4722 replies to this topic

[GeorgeBC]

Im off climbing today for the first time since I broke my back, ribs, arm and heel - Im quite excited ! [/quote] Ouch!

Edited by georgebc, 27 March 2011 - 07:36 AM.

[Nev]

Im off climbing today for the first time since I broke my back, ribs, arm and heel - Im quite excited !


Ouch!

Ouch indeed!

The pain in my heel (which exploded into approx 12 pieces) was so much I didn't even realise that I had broken my arm in 2 places for 5 or minutes or so. I also didn't realise that I'd shattered mt T4 vertabrae in half for about 1/2 an hour.

[Arno]

2: Find out why the brake foot pedal is hard.

With wilder cams you may have significantly reduced vacuum in the intake manifold at idle, especially if your map isn't adjusted yet.

If this is the cause then it may be back to normal after some idle map tweaks, but depending on the cams the intake cam may need some timing adjustment with some adjustable cam gears to get it spot on.

Or you have a big vacuum leak at the moment somehwere

Bye, Arno.

[cnrandall]

Check the intake manifold doesn't have any leaks. On mine I had to machine the front and top face where it bolts up to the head, the face where the throttle body mounts and also run a tap through all the threads. Until I had that all sorted the idle was all over the place as you would expect.

[Duncan VXR]

Check the intake manifold doesn't have any leaks. On mine I had to machine the front and top face where it bolts up to the head, the face where the throttle body mounts and also run a tap through all the threads. Until I had that all sorted the idle was all over the place as you would expect.

Chris the machine work has been done already but may be worth checking to be sure

DG

[Nev]

Thanks Chris.

The unit was sent back to CMS and had the mating faces re-machined. I did inspect it a couple of times and it was/is flat. There is a minimal curvature on the TB flange face, but I think the TB green rubber ring can compensate . If not I have some 3mm rubber gasket material I can make my own gasket out of.

I will re-inspect all this on your suggestion.


Anyway on a more important note, I have got my AFR working and I was flabberghasted to see my AFM at idle was 17.2 !!!! Full write up here explaing this.

[Nev]

I've just tried taking the vacuum pipe off the FPR but it didnt increase pressure. I was watching the guage again and the AFR actually went upto 17.8 at times !!!

[cnrandall]

Just watched the vid then saw your post. Really sounds like there isn't enough fuel. I doubt the reg is an issue at idle, you won't need much fuel pressure at all at that point, that's unless the reg has failed and not holding pressure. I would check the flow from the pump though, just pop the line in a pot and measure how much fuel is coming out and check it's not coughing and spluttering.

[Nev]

Thanks Chris, I might well disconnect a fuel pipe and see what the flow is like. As I changed the fuel pump it's quite possible that it isn't operating correctly, it was a bastard job and I'm not looking forward to trying to fiddle with it again. My logic about increaseing the FPR from 3.3 Bar to say 4.0 Bar is that more pressure in the rail will mean that when an injector opens, more fuel will squirt through, simply because of the increase pressure. I've had a look on eBay and 4.0 Bar Bosch regulators are just £10, so it would be an easy test. As you can imagine, I really have to get this problem addressed before I can safely take the car for a drive without the engine detonating or melting. Another thing that has struck me is that the AFR might be showing ultra lean because of reversion of some exhaust gas back into the inlet runners. My new cams have considerably more duration (and hence probably overlap more), so this would mean that partly oxygen-less air was being fed back into the combustion chambers. If this is the case then the reversion should reduce as the revs mount (according to my limited engineering knowledge).

[siztenboots]

My logic about increaseing the FPR from 3.3 Bar to say 4.0 Bar is that more pressure in the rail will mean that when an injector opens, more fuel will squirt through, simply because of the increase pressure. I've had a look on eBay and 4.0 Bar Bosch regulators are just £10, so it would be an easy test.

in simple terms yes, but the fuel pump will deliver less flow volume at a high pressure. you'll only be okay for short durations.

If you see your injectors running beyond 85% fuel duty, then bigger injectors is the answer.

[Nev]

Im trying to get hold of a 4.0 BAR FPR before the weekend, it should help get the AFR nearer to stoic.

[Duncan VXR]

Im trying to get hold of a 4.0 BAR FPR before the weekend, it should help get the AFR nearer to stoic.

Have a brand new one in the garage Nev but not 100% sure if it fits the VX fuel line - should be able to check if needed in fac have an adjustable one for the vx which can go to 5bar again brand new

You need / want any of them?

DG

[Duncan VXR]

Bosch 044 time nev as 2nd pump with swirl pot :P:P

[Nev]

I have got 2 new fuel pressure regulators on the way to me now: 1: A 4.0 Bar unit off an Audi S2 which may or may not fit the fuel rail exactly, bought of eBay for £15. 2: An adjustable 3 to 5 bar unit from Liam at MMG Performance. Liam has very kindly lent me this unit to see if it does the job. According to my maths the 4.0 BAR unit won't raise the pressure enough to reach stoimetric combustion, but the MMG one should be able to achieve this.

[cnrandall]

I'm stick on the stock 3 Bar unit... Never had a problem with it.

[Exmantaa]

Just pull the manifold (under-)pressure hose from your current regulator and you will have instant ~0.7bar of extra fuel pressure on idle to test... Don't drive like this though, escpecially not with boost...

[Nev]

I've already pulled the vacuum pipe out, but it made no difference to AFM for some reason. The higher fuel rail pressure is hopefully just a temporary measure to allow me to get closer to lamda 1 and allow me to drive it. I am begining to wonder if fresh air is entering my exhaust system giving me a faulty lambda reading.

Edited by Nev, 31 March 2011 - 02:02 PM.

[Nev]

Nipper is ready to drive and all systems are working.

The adjustable fuel pressure regulator kindly sent to me by Liam of MMG Performance has resolved by under fueling issues. I have written up a bit to explain here.

[VXT Tim]

Go for a drive

[Vespa]

Great news mate and very glad the fuel pump is functioning properly and doesn't need to be removed again, the blisters have only just healed from last time pushing that pipe on