Dark smoke when on boost limit/high revs

[Tayhlor VR4]

So when I floor my car a puff of black smoke comes out I have a feeling its got something to do with the vacuum source on the fuel pump/fpr (I'm unsure of what the black cylinder is I'll have to take a pic tmoro) but would anyone have a clue what it would be and if it's serious ? Could I need an engine oil change ?

[Badger_01]

Its caused by your car over fuelling, it used to happen to me

[exevoowner]

Black smoke is rich fuel which most will get as when you floor the pedal its just unburnt fuel going through the system most turbo petrol engines do it if its just a puff not so bad but if it does it for ages then there could be a problem (think i got it right lol)

[Tayhlor VR4]

So it's normal if it happens every time I floor it ? Mid range rpm is fine no black smoke at all

[Nick Mann]

Black smoke is normal when over fuelling. Over fuelling to that extent is not normal. Check for small boost leaks. Have you got an uprated fuel pump or fuel pressure regulator?

[Tayhlor VR4]

Black smoke is normal when over fuelling. Over fuelling to that extent is not normal. Check for small boost leaks. Have you got an uprated fuel pump or fuel pressure regulator?

I believe it's stock i can take a picture for you tomorrow morning (it's 11:20pm) you might be able to recognize what I'm talking about without a picture though (it has a vacuum hose that connects to the top of the manifold , I took off the hose and no suction was coming from that source so I'm thinking of putting a tee piece on the vacuum source that goes from the block directly to the waste gate . Does the fuel pump/fpr need a vac source ? I believe that's what the problem is

[exevoowner]

post pic as only one i can think of is the black n grey one with 2 vac hoses on

[crazydriver81]

Do you have a blow off valve venting to atmosphere? My car did similar things too until I removed it for a recirc BOV

[Tayhlor VR4]

Do you have a blow off valve venting to atmosphere? My car did similar things too until I removed it for a recirc BOV

Yup it's venting to atmosphere , I'm sure it can't be the blow off valve as boost doesn't drop at all ? High pressure spring aswell

[Subaru ETA]

If it has a VTA the car will over fuel. The computer is anticipating the BOV to dump back into the intake system so fuels accordingly.
I use to get some pretty good backfires out of mine :p

[crazydriver81]

Yup it's venting to atmosphere , I'm sure it can't be the blow off valve as boost doesn't drop at all ? High pressure spring aswell

my VTA BOV was holding boost, but the car was overfuelling on cruising and lift throttle. When on WOT, there was enough flow, to blow out the residues of this overfuelling. Actually it does not overfuel when on acceleration but it blows out the carbon residues.

Got rid of that after changing back to closed BOV.

[Tayhlor VR4]

Surely someone else on the club has got a vta bov that doesn't cause black smoke ?

[Subaru ETA]

Think about it logically. The car is designed to have the BOV recirc back into the intake. You have now taken that extra air away, but not the fuel, so it will run rich. This is why it will use a lot more fuel if running VTA.
The way around it would be to remap or go for another ECU.

[Tayhlor VR4]

http://www.trademe.co.nz/motors/car-parts-accessories/mitsubishi/ecus/auction-687643428.htm opinions on this ecu chip ?

[Chris.W]

I have a VTA dump/BOV and when running on the stock tubs and ecu as far as I remember it didn't put out any discernable black smoke from the exhaust during lift off or full throttle.

It's hard to coment though as I have been running bigger tubs and stand alone Vipec ECU for a while now.

[Tayhlor VR4]

I have a VTA dump/BOV and when running on the stock tubs and ecu as far as I remember it didn't put out any discernable black smoke from the exhaust during lift off or full throttle.

It's hard to coment though as I have been running bigger tubs and stand alone Vipec ECU for a while now.

yeah i guess ill just have to live with it lol

[Nick Mann]

I run a vta and don't have any smoking issues.

[Subaru ETA]

My car would puff black smoke and even spit a few flames when it had the VTA

[Humpty's Revenge]

All my Vr4's had VTA & I too never had smokin issues what so ever

[WOODY72]

I can only ever see "smoke" when the sun is down low right behind me, from a standstill that is, accelerating fairly hard.