still not reving

[NightKids2]

Got a boost controller and a boost gauge. Ive got somewhere in between a 12 and 15 vacuum at idle, when I start to give it some gas it somewhere around 2k RPMs the car cuts out, I get 0 PSI. Wont go over 0. We took off the pipe where it connects to the pipe going to the throttle body and its blowing cold air through it. The air filter is sucking in air. Im not sure how to check the MAF, I dont know what signals it should be sending. I feel like Im so close to driving this thing again but I have no clue whats causing this problem, why it worked before and not now. Any help?

[Joe]

sounds like a boost leak

[Carl H]

i concur. most certianly a boost leak if its not making any boost.

[SeVa-S13]

You should have a considerable amount more vacuum at idle...LEAK.

[NightKids2]

But would making no boost stop the car from reving at all? I mean once it hits around 2k theres a complete drop off, no power at all.

[sean8564]

eather one of two things your MAF is going bad 2 boost leak do you hear a loud hissing noise

[NightKids2]

A crack in what I think is an oil line into the turbo. Would that cause my boost failure?

[krayton]

turbo needs oil me thinks.

maybe your turbo took a dumb

[NightKids2]

Im positive the motor mounts knocked that hole in it. Blue paint was all around it. We probably did it while putting the motor in, I dont think the motor shifted into it.

[240sxed]

Im positive the motor mounts knocked that hole in it. Blue paint was all around it. We probably did it while putting the motor in, I dont think the motor shifted into it.

I'd see if you can take your turbo off examine it for shaftplay, oil , see if it spins freely etc.

Certainly dont' run that thing unless you know you have good oil flow. The line that goes to the turbo is a pressurized line, the return is not under pressure, usually the line that goes to is not always supplying the thing with enough oil if it were gravity feed, so you may be starving the turbo of oil. Check if any oil is around that area maybe? do you lose oil ?

[NightKids2]

Thats oil in the picture on the line. Its not a whole lot of oil, there wasnt any on the ground under the car.

[240sxed]

Try making a pressure tester, or again do the carb cleaner to find vac leaks. Did you try changing / looking to see if your plugs are fouled or if the coilpacks are on good? sometimes one cyl off or slightly off will mess things up.

Take off your intake elbow, and spin the turbine see how the play is etc.Just to confirm its not an oil issue

Thats oil in the picture on the line. Its not a whole lot of oil, there wasnt any on the ground under the car.

[USMCgetsome]

just something to through at ya. Maybe the internal waste gate is stuck open if he finds no leaks. Check your intercooler piping and throttle body for secure bolts and nuts.

[Nameless EJ6]

Check wastegate operation.

You should have more vacuum than that at idle.. so check all your vac lines.

hmm.

[NightKids2]

The picture I posted clearly shows a leak. Im just hoping its not so bad enough to lock up the turbo, cause Im pretty sure its an oil line into the turbo.

[foCk]

the only external oil line is the ones to and from the turbo

[USMCgetsome]

by the way have you checked the ecu codes and reset yet?

[NightKids2]

The leak is in the turbo oil return line.

ECU is throwing the code for Mass Airflow Sensor. I have a MINEs ECU programmed for a Z32 MAF, but I have the stock MAF.

HOWEVER, I still have the stock ECU... and using it yeilds the same results.

[eh?]

I think i told you in a previous thread to check your maf wiring and voltages.. You messed up on the Rad Fan wiring and that's when the problems started correct?

[NightKids2]

Yep.

Any idea what the MAF should wiring should be reading?

[eh?]

Don't remember of hand, check the fsm, key on it should be .3 or .5 and idle ~1V ? Double check that.

[Bluefire]

boost leak and busted turbo and wastegate will have no bearing on how the car revs. i say you redo your maf wiring and make sure you use shielded wire.

-Bluefire

[Nameless EJ6]

boost leak and busted turbo and wastegate will have no bearing on how the car revs. i say you redo your maf wiring and make sure you use shielded wire.

-Bluefire

Please elaborate.

Have you driven a turbo vehicle with turbo/wastegate/boost related problems?

They tend to 'rev' up like crap whether it's MAF or MAP..... so try not to deter him from looking into these areas simply because you think it's a shielded wire problem. Not many people have low vac and no boost problems because of unshielded MAF wiring..

Are we even on the same page here?

And speaking of the MAF wiring.. don't just 'redo' it. Get out a damn meter and do some checking before ripping into the wiring.

[CursedGTR]

boost leak and busted turbo and wastegate will have no bearing on how the car revs. i say you redo your maf wiring and make sure you use shielded wire.

-Bluefire

I drive a GTR (I know so what) but I will tell you that I have owned an RB25DET powered R33 before as well. Everytime I have had that problem (both on the GTR and the R33) it was a boost leak.

Boost will definitely have bearing on revs because it is a forced induction motor, you can usually rev to a few thousand RPM but then you are going to hit a wall. I recently had the problem and found a small crack in a grommet (20.00 fix to replace) after fixing the grommet it was done. A forced induction car (turbocharged) absolutely requires its turbines to run properly, therefore boost has every effect on rev, because when pressure starts to build and then leak your engine is not getting the air it needs to run.

I agree to check the MAF's as well but I am pretty sure it is one of the two problems, and has nothing to do with ECU or wiring.

[Bluefire]

I drive a GTR (I know so what) but I will tell you that I have owned an RB25DET powered R33 before as well. Everytime I have had that problem (both on the GTR and the R33) it was a boost leak.

Boost will definitely have bearing on revs because it is a forced induction motor, you can usually rev to a few thousand RPM but then you are going to hit a wall. I recently had the problem and found a small crack in a grommet (20.00 fix to replace) after fixing the grommet it was done. A forced induction car (turbocharged) absolutely requires its turbines to run properly, therefore boost has every effect on rev, because when pressure starts to build and then leak your engine is not getting the air it needs to run.

I agree to check the MAF's as well but I am pretty sure it is one of the two problems, and has nothing to do with ECU or wiring.

Maybe my comment was a little too black and white. In the case where you have a very large leak it will affect revs. But if you have a leak this big anyways, it should be very noticeable.

Anyways I responded the way I did because of the countless SR's and RB's that I have seen with rev problems. And the number 1 culprit is improper wiring. The maf itself, turbo or wastegate are really the last culprit.

I was actually wondering if you guys were on the same page as the threadstarter. To me, a car consistently cutting out at a certain rpm is a maf problem. And obviously the car isn't going to make boost since its cutting out at 2k without load.

by the way cursedGTR, I would really like a more detailed explanation of why you believe a turbo motor requires its turbo to run properly other than the lack of boost

-Bluefire

[Nameless EJ6]

There's a lot of people who have used unshielded wire on the MAF's without problems..

And when it comes to vac issues at idle, it's not gonna be a wiring problem. It'll be mechanical.

There's two reasons to point towards faulty mechanical parts. Firstly, the vacuum is low. Secondly, boost won't build BECAUSE of that leak.

Try unplugging the MAF if you think it's a MAF wiring issue. The engine will still run and operate in limp mode..

After that, test for vac. It's gonna be the same. Try building boost. It's gonna leak.

See what I'm getting at? Chances are slim of his problems being caused from using unshielded wire.

[eh?]

WRONGMechanical issues are NOT the only thing that can affect vacuum. Fuel and Timing WILL. IF you think otherwise go ahead and pull your maf plug, see what happens.Secondly his problems started after he messed up his Radiator wiring, Do you think wiring his radiator fan would cause a boost leak?

[Bluefire]

There's a lot of people who have used unshielded wire on the MAF's without problems..

And when it comes to vac issues at idle, it's not gonna be a wiring problem. It'll be mechanical.

There's two reasons to point towards faulty mechanical parts. Firstly, the vacuum is low. Secondly, boost won't build BECAUSE of that leak.

Try unplugging the MAF if you think it's a MAF wiring issue. The engine will still run and operate in limp mode..

After that, test for vac. It's gonna be the same. Try building boost. It's gonna leak.

See what I'm getting at? Chances are slim of his problems being caused from using unshielded wire.

Just because other people haven't run into problems doesn't mean its no big deal. Why not properly wire the maf now, so that you can eliminate that apsect of the swap as a problem area. If its not causing problems now, why leave the chance of it creating problems later. Or maybe the affect from having an unshielded signal wire makes you run slightly rich or lean. The car may run ok, but it will never run top notch. IMO fix the obvious problems first.

And like I said before if you have a big enough leak that your only hit 2k rpm, you must have a massive and very obvious leak. This would be easily felt by running your hand around all connections. Not only that you would get hunting during idle with even a decent leak.

-Bluefire

[NightKids2]

The boost leak that Ive found was caused by the motor mounts putting a crack in the oil return line on the turbo.

I tried to start the car the other day with the MAF unpluged and it wouldnt crank period.

[Nameless EJ6]

WRONGMechanical issues are NOT the only thing that can affect vacuum. Fuel and Timing WILL. IF you think otherwise go ahead and pull your maf plug, see what happens.Secondly his problems started after he messed up his Radiator wiring, Do you think wiring his radiator fan would cause a boost leak?

You really need to think about how you personally diagnose probs. The first thing involved is listening and taking everything he said into consideration. How extreme is the problem compared to other's who have had similar problems? You can determine a probable cause pretty easily after mental calculation.

As for what you've said.. I know this already. I chose not to say anything because I'm speaking in broader terms to point him in the direction of mechanical faulure, NOT MAF wiring. Look at his original post. If it was a fuel/timing problem caused by the MAF either being unplugged or sending improper voltages to the computer, of course he's gonna have different pressure readings because the computer sends itself into limp mode which compromises your entire powerband and idle on 'back up' maps and settings. However, it'll still operate and run unless there are a number of problems that all contribute to engine shutting off.

If you think unplugging your MAF is gonna give you the same results he originally had.. then do it and report back with your readings of before's and after's.

The boost leak that Ive found was caused by the motor mounts putting a crack in the oil return line on the turbo.

I tried to start the car the other day with the MAF unpluged and it wouldnt crank period.

I'm curious. Have you fixed the leak yet, and are things back to normal?

And have you tried unplugging the MAF while the engine is operating?