RB25 not able to take load

Post by **stevespeed** » Mon Sep 21, 2009 4:49 am

So here is my problem, and I searched high and low about this issue.

Here is what I have as a problem, I just swapped an RB25DET series 1 with a Greddy intake manifold, Q45TB, Walbro 255 etc, ya know the standard stuff, and the car is running pig rich with all the sensors connected.

Whenever the car is loaded under any driving condition including reverse it just bucks and dies immediately and will no longer move,

Sensors I have replaced, 2 Maf's, 2 COolant Temp Sensors, 2 o2 sensors, I even went through all my wiring and check for continuity, and everything.

Any one have any suggestions at all.

BTW VSS is not connected

Post by **240z4u** » Mon Sep 21, 2009 4:50 am

What does your base fuel pressure look like.

Post by **PorkChopExpress** » Mon Sep 21, 2009 5:30 am

sounds like its in limp mode for some reason. check the vital sensors. the crank angle sensor,tps, maf.

i suggest everyone get the nissan data scan or nistune. seeing whats going on in real time saves time and headaches.

--edit--

i read that the q45 maf can be a pain to tune. did you try putting the stock one back on with stock tune? what you using to tune?
Modified by PorkChopExpress at 8:36 AM 9/21/2009

Post by **DrifterProdigy85** » Mon Sep 21, 2009 7:26 am

Do you have a wideband? It helps alot having one. Mine used to be real doggy under load and found it was a boost leak and the timing was retarded.

Post by **stevespeed** » Mon Sep 21, 2009 8:53 am

I have a Q45 Throttle body, Stock Mafs, Stock 02, Stock everything in the world, I do not have a wideband, I have like... an old Narrowband I havent hooked up yet. and that is about it

I have no way to measure Fuel Pressure as of right now

Post by **240slidekat** » Mon Sep 21, 2009 9:05 am

"RB25 not able to take load" maybe you should pull out next time...hehe

like mentioned above make sure you dont have a boost leak, did you ever run it without all the mods you mentioned? your wiring correct on the maf? and the vss has nothing to do with it so you can rule that out.

Post by **Darius** » Mon Sep 21, 2009 9:12 am

Did you say that you're running without a narrow band O2 sensor either? Or did I just misinterpret what you wrote?

Post by **gawdzilla** » Mon Sep 21, 2009 9:44 am

how do you know it is pig rich? via a wideband?

is your timing belt set correctly? what about your ignition timing?

Post by **stevespeed** » Mon Sep 21, 2009 11:03 am

Here is the current list of the car and its running conditions

-Have I ran it stock without the Upgrades : No, the engine was purchased as in boxes and pieces and reassembled to its current form and then ran

-Have I checked MAF wiring: Yes, used a tone tester on it yesterday all are correct including ground

-Have I tried Switching the MAF: Yes, I used a Maf from another known good vehicle that I saw running and running perfect 30 minutes before I put it on my car if that

-Do I know if my Timing Belt is 100% spot on: Yes I triple checked it before ever starting up the engine, and its a brand new belt on a remachined head.

-Did you switch out the Coolant Temp Sensor for the Ecu with a brand new one : Yes I purchased one this morning and put it in and it made no difference.

-Modifications to the motor in fullISIS RB25DET Intake ManifoldQ45 Throttle Body HKS SSQV BOVXS Power Front mount ICKOYO RadiatorNismo Rad CAP

Other Conditions, the engine temp sensor for the gauge is pegging at FULL scale at all times, I am suspecting my wiring.

I did not follow 100% any write ups for wiring anywhere

MAF, AAC and all powers are verified with a tone tester.

I do not have the consult port wired, or a consult cable/program.

Running conditions:

Runs rich at idle with MAF connected and dies out under load except for reverse now it works a little bit...

Runs fine with MAF unplugged but I can only go to 2k and I hear no extreme boost leaks.

Post by **stevespeed** » Mon Sep 21, 2009 11:06 am

Other things

Timing is not set at all, I have the Cam Angle Sensor plugged in and just kind of chilling around the middle hopping I would have hit something good.. didnt

I havent rechecked timing first thing that is going to happen tonight when I get home.

And the way I know its running rich is well the soot on my bumper and the insane smell of fuel in my garage, not to mention the pumes of black smoke after about 3 seconds of running.

I will hook up my Narrow band as well this evening and verify it, but I wish they Yousmelltube invented already, you can jsut smell the fuel in the air.

Post by **DrifterProdigy85** » Mon Sep 21, 2009 4:08 pm

Dont even bother with that narrowband gauge crap. You need a wideband. If its running excessively rich and wont rev then it sounds like the MAF. Something else it could be is leaking at the throttle body. I put a Q45 TB on my SR and found it leaking around the flange with only a gasket and also leaked where the TPS hooks in. RTV fixed both the leaks. Something else it could be is an injector leak. Its worth checking since there easy to get to using the greddy manifold.

Post by **stevespeed** » Mon Sep 21, 2009 7:12 pm

Well Ill take off the Throttle body tomorrow morning and put some more Anerobic sealer on it,

Also should I be using the Q45 TPS or the RB TPS?

I was messing around with the TPS tonight and that made it run worse.

I rechecked the timing and Set it to +15 Degrees of Advance

and its still running rich

Post by **virus77** » Tue Sep 22, 2009 5:48 am

boost leak or timing or tps adjustment

Post by **streeteg** » Tue Sep 22, 2009 7:05 am

IF I could make an off topic comment about the title---my girlfriend has the same problem. ZING!

ha anyway enough with the joking.. could be a bad boost leak. or i had this issue with a bad boost solenoid from an AVC-R---

Post by **stevespeed** » Tue Sep 22, 2009 7:15 am

virus77 wrote:boost leak or timing or tps adjustment

I am checking for boost leaks tonight.

I fiddled with the TPS last night and it started idling even worse, and after I messed with timing and set it to I think the 4th timing mark near the top... It had absolutely no effect.

Alot of signs keep pointing back to the BOV, and its an HKS SSQV, so I dont know if those tend to go bad... or what

Also I am not running with the factory boost soloniod.

Another thing, is that when the vehicle is at rest with no load, during a free rev it revs out to what seems to be only around 4-5K ish not the full stock redline, and now usually dies after such
Modified by stevespeed at 10:46 AM 9/22/2009

Post by **l0nestar** » Tue Sep 22, 2009 7:45 am

Like I told you Sat, dump the Q45 TB. Check for leaks in the plumbing.

Post by **stevespeed** » Tue Sep 22, 2009 10:17 am

Tonight I am going to check over and recheck the following things and post up what I find

TPS Sensor TPS wiringMAF Wiring ResistanceO2 Wiring ResistanceIACV and AAC Wiring ResistanceBoost LeaksWastegate Acuator

yeah yeah I hear ya l0nestar I ll try to borrow my friends adaptor plate for the stockre

Post by **streeteg** » Tue Sep 22, 2009 10:21 am

a quick fix if you really want to see if its the HKS or not-- because it does really sound like a boost leak. Take it off and wrap it with ducttape and get 1 pull in. Youll get compressor surge however youll tell really fast if the spring on the bov is screwed up.

-Eric

Post by **stevespeed** » Tue Sep 22, 2009 10:26 am

I cant even drive it more than 3 feet, but Ill do that after I check all the IC pipes

Post by **virus77** » Tue Sep 22, 2009 12:06 pm

Dont just check your pipes, pressure test them. 90% of the time these things end up to be boost leaks, its the number 1 thing to go wrong on a boosted car. If you have a tear in a coupler the vacuum of your motor will keep it sealed until the pressure opens her up and you fall on your face. The first thing you should have checked was for boost leaks before the rest of the stuff.

Post by **stevespeed** » Wed Sep 23, 2009 5:14 am

Virus was right, MASSIVE boost leaks, and I forgot to put a throttle body gasket on it....

its um running great now...

/turns in man card....

Post by **l0nestar** » Wed Sep 23, 2009 5:27 am

To quote my Pop " Damn I'm good!"

Post by **virus77** » Wed Sep 23, 2009 6:58 am

Good to hear its running man. I cant tell you how many peoples cars I've diagnosed with boost leaks, it's all to common.

Post by **stevespeed** » Mon Sep 28, 2009 11:36 am

at first it was a boost leak, but then we ran into another problem...

After that the 240 started to do this really odd thing like it was fuel cutting..

So here is what was REALLY wrong the entire time.... kinda comes back to what Evan originally posted,

So Scotty was at a BBQ with me this weekend (SKYNOMA) and he was giving me a hand working on it, and noticed that my fuel lines could be very very easily pinched while running, which is not right,

also my walbro was whining like HELL it was the loudest part of the whole car, even at full revs you could still hear the walbro

So after Scotty point that out, i took the car to a friends house and we cleaned the fuel pump out and the fuel strainer off the pump, as well as putting an inline fuel pressure gauge tester on it that we could read in the car.

Turns it out the entire problem was a clogged pump which caused low fuel pressure and fuel flow... which threw the car into a fuel cut and caused it to stay in Limp mode...

now it runs f***ING Awesome, and its retardedly fast.

Also we had a lot of compressor surge, which turned out to be nothing more than the blow off valve's vacuum line being pinched.

Website · Post by **USMCgetsome** » Mon Sep 28, 2009 12:37 pm

glad you got some help with all that and figured it out. The community helps out again! I've always said this. It helps when you got an experienced rb guy around with ya. It always seems to be the repetitive issues. Damn those fake walbro pumps!

Post by **stevespeed** » Mon Sep 28, 2009 1:57 pm

its def not a fake, you can tell its a real walbro, besides the thing is like SUPER hella old, its off a buddy's build that he didnt drive all that much from like 06

Post by **RustspecS13** » Tue Sep 29, 2009 4:18 am

Ug after all this time your running now and my RB is blown up again. SOAB.

Congrads on getting the major bugs worked out! Not bad for starting out with a pile of parts!

~Alex

Post by **l0nestar** » Tue Sep 29, 2009 10:11 am

Cool deal man!

Post by **stevespeed** » Tue Sep 29, 2009 2:32 pm

RustspecS13 wrote:Ug after all this time your running now and my RB is blown up again. SOAB.

Congrads on getting the major bugs worked out! Not bad for starting out with a pile of parts!

~Alex

Well remember I got a lot of extra's lying around I might have some stuff you need.

RB25 not able to take load

RB25 not able to take load

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