Jump to content
SAU Community

Rsfours Strange Boost Issue

Sunkist

By Sunkist,
in Four Door Family & Wagoneers

 Share

Recommended Posts

flapsIOW Apprentice

flapsIOW

Posted
Posted

Tried to post this earlier, had a few issues with my computer, I apologise if it is a double post.

Been scanning through the topics, and I can't really find a definative answer.

I have a 1998 Series 2 Nissan Stagea RS Four S(neo engined).

It has developed a strange boost issue, after using the turbo for a short period, it will go from making full boost to making only half boost.

If I stop the car and switch the ignition off, start it again and drive down the road, I will get full boost again for a short time, then the issue will return.

The car is standard apart from an apexi air filter.

Always run on 99 ron petrol.

When the car recieved a full service the mechanic noticed, the recirculating dump valve had been disconnected and blanked off. He reconnected it and plumbed it back in, however I didn't experience the boost loss immediately after this had been done.

Is it safe to run the car without the recirculating dump valve? I experienced no issues before the car was serviced, apart from coilpack failure, the car mis-fired and shuddered from 3800rpm to 5000rpm.

I have checked all the hoses and can't find any leaks.

I have been told it could be a temp sensor, near the top radiator hose.

The recirculating valve could be leaking.

The turbo actuator, could be sticking open.

Does anyone else have any suggestions, or let me know if you have experienced this problem.

Cheers everyone

Chris_Beli Collaborator

Chris_Beli

Posted
Posted

I'm sure someone will be able to clarify this, but I used to have the same issue, it happened when I ran less then 98 octane fuel, engine would knock and computer would retard boost to factory 7 psi instead of the 11 that it normally ran, so if ur running increased boost on factory computer it could have something to do with this? Like I said I'm no expert just saying that was the case with mine, only use 98 octane and problem has not resurfaced

Sunkist Grand Master

Sunkist

Posted
  • Author
Posted

block vacuum lines to boost solenoid.

its for cold start boost and warm boost. it will also revert if boost is increased for whatever reason.

just bypass it by removing and blocking boost solenoid.

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

block vacuum lines to boost solenoid.

its for cold start boost and warm boost. it will also revert if boost is increased for whatever reason.

just bypass it by removing and blocking boost solenoid.

???what??

Test temp sensor by disconnecting the one that goes to the ecu - the three wire one not the two wire one (or the two wire not the one wire - don't have a car to look at just now).. The ecu will revert to stored maps. If it runs better that way get a new sensor. The sensors are relatively expensive and you don't want to replace it just to see.

Sunkist Grand Master

Sunkist

Posted
  • Author
Posted

???what??

Test temp sensor by disconnecting the one that goes to the ecu - the three wire one not the two wire one (or the two wire not the one wire - don't have a car to look at just now).. The ecu will revert to stored maps. If it runs better that way get a new sensor. The sensors are relatively expensive and you don't want to replace it just to see.

isnt there a line into a boost solenoid fron the wastegate vacum line. goes into a elctric module, and exits a vacuum line into the suction pipe(filter to turbo)

i saw a thread somewhere in the DIY section explaining how to bypass it to avoid that low boost setting, and runs all the time on hi boost.

i dont think i made sense.

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

You mean like this:

This is the 10 minute no cost boost to 0.5 bar rerouting of the vacuum hoses [thanks to SK]. Disconnect the two vacuum hoses from the solenoid. Then connect the boost feed (from the cross over pipe on the left of the picture) to the standard T piece. Connect one side of the T piece directly to the wastegate actuator (on the right of the picture). The remaining connection on the T piece goes back into the inlet via the BOV return pipe (on the standard fitting). Make sure to put the standard brass restrictor in that vacuum hose to bypass the desired amount back into the turbo inlet. The standard bypass hole of 1.25 mm bypasses enough air flow for 0.5 bar. (See photo)

PS: If you want more boost you can drill out the bypass, 1.5 mm = more boost (around 0.7 bar) 1.75mm = a bit more (around 1.0 bar).

QWK32 Veteran

QWK32

Posted
Posted

there is no such thing as cold start / warm boost levels on the C34 stagea's, and for the RS4-S there is only one setting, 7psi (it does lift a little more after a fmic and exhaust is fitted). the auto's have the 2 stagea boost switching from 5 - 7psi. i'd say the solenoid is working perfectly fine considering your getting high boost, and that something is triggering it to turn off giving only safe low boost, my bet is with what Chris_Beli said, you are getting some knock causing the knock maps and low boost settings to kick in. turning the car off for a bit resets this.

Shaun, assuming your only running the stock boost control setup, first thing i'd be checking is the base timing with a timing light. it is possible that it has been set a little bit too high, therefore adding a few degrees to the stock timing maps and causing it to knock on load. is the apexi air filter you have a pod filter, if so do you have a heat shield around it? if not sucking in hot engine bay air wont be helping.

running the car with no recirculating BOV and stock ecu in most cases is a real pain in the ass because nissan uses a mass air flow meter to calculate load. with no BOV, when you back off your essentially stalling the airflow meter, no airflow across it means no fuel injected, which leads to constant engine stalling. thats just the main issue, there are others associated with it, do a search of SAU and you'll find tonnes of threads about it.

lachlanw Veteran

lachlanw

Posted
Posted

your car is trying to tell you something is wrong .

my car would do that some days if i launched it and wound out 3rd .

there is a big matrix in the manual for symptoms and possible faults .

solenoid off = 7 psi . solenoid on = 10/11 psi . it is on all the time unless something goes wrong .

unfortunately "boost solenoid remains off " come up very often in the chart so it doesnt narrow it down to much .

most likely too much boost . boost on my car became unstable with a fmic and cat back exhaust . could peak to .9 bar .

flapsIOW Apprentice

flapsIOW

Posted
Posted

Thanks for all the suggestions, I am not running any sort of EBC, I added the airfilter after the problem had already started to happen. It is an apexi cone filter, fabricated my own heat shield, and left the airduct on the grill in place.

I will have the timing checked, however I have no idea what the standard timing should be.

Thanks for your help guys.

If anyone else has any ideas let me know.

bubba Grand Master

bubba

Posted
Posted

running the car with no recirculating BOV and stock ecu in most cases is a real pain in the ass because nissan uses a mass air flow meter to calculate load. with no BOV, when you back off your essentially stalling the airflow meter, no airflow across it means no fuel injected, which leads to constant engine stalling. thats just the main issue, there are others associated with it, do a search of SAU and you'll find tonnes of threads about it.

Umm no...

Running no bov means you get reversion through the airflow meter.. air moving through piping gets to closed throttle body, bouncing back through piping and gets chopped up by the air still exiting the turbo, this is the TU-TU-TU sound that VL boys crave so badly.

What happens when this air passes back through the airflow meter is that it gets read again, the afm doesn't know which way the air is moving, just that there is air moving over it. So what happens is, the stock ecu sees more air and throws in more fuel. It is this over fuelling that causes the engine to stall.

lilcrash Veteran

lilcrash

Posted
Posted

Just to add, having the dump valve open to the atmosphere instead of plumbed in will cause your car to use excessive fuel as the ecu is programed to use the air that gets recycled and pumps fuel in. Unless you mean it was blocked off at the intake pipe side so the valve didn't work, then that will cause back spool and early failure of turbo.( topic for discussion, not everyone will agree to this as there was a few cars factory with out them.)

QWK32 Veteran

QWK32

Posted
Posted

Umm no...

Running no bov means you get reversion through the airflow meter.. air moving through piping gets to closed throttle body, bouncing back through piping and gets chopped up by the air still exiting the turbo, this is the TU-TU-TU sound that VL boys crave so badly.

What happens when this air passes back through the airflow meter is that it gets read again, the afm doesn't know which way the air is moving, just that there is air moving over it. So what happens is, the stock ecu sees more air and throws in more fuel. It is this over fuelling that causes the engine to stall.

i understand what turbo reversion is, i ran may car for 6 months or so with it after my turbo upgrade. however i experienced the complete opposite to running rich and stalling. i could have worded it better than saying it stalled the maf completely, my maf output voltage would become very unstable and lower than normal idle time output voltage (so to me thats as good as a stalled meter) and the wideband O2 readout would lean out causing an engine stall.

thats just my experience and hence why i wrote it. i personally haven't seen an engine run rich during reversion, running an atmo bov i have though. i guess afm placement would have an impact on it and could give a different result, my afm/intake setup is very similar to stock in shape and distance from turbo.

anyway in either case it will cause the same result and i regards to the OP's original question the answer is still yes, it is a bad idea to run without a recirculating BOV.

bubba Grand Master

bubba

Posted
Posted

I had no bov for a couple of days (while piping was being fab'd) and it acted pretty well the same as when running the atmo bov (my tune was well on the rich side anyway and you could see big clouds of black smoke heh).

It's interesting that the maf voltage was all screwy, unfortunately I didn't have my carpc at the time so no idea what maf voltage was doing.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • MBS206
      Duncan's V37.......race car?

      By MBS206 · Posted

      Even more fun, leave all the ADAS stuff plugged in, but in different locations, hopefully avoid any codes!   And honestly, all these new cars with their weird electronics. Pull all the electronics out Duncan, and just shove an aftermarket ECU and if needed a trans controller in, along with a PDM. Make it run basic but race car styled!
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      To follow up a question from earlier too since I had the front bar off again (fking!) This is what is between the bumper and the drivers side wheel And this is the navigator side, only one thing but its a biggy! So basically....no putting coolers in the wheel arches without a lot of moving other stuff. Assuming I move to properly race prepping this car I'll take that job on and see how the computers respond to removing a whole bunch of ADAS modules
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      So I prepped the car for another track day on Wednesday (will be interesting to see coolant temps post flushing out and the larger reservoir, with a forecast of 3-14 being 20o cooler than last time I took it out). Couple of things to mention; since I am just driving the car and not taking a support vehicle, I took the rear seats out and just loaded the back up Team Trackday style. Look at all that space! To cover off removing the rear seat....it is weird (note the hybrid is probably different because it wouldn't have folding rear seats) Basically, you remove the lower seat base, very similar to a r series but it is a clip that pulls forward to release the base rather than it being bolted down. Easy Then, you need to remove the side section of the rear seat on each side. There is a 14mm head nut at the bottom of the side piece, the it slides upwards off a hook at the top to release; you also need to unhook the seatbelt from the loop at the top. Then the centre piece is weird. You need to release/fold the seats forward with the tab in the boot on each side From there, there are 2,x12mm headed bolts holding the rear of each seat to the folding bracket, under the trim between the rear seat and the boot (4x christmas tree clips there, they suck). The seat is out but you can see where the bolts attach to the bracket
    • RP1421
      S15 Spec R

      By RP1421 · Posted

      As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • joshuaho96
      R32 GTS (RB20DE) Injectors Replacement

      By joshuaho96 · Posted

      I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
×
×
  • Create New...