RB25 idles wildely and runs rich

[FairladyRBZ]

Youtube video of it running like crap :

https://www.youtube.com/watch?v=cN5TBYtUyYA

I'm trying to get my Z finally on the road but it won't idle or stay running once I touch the throttle. It will start and Idle fine for minutes till I touch the gas pedal.
All plugs are connected and getting fuel.
I installed a new coolant ECU Temp sender. All coils seem to be firing. I pulled the spark plugs a cleaned them up.
Before I start buying a bunch of parts to guess my fix I'm sure some of you guys have seen simlar situation.
When it starts running rich and idleing crazy I pulled the MAF clip and it seemed to fix the Idleing but not the rich black smoke.
I sprayed carb cleaner everywhere and found no Vacum leaks

Stock ECU and MAF.

[kat7]

it could be a vacuum line make sure everything is were its has to be.

[s14-rb20det]

check the size off your injector, Because you have 30PSI on fuel pressure, you going to need to raise to normal 42, and is going to be even worse.

[FairladyRBZ]

It has stock injectors and I had the Fuel pressure set to 43psi. You know though since you mention injectors I wonder if bad or worn injectors would make it run so bad?

[s14-rb20det]

http://www.nicoclub.com/FSM/Skyline/R33-engine-manual.pdf
Look page EN363

[usmcgetsome]

bro... You gotta plug up the vacuum lines on the valve covers!!!!!! MAJOR VACUUM LEAK RIGHT THERE MAN! also your fuel pressure seems low. Should be set to 43psi vacuum line off and sit around 38psi idle.

[usmcgetsome]

The same with the pcv valve! it all needs to be connected or plugged up. Best to run. Also, when you run without the maf unplugged yes it will run but you rev cut at 2500rpm because it's in limp mode.

[FairladyRBZ]

Plugging up the valve cover holes with duct tape(temporarly for testing) made a difference. Still more to diagnose.
Gonna post up new video.

[chidadouxian]

your fuel pressure seems low. Should be set to 43psi vacuum line off and sit around 38psi idle.http://goo.gl/oVU9zE

[FairladyRBZ]

https://www.youtube.com/edit?video_id=-RqVJhLx2Bo&video_referrer=watch

[usmcgetsome]

well I know why it's dying after you plugged up the holes.... YOUR RUNNING A VENTED BOV! RB25DET does not like vented bov to atmosphere. You'd literally have to vent the air back to the air intake pipe where the turbo inlet is also or run a blow thru maf setup in the intercooler piping. Then she'll be running properly. Are you running the stock ecu? I assume so. Usually if you get a tuneable ecu you can correct for the vented blow off valve.

Yeah man the holes on the valve covers pull vacuum and so does that hole on the side which is for the PCV VALVE. best to just replumb the hoses(connect them).

good luck wrapping it up man.

as for setting the fuel pressure.. you did it wrong on the video.

STEP 1: RUN ENGINE PULL OFF VACUUM LINE TO FUEL PRESSURE REGULATOR
STEP 2: ADJUST FPR TO 43 PSI WITH THAT VACUUM LINE OFF
STEP 3: REATTACH VACUUM LINE AND IT SHOULD BE AROUND 38 PSI

also I noticed you have an interesting fuel pump setup. Are you using the BLACK/PINK striped wire for the fuel pump signal from the ecu?

[FairladyRBZ]

Thanks for the feedback. I'll difenitely fix the BOV issue and the tape on valve covers is just a vey temporary fix to get the car ballpark running.
I'll redo the fuel pressure as per your instrutions.
Thanks again

[usmcgetsome]

no prob man. I was in that exact same situation back in 2005-06 trying to get my 1st rb25 swap finished up. Needed to learn alot about that engine. Everything your going through is what i had to learn. You should look at that blow thru maf setup it cleans up the engine bay alot and you won't have to run that stupid recirculation pipe off that blow off valve to the turbo inlet.

[Kingtal0n]

1. boost leaks
2. maf is too close to the turbocharger

3. I am not making fun of you, haha wire that $#!t up lol

loooved. loved loved your video. fuel pressure is fine btw. lower is better for your fuel pump longevity, but not if you need the gas at WOT.
set your fuel pressure as low as possible while still being below 12's at wide open throttle.

also just as a side note. if you have stock injectors, stock computer, stock maf, stock turbo, keep boost below 10psi. Until you get a real computer/inj/maf/turbo of course.

[FairladyRBZ]

no prob man. I was in that exact same situation back in 2005-06 trying to get my 1st rb25 swap finished up. Needed to learn alot about that engine. Everything your going through is what i had to learn. You should look at that blow thru maf setup it cleans up the engine bay alot and you won't have to run that stupid recirculation pipe off that blow off valve to the turbo inlet.

I might have to relocate the MAF because I know it's too close to the turbo but I don't have any room in that area.

A blow thru MAF might be the only option for now.

Where would be the best spot for A blow thru MAF on this car?

As for my exposed wiring.... yeah it still needs to be finished off. I's an EZ Wiring harness tied in to the stock RB25 S2 harness.

For boost I'm gonna keep it below 10 because I hear you can blow the ceramic wheel turbo wheel.

Thanks again

[Kingtal0n]

You do not want a blow through maf on that engine... trust me Ive been there. I cannot stress how sensitive that motor is when stock to fueling issues. Seriously, keep it at 7psi and run the maf where it belongs until you can go with a MAP based tune to delete the maf all together. Over-fuel it massively. get injectors that are about 30% bigger than what you need and dump it off rich around 6500rpm~ and if that is a street car, don't even take the motor to 7,000 unless you are racing.


For now, to sort out your issue, just use couplers to make a long tube before the turbo. just to see if that is the only issue.

[usmcgetsome]

just an fyi... You can run tt z32 maf setup in the future. So you don't necessarily have to go map to make big numbers. glad your making progress.

[FairladyRBZ]

Latest update isn't much better but I got to drive it for the first time since starting the project years ago. Mainly because I finally registered it and got my TAGS. I changed out the spark plugs( NGK BCPR7es). I double checked the timing marks on the cams and Balancer.
I noticed oil under the air filter and MAF and found oil in the front the compressor wheel it also had coated the MAF. I sprayed down the element with MAF cleaner and took it for a short drive.
Well it smoked alot of white and ran like shit. It wouldn't rev out and stumbled alot.
I'm thinking the turbo seal is bad and messing with MAF.
So any suggestions besides expensive new turbo cuz everything else is basically stock.

[usmcgetsome]

just a thought...
http://www.ebay.com/itm/T2-T25-T28-TB02-TB25-TB28-Turbo-Rebuild-Repair-Kit-360D-Thrust-Bearing-Dynamic-/380390903018?pt=Motors_Car_Truck_Parts_Accessories&hash=item5891108cea&vxp=mtr

[Darius]

Openings in the valve covers are not vacuum leaks and will not affect the idle. A reason they may have effected the idle may be because the crank case was pressurizing and causing weird things to go on in the block pressure wise. And this is bad so don't plug the valve covers. It is like getting hit in the chest with a ball gag in your mouth.

1) Make sure the coupler between the MAF and turbo are sealed tightly.
2) Pressure test your piping from turbo to intake manifold.
3) The fuel pressure in the video is low. Adjust it up to stock settings with the vacuum reference line removed from the regulator.
4) Make sure all the openings on the intake manifold are plugged or have a tightly sealing fitting with vacuum/boost line attached.
5) Make sure the IACV on the bottom of the intake manifold is set correctly and the air hose feeding it is connected to the cold pipe without any leaks in between.

When you have done all of these thoroughly, I will guarantee that you will have either solved the issue directly or at least found what was wrong.

[FairladyRBZ]

I forgot to mention I removed the HKS BOV and blocked off the flange to eliminate that variable.

Darius I was thinking that by completely blocking off the ports on the valve cover I may have pressurized the engine and it pushed oil out of the turbo.
I bought this motor years ago in supposedly good condition so I don't know what to expect.
I sent the head out for a valve job and replaced valve seals. The cross hatching looked good in the bores.
I'm hoping I don't have to tear into or replace the turbo yet. This is just gonna be cruiser that hopefully just runs solid.
I'm gonna go down the list you gave and find the problem.
But just to show what circulates on the internet: Someone mentioned that the open breathers on the Valve cover are vacum leaks. You mention that they are not. I always believed they were not.

[Darius]

I forgot to mention I removed the HKS BOV and blocked off the flange to eliminate that variable.

Darius I was thinking that by completely blocking off the ports on the valve cover I may have pressurized the engine and it pushed oil out of the turbo.
I bought this motor years ago in supposedly good condition so I don't know what to expect.
I sent the head out for a valve job and replaced valve seals. The cross hatching looked good in the bores.
I'm hoping I don't have to tear into or replace the turbo yet. This is just gonna be cruiser that hopefully just runs solid.
I'm gonna go down the list you gave and find the problem.
But just to show what circulates on the internet: Someone mentioned that the open breathers on the Valve cover are vacum leaks. You mention that they are not. I always believed they were not.

Good idea to remove the BOV for troubleshooting.

The engine sounds like it is running okay so I wouldn't worry too much about it. The turbo could be bad but, like you said, pressurizing the crank case could have pushed oil through the turbo and into the compressor and exhaust housings. Keep us posted on what you find out.

[Suit]

Latest update isn't much better but I got to drive it for the first time since starting the project years ago. Mainly because I finally registered it and got my TAGS. I changed out the spark plugs( NGK BCPR7es). I double checked the timing marks on the cams and Balancer.
I noticed oil under the air filter and MAF and found oil in the front the compressor wheel it also had coated the MAF. I sprayed down the element with MAF cleaner and took it for a short drive.
Well it smoked alot of white and ran like shit. It wouldn't rev out and stumbled alot.
I'm thinking the turbo seal is bad and messing with MAF.
So any suggestions besides expensive new turbo cuz everything else is basically stock.

When you took it apart as stated, did you get new head bolts and assemble everything in correct order and torque? We all know what white smoke means, and on that note I have had multiple motors run with completely similar symptoms after replacing a head gasket and having residual coolant in the crankcase from a leaking head gasket. Sounds like you got a hg issue, mostly from the burning coolant and therefore its more than likely making its way into your crankcase and probably vice-versa with the coolant system, might want to check out things in that area.

Another idea to think about here may be residual gunk solidifying in the motor from sitting for so long that is now making its way through the passages and jackets.

[FairladyRBZ]

I got a Youtube video loading up...dang those take forever.
But for now here's where I'm at.

I was able to get the car running better. I moved the MAF about 5 inches forward but could'nt fit a filter.I sprayed down the MAF again of oil residue. I uncapped the valve cover holes and less oil seemed to push out the front compressor wheel.
I unwrapped the MAF extension that someone had made and redid the connections. I didn't have any shielded wire so it sits unwrapped.
I drove it around switched wires around on the TPS and it just cleaned up the revs and felt alot better.
I also reset the Fuel pressure to about 40 psi once the vacum was back on.
The car cruises fine up untill 1800 to 2000 rpm then it sputters and won't rev past that.
The vacum on the wastegate isn't hooked up and it seems to hiss loud out of the MAF like it's slipping the clutch(not literally). It's like boost is escaping and the car won't take off.
I'm wondering since it has no air filter that too much raw air is keeping it from reving out and picking up speed at 1800 19000 RPMs?
Or Maybe the MAF is bad?
So after driving around for about 45 minutes without stomping it around i'm hoping to loosen up all the shit it built sitting for years. Not to mention the small modifications I made.

As far as head gasket leaking.....well I hope that isn't the case.

[FairladyRBZ]

https://www.youtube.com/watch?v=wd8LEM5_g-I



https://www.youtube.com/watch?v=fEqo32gdvBE

[Darius]

Sounds WAY better!

[usmcgetsome]

DARIUS TO THE RESCUE!!!! good info about the valve covers.

[usmcgetsome]

also, the tps wiring tell us what you have hooked up and I can tell you how it's supposed to be wired.
Q45 SIDE RB25DET SIDE
red YELLOW/BLACK
black BLACK/BLUE
white BLUE/RED

[FairladyRBZ]

Long story short...so I thought my Tps was wired wrong so I tried different variations from what I found I online. I moved the MAF and put back on the air filter and it just got worse. So I was trying to make the MSA Nissan show in Orange, Cali (it's down by the Anaheim Angels stadium) today,Saturday 4/26/2014, and I was about quit. Fuck it! everyone points to a bad MAF so I started to tear into it and backed off; but not before I tore the plug with 4 phillips off and the 3 contacts soldered to the inside. I just jammed backed in, tightened up the screws and called it a day.
I told my buddy what the deal was and he says " check the new sparkplugs you just put in cuz they might be fouled out"
So I take them out and they are black... I buff them out and the Z just rips like it hadn't before. Reving, boosting and hauling ass. But then it loaded back up and fouled the plugs again.
So I probably fouled them while dicking around with everything else.
I got a new O2 sensor just incase $50 bucks at Oriely's. The MAF is there with the f'ed up contacts but it still running great till it fouls the plugs.
Conclusion......I think I can make the 50 minute drive to show and back home. As far as my engine issues? I noticed it's only getting to 155 degrees temp. I gutted the thermostat way before I even started the motor becuase I welded a different tube on the housing. I think I might have an air bubble? It's not reaching op temp so ECU keeps pumping fuel and fouls plugs? My fuel presure reg is needs more fine tuning?

I'll post a video of the Z if I make the show.
Thanks to all that have chimed in to help me out. Late, Rick in Monterey Park ,California