SR20 is "Bogging"

[Sphynx]

Sorry i dont know the technical term for bogging but thats what my sr20det is doing...

I recently came across this problem and i thought maybe it was the fuel i put in...but it isnt...here is what my symptoms are:

Rough start...dies time to time if cold.

When pressing on the throttle in gear, sometime the car hesitates and feels as tho there is no power or engine being flooded and there is no spark...this happens in low rpm's then all of a sudden it kicks in and runs fine is higher rpm's...so its basically a bog.

I have changed spark plugs within this month a couple days before this happened...Its not the CAS cause it didnt run like this before and i have been adjusting it to see if it would work...I been looking for a vacuum leak but i changed all my hoses and im pretty sure everything is tight...

I donno what it could be...i gottah check the gap on my plugs and change my fuel filter...

Oh and my sr is stock...running stock boost with the stock intercooler...

If anyone has an idea please help me...cause right now im lost hahahaha...So someone please help me :)

[Yoshi]

what's your fuel pressure?
mine did that when the pressure was too high, regulated it down where it should be once I got my FP gauge in and it all went away :)

[Sphynx]

Im running the stock fuel pump and the stock sr injecters...I dont know what my fuel pressure is...how do you check or adjust that with the stock unit? Thanks for youre help :)

[Yoshi]

well, the only way to check it really, is with a fuel pressure gauge, and then you can only adjust it via fuel management computer and/or Fuel pressure regulator.

however, since you're running stock injectors and pump, I'm thinking this may not be your issue. You really SHOULD have a fuel pressure gauge no matter what tho when u go to the SR.

[Muzzy]

y SHOULD i have a fuel pressure gauge????

cuz after doin some thinkin..its jus a stock motor with a bit of external mods. not necessary..i dont think..oil pressure would be more important as well as boost.

i dont think u need any gauges except water temp..stock that is. cuz like i said before..its is just a stock motor.

[Sphynx]

Here is what i have...I bought some gauges last month but i havent put them in...I have procomp series 2 1/16 mech water temp and oil pressure gauges from autometer...

Well Ive checked for a blown turbo...there is no oil in my pipes...Ive looked for any vacuum leaks...tightened the clamps on the stock hot pipe...and so forth...I still have to recirculate the blow off but inorder to do that i need to bend some sheet metal that is in the way...im going to set the timing tomorrow...

Anything else i have to do?

Thanks again for the help :)

[Dutchmalmiss]

is the fuel pump fine? is the fuel filter fine? are the injectors fine? is the ecu fine? is the MAF fine?

[the3SecondJerk]

I am having the same problem. Low RPM's / low throttle position the car will bog down. This only happens for a while (15-20min) just after the car has been started cold. At first I was thinking it was the TPS, but my AFC reads fine. Heres all my detective work so far....

Problem occurs when....

1.S-AFC reads under 10% Throttle position
2.Only when under load..ie. in gear
3.Only when engine is cold and occurs for 15-30minutes, after that everything runs fine...like nothing is wrong
4. Sometimes I can prematurely fix the problem by letting off the gas put it in neutral letting RPM's drop to 800 then put it back in gear....not always though.
5. When problem happens all I have to do is apply more than 10% throttle pressure and car accelerates fine.
6. I have no other engine problems other than this.

My SR20DET is stock, with stock IC, Boost. I have a S-AFC, and HKS SSQV BOV. And Nismo Fuel Pressure Regulator set to 32lb at idle.

Thanks
Dan

[240KAT]

does it idle rough? My car does the bogging every now and then, but nothing really serious. It's idle isnt rough according to the tach, but you can hear a slight lope. Put in a z32 fuel filter, NOT A 240SX FILTER! It's a cheap mod, but a really helpful one..everyone does it for a reason. If that doesnt fix your problem..time to bust out the multimeter. Lol.