RB20DET 240sx motor bogs and dies?

[colbol89]

So I was in the market for a 95+ 240sx that had an SR20DET engine in there and had literally lost 3 of the cars due to them being sold in a day before I was going there to pick them up with cash in hand. After getting frustrated I kept searching when out of the blue I found an RB20DET 240sx that was a little above my price range but had much of the work I intended to do done on the car. Now like all project cars it's not perfect but runs...sort of.Here is my current situation. I searched the forums for awhile and found things kind of similar to what I'm experiencing but nothing seemed to really sound like the exact problems I've been facing. If I missed a thread feel free to post it. Onto the problems

So recently the car has acquired a few problems. When the car is first started up especially from a cold start, there is a loud, high pitched whine which I believe is from my power steering pump. I'm not positive as I'm fairly new to this all but the sound seems to be coming from the pump and during driving I can feel the power steering struggle and sometimes fade completely for brief periods of time. While this isn't the big problem I just wanted to give all the background symptoms. What's really getting at me is that the car idles usually at 1300rpms, sometimes at 1500rpms and one time idled at 1900rpms. It doesn't typically oscillate between them, mostly just when the engine warms up it picks either 1300rpms or 1500rpms as what it's going to idle at until the car is shut off. Now from a cold start if I start the car and don't give it gas it will start up and then quickly bog down and die. If I do give it gas it will start up and I have to keep giving it a little gas for awhile until the high pitched whine goes away and then most of the time the car will settle at a high idle. Now sometimes even after I've been driving the car for 10 minutes or so, I've been coasting out of gear and the rpms will just drop completely and the car will die. It's happened to me a few times on a highway and definitely is not something I car to continue happening as going 70mph and suddenly having your engine die is not the greatest of times.

For the high idling issue I've heard something about cleaning or adjusting the IAC but I'm lost as to what "cleaning" or "adjusting" really entails. Something about turning a screw to set the idle level lower but then someone else said I'd have to disconnect my tps when setting it and I don't even think my car is equipped with tps. Another person said that my power steering pump failing might be the cause of the car bogging down and wanting to die when I first start it up because after about 15 minutes of driving the car drives like a champion and has no problems. Now just recently today I was coming up a hill in 3rd gear on the way back to my house and I've taken this route many times without any problems but today the car seemed to choke and sputter a little bit, I down shifted into 2nd to try and get a little more torque to make it up the hill and it struggled just the same not being able to get past 3000rpms and a small amount of smoke came out of the exhaust. After getting over the hill it was driving fine as usual but it nearly stalled on me and I had to put my emergency lights on. I think it's running a little rich and am going to try and take it to a performance shop tomorrow to see if they could tune the car for me and check out my a/f ratio and put it on a dyno just to try and figure out what's the story on it.

So I've put some injector cleaner into my car since it couldn't hurt and am trying to diagnose/resolve these problems. Any and all feedback is welcome but please understand if I ask stupid questions as I'm new to this engine and car but I've got to start learning somewhere. Thanks! I'll try and get some pictures up of my car soon Long live the RB's

[colbol89]

Adjusted the TPS today and got it to idle at 900rpms for the most part. Had it on a dyno and discovered that it was running like 10.7:1 a/f at idle and leaned out to like 14.7:1 at around 6200rpms. Going to look into changing the fuel filter, get a custom hard intake pipe made because my current one is a s***ty plastic one that bends and flexes a lot. I popped it off earlier and noticed oil on the MAF and some in the intake tube. I figured a catch can is in order but is there something else I might be missing? I remember reading up about how the oil from the crank case had some problems or something another. Going to research it now but just giving everyone an update on the car so you all know what I know. Going to try and do a compression test and leak down test this weekend. Hope it's nothing too serious

[Yellow4g63]

Kinda sounds like a boost leak.

[colbol89]

Might be. I know one of my pipes is rubbing against the radiator and rubbed a slight hole into the silicone pipe cover thing but I have a boost gauge and it's spooling up to 10psi just fine so I dunno? Going to replace the pipe part soon but I don't think that is the big problem

[colbol89]

Bump

[Vkoslak]

I saw this car on craigslist. I almost went to look at it. Do you know what fuel pump is in it? When you go to dyno it, I would check the fuel pressure. Are the injectors stock? Maybe its just a bad tune.As for the whining noise, mine was making a similar noise. Try taking the power steering belt off and see if it still makes the noise.

If you're up around 11am and can find Cupprimo off Spicewood next to the big-lots, I have Sunday coffee there every week with a few friends from the local Z club. I may have an extra IAC. I'll try and remember to check before I head out tomorrow.

[colbol89]

He said it's a walbro 255 fuel pump, going to investigate later today and see if it actually is. I definitely think it's got a bad tune and am looking into getting a stand alone ecu and ever since I adjusted the TPS it hasn't bogged out on me. I think it was mainly that just because the previous owner was a retard and thought the TPS was the IAC and f***ed with it. The guy had no clue what he was doing under the hood, or above it actually. He cracked the windshield putting on Autozone plastic chrome wiper blades...they're gone now though so don't worry. I'm a little worried about the oil in the intake though, there wasn't much and I'm hoping that it was just some built up mist from not having a catchcan on there, also the piping rubbed a hole I believe in one of the silicon connecting pad things. *Sigh* in time I'll figure this out I guess.

Next sunday I should be able to come out to Cupprimo, I would have come today but I just got your response.

[Yellow4g63]

Might be. I know one of my pipes is rubbing against the radiator and rubbed a slight hole into the silicone pipe cover thing but I have a boost gauge and it's spooling up to 10psi just fine so I dunno? Going to replace the pipe part soon but I don't think that is the big problem

What is your vacuum reading at idle on your boost gauge?

[colbol89]

20

[colbol89]

Just got the compression check and leak down tests done. Both came back normal so hooray for the engine not being f***ed over! Still trouble shooting but I think it's really coming down to needing a new fuel filter, some piping adjustments, change of oil and oil filter, and a stand alone ecu with a good tune to be on top of the world. Anyone have that Apexi Power FC running on RB20DET's? I've heard it's pretty solid and might be within my budget.

[Yellow4g63]

Just got the compression check and leak down tests done. Both came back normal so hooray for the engine not being f***ed over! Still trouble shooting but I think it's really coming down to needing a new fuel filter, some piping adjustments, change of oil and oil filter, and a stand alone ecu with a good tune to be on top of the world. Anyone have that Apexi Power FC running on RB20DET's? I've heard it's pretty solid and might be within my budget.

Get a Nistune board for your stock ecu. The PFC is going to cost you alot more.

[colbol89]

Can you elaborate on what the nistune thing is exactly? And wouldn't the PFC be worth it in the long run if I'm looking to daily drive 350rwhp and be able to boost up to 380rwhp? How much would the nistune thing cost too. If I had to guess, it's where I pull my ecu, send it off to a shop and list them all the mods I have on the car and have them just reflash the stock ecu and ship it back, correct?

[RustspecS13]

No nistune is software for your stock ecu, and you can then tune it any time any where. Its also cheaper and better then a PFC setup, and because its based on your OEM ECU its just as reliable IE starting in extreme conditions. Its also very easy to use.

Its something you can tune yourself or take to a tuner. Just google Nistune and you'll find it.

~Alex

[Yellow4g63]

Can you elaborate on what the nistune thing is exactly? And wouldn't the PFC be worth it in the long run if I'm looking to daily drive 350rwhp and be able to boost up to 380rwhp? How much would the nistune thing cost too. If I had to guess, it's where I pull my ecu, send it off to a shop and list them all the mods I have on the car and have them just reflash the stock ecu and ship it back, correct?

It's a realtime rom tuning board. http://www.nistune.com

You buy the board and the software The board is like 200 aud and the software is about the same. Far cheaper than the PFC (use to have one). I bought my PFC brand new for $900 USDat the time no commander, that was a extra $300+USD tuning software was around $400 USD. You won't be limited to the Z32 MAF when you upgrade to the nistune.

[Vkoslak]

I have the nistune software. I used it on my rb20. I can show you sometime since you're local.

[colbol89]

Are you free anytime tomorrow or Thursday?

[Vkoslak]

email sent.