Down on power....

[Soundlab]

Glad to hear it's all sorted now Robin   

Daz

[RedRobin]

I'm not having any fuel pressure problems as such but my dyno plot is showing a very slight dip which would be got rid of if the APR fuel pump was installed - So it's very likely my next mod. It would just help everything run better and with less demand.

Interesting to note that on one hand VW Racing who you seem to have great faith in don't recommend an uprated HPFP whilst JMK are trying to sell you one because of a slight power dip that you probably don't even appreciate when driving.

Decisions, decisions... 

....I had further discussions with VWR about the HPFP and found that they were basing their opinions on what was known about faults in the early FP versions. Also, they don't use FP's in their race cars and I have also learnt that they are always very reluctant to recommend anything which they don't have direct and fairly extensive experience of. I think that's fair enough and at least it means that the things they do recommend are as a result of some heavy-duty use.

I don't know if the particular racing rules allow an aftermarket fuel pump.

JKM aren't trying to sell me one - Keith actually said I don't need one based on my plot but it was myself who raised the subject of the dip (only very slight) and asked why and how it could be changed - An FP was the answer and certainly would be recommended if a car was experiencing fuelling problems and a more dramatic dip in the curve.

[RedRobin]

The standard fuel pump cant cope with the extra fueling requirements of the stage 2 map, which results in falling fuel pressure, which again will result in a misfire as pressure falls further. He would notice the misfire no doubt.

....Not necessarily as I understand it. It will depend on the settings (boost, I believe) in the Stage2 map.

For example, B7 and higher may induce the problem more than B6.

JKM data logged mine to check that very point and I'm okay on B6 - At least at present.

[WhiteGTI]

The standard fuel pump cant cope with the extra fueling requirements of the stage 2 map, which results in falling fuel pressure, which again will result in a misfire as pressure falls further. He would notice the misfire no doubt.

....Not necessarily as I understand it. It will depend on the settings (boost, I believe) in the Stage2 map.

For example, B7 and higher may induce the problem more than B6.

JKM data logged mine to check that very point and I'm okay on B6 - At least at present.

Yes, much better put than how I wrote! What you said above it what I meant!! 

[RedRobin]

....

I forgot to add that VWR's GTI's don't run above 250 bhp IIRC.

Shouldn't we be splitting this thread off into the different subject of Fuel Pump?

[bacillus]

....

I forgot to add that VWR's GTI's don't run above 250 bhp IIRC.

Shouldn't we be splitting this thread off into the different subject of Fuel Pump?

RR can I suggest that before you embark on the upgraded HPFP route, you first find out what version cam you presently have i.e. type A or B. The earlier A type is known to suffer with premature wearing of the fuel pump lobes and that may be exacerbated by the higher loads that an uprated pump puts on the cam.

The cost for a replacement cam can be quite pricey when labour for fitting is included.

[RedRobin]

RR can I suggest that before you embark on the upgraded HPFP route, you first find out what version cam you presently have i.e. type A or B. The earlier A type is known to suffer with premature wearing of the fuel pump lobes and that may be exacerbated by the higher loads that an uprated pump puts on the cam.

The cost for a replacement cam can be quite pricey when labour for fitting is included.

....That sounds like an extremely sensible thing to do!!

Is this anything to do with what's called "cam followers"?

[bacillus]

....That sounds like an extremely sensible thing to do!!

Is this anything to do with what's called "cam followers"?

The A cams have softer fuel pump lobes and tended to wear more quickly than originally anticipated even when the fuel pump cam lobe follower was in good condition. This could occur with the standard pump.

VW recognised this "deficency" and updated the cam to version B on later cars that is less prone to premature wear. I think they also altered the hardened coating on the surface of the fuel pump cam follower to compliment this change.

The fact that you have one of the earlier cars prompted me to alert you to a potentially costly upgrade in the short to medium term should you go with the upgraded pump and find that your cam has worn prematurely.

[ukdub]

RR I think you will have the AXX engine like myself.  Which is what is fitted to the early GTI's.  I took out my HPFP about a month ago to have a look at the follower and cam lobe.  Everything was fine and showing no sign of wear.   As for which cam, I have the 2 piece cam fitted.

Which means it has the hardened lobe on which the follower and HPFP runs on. Yours should be the same.

Oh my engine has 67k on it and has been running APR stage 2 for 45K

Have a look at this
http://forums.vwvortex.com/zerothread?id=3754451

[neg]

Not all A cams are soft, it was the later batch which there was an issue with and so had a recall on - if you have an A cam but not in the recall list it will be ok - I looked into this before swapping mine.

Thanks for all the info Robin, although an expense at least its now sorted.  I will speak to JKM regarding your logs and look forward to your pics etc.

Regarding your turbo I meant if you sold as-is and then someone else then got it refurbed .. but like you say it might not be much different that getting an exchange unit from VW - hopefully the let you do an advance exchange.  Also again like you said warranty might not count

[RedRobin]

RR I think you will have the AXX engine like myself.  Which is what is fitted to the early GTI's.  I took out my HPFP about a month ago to have a look at the follower and cam lobe.  Everything was fine and showing no sign of wear.  As for which cam, I have the 2 piece cam fitted.

Which means it has the hardened lobe on which the follower and HPFP runs on. Yours should be the same.

Oh my engine has 67k on it and has been running APR stage 2 for 45K

Have a look at this
http://forums.vwvortex.com/zerothread?id=3754451

....Ah! That's good news - Thanks ukdub My VW dealer has already checked my follower and cam lobe when there was first news of that recall on the subject. Yes I am AXX - 06-Build in July 05.

The A cams have softer fuel pump lobes and tended to wear more quickly than originally anticipated even when the fuel pump cam lobe follower was in good condition. This could occur with the standard pump.

VW recognised this "deficency" and updated the cam to version B on later cars that is less prone to premature wear. I think they also altered the hardened coating on the surface of the fuel pump cam follower to compliment this change.

The fact that you have one of the earlier cars prompted me to alert you to a potentially costly upgrade in the short to medium term should you go with the upgraded pump and find that your cam has worn prematurely.

....Am I right in understanding that you and ukdub are talking about the same thing?

[As SteveP will confirm, I'm not even capable of removing my stock engine cover!]

Thanks

[Top Cat]

Really great news your car is back to rude health. 

And well done for resisting the calls for the KO4 

[RedRobin]

Regarding your turbo I meant if you sold as-is and then someone else then got it refurbed .. but like you say it might not be much different that getting an exchange unit from VW - hopefully the let you do an advance exchange.  Also again like you said warranty might not count

....Yes, I could sell my turbo with its crack (pics coming soon) for someone else to have a professional turbo specialist check out, but that would cost probably about £200 without their extra cost of putting it right. Also, if the casing has already failed, how do we know it won't fail elsewhere - I think this is why people advise against used turbo's.

We don't actually know why it failed - Was it metal failure due to VW manufacture? Was it due to being overstressed by modifications? - We'll never know for certain.

 

[neg]

Good point - but I suppose if you had exchanged yours no doubt it (most likely) would have been reconditioned and put back on the shelf.  Either way I understand what your saying.

[ukdub]

RR I think you will have the AXX engine like myself.  Which is what is fitted to the early GTI's.  I took out my HPFP about a month ago to have a look at the follower and cam lobe.  Everything was fine and showing no sign of wear.  As for which cam, I have the 2 piece cam fitted.

Which means it has the hardened lobe on which the follower and HPFP runs on. Yours should be the same.

Oh my engine has 67k on it and has been running APR stage 2 for 45K

Have a look at this
http://forums.vwvortex.com/zerothread?id=3754451

....Ah! That's good news - Thanks ukdub My VW dealer has already checked my follower and cam lobe when there was first news of that recall on the subject. Yes I am AXX - 06-Build in July 05.

The A cams have softer fuel pump lobes and tended to wear more quickly than originally anticipated even when the fuel pump cam lobe follower was in good condition. This could occur with the standard pump.

VW recognised this "deficency" and updated the cam to version B on later cars that is less prone to premature wear. I think they also altered the hardened coating on the surface of the fuel pump cam follower to compliment this change.

The fact that you have one of the earlier cars prompted me to alert you to a potentially costly upgrade in the short to medium term should you go with the upgraded pump and find that your cam has worn prematurely.

....Am I right in understanding that you and ukdub are talking about the same thing?

[As SteveP will confirm, I'm not even capable of removing my stock engine cover!]

Thanks

My understanding is that the yanks never got the AXX engine.  So their first engine had the cheaper single piece cam (revision A)
Lots of them had problems with fuel cuts and fuel codes being logged due to this cam begin too soft on the lobe.  So revision B came out (2 piece cam) If you look at the link it explains this better that my waffling.  I know a few cars over here have had this issue.  Awesomegti's demo car being one.  That failed at 20K.  It seems the early gti engines (AXX engine) are pretty different to the later engines (GTI only not ed30) We have the 2 piece cam and different pistons as well.  I was told by Keith at APR that the AXX is the only true lean burn engine. What that means I havn't a clue