Fixing the overboost issues with the MN 2.5HP

[Tony]

No, you only need the dawes (In this configuration) if experiencing overboost limp modes, massive boost spikes (Over 30psi) or repetitively blowing charge pipes off.

The blank just adds to the above issues in my experiences.

[fraz91]

Digging up an old thread because I've just pulled a P1298 code from the OBD2 reader.

For reference - I have an EGR blank, muffler eliminator pipe and 6.5mm hole in throttle body butterfly valve. No other mods to the engine. The vehicle has recently had its 135k service (approx 2k ago), and did not have this issue beforehand.

Since the service, the boost spike has been a little higher (around 23-24psi as opposed to 21-22psi), as well as taking longer to drop back to the standard figure of around 19psi. Now, I'm consistently seeing 25-27psi under full load, with spikes up to and possibly above 30psi (that's all my boost gauge reads to). The ramp up is not savage by any means, and I can hold it at 25psi for 5-7seconds without a limp mode.

Any ideas? I know it's not great to be running the motor that lean, but am liking the lower EGT's as a result of this fault. I didn't see over 380*C on the way home from dads, where normally the cruising temp is around 400-450*C at 80km/h in 5th.

[Cowboy Dave]

Put the hole back in the throttle plate, if you know what I mean? The hole is redundant now if they've re-flashed your ecu which surely they would have done by now. Maybe the dawes valve approach might be the go?

[gregned]

Dave any idea what the reflash you're referring to does?
is that the one that they fixed the underboost issue or is there a newer one?

[Cowboy Dave]

No idea what it does to be honest but as far as anyone had heard, no one with it has had a code from an EGR blank so there's something getting changed there.

[srb]

This is vgt discrepancy code, not a manifold low pressure code like some get after egr blank.
I know Tony still see's the occasional MN over boosting even after the new soft ware update. Apparently made worse by egr blank and high flow exhausts.

Fraz I'd be contacting Tony for a Dawes valve setup. This has been the only mod to fix to this problem. . While you're at it ask him for the new egr mod as well.

[srb]

Oh and diesels are ok to run a bit lean. Worse is to over fuel them and get too high EGTs.
Its petrol engines that don't like to be too lean. Burns the valves out I think.

[fraz91]

Checked out the MAP readings from the torque app on the way to work this morning, apparently the MAP isn't seeing more than 22.1psi, and rises in line with the boost gauge.

I've also lost all lag associated with the MN. If I put my foot down, it boosts as hard as possible straight away, and that's with the sprintbooster turned off.

PM Sent srb

[Tony]

Replied to PM then seen this.

Test the map sensor (carefully) by using compressed air and record the mv output at given pressure (NO MORE THAN 30PSI) . (I suspect someone has stuffed it by poking a small object in to clear carbon etc) If the sensor isn't reporting well over 3600 to 3700mv momentarily, the VGT can runaway as yours appears to be. The OEM solenoid controls boost with vacuum, no vacuum = no boost. To retain boost as yours, either there is vacuum getting past the solenoid, solenoid is malfunctioning due to map sensor. I think the latter.

Other possibility is over fuel but you have ruled that out as EGTs are cooler.
Anyway, so long as actuator is OK, the dawes will work a treat for you.

[jamesb_bau]

i had a drama with mine just recently.
(2012 MN with dawes and bypass/ ramp up, egr blocked, 21000 + k's)

On way home down the freeway i was motoring up ($1.20) a reasonably long hill section, when i noticed
the engine light was on + asc on/off/ active lights as well.
Stopped off to get some bits and checked scan guage for codes... None present.
Force cleared the engine light but asc lights still on...
Shut down engine for while, started up all lights off...

Baffled...

Ta

Rob

[srb]

i had a drama with mine just recently.
(2012 MN with dawes and bypass/ ramp up, egr blocked, 21000 + k's)

On way home down the freeway i was motoring up ($1.20) a reasonably long hill section, when i noticed
the engine light was on + asc on/off/ active lights as well.
Stopped off to get some bits and checked scan guage for codes... None present.
Force cleared the engine light but asc lights still on...
Shut down engine for while, started up all lights off...

Baffled...

Ta

Rob

Hi Rob, I assume it went into limp mode then?
If so I had this exact thing happen to me twice a while back.. (First ever limp mode for me) I'm still not sure why It happened because I didn't get a code either? My MN is setup similar to yours with dawes and enterprise. My CEL happened while going flat out up a long hill in 4th gear... went into limp at around 4000rpm just as I was about to crest the top. It did do it once before on a separate trip... this time going flat out in 5th gear on level bit of road and chucked a limpy at similar rev's but going way faster. but at the time though I thought it was related to something else that I was trying.
This CEL could point to VGT fault but apparently shouldn't happen with Dawes in place. Could be hard to diagnose as it hasn't happened to me since. Although the last time I did have a small fuel leak so could be related to that but I doubt it.
Rob what conditions where you driving in? Any altitude? Hot or cold day? Did you have the enterprise at full ramp? Is yours auto or manual? What other mods do you have?
Let us know if or when it does it again.
Steve.

[jamesb_bau]

hey Steve,

Thanks for the reply.

It happened again on way home from work this morning... same place/ hill. Second ever engine light...
Mine's a manual.
was in 5th up longish hill (not a massive climb) probably doing around $1.20....
Intake temp =38, water temp 92, boosting around 16psi (guage+ sacnguage)
outside air temp around 20.
ramp up open and bleeding air (maybe 3/4> 1 turn out from closed).
It didn't limp as i still had boost and driveability...
Again, engine + ASC off + ASC active all came on....
No code recorded on scan guage, but cleared all as before...

I did today disconnect the battery for several hours and take ramp up out of system, reinstated boost solenoid... Also had a good check around engine area for anything not looking right..
Took it for a good blast and seems to go better, plus no CEL's... Didn't go to same patch of road though...

still guessing it seems... so more testing needed..its getting a run to sydney on monday for service anyway...

thanks again all

Rob

[biggibbo]

Dont suppose its the hill up mooney. Thats where mine and Trumpys used to do it all the time. Definately an overboost and never really got to the bottom of it. Just wound the boost back a little and seems to have settled.

[jamesb_bau]

na big,
its down south .
Last long hill before you reach Bowral/ mitt/ Moss vale turn off (3 lanes...)

Hoping Steve or tony will chim in with some hints/ answers..

Rob

[Tony]

When running the dawes or enterprise in stand alone you are very reliant on keeping boost within limits depending on state of tune.
Stock cars are a pain as most want to push harder than 20 psi, also the chipit tunes (Out of the box) leave overboost protection mapped in so if pushed hard they will code. I have custom tunes that overcome limits but can cause clutch slip with the savage ramp up.

As for SRB, his cannot see overboost if he has (What I label bomb proof) tune loaded I sent some time ago. Not possible. His tune is very mild due to nature of what he's been doing. Around tune 4 in old talk.


The ramp controller is very sensitive so others may be experiencing underboost if only 16psi or as covered below, the valve may not be seating as should. This is very important.

Boost discrepancy with MN will not always go into limp mode but does normally disable the boost solenoid. If the said solenoid is bypassed, this will not be apparent.

Interestingly, mine has never faulted to date and I have done things out of limits too.

Another thought is, a failed T (Holed) piece in the map line.

Any having issues for what ever reason, 100% close the ramp, reconnect the boost solenoid and see if settles down.

Other trick is, if any carbon etc gets in the valve they can leak off. This can be checked with compressed air and a regulator. It should make a burp sound at set boost (say 22 psi for example).
If a hissing is heard from lower levels it is not seating.

Remove the top gland and inspect for carbon etc, clean as necessary then fit the ball and bump with a soft drift to bed it back in.

You can then test this by (This sound wrong ) sucking on the lower barb by some means (Most use mouth) If it wont make a vacuum, you have a poor seal at the ball valve so clout it a bit harder so beds in again. The ball is very tough to takes a reasonable hit.

Other point is, it's very difficult for me remotely setting these up as every vehicle is different so some may not be dot on. The not tuned vehicles are most difficult as boost must be kept under 22 psi.

Regards T

[srb]

That's a good check list Tony, I'll eventually get to it. I've recently lost boost a few time over last week too? No codes or CEL's just lack of boost? Like yesterday while on the M2 it would only boost to around 3psi and 8psi max? EGT's ran away a bit.. shut engine down once off the highway and restarted and boost was back to normal?
I'm still running that modified Tune but not really 100% sure if that young bloke at Chipit WA really punched in all the correct number at the time? This used to happen occasionally before our trip though and before enterprise so it could be connectivity issue with chip wiring harness or plug?

As for the CEL's and limp modes..This only happened after visiting your place Tony!

[jamesb_bau]

grrrrrrr....

Now this is starting to piss me off...

Just did a lil trip up to hunter with family...
At lease 6 CEL appeared (TF for the scan guage) during trip up and back....
All were long hill climbs (hawkesbury bridge hills<both ways>, mooney bridge, tuggerra climb )
These all brought on the CEL....and the limps.. (thanks again to scan guage)
Same set up as before but no ramp up in system (so using boost solenoid and dawes valve).
I did how ever notice, while keeping a good eye on boost guage, that boost pressure seemed to 'SPIKE'
many times during the trip ... It went from, say, 14 psi to above 20 psi in a spike then settle back to about 12 psi....
I even put in the old ' lone ranger' one-way valve mod in for the trip home to see if this helped... NA.same same.

I will check a few more things as tony suggested....

Any other help appreciated...

Oh, it did get a oil leak fixed in november by dealer but unsure if they would have played with anything.
(it never did this before the leak was fixed) i'll be heading back to them to check ECU software too..

thanks again all

Rob

[Tony]

Hey Rob, if you think it's causing issues, shoot me a PM or email tony@spvindustries.com and I'll send you a new one.

As per my above post, like any partially mechanical device, they do eventually require maintenance if get any carbon etc.

Also, I have found some get lost in these things when trying to cap boost if the VGT has already reached it's minimum attack position.

The boost fluctuations would be from the solenoid, I would also expect around 2psi under full load due to nature of the beast.

regards,

Tony

[biggibbo]

I just had mine serviced last week and saw 2 CeL's up mooney a few days later on the way to the airport. Thinking they may have changed something in an update as haven't seem a CEL for over 6 months.

Didn't display a code ???

[Tony]

Some very strange things happening with updates.

We need to reload that custom tune on yours now clutch has settled down.

It will fix this as I have done several others recently with same issue.

[srb]

Tony was that at me or Gibbo?

Anyway had good drag up the mountains on weekend, mate in his chipped Hilux had trouble staying with me again.

I did lose boost again on 3 occasions on light throttle... No cel or code... Turn ignition off then on and then back to normal it goes, bloody annoying.

[biggibbo]

I think that was for me. Wi flick T an email when I get back to Aus

[Tony]

Dang, data must be valuable over there.
We'll sort you when your back.



SRB, I need to see yours as have no idea what those guys may have loaded tune wise.

The behaviour as you describe is a VGT system discrepancy so not easy for me to nail with out hands on but we'll try remotely if necessary.

I'll take this to PM as your set-up a bit crazy for this particular thread.
I'm thinking a certain added electronic component could be breaking down. That will confuse a few.

[srb]

Cheers mate... I think I know what you're going to say. I'll try it with it removed.

[biggibbo]

Data is free. Just not home to do anything with it. Will PM u my email address