Tuned fuel screw 1 turn - idle now 3200 rpm!!!

[regcheeseman]

I turned my fuel screw (just below inlet union) one turn in. The idle immediately shot to 3200 rpm.

Thinking it was far too much to recover on the idle screw I turned it back half turn - no improvement.

I ended up having to go one half of a turn out from it's original setting to get normal idle.

Is this correct?

It may be possible that the throttle linkage is not quite on it's original spline but it was running fine prior to my messing with the fuel screw.

When it was at it's normal setting it was idling about 1300rpm I tried to get the idle down with the idle stop screw it helped but seemed to make no difference after backing it out more than 5 turns.

[burnt_servo]

about 1/2 turn is all i got out of mine .....

after i modded the govenor spring , and fuel pin , i ended up turning it back down 3/4 of a turn ( just to get it to idle again ) , and have way more smoke and power than before .

[myke_w]

1 turn is a huge amount! i hope you have an egt guage

[regcheeseman]

1 turn is a huge amount! i hope you have an egt guage

Aha you live and learn, my searching on here revealed a few guides and the all said turn the screw in without quantifying. So I'm thinking 3-4 turns will probably be the amount required.

So erring on the side of caution I thought I'd try 1 turn.

So are we really talking about fractions of a turn?

I have got a bit of smoke and I have got an EGT gauge which was creeping towards 700 C on a flat out run - so I guess i'm in the right ballpark?

I could probably mod the pin a bit now.

Thanks for your help.

[RabbitJockey]

i usually do quarter turns

[jtanguay]

1 turn is a huge amount! i hope you have an egt guage

Aha you live and learn, my searching on here revealed a few guides and the all said turn the screw in without quantifying. So I'm thinking 3-4 turns will probably be the amount required.

So erring on the side of caution I thought I'd try 1 turn.

So are we really talking about fractions of a turn?

I have got a bit of smoke and I have got an EGT gauge which was creeping towards 700 C on a flat out run - so I guess i'm in the right ballpark?

I could probably mod the pin a bit now.

Thanks for your help.

700C pre or post turbo??? some people say 1600C max pre-turbo for short periods :shock:

[jimfoo]

700C pre or post turbo??? some people say 1600C max pre-turbo for short periods :shock:

What? 1600C pre turbo? Never on my engine. With a short periods of 815C on my VNT(and piston pieces going through) my turbo looked like it had gotten too hot, pitted and a little melty looking.

[cyrus #1]

Aren't most people saying short periods of 1600° F pre turbo?  1600° C is almost 3000° F, and most steel melts at about 1400° C.  Aluminium melts at about 660° C.  Exceeding the melting point of your cylinder head by nearly 3 fold is a scary though, even for a short period.  :shock:

[Op-Ivy]

3-4 turns and the engine will just run away at startup! Trust me, I know from experience haha!

[saurkraut]

The rule of thumb for SAFE operation is 1300° FAHRENHEIT.

The VW TD white paper says 1500° FAHRENHEIT is OK but I have my doubts.

1300° F = 704.4444° Celsius

1500° F = 815.5556° Celsius

Be careful out there people!

[burnt_servo]

The rule of thumb for SAFE operation is 1300° FAHRENHEIT.

The VW TD white paper says 1500° FAHRENHEIT is OK but I have my doubts.

1300° F = 704.4444° Celsius

1500° F = 815.5556° Celsius

Be careful out there people!

good post , i think people where getting their "f" and "c" 's confused

[denroldiesel]

I turned my fuel screw (just below inlet union) one turn in. The idle immediately shot to 3200 rpm.

Thinking it was far too much to recover on the idle screw I turned it back half turn - no improvement.

I ended up having to go one half of a turn out from it's original setting to get normal idle.

Is this correct?

It may be possible that the throttle linkage is not quite on it's original spline but it was running fine prior to my messing with the fuel screw.

When it was at it's normal setting it was idling about 1300rpm I tried to get the idle down with the idle stop screw it helped but seemed to make no difference after backing it out more than 5 turns.

Make sure the throttle is returning to the stop position.  If not ...undo the two Torx bolts and central spindle bolt on the throttle assembly..enough to adjust so the throttle snaps shut under the spring pressure.  With your foot off the gas pedal it should snap shut..you need a pal to adjust this.

Just a shortfall of 1mm can set the engine racing, if you have done other mods..like a turbo adjustment with fuel addition the rate of increase can be exponential..can be dangerous hence all the yellow paint and tags on the pump components.

[regcheeseman]

Cheers everyone!

I thought 800 was a safe limit, now I wonder....

My EGT has yet to go much over 600 yet.

I'm getting a light haze off boost/low revs and clear on boost (hard to tell as the car is really shifting)  

I think there is more to go on the pin...

[Benjamin]

Probably my head broke becouse to high EGT (could also be the high turbopressure or just having luck...), i was hitting 1500F for long some 3a5minits or so, i thought i had a blown headgasket, after long i have seen the headgasket was bad. didnt seen cracks or so, the head was flat on the surface also. with 1500F you are also making lots of smoke, even above 200km/h  :lol:

Greetz, Benjamin