Need help: ka24de s13 no power after 3500 rpm.

[celbii]

Hey guys I've been at this for about a month now and yes i've searched hundreds of times.I have a 92 s13 with a ka24de. Unknown mileage on motor.Problem: Car drives fine untill about 3500 rpm and then it just loses power really, feels the same whether you are giving it 1/4 throttle or full throttle. It just does not want to get up and go. When I got the car it had a bad injector and alot of rust in the gas tank. Since i've had the car this is what i've done.

Cleaned out gas tankInjectors all good and serviced.new fuel filterno cat3inch exhuastaftermarket intakenew ngk plugsnew ngk plug wiresnew dist cap and rotorSet timing between 20-25checked timing marks via pulling off valve cover (Looks fine)

Im at a loss for what would be causing it to just lose power after 3500 rpm. This is in gear btw, i can free rev it fine in neutral. I changed the fuel pump but im not 100% sure if its great or not, just got it from my friend.

If anyone has any ideas please post up, for what its worth, with the car driving the way it is , i still get 25mpg.

[Shabbernigdo]

have you checked your secondarie throttle plates / butterflies or whatever they are called?

the butterflies in the upper intake mani. i know when i was removing my vac lines i flipped em closed on accident and my car ran fine up till about 3k rpms then it felt like i was draggin somthing that just got worse as the rpms climed.

duno if this is the problem u have but its somthin u could check out just to make sure.

[Dattebayo]

Check your ecu codes, see if you are in limp mode or something.

[Soravia]

It might be the same issue I had. Running to rich.Mine was caused by air leak in the vaccum system because the rubber hoses were cracked after so many years. So the car was getting too much fuel for too little air. And bogs down whenever I pushed on the accelerator or go to high rpm.

Check for vaccume leaks, there are small crank case hoses under the intake plum. The big crank case hose from the timing valve cover should also be returned tightly to the air intake tube.Good luck.

[celbii]

have you checked your secondarie throttle plates / butterflies or whatever they are called?

the butterflies in the upper intake mani. i know when i was removing my vac lines i flipped em closed on accident and my car ran fine up till about 3k rpms then it felt like i was draggin somthing that just got worse as the rpms climed.

duno if this is the problem u have but its somthin u could check out just to make sure.

Do you have anymore information on how to check these?

Check your ecu codes, see if you are in limp mode or something.

ecu shows code 55 all clear

It might be the same issue I had. Running to rich.Mine was caused by air leak in the vaccum system because the rubber hoses were cracked after so many years. So the car was getting too much fuel for too little air. And bogs down whenever I pushed on the accelerator or go to high rpm.

Check for vaccume leaks, there are small crank case hoses under the intake plum. The big crank case hose from the timing valve cover should also be returned tightly to the air intake tube.Good luck.

I've replaced almost all of the vacuum hoses, i don't think its a vacuum problem

[OutToWinPAHC]

Sounds like a rich/lean issue. I would lean towards a MAF or o2

[celbii]

Brand new o2 sensor. I think maf is good, but when i tryed swapping it out with two other mafs was when one of my injectors was bad so i couldent tell. So I need to try again.

[OutToWinPAHC]

brand new 02? did the problem happen shortly after installing? What brand was it?

[celbii]

Nope problem was there with the old o2 sensor. New one is universal Bosch, no change really when i changed them out so i ruled that out.

[OutToWinPAHC]

Yeah try one of the other MAFs, also check the fuel pressure at idle and ranging too.

[celbii]

What psi should i be looking for?

Thanks for the help btw.

[Dattebayo]

Three parts work together to create this issue:The TPS, the O2 sensor and the MAFS. A fault in the TPS or the MAFS can cause the O2 sensor to get clogged or burnt out.

Also, it the knock sensor is faulty, it would show up intermittently in your codes, not all the time. I assume you have one of those, right? (I don't remember)

Some have said the FPR, but that would mean your acceleration is really choppy too, and that warm starts would be impossible.

I can see the fuel pump possibly being an issue tho.

[celbii]

Yea I could go try a new tps for kicks and giggles and try to find a maf here local to swap out.

[Dattebayo]

Try wiggling the wires going into the TPS first, I had an issue once when I owned an S13 where the connector pins were bad.

[celbii]

Well referring to the tech article on 240sxtech i measured the resistance in ohms and it was the opposite of what it should be. I am trying to figure out how to measure the voltage, im a noob when it comes to electrical stuff like this, do i just turn the car on and stick my voltmeters probes into the connector while its connected or do i disconnect it ?

[Dattebayo]

Well referring to the tech article on 240sxtech i measured the resistance in ohms and it was the opposite of what it should be.

There's no such thing as "opposite" ohms.

I am trying to figure out how to measure the voltage, im a noob when it comes to electrical stuff like this, do i just turn the car on and stick my voltmeters probes into the connector while its connected or do i disconnect it ?

You don't check ohms that way, but you can check voltage that way if you know what you are doing... Otherwise you need p0ker clamps.

[celbii]

Just replaced the CTS and didnt seem to make much difference, car was idling a little higher(around 1k). at least it did just die on me every time like the last cts i installed did. I checked my tps and my voltage seemed fine, it was set at .52 and i changed it to .43 with no real difference, i went ahead and ordered a new TPS while i got the cts anyways though just to try it, supposed to get here in 2 days.

[GoldenZenki]

celbii, did you figure this out? I'm wondering because this is also happening with my car now.

[RustspecS13]

Sounds like your knock sensor. Its inbetween the #2 and #3 cyinders.



There's where it is on the block. I actually picked up a coupe yesterday, and it got so hot the knock sensor melted, the spark plugs got discolored and one plug wire melted. It was pretty crazy.

Any way I bet its your knock sensor. If its bad the computer will "see" knock all the time and so above 3500 it will retard timing to save the motor. To test it find the 2 wire connector by the coolant sensor, it should be to the right of it, and stick a 470K ohm resistor in the pins to tell the ecu theres no knock. Take it for a drive and enjoy. If thats your problem i would get a new sensor and subharnes.

~Alex

[cracka400]

Check your fuel pump/pressure. I checked and replaced everything you noted and it didn't change a thing. I put a fuel pressure gauge in-between the fuel filter and the rail and it read 30 psi idle and 38 wot. Once I changed the pump it ran like a charm again. Hope this helps.

[Rsmithcns]

[quote="celbii"]Hey guys I've been at this for about a month now and yes i've searched hundreds of times.I have a 92 s13 with a ka24de. Unknown mileage on motor.Problem: Car drives fine untill about 3500 rpm and then it just loses power really, feels the same whether you are giving it 1/4 throttle or full throttle. It just does not want to get up and go. When I got the car it had a bad injector and alot of rust in the gas tank. Since i've had the car this is what i've done.

Cleaned out gas tankInjectors all good and serviced.new fuel filterno cat3inch exhuastaftermarket intakenew ngk plugsnew ngk plug wiresnew dist cap and rotorSet timing between 20-25checked timing marks via pulling off valve cover (Looks fine)
quote]

This all sound so familiar. I am having the same problem with a 91 240sx I bought and rebuilt bottom and top. I replaced the fuel pump at the time of build with a new pump. Same issue of rust in fuel tank fuel was badly laquered. My only difference is mine will very at which RPM it bogs down. most common is at 4500 but have had it occur as low as 2500. It does it regarless of which gear you are in. The other part that I find interesting is it only bogs if I I have the gas "to far down. If I Slowly let off the accelerater until it stops bogging down I can slowly drepress the accelerater and am able to get the car to higher RPM. I am going to taking it back in my shop tomorrow and check the knock sensor and get a Fuel pressure gauge installed luckily the pump is under warranty. On a side note unsure of its relevence while idleing if I do anything to increase electrical loading IE Fans, Lights, Blower, Car will search for idle between~550 and ~950, doesn't stall.

Thank you in advance for all your help. I am passing my headache on to you

[R240sxSE]

Im having the same exact problem with my car. Anyone have any ideas what it can be?