4000 RPM Hesitation

[punxva]

Hey guys, i've got a KA24DE and have done everything that i can think of to end this damn hesitation in 2nd gear around 4k. It's like it hits a damn brick wall...

heres what ive done...
fuel filter, cleaned air filter, swapped maf, changed coolent temp sensor, fixed minor exhaust leak, new plugs, new cap and rotor, new spark plug wires, seafoamed the engine-crankcase (changed oil after) -through brake booster (replaced plugs and O2 sensor afterwards) -and into fuel. I'm completly stumped. BTW the car has 206,000 miles on it. I've also checked for any vaccuum leaks, and ive found none at all. Please help me out with this guys...

[punxva]

could it maybe be my fuel injectors?

[kabukie]

I recently had the same issue and I changed out my MAFS and it runs good now. I changed everything thing you listed and then some.

[punxva]

this is my 2nd MAFS because i thought of that too, actually i posted this like at 12 am lol so i might have forgotten some things also.

[kuramaya]

What gap are you running on your plugs? gap down a bit and see if your stutter goes away. If it doesn't and your wires tested good and you changed all the other stuff im not sure...check the gap

[punxva]

hey, ive got the Bosh +4 ones, where it says not to gap them at all, like when i bought them, the people at autozone said not to gap em. Also i checked the timing, and it seemed to be at 15 degrees BTDC, but im not positive if thats what it was at tho. It was pointing at the 5th mark from the left, not the last one to the right but the 2nd to last. lemme see if i can find a good pic of where its at.

[kuramaya]

hey, ive got the Bosh +4 ones, where it says not to gap them at all, like when i bought them, the people at autozone said not to gap em. Also i checked the timing, and it seemed to be at 15 degrees BTDC, but im not positive if thats what it was at tho. It was pointing at the 5th mark from the left, not the last one to the right but the 2nd to last. lemme see if i can find a good pic of where its at.

hmm i dont know sh1t about KA's but on an NA SR20DE that would be 15 degrees. 20 Degrees is the last notch..maybe someone can tell you if that gap is good...breaking up at 4,000 could be plugs gap though

-5 0 5 10 15 20
late
daryl

[CHARLIE2020]

Check your ECU for Code 34 (Knock Sensor) I had the same problem it turned out to be a SHort to ground in the knock sensor signal wire and not the knock sensor and it to felt like I hit a brick wall but not anymore :).

[GazXL]

Try simply checking all of your ignition wires to make sure they are in the right order.

Sounds really stupid, but it happened to me once, plus its an easy thing to check.

Good luck fixing it! :x:

[punxva]

ok, checked all of the above, i only got code 55, so everything is clear. I havent changed the timing though, does anybody think that may be the problem?

[punxva]

ok, when i checked the timing with the TPS unhooked, it was at 20 degrees, but the weird thing is that every few moments the engine would surge and you could hear it going down then up, and the timing would fluctuate from around 13 degrees and then go back up to 20. What could be causing this to happen???

[kuramaya]

ok, when i checked the timing with the TPS unhooked, it was at 20 degrees, but the weird thing is that every few moments the engine would surge and you could hear it going down then up, and the timing would fluctuate from around 13 degrees and then go back up to 20. What could be causing this to happen???


okay on an NA SR again, I am not sure about the KA, I am only proficient with SR's NA and Turbo... To check the timing you have to bring it up to Operating Temp..go get an ice cream at Mcdonalds or something...then rev the car to 3,000 Twice, then un hook the TPS..when the TPS is unhooked, the timing should not fluctuate..the motor will raise and lower in sound and revs, but not the timing. If you timing is adjusting then it could be the ECU adjusting it. 20 is too high I am sure. Especially for the Octane of gas you are using. On the SR N/A if you run 19 Degrees of timing, you should run 93 Octane...that is as high as you should go with timing on pump gas....it is possible at over 4,000 your shit is detonating. Try retarding the timing to say 17 and see what happens. You know how to check timing correctly right? Hook the battery up to the gun, then hook the sensor clip to the Number one cylinder wire, then you are good. SOme timing guns have an advance setting, make sure yours doesnt or if it does it is set to zero.
late
daryl

[punxva]

Hey thx for the reply, i found out that the stock timing for the ka is 20, but i really need to figure out wtf its doing this for...

the engine would surge and you could hear it going down then up, and the timing would fluctuate from around 13 degrees and then go back up to 20. What could be causing this to happen???, ima try making a movie with my phone really quick, so you guys can see what im talking about.

[punxva]

ok, well i've found that it starts to hesitate around 4000 rpm's and then you can feel it get powerful again at, around 5500 rpms, then it pulls pretty hard after that. Now it seems to do it in every gear, so, hopefully someone can help me narrow this problem down pretty soon.

[CHARLIE2020]

I got another thing for you to check wiggle the (red) water temp sensor wire while the car is idle and pay attention to any idle fluctuation, I've found this to be a pretty comon problem on alot of KA's.

[punxva]

ok, i did notice before i taped the hell out of it, that it would make my aiv, when i had it, make different pitched noises. If the plug is the case, how should i go about fixing it?

[CHARLIE2020]

Most of the times its been a really corroded connection im my experience with cars I've seen, I would recommend replacing the temp sesnor with a new one and also check and repair the harness side if need be, this will have a big impact on performace and your gas milage if its failing or making a bad connection.

[punxva]

ohh, i replaced the actual sensor, just not the harness, how should i repair it?

[punxva]

ok, new thought, my rear tires have almost no tread on them, and i've got a Clutch master stage 2 clutch, do you think that at about 4000 rpms, the weighted springs on the clutch are applying the max power? Cause maybe since my tires have little tread, im loseing traction a little bit or something like that.

[BigVinnie]

HMMMMMM
If the problem first started in other gears than first gear, it isn't an electrical problem. Your car is showing signs of drive train problems.
Could be:
Bad and worn clutch
Flywheel hasn't been machined or replaced and is warped with hot spots.
Basically no grip to the drive train.

[punxva]

well, ive got a brand new clutch that was properly broken in and a fidanza flywheel that was put in the same time. It happens in all of the gears, i've now noticed.

[kuramaya]

You may need to take your car to someone to have it looked at...I could but I am faaaaaaaaaaaaar away...sometimes forums are actually bad for some problems as you end up going in circles due to opinons...the opinions we all are making are good assumptions but it is hard to troubleshoot..plus you are adding a little info here and there..most places wont charge to look at a car for a problem...then once they tell you what the problem is, fix it yourself..:eek3d: or a buddy could help out..just an idea

[punxva]

alright, btw maybe you could pick some stuff up for me from a jap junkyard ;)

[punxva]

ok, so no1 has anymore suggustions?

[punxva]

ok checked the ECU for codes and all i got was 55 which is the normal code, could some1 please help me out.

[slideways2004]

i'm also having the same problem except no power after 5500. i am going to be replacing my spark plugs and spark plug wires and see if that helps

[tsjohnson25]

Hey man i was wonderin if u got the 4000rpm hesitation thing figured out. I just got a ka24de from a s14 put in my 93 s13 and it is doin the same shit.

[i20ar]

i got the same thing.. i dunno what causes this.. but i found that when i added a vent tube comming from under the headlight up to my intake.. the problem wasnt as bad.. its still there but not as bad.

[s14slide]

Try using a different plug. This seems to be the same problem a friend of mine had with those same plugs on his Mitsu GTS-T. Did this problem arise around the same time you put those plugs in? He changed them out for good 'ol NGKs and it ran fine after that. The guys at the parts store said a lot of engines don't like those four point plugs, or the Bosch platinums either. Good luck with it.