ka24de hesitation 1800-2100rpm

[CraftHell]

Hello everyone first let me start with some information

91 s13 /w 95 ka24de.. automatic tranny..

The engine was swapped professionally @ localshop.. Original engine was knocking, so they pulled it before i purchased the car from them about 2 months ago.. The car was driving perfectly, still is except for this hesitation from a dead stop around 1800-2100rpm.. Only does it when im "trying to save gas lol" it wont hesitate if i push the pedal down a little more and get up to speed..

Entire egr system was removed during swap, I have replaced the spark plugs (gaped 0.044), replaced stock fuel pump with walbro 255, checked the wires they look great, fuel filter and engine bay fuel lines replaced @ swap, newer steering rack ,w TEIN inner/outer just installed (old one was leaking bad).. Cleaned the MAF twice now, check for vacuum leaks but didn't see anything odd (could have missed something tho)

I do know the guy who did the swap advanced the timing ~2 degrees but i don't believe this would be related to the issue im having cause the engine was doing great for a while..

Anyone have any ideas or experience in the similar issue it would be greatly appreciated :)

Thanks in advance. :wavey:

[Butcher240sx]

Check the O2 sensor.

[CraftHell]

Yea? alright ill try that..

Denso/Oxygen Sensor (234-1000) | 1991 Nissan/Datsun 240SX 4 Cylinders M 2.4L SFI DOHC | AutoZone.com (http://www.autozone.com/autozone/parts/Denso-Oxygen-Sensor/1991-Nissan-Datsun-240SX/_/N-itl7lZ9l2xh?itemIdentifier=707433_170891_5320_)

Will this one be a perfect replacement?

[CraftHell]

No1 else? :( man this problem is going to be the death of me :/

[godsmack]

are you running rich at all? how's the idle?

[CraftHell]

i do smell gas fumes here and there, and the rough idle occurs more freq now than last couple weeks.. thinks the problem is getting worst..

But mostly idle around 700-750ish at a red light etc..

[godsmack]

keep looking into the vacuum. might be a leaky injector start the car turn it off and then check the plugs. if one has fuel on threads there's something going on in that cylinder. if all checks out good then i'd say timing or vacuum leak

[CraftHell]

Thanks for your response, ill try the plugs idea tomorrow.. Whats the best way to check for vacuum leaks? Water-bottle /w soap? spray when engine is running and watch for bubbles?

[godsmack]

i always traced all vacuum lines and unpluged them one at a time. if you unplug it and nothing happens then somewhere in that line is the problem

[CraftHell]

true ill try both ideas tomorrow ;)

Have you had a similar issue b4 ?

[godsmack]

I've just been around cars my whole life and picked up stuff along the way on trouble shooting things. not sure if those are the problems but its something to rule out.

[CraftHell]

alright cool thanks ill let you kno :)

[CraftHell]

Update: wasn't able to try the injector or vacuum leak check cause of this wonderful Florida weather.. ugh but before it started storming I disconnected the brake booster hose and dumped 1/2 bottle of seafoam while the engine was running (had my cousin in the car keeping it alive) and turned the engine off let it sit for 15 min~ and put the other 1/2 bottle in the gas. Turn the car back on and let it do its job and i believe it did pretty well lol.. Almost got the cops called on me there was so much smoke lol. (i live in a apt complex).. once the smoke died down i drove her around for 30-45min~ and i must say the idle is like better than when i first bought the car 3~ months ago and the acceleration around 1300-2000 is there and not bogging.. Let is completely burn out and fill the gas up with reg gas and see if the problem comes back or not.. I'll keep everyone posted for people having the similar issue :)

[Edwin562]

could be a faulty MAF.... usually any hesitation below 3k, is MAF related.

[CraftHell]

Thats what i read and heard about also the MAF but it seems to be running normal, i cleaned it 2 different times about a week apart just making sure its clean.. I unplugged it while the car was running and it limited the rev to like 3k so i assume its working? im not sure tho :/ Also its hesitation with light throttle around 1800-2000 but if i get it mid to high throttle it runs soo smooth so i don't kno :/ After the seafoam today seems to have fixed the issue.. we shall see though.


EDIT sorry is there a better way to clean the maf than just unbolt it and spray it with MAF cleaner? like could you physically take it apart and clean it with cuetips or something?

[Edwin562]

my method of find vacuum leaks is spraying carb cleaner around the intake side. if car reacts(revs up) then you have found the vacuum leak.

[Frank_Jaeger]

my method of find vacuum leaks is spraying carb cleaner around the intake side. if car reacts(revs up) then you have found the vacuum leak.
Starter fluid works as well.

[CraftHell]

Hello people. Let me start by saying that seafoam did clean the engine, and it ran awesome last night.. Until this morning its back to running like it was.. So when i got off work i tested the injectors by pulling the connector to each one 1 by 1, and each one had the same effect it would start to run really rough.. So i believe the injectors are fine.. Got a can of carb cleaner on the way home i sprayed every single hose i could find 1 by 1 and the engine had no reaction either.. So this only leads me to believe its the MAF sensor is faulty? if anyone could clarify it would be great ;)

[Butcher240sx]

If you are using the stock FPR with an aftermarket pump you should be running rich. Fouling the plugs. Seafoam probably just cleaned the plugs enough for it to run fine.

[CraftHell]

understandable,

but this issue im having me came to believe i had a bad pump so i swapped for a new one, changed the plugs a week ago with bkr5e-11's and checked the wires as well.. still the same issue..

either its a grounding issue.. or a bad maf..

reason i say grounding issue cause the motor was swapped once upon a time before i bought the car and possible a ground or 2 wasnt attached properly, or at all.. even though a shop did the swap.. things happen. and the car from cold start takes a cpl sec to start even when i let the pump prime..

this shit is really getting frustrating lol.. my gas mileage is as bad as my cousins rb25 @ 16psi and 468hp..

[Butcher240sx]

Did you pull any ecu codes? What do the plugs look like? I had a slight bog off idle to 2500 rpm. Was the O2 sensor being fouled. The ecu stops referencing the sensor at 2500 rpm. The one wire sensors foul pretty easily.

[Butcher240sx]

Fuel pressure does need to be checked of you have an aftermarket pump.

[hardtime21]

Just a thought, have you pulled the ditributor cap and checked for residue? Sometimes it can be a build-up between the rotor and the distributor cap. I had a similar problem and did a complete runthrough but didn't find shyt! A little light went off in my head and it said, "Hey Dumbass, Check the Distributor!" I did and BAM! That was the problem! I kicked myself for such a noob problem but the distributor could also be a culprit! By the way, I have a 95! Hope this helps!

[CraftHell]

Nice thanks both for your help daylight tomorrow ill pull the cap off and check :) and is there only 1 o2 sensor right ?

[Butcher240sx]

Only 1 O2 on S13 its a maintenance part to be replaced every 15k miles. It's cheap and if the car has been running rich its likely to cause problems.

[hardtime21]

Yes, there's only 1 for an S13 but if it's setup like an S14, you're gonna need two! Lmk what you come up with after you pull the cap.

[CraftHell]

Checked the cap all is good under it :/

I been reading about possible grounding issues, today i took home a digital reader from work. Im gonna measure the ohm resistance and if its bad ill put together some kinda grounding kit and yea.. we shall see ;/

[hardtime21]

Keep us posted! Are you using the 95 engine harness?

[CraftHell]

alright i will :) the entire engine it self (intake, head, block) is from the 95.. rest is factory from the 91.. ecu, harness, accessorys, etc..

[Zilviasr20]

Sounds like a bad maf. Swap with a friend and check. How does it idle?

[CraftHell]

when i first crank from cold it idles around 1-1200k then slowly goes down to 600-650 while its warming up where it feels like its missing/stumbling a bit.. mind you that when i used seafoam that one night it ran perfect idle and everything, i couldn't even tell it was running to be honest lol.. it was such a smooth idle..

havent had a chance to do the ground check yet, just woke up lol.. going out there in a bit


edit: i would love to borrow some1's maf if i knew someone with a ka around me.. everyone has sr,rb, or vq /w z32 maf's etc..

[CraftHell]

Well just got done testing all the ground under the hood and everything is perfect.. anywhere from 0.1~0.48ohm on the head, block, intake, exhaust, and random other spots i tested on connectors..

I'm so mind boggle this is ridiculous..

[Butcher240sx]

You are running rich from too much fuel pressure I bet. Get a gauge and check it. Change the o2.

[CraftHell]

so should i change the pressure regulator then /w a new o2 also? cause this problem was before i changed the pump.. i changed the pump thinking it was going bad.. :/

also i never hooked up a gauge.. you recommend any? and how?

Thanks ;)

[CraftHell]

Butch couple posts you said change the o2, and so i just ordered oem replacement for 15$ shipped from rockauto.com when it comes in we shall see :)

Even if it isn't the culprit its gotta have some hand in my gas problems it looks like original one lol..

[Butcher240sx]

The factory fpr works with the factory pump. You need an aftermarket adjustable . You can rent a gauge from most any auto parts store. Follow the instructions included with it.

[S13ZX]

from my xperience i did a cupple of things.....
replaced my battery wich helped my low rpm range.
in 5th gear around 1500 rpm my car would hesitate alot but now rpm is smoother when shifting under 2k......
it would also not go past 3k so i replace the maf and its all good now.
clean the throtle body and since the egr has been disconneted check the vacuum lines that go to the egr

[CraftHell]

@s13zx - how many vaccum lines go to the egr? just at glance i can see one is plugged with a screw, (i was told it was blocked, but why it was left on i dont know..)..

@everyone - lil' update.. i got the o2 sensor in yesterday, installed it last night.. here is a picture (@bottom) of the old one.. (funny thing is i read never use a Bosch one cause they are shitty, well this one has to be the original one. It has a lil' Nissan emblem stamped on it, and it says Bosch on the opposite side lol..) and it seems to be running a lil better but still a lil rough idle, not going to say much on it until i drive it a few days ill see if it fixes anything..

Also i took off my cap/rotor this morning and snapped some pictures, i noticed the rotor had some burn mark or something in the middle, i hope you can see it from the first picture of it there.. i got a new cap/rotor kit on order already cause i don't like the way that looks.. also isn't there supposed to be some kinda seal between the cap and the distributor? Mine doesn't have a huge gap or anything but water/moisture could def get in it no problem..

:2f2f:

[CraftHell]

Update: Day #3 car is driving better now with the new o2 sensor.. the hesitation is completely gone as far as i can tell.. but.. yea there's always a but :/ the idle is more distinctive now.. its smoother, but still has a shake here and there.. i still believe a injector is causing that portion..

Wish my trip meter worked :/ i could gauge gas mileage better..

[Butcher240sx]

Good to hear its better. Start the car and pour a little Seafoam into the IACV vacuum hose on the air intake. Might help the idle some.

[CraftHell]

okay thanks ill try it maybe tomorrow..

[CraftHell]

one quick question before i pass out lol..

I have already seafoamed my car 1/2 in the hose going from the brake booster.. and 1/2 in the tank.. it cleaned alot i presume alotta smoke.. the hose going from the brake booster.. where does the other end of it go into? and this would be the same hose would it on the IACV ?

[zerodameaon]

So you did the seafoam, did you change your oil after? Its always a good idea as that stuff can thin your oil out a bit. Clean your fuel pump strainer to, I did that today and the random breakups I would feel under hard acceleration are completely gone.
And if I am on the same wavelength as Butcher the hose with the arrows is the one hes talking about.
http://i216.photobucket.com/albums/cc86/SRni-ju/IACV.jpg

[Walperstyle]

I had hesitation at 4500 RPM, never did figure it out with my engine. BUT, when I pulled the stock engine, I had low compression on no 1 and no 2 cylinder... so it balanced out rather well enough where it didn't seem like anything was seriously wrong. I have no idea how long I ran it like that.

Anyways, do a compression check.

[CraftHell]

thanks guys ill check it out if it ever stops raining.. also when i sea-foamed the first time i didnt pour any in my oil.. just 50/50 booster hose/gas tank

fuel pump strainer? would be the sock on the physical fuel pump ? if so it is brandnew not even a full month i believe.. the pump is as well.. wal255.. and the fuel filter is new as well..

[Butcher240sx]

I use the VC breather hose on the Intake tube to introduce the Seafoam thru the throttle body. It seems that the brake booster hose would just feed one cylinder more than the rest. For the iacv valve I use it in the air supply end.

[zerodameaon]

thanks guys ill check it out if it ever stops raining.. also when i sea-foamed the first time i didnt pour any in my oil.. just 50/50 booster hose/gas tank

fuel pump strainer? would be the sock on the physical fuel pump ? if so it is brandnew not even a full month i believe.. the pump is as well.. wal255.. and the fuel filter is new as well..

It can still make its way down. It wont be a lot but its still a good idea.
As for the fuel pump your good to go then, assuming you have a new fuel filter (in engine bay).