SO FRUSTRATED!

[HotRB240]

I bought this car 2 months ago and it still isn't running right. The engine is a series 1 RB25DET, and pretty much everything is stock. I just spent $800 to have a board wired on to my ECU and have it tuned. It just isn't right. Normal driving it does ok, and it pulls on the top end, but around 3000RPM you put the gas down and it just sets there-hesitates like crazy! It isn't a tuning issue, it is something mechanical. For some reason it's running thin, and the mechanic determined it must somehow be getting unmetered air. Does anyone have any ideas on what this could be? It's driving me nuts-I can feel what the car has in it and it's just not giving it to me! What is the hose coming out of the top of the block? He said it is to vent pressure...mine wasn't connected and he said that may be where the unmetered air is getting in. Please help me in gettin a discussion started-I really need some ideas!!!

[StricNyne]

maybe a leak ? check bov

[mello88]

CHECK YOUR COILPACKS!

also look for the usual stuff, Boost leaks/vac leaks, etc..

[FAST-DATSUN]

Troouble shoot it like any car makke sure the mechanical thinng are good like compression spark plug gap, turbo condition, then timing, tps, boost leaks , fuel pressure, reduce plug gap to check to see if its blowing out under pressure..

[l0nestar]

What is the hose coming out of the top of the block? He said it is to vent pressure...mine wasn't connected and he said that may be where the un-metered air is getting in.

What hose are you speaking of? Where at on the block? On the head?

Check coil-packs and pressure-test your piping for leaks.

*edit* wow, that is basically what mello88 said :-\ I believe in the 240sx Tech section, there is a how-to on building a leak-tester. price is under $15 and worth it.

zerothread?id=158784

[HotRB240]

mello88: It used to be missing on the 6th cylinder. Swapped coilpack with 1st cylinder and then that one was missing. So we replaced the coilpack on the 6th cylinder and now it is running smooth. All cylinders are firing now, and again, it idles smooth. It's just really weak. Is there any way to check coilpacks other than replacing? Paid $60 for the one I replaced-an expensive way to go if we're not sure, no?

[HotRB240]

The cover is off the top of my engine to allow heat to escape. Looking down on the top of the block, on the right side there is a hose coming out of the top that has a metal pipe of some sort in the end of it. I'm gonna see if I can find a picture of the engine so I can better describe what hose.

[HotRB240]

I found a great pic to illustrate the hose I'm talking about, but I'm having a hard time figuring out how to insert it....

http://www.ehautolink.com.my/I...t.JPG

If you open that link and look at the pic, it is the hose coming out of the right side of the block that has the metal pipe clamped inside of it. Where does the other end attach and could that be the problem??

[l0nestar]

If you are speaking about the line that is directly above the turbo heat-shield. (it passes right behind the blow-off valve.

I believe that is EGR / Emissions. You should be able to cap it and be done with it.

[Abdo]

Did you upgrade your fuel pump whenever you did the RB swap?? If so, what fuel pump are you running? If not, that could be your problem. A great solution to this would be a Walbro 255lph fuel pump, found easily online for $99-$120.

[HotRB240]

lonestar: That was one of the suggestions that the mechanic had - he said it isn't really necessary...

[HotRB240]

Has Walbro 255lph ;-) Thanks!

[HotRB240]

If you click on the link of the pic, it is the hose coming out of block directly below where you see "2500 Nissan"

[Abdo]

That's not the block, that is the head of the motor..

the hose coming out of the right side of the block that has the metal pipe clamped inside of it. Where does the other end attach and could that be the problem??

The other end of that metal pipe should clamp into the air intake hose that is normally found between your turbo and your mass air flow sensor. Here you go, I hope this makes things a bit easier for you.

[digzsublime]

^ +1. Abdo is correct. If you are still using the stock intake tube for the turbo, and did not plug the hole in it for the PCV tube, this would be a likely source for your unmetered air.

Good explanation Abdo. BTW Abdo, hope that front bumper is working out for you.

[Abdo]

BTW Abdo, hope that front bumper is working out for you.

Yeah thanks man, it worked great. I actually already sold the car that it was put on, a '93 beater hatchback that me and my brothers restored. How's your car??

Sorry for the thread-jack

[HotRB240]

Abdo: Thank you for taking the time to diagram that for me and explain what to do. I think that will be clear enough even for someone who knows absolutely nothing about engines: Me! Thanks again, Ron

[Abdo]

no problem man, I'm here to help and get helped.