Jump to content
SAU Community

Recommended Posts

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

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

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.

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.

???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.

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).

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.

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 .

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.

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.

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.)

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.

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


  • Similar Content

  • Latest Posts

    • Seat of the pants assessment of the new intake: The car is way less "doughy" when hitting the loud pedal, especially off idle when stopped or in traffic, I did use a cheapo lazer thermal thingo to measure the temp around where the pod filter got its air, it was between 55 - 60°C, in saying this the car was shut off and not moving, so the OEM intake pipe was not supplying any fresh air to where the pod was when the car was at least moving A weird bonus was induction noise on the throttle in the cabin increased a bit,  I was worried that I was actually going to lose some of that induction noise I love so much, outside though, when I got the daughter to do a WOT drive by pass for me, the induction noise has increased alot when on the throttle, not quite ITB doort, but well up there I'm extremely happy with the results and have been exploring the country roads in the region  As for house mods: 1.New front fence is up and is awesome, it really upgraded how the joint looks from the street, and the added security is nice 2. Electricians have replace some interior lights, and with more lighting in the garage, a few new motion detecting lights out the front above the garage, front room, and at the front door, which I have already found heaps helpful coming and going, also now has fancy pants CCTV all round the house The only hold point for power though is the solar and batteries due to supply issues, although this will happen over the next few weeks 3. I have done a heap of landscaping out the front and I'm almost ready to do a new small retaining wall with some nice blocks to replace the brick and cemented in rocks around the raised garden beds cemented in river stone "was the fashion at the time" the house was built. I currently have a pallet of retaining wall blocks and 2 bulka bags of 20mm blue metal to replace the wood chip that is in the raised garden beds around the house 4. I now have 3 big raised garden beds for out the back to grow some vegetables, about 70cm high, 200cm long and 100cm wide 5. My 2 compost bins are already pretty full with brown, green and kitchen waste from the landscaping I'vedone so far, but they will probably take a few months to break down, so anything else that gets chopped, trimmed, and kitchen waste will just start filling the base of the raised garden beds to about 30cm before I start throwing 40cm of good compost, and stuff, for the vegetables to grow in, I'll need a few ton of compost and soil, but the local supplier can sent me bulka bags of the stuff Basically the logs, wood chips and a few strategically placed rocks for drainage, will give the beds some good organic materials down low to break down over time, and they will hold moisture during the warmer months to save the water in my big arse water tank if we don't get alot of rain So, all in all, the car and house mods are going well, and I'm really enjoying being retired, I sleep in too 0700 and slowly plod around inside until I feel like actually doing anything, and only work in the yard for as long as want, which has actually been alot over the last few weeks,  although when you look at it, it seems that not a huge amount of work has been done,  until I look at the before I started the work pics Happy days and good times indeed 
    • hahaha yeah. Plan is to get side skirts and probably just rear pods. But going to do them one-by-one. I've got a set that I really like from RHDJapen, but that one isn't shipped to AU. So need to find someone who can get it for me
    • Here's an idea, answer the questions I asked you as they are trying to work out WHY the LSD will be binding up in a straight line.
    • You haven't driven many modern cars then have you? Most of them have sfa steering feel with their stupid electric bullshit steering systems.
×
×
  • Create New...