above 3k... hesitation and choking

[miucus]

hey, just got my s14 sr20det swaped into my s13 today.
while driving home today, the engine started to hesitate/choke and shake violently when going above 3k rpm in every gear. seems like the fuel is getting cut off or something. the engine idles fine though. im a newbie when it comes to problems so please help me out.

mods
greddy turbo pipe and downpipe
greddy intake
stock exhaust =/
stock fuel pump =/ replacing soon but can this be a problem?

thanks for the help

[DJPimpFlex]

search....your maf probably isnt properly grounded. Common problem. Check codes.

[Nizzan4u2nv]

I concur. Seems like a maf problem.

[240silvia]

nope nope nope nope nope, wrong answer. It's s fuel problem. What do you have for fuel management? SAFC or anything? You aren't getting enough fuel. Since you are new, and I don't know how new you are, I'm going to assume that you don't know anything, lol. When you don't have enough fuel, you motor blows up, lol. Generally, in a turbo car, it's better to be a little on the rich side before you get it tuned.

This is what you do...

1.Park the car, DO NOT DRIVE IT
2.Get a Walbro 255 Fuel pump, and an Apexi S-AFC
3.Take it to a shop and get them to tune it

When I first installed my KA-T my car did the exact same thing. 3K, the damn thing died. I added more fuel on the SAFC, bingo, no more problems.

-Charles

[Nizzan4u2nv]

Yea, but hes saying that even under no load it still does it. It also starting doing it out of nowhere meaning, it ran fine before that. From what hes saying hes running an all stock setup(stock ecu, stock maf and injectors) so theres no way he could have that severe of a fuel problem. His ecu is tuned for that setup where as your ka-t was not, so of course its not gonna run right when your injectors and maf are maxed out with an ecu not tuned for that setup. I still think its a maf problem, or a massive vac leak. I had the same problem when my maf connection went out. Just driving down the hill, it starts bucking like crazy, hesitates, chokes wouldnt rev above 3k etc. Ended up being a bad connection at the maf.

[lex_0105]

Hey, (since this is one of the few threads i found regarding 'choking'). I have a 180sx (jap ver) with ca18det engine with auto transmission and just got my turbo and the injectors replaced with new ones.
Problem: when i accelerate from 1st gear-2nd (at high revs) its works fine, but when 3rd-4th gear, the revs/enigne starts choking (at 4000rev)n it doesnt want to change to 4th gear unless i release the throttle pedal abit. It sounds abit like it ran out of gear to go (if that helps). Could it be the same problem as above...honestly i have had half a dozen of answers to this problem but none of them did actually fixed it!!so i wasted alot of $$$ for nothing!!
Ive also changed the a'c compressor recently just fyi.

currently on:
Stock ca18det
3" exhaust

HELP PLS, DESPERATE!

[ranger240]

my stock sohc did that same thing... check for loose hoses. a loose hose clamp on a hose that goes to the intake tube between the maf and intake manifold seemed to be the problem.. as it stopped once tightened

thought the problem was fuel delivery too as it felt the like speed limiter was kicking in around 3000.. but it turned out only to be a loose hose

[s13coupedrfter]

I'm with ranger240 on this one, seen many posts with the same problem and the same fix. You said you just got the swap so maybe a hose clamp was overlooked. Around 3000 rpm is when the stock turbo starts to make boost and you could be bleeding some boost pressure out. Also, replace the fuel filter with the z32 one. Chances are the fuel filter hasn't been changed in a very long time and get a higher capacity fuel pump. I wouldn't trust the stock fuel pump once you start raising the boost. Wahlboro pumps go for 100-130 bucks and are easy to install. G/L

[lex_0105]

thx guys,finally got it running as i want it to be. though, a new problem jus came up: at high revs, the whole vehicle vibrated like crazy. i (think) its the coupling on the shaft underneath. i found out it was jammed abit. process of replacing the coupling. alrighty then...

[xxsptcuztomsxx]

Try checking all your COILPACKS with a new spark plug for spark.

Remove a coilpack insert a new NGK standard v-power plug or somethin similar into the end of the coilpack. You dont have to spend a lot on this plug. Its just to test with.

Next, touch the spark plug electrode (the small L shaped metal thing at the end of the plug) to something metal on your engine. (i suggest somewhere on the valve cover that is unpainted. Do not touch on the fuel rail or manifold. Somethin bad could happen. Just be careful)

Then, have an assistant crank the engine a few times but do not start the engine.While the engine is cranking, check for a spark from the spark plug.

If a coilpack doesnt produce spark swap it out for one of the others that did create a spark.

This same thing happened to me on my s13 sr. I would be driving down the highway and try to get in the throttle and the car would start bucking and hesitating. Turned out to be a bad coilpack. The coilpack can not be interchanged with any US car part. Must be ordered from Japan or a specialty shop. The maxima coilpacks can work with modification. In my opinion, i wouldnt spend hundreds of bucks on a coilpack that im gona hack up to TRY to make it work. I wouldnt risk that much money. Just get a replacement if indeed it turns out to be your coilpack. I think i paid 60 bucks shipped overnight from Tophat performance (might of been titan motorsports).

Update once you figure out what the problem is. Sry for such a large post. Thought this info might be helpful to others.