s14 ka having some throttle issue when at Operating Temp.

[240sxdriftrat]

So here is the deal with whats going on with my car.

Lets say I wake up my car is completely nice and cool, I can get in it and as long as my temp gauge is reading really close too cool temp. (below half on the temp gauge) when I step on it i have excellent throttle response but lets say I drive it for about ten minutes when in its during the day; I live out here in tucson, AZ. It starts bogging out or when ever i step on it, it just stays there but gets louder no progressing at all. But at night, I drove it all the way home for about 35 minutes and it did great the whole drive, but the gauge was reading pretty cool! So idk what it could be, hopefully one of you guys have been through the same problem or can help me diagnose the issue further. I will try all suggestions and get back to you guys with any results.

Thanks! :rimshot:

[Sileighty_85]

check ECU for codes

[240sxdriftrat]

thanks for the reply, ima try looking up a list of all the codes and a write up on how to do that today and ill get back to you guys later on today

[240sxdriftrat]

ok so i checked codes and i got 25,82, & 84 which is crank pos. sensor, a/t comm line (never heard of it), and iacv-aav (idle air control valve). Correct me if im wrong with anything.

I checked the valve and felt around a little, seems like all plugs are connected so im thinking i might try giving it a nice clean.

As for the crank pos im not sure but i think who ever owned the car before me used an s13 tranny so im not 100% sure there isnt even a crank pos. sensor but i have to take a look. (im not quite sure on its exact location.

As for the A/T comm line, I tried searching it, but found no info on it.

Thanks

[240sxdriftrat]

Any suggestions on what i should do to get these codes clear?

[Mishkin_707]

seems like im having a similar problem, i have i 89 S13 SOHC 5spd, when it's cold or like you said below normal operating temp it's good, but after my car is warmed fully to operating temp it seems as if i have no torque when i try to take off from a light, i checked my ECU for codes and i got a 55 which is everything is fine, hopefully i can find out and let you know, and if you find out please let me know.

[240sxdriftrat]

I have had no luck in finding what could be causing this, although the previous owner of my car put a new head on the engine and supposedly had the engine upgraded with low compression pistons.

I think he was lying the pistons, but it has crossed my mind that maybe this could be the reason? although i doubt it.

I also have been thinking maybe its my fuel filter or timing could be off. I dont have the tools or funds to be replacing parts at the moment to try and diagnose the problem.

Things I have done though to the car is swap ecu's which showed no difference, I also cleaned my IACV (idle air control valve) and that showed no change.

also i notice that there is a lag in torque sometimes. as the rpms climb between 1500-4000 it shows no torque and climbs fairly normal in rpms but as soon as it passes 4g's the torque kicks in almost like v-tec. (weird)

any help or suggestions are appriciated, I will continue trying to investigate whats causing this.