying to get your post count up to post in for sale i see?

BenZor · « **Reply #18 on:** Sep 18, 2005, 11:04PM »

Quote from: H on Sep 18, 2005, 10:43PM

remove & clean injectors with ultrasonic bath fit new seals & filters this will get rid off 70-80% of it

Man that's awesome. I never knew cleaning my injectors could retune my car. Cheers bro!

SSS · « **Reply #19 on:** Sep 18, 2005, 11:10PM »

Quote from: BenZor on Sep 18, 2005, 11:04PM

Man that's awesome. I never knew cleaning my injectors could retune my car. Cheers bro!

It also "magically" retunes your ignition timing in the rom in your ecu right at the inherent flat spot that EVERY KA24E suffers from!

All flaming aside, so-called "ultra sonically cleaned" injectors will most likely leak internally while there is static fuel pressure when the car is off. I know my cleaned injectors certainly do. Waste of $130.

BenZor · « **Reply #20 on:** Sep 18, 2005, 11:17PM »

Quote from: SSS on Sep 18, 2005, 11:10PM

It also "magically" retunes your ignition timing in the rom in your ecu right at the inherent flat spot that EVERY KA24E suffers from!

All flaming aside, so-called "ultra sonically cleaned" injectors will most likely leak internally while there is static fuel pressure when the car is off. I know my cleaned injectors certainly do. Waste of $130.

What's a better alternative then? Just to replace them?

SSS · « **Reply #21 on:** Sep 18, 2005, 11:21PM »

If you can, yes. Because they're 240cc/min high impedance injectors, they're not worth a lot compared to what's out there.

RichTRX · « **Reply #22 on:** Sep 19, 2005, 11:43AM »

That's not what I heard - last time I read something about injectors Nissan was asking what... $400 each for them? Or was that for all four?

SSS · « **Reply #23 on:** Sep 19, 2005, 12:20PM »

Do not buy them genuine from nissan.

You should only replace the injectors as a last resort, after the following has been done:
-checked fuel pump pressure and operation of FPR
-changed fuel filter
-checked to make sure spark or lack of is not the problem
-checked the injector wiring to make sure it is getting the correct signal to the injector (a thing called a "noid" light is used)
-compression test
-remove the injectors and have them flow tested and spray pattern checked

if you can't afford to replace the injectors in one go, get them cleaned, but be warned that they will most likely drip small quantities of fuel when the car is off.

RichTRX · « **Reply #24 on:** Sep 19, 2005, 12:28PM »

is that only with ultra-sonic cleaning? What about more conventional cleaning methods?

Chadza · « **Reply #25 on:** Sep 19, 2005, 12:42PM »

u talking about using a pipe cleaner Rich? hehe

Benzor, time to turn the old "bullshit-o-meter" on with some peoples posts mate.

Chad

BenZor · « **Reply #26 on:** Sep 30, 2005, 11:29AM »

Quote from: ChadzaTRX on Sep 19, 2005, 12:42PM

u talking about using a pipe cleaner Rich? hehe

Benzor, time to turn the old "bullshit-o-meter" on with some peoples posts mate.

Chad

Hahah.

I just got quoted $145 per injector from nissan...so there goes that idea.. time to try other places =)

RichTRX · « **Reply #27 on:** Sep 30, 2005, 02:43PM »

must've been $400 something for all 4 that I heard. I couldn't remember whether it was each or all four.

And Chadza I thought you could dislodge most of the dirt by hitting the injector really hard with a hammer 10 or so times. It cleaned them so well that they didn't work any more.

Oh well $:-\$ Only kidding

SSS · « **Reply #28 on:** Sep 30, 2005, 04:18PM »

http://www.tweakit.net/shop/index.php?cPath=57_40_48

$165 max for even 1600cc/min injectors. The closest you could get away with on a stock KA with a ecu re-tuned for the injectors is the 370cc/min ones.

mike1988 · « **Reply #29 on:** Oct 13, 2005, 04:38AM »

i just shift 1st,2nd,drive and i dont have any problems with the flat spot in my car which is an auto

ashman01 · « **Reply #30 on:** Oct 13, 2005, 08:14AM »

My friends Auto 90 Trx has a massive flat spot. Its as if its not getting enough petrol and is choking around the spot. Its even worse when u drive it. Mine has 1 that is noticable but i hardly ever hit it. Normal driving = change at about 2700rmp and fast driving = changes at 4-5000rmp so it doesnt worry me that much.

BenZor · « **Reply #31 on:** Oct 14, 2005, 01:37PM »

Quote from: ashman01 on Oct 13, 2005, 08:14AM

My friends Auto 90 Trx has a massive flat spot. Its as if its not getting enough petrol and is choking around the spot. Its even worse when u drive it. Mine has 1 that is noticable but i hardly ever hit it. Normal driving = change at about 2700rmp and fast driving = changes at 4-5000rmp so it doesnt worry me that much.

I don't think its underfuelling, I'm pretty sure looking at the fuel maps it overfuels

ashman01 · « **Reply #32 on:** Oct 14, 2005, 05:18PM »

I new that im just saying the result feels like its underfueling, like its chugging even tho its getting 2 much fuel.

dobz · « **Reply #33 on:** Oct 20, 2005, 01:40PM »

I've had my car for a couple days now and i havent really noticed a flat spot it doesnt pull quite as hard down low but thats 2 be expected, but nothing like the engine is struggling.

ashman01 · « **Reply #34 on:** Oct 21, 2005, 05:38PM »

its different in every car. My friends car is an extreme. My car u can feel it especialy when u arent going fast in a high gear and then start accelerating, once it hits 2700 then it feels alot faster.

but if ur going thru the gears normaly u cant feel it in my car. u cant feel it in first at all,

Chadza · « **Reply #35 on:** Oct 21, 2005, 05:44PM »

Quote

its different in every car. My friends car is an extreme. My car u can feel it especialy when u arent going fast in a high gear and then start accelerating, once it hits 2700 then it feels alot faster.

Thats called having only a 4 cyl engine with a chunky 10kg crankshaft.

Chad

camo · « **Reply #36 on:** Oct 29, 2005, 10:40AM »

I had this flat spot problem, it felt like lack of fuel and sure enough yesterday the fuel pump sh*t itself

FalconGuy · « **Reply #37 on:** Oct 29, 2005, 04:30PM »

Quote from: camo on Oct 29, 2005, 10:40AM

I had this flat spot problem, it felt like lack of fuel and sure enough yesterday the fuel pump sh*t itself

You are also turboed but arent you camo??? Surely that would exacerbate the problem?

As a side note, I had an ANTRX Stage III Chip fitted yesterday to my relatively stock KA24E and though I didn't notice much of an outright power improvement (I didnt expect it on my engine) BUT it pulls a hell of alot cleaner all through the rev range with no chuggs, flat spots or 'misses'. Idle is also alot more stable and smoother.

Cheers,
Brendan

STU84W · « **Reply #38 on:** Oct 30, 2005, 01:33AM »

isn't installing the stage 3 chip with no mods a bad thing? i mean, i'm just going by the recommendations, but stage 2 would have been more appropriate for the unmodified..

i've got a stage 2, with a pod filter and catback, pulls nice and evenly through the range...

FalconGuy · « **Reply #39 on:** Oct 30, 2005, 01:22PM »

Perhaps it is? I'd say it would be more of a bad thing if I ran it on regular unleaded and changed the oil every 25,000KM with BiLo Special! However, I have regular services with the good oil and am always on 98 Octane (Ultimate).

I have a CAI and Catback too. WIth a bit of work around the head.

Cheers,
Brendan

Milford · « **Reply #40 on:** Oct 30, 2005, 01:40PM »

stage 3 is fine for a stock car. its just it will have more effect on a car with a bit more work done to it.

those mods will support it nicely brendan

Trx · « **Reply #41 on:** Nov 7, 2005, 09:33PM »

Quote from: SSS on Sep 18, 2005, 11:00PM

H, if you read this, you are an absolute fucking idiot. You just have no clue whatsoever do you? Trying to get your post count up to post in for sale i see?

LMFAO hahahahahahah .. funny.

Jono · « **Reply #42 on:** Nov 8, 2005, 01:51AM »

Mate, don't drag up threads just to "ROFL LMFAO LOL hahahaha" at something someone posted months ago.

SSS always gives noobs shit, it's the way he is. I bet he'll give you a mouthful for that post.