Ok i'm hoping for some good idea's here as I have tried everything I can think of!
This is an intermittent fault so sometimes it's fine other times it's not but it will do it everytime I drive so it's a problem that needs sorting!

Start accelerating and as the turbo spools up it will not hold boost, the boost gauge needle will flap around something crazy, the car will splutter, backfire and jerk around as the boost tries to increase but doesnt in a on/off type fassion.
It feels like a boost hose has come off or there is a big boost leak some where?!

The car is MFI with Bailey breather setup and metering unit return blocked venting to atmosphere, I have tried.........

Removing every boost/vacuum hose and checking for splits, twice! (all hoses are Samco and done about 5000miles).
Brand New Turbo/Manifold/Garrett -31 Actuator.
Brand New Apexi AVC-R Boost controller (fault is still there if i remove it and pipe turbo direct to actuator).
New NMS Head.
2x Different Cam/lifters (one was a brand new set and ran in properly).
New Plugs, leads, Dizzy Cap, Rotor Arm, Dizzy, Coil, ECU's (Ignition and Fuel).
New Fuel Filter.
Voltage to Coil and Fuel Pump is 12.5v.
Timing.
Disconnecting boost gauge.
No Dump Valve.

So i'm left thinking, cracked inlet manifold, charge carrier pipe, throttle body, or maybe an injector not seating correctly?
Any and all idea's greatly appreciated!!

 

You could make up a bung to put onto your inlet where your air filter goes and try pressurising the system, i just used a bit of metal tubing the correct diameter, welded a plate on the top drilled a hole through the plate and super glued a bit of inner tube with the valve in the hole, has worked upto a 18 psi so far, nice easy way of checking for leaks. just hook a compressor up to it and away you go.

Alex

EDIT: hope that makes...

 

get it to a rolling road karlos i think your clutching at straws thinking the inlet is cracked?

 

Did you say you are venting to atmosphere?

 

The ONLY way to find leaks is to spray easy start around your engine when its running if the idle speed increases you have a leak. Worked great for me.

 

You shouldnt be venting to atmosphere on an MFI, this is simular to taking the oil filler cap off while the engines running!

 

This probably makes more sense. Its Australian but a good vid.

http://www.youtube.com/watch?v=atretf9u-Mc

 

Thats a good idea mate!

Yeah I did think it a bit unlikely!
Return to metering unit is blocked mate, if I were venting to atmosphere without doing that it wouldnt even start! lol

Interesting little vid, although only tests the IC and piping not whole system.

A pressure test is a very good idea though so i'll probably do that next.

 

Have you blocked the pipe from the bailey breather aswell then?

 

No it vents to atmosphere, otherwise where would my crank case pressure go??

 

you could have a dry joint on the ecu?

or the boost pipe from ecu to inlet can become kinked and the ecu then tells the engine crazy things.

 

Already tried different ECU's as above.
I will check for kinks though!

 

Thats no good, the std setup has the pipe going to the metering unit for a reason, it runs on a vacuum system, venting your bailey breather to atmoshpere is like i said before, its like running with your oil filler cap off or a breather pipe off.

 

ah, i didn't see that hidden away there.

 

It's perfectly good mate, as long as you block the return to the meting unit off! Otherwise yes you have introduced a big air leak (like removing filler cap) and the flap in the metering unit will not get sucked down and so it will not fuel and so not start or run at all.
But it's blocked so there is no air leak.

 

lol yeah lots to take in!

 

Ok after further testing it seems that if I put my foot flat to the floor in any gear then the problem stops immediately, if I lift off even a little then it will start again.
So i'm thinking it's not a boost leak or it would still continue whether my foot was down or not!
That leaves ignition and fuelling, seeing as I have replaced nigh on the entire ignition system i'm thinking maybe my metering unit is at fault?!

 

have you re checked your tps by throttle and what pre setting have put on new actuator on the new turbo

 

Karlos, you dont have amal valve any more? right?

 

TPS was set by Torque of the devil in september. Preload is half a hole.

No Amal valve, Apexi AVC-R Boost Controller.

 

I had this happen to me for a day, same problems as u mate.

It was caused whit moist getting thro my air filter

 

Karlos ok

 

sounds like its surging ? interesting try turning the boost down for a test or have u tried that

 

Silly question but have you had your plugs out to check Karlos?

 

to add: I know you've fitted new ones but have you had them out to see if any cylinder stands out etc

 

Only running 7psi until i get this prob sorted cant go any lower! lol

Yup had them out when I fitted the NMS head last week, problem was there with old head too.

 

a simple test for you to try, run the boost set up as ford intended pipe wise and set your pre load on your actuator with a foot pump to read 6 psi then try that as it will rule almost everyting out

 

The boost setup is piped as Ford intended I just have my Apexi in place of the Amal valve, i've tried it without and makes no difference. Preload is about 7psi as this is what boost it holds mate.

I'm thinking it's a metering unit fault as when my foot is planted it's fine, when I lift off slightly the problem starts again......... When my foot is planted the TPS signals the EMFPA to increase fuel pressure for full load and all is well, when I lift off it fuels only based on the air flow (flap being sucked down) and that is when i'm having the problems.
I think my EMFPA might be fucked so i'll try another one tomorrow and see what happens, if not then the metering unit itslef which I also have a spare to try.

 

Swapped the EMFPA for a spare I had and instantly the problem has gone, so fingers crossed i'm all sorted!

 

Nice you have problem sorted, i next would recommed efi conversion if you cannot find problem

 

I had that prob and i just needed a setup to sort. TPS was out,fuelling and timing was also out.

 

Glad to see its sorted

 

whats a EMFPA

 

Electro Magnetic Fuel Pressure Actuator, it's what controls your fuelling and is found on the side of the metering unit.
It's what they adjust on the RR to match fuelling to boost.

 

does that mean your going to need to have it re-set now as you`ve changed it ????.

dave.

 

Yup, i'll be running 7psi until i get up to APT for a setup! Not worth the risk running any more in case i'm lean.

 

if you don't mind me asking how come your swapping tuner now do you not feel confident with totd any more

 

TOTD are 100% spot on mate IMO!
But APT are 1 hour closer to me so thats why i'll be going there, I didnt realise just how long it would take me to get to TOTD until I went there!