Attempted N249 bypass... Oops...

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Hadders

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Right, so let's get the mickey taking out of the way. Basically, replaced the DV spring earlier with the yellow one and figured I'd have a crack at doing the N249 bypass while I was at it as I've bought myself some 3mm silicone vacuum hose. This was the error. Firstly, I managed to break the dipstick. Not uncommon, but frustrating nonetheless. Unfortunately it got worse. As I was trying to remove the existing vacuum hose from the intake manifold (it was on ****** tight and it's hardly in a convenient place!) it full on snapped the brass nipple off. :sadlike:

So right now I have a loose hose hanging out in the engine bay and a hole in the intake manifold. Round of applause.

My skills with tinkering have been exhausted by this so I think it's "take it down the garage" time. Hopefully the brass nipple can simply be drilled out and replaced. What do you reckon?

Might as well get them to replace the dipstick while I'm at it I guess. Pain really as I'm sure it's been done once in my ownership already!
 
Hadders said:
Might as well get them to replace the dipstick while I'm at it I guess. Pain really as I'm sure it's been done once in my ownership already!
Click to expand...

They're only £2 ish for the dipstick shroud and about 5.6 seconds to fit. Panic not.
 
Welly said:
Don't feel too bad - Have a look at this thread:

http://www.audi-sport.net/vb/showth...-nipple-off.....&highlight=snapped+nipple+off

Anyway, I suggested a fix in there which I would recommend you do - as it has already worked for zseth.
Click to expand...

Thanks for that chap. I was under the impression you could get replacement nipples though? I saw on another forum where they appeared to have gotten hold of a replacement and had it fitted. Then again, I guess if hooking it up to the FPR line hasn't caused issues elsewhere! I was thinking I might as well get the FPR hose swapped as well now seeing as the manifold will have to come out anyway. I just don't like the idea of welding the manifold I guess! But if I will attempt these things myself...
 
Hadders said:
Thanks for that chap. I was under the impression you could get replacement nipples though? I saw on another forum where they appeared to have gotten hold of a replacement and had it fitted. Then again, I guess if hooking it up to the FPR line hasn't caused issues elsewhere! I was thinking I might as well get the FPR hose swapped as well now seeing as the manifold will have to come out anyway. I just don't like the idea of welding the manifold I guess! But if I will attempt these things myself...
Click to expand...

Nothing wrong with that mate, and it doesn't have to be weld as in using a welder. You can get chemicals to produce a super strong layer over the hole created by the nipple leaving...
 
audi upgrades
Excellent. Thanks mate. Nice ammunition to take with me to the garage. So all I should need is a bit of chemical weld and a t-bar connector.

Slightly topical question: is the FPR to manifold hose a one way thing? I guess what I'm asking is, how does it work :)
 
tufftybloke said:
2 way bud, sees vacuum and boost

<tuffty/>
Click to expand...

Which makes me wonder whether dumping extra pressure into the FPR is going to cause a negative impact? Surely it means that the FPR will end up with a "wrong" reading? Not trying to make it sound wrong or anything, I'm just trying to get my head around it!

I've booked the car into the garage who are happy to try out the chemical weld and the T-Bar in the hose. Quick check on whether having the T-Bar quite close to the FPR is going to be a problem or whether it's worth putting it closer to the manifold? Also, any ideas on where I can get a T-Bar that suits 3mm silicone hosing?

Thanks guys!!!
 
Well, seeing as this is by design then why question it...

Below is an explanation gratuitously ripped from the internet...

How does a fuel pressure regulator work?
The fuel pressure regulator is able to maintain proper fuel pressure to the vehicle it has been designed for because inside the regulator housing there is a spring pushing against a diaphragm, the spring pressure has been pre-set by the manufacturer for the desired fuel pressure, so the fuel pump has to pump enough fuel and enough pressure at the same time to overcome the spring pressure.
The extra fuel not needed is sent back to the fuel tank through the fuel return line.
When the vehicle is at idle, there is less pressure against the fuel coming inside the regulator because the fuel pressure regulator has a vacuum hose attached to it, this way the fuel pressure will be lower ( from 5 to 10 psi depending on the system) due to the fact that the vacuum is forcing the diaphragm inside the regulator housing to have extra pressure against the spring, resulting in a lower fuel pressure when the car is at idle because there is high vacuum inside the intake manifold; when you accelerate and the vacuum drops, the fuel pressure increases to allow the engine to have more fuel as it needs it.
Click to expand...

<tuffty/>
 
Cheers for that. As I said, I'm more interested in getting my head around how it works. I'm just worried that dumping extra pressure into the FPR line will cause the fuelling to go awry. In normal installations the FPR reads the pressure from the whole inlet manifold only rather than the inlet manifold and lots of extra pressure from the DV. But I'm guessing that all that will happen is that it will potentially increase the fuel pressure while the DV is operating. Maybe I'll end up with popping on the overrun? :p
 
Hadders said:
Cheers for that. As I said, I'm more interested in getting my head around how it works. I'm just worried that dumping extra pressure into the FPR line will cause the fuelling to go awry. In normal installations the FPR reads the pressure from the whole inlet manifold only rather than the inlet manifold and lots of extra pressure from the DV. But I'm guessing that all that will happen is that it will potentially increase the fuel pressure while the DV is operating. Maybe I'll end up with popping on the overrun? :p
Click to expand...

its been well over a week now and iv not noticed any funny behaviour mate, seems good to me
 
Indeed, I had mine down the garage last week and they've sorted it all out for me. T-pieced into the FPR line close to the manifold to be safe. I just need to get in the engine bay and remove the now-excess hosing and vacuum chamber now.

Thanks to all for the help!
 
My brother snapped 1 of the nipples of my manifold too. We sealed it up and t-pieced off the fpr.
 
funny-picture-95133233.jpg
 
Hadders said:
In normal installations the FPR reads the pressure from the whole inlet manifold only rather than the inlet manifold and lots of extra pressure from the DV.
Click to expand...

The manifold is feeding the pressure (or vacuum) TO the dump valve just like it does to the FPR. The dump valve is not sending pressure back up that pipe.
 
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