Hard Startup

I am trying to figure out my truck. It seems that when it is warm out the truck starts up and idles rough for about 40 seconds and then clears up. I can't seem to figure this out. When it is cold out that morning it sometimes starts a little hard but normally good. This mainly occurs on warm days after it sits for a little while. Could this have anything to do with my Idle Air Control Valve? Any input or theories is much appreciated. BTW - I have the KA24e.

I am trying to figure out my truck. It seems that when it is warm out the truck starts up and idles rough for about 40 seconds and then clears up. I can't seem to figure this out. When it is cold out that morning it sometimes starts a little hard but normally good. This mainly occurs on warm days after it sits for a little while. Could this have anything to do with my Idle Air Control Valve? Any input or theories is much appreciated. BTW - I have the KA24e.


I'm having a startup problem in my 89 240sx (ka24e) as well. It fires up and idles to 1500, but stalls out after like 30 seconds. I'm pretty sure that my MAFS is my culprit, but I still am not sure for sure.

seems like lots of people have this problem, including myself, i hope someone figures out something fast, cuz i'm all out of ideas

why is he asking about his truck in a 240sx forum i mean i understand the engine is the same but still....

who the fuck cares....he needs help with the same engine and im sure there are more people on the 240 forum than the truck one...and y do u care anyway its not like it isnt related to 240s ...he didnt ask about his freaking chevy truck now did he???

for the problem i dont know....i have a 24de and it idles a little rough engine shakes and shit lol..and low like at 500 rpm then jumps up to like a grand...its weird but it still runs like a champ

Check Your Egr Valve To See That It Is Not Sticking Open At Low Rpms, Make Sure Your Iac Vavle Is Plugged In And Working, And Check To See That Your Maf Is Working Properly.

Check Your Egr Valve To See That It Is Not Sticking Open At Low Rpms, Make Sure Your Iac Vavle Is Plugged In And Working, And Check To See That Your Maf Is Working Properly.


Okay in my intake tube, there are 2 big vaccum lines (right next to each other) running into it. I disconnected these, thinking that one is bound to be the EGR dumping into the intake, but it does the same thing.


I don't know where my IAC valve is, but I took apart this thing called an AAV, located behind my intake manifold and cleaned the hell outta it.


As for my MAF, I took it apart and cleaned it and the sensor wires (without damaging them of course), but I have no idea how to test if it's okay.

After all this, the problem is still there.

The Egr Valve Has A Three Bolt Flange On The Intake Side Of The Motor And You Need A Block Off Plate To Disable It.

The Aav And Iac Valves Are The Same Thing I Am Just Used To Domestics And Thats What They Call It. Is The Sensor Sending The Right Voltages To The Ecu?

The Maf Just Test The Lead At The Sensor And Ecu To Make Sure The Voltages Are Correct.