Well, after getting my 250KM award today, I felt a bit like the Fonz and decided to do some mechanical work on the car. Now, I got a really sharp running 300D. Nothing is ever neglected or left to chance, however, I've never cleaned the banjo bolt. I took it out, cleaned it with WD40. It wasn't really clogged. I put it back nice and snug, two tight twists... Is this too tight? I've heard you shouldn't over tighten. Why? So, I took it for a drive, and it felt the same. Oh well. What else can a guy do that's as easy as the banjo fitting cleaning?

Which banjo fitting did you clean out? Just wondering...I cleaned out both fittings on the top of the fuel filter (the one that the filter itself screws into, and the one that you unscrew to bleed whem you pump the system)...

Thanks!

I did the fitting on the intake manifold.... People swear it makes a world of difference when clean.

It's important to make sure that not only the banjo fitting is clear but the line from the manifold to the boost sensor, boost sensor to ALDA, and of course the banjo fitting at the ALDA. Clean out the overboost sensor too - they like to get gunked up after this many years.

Is there a diagram of where all this is? Maybe it'll become more apparent when I actually go to do it although I didn't know we even had an overboost sensor...unless that's another word for a wastegate

Trace the plastic line from the intake manifold to this "thingy" on the firewall. That "thingy" is the overboost sensor, which has another line that leads to the ALDA.

How does one clean the overboost sensor? Is it as easy as the banjo?

Randall,

I spray brake parts cleaner into the ports my overboost protection solenoid until what comes out is as clean as what goes in. I don't know if it still works to block boost but it does a good job of letting boost through

Warden,

It wouldn't be much of a diagram. There's a line from the banjo fitting on the intake manifold to the overboost protection solenoid on the firewall near the throttle pivot. There's a line from the overboost protection solenoid to the ALDA. Make sure everything is clean.

Tee a boost gauge into the line before the solenoid, then try again after the solenoid. Compare readings to make sure you're not losing anything through the solenoid. You can simply bypass the solenoid but seat-of-the-pants methods are subject to mind games.

Sixto
91 300SE
87 300SDL
83 300SD

Is this banjo fitting on the intake manifold accessed from above or below the engine?

Above, near the firewall.

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

Start at the ALDA and locate the banjo bolt usually located on the driver's side. Follow the plastic tube that runs from the banjo bolt to the firewall. There you will find that the tube from the ALDA junctions with a small cylinder attached to the firewall (this little cylinder is the backup in case the wastegate fails and too much boost is detected; the excess pressure bleeds right out of the top of the unit = overboost protection). Remove the banjo bolt from the ALDA and disconnect the tube from the overboost protector. Blow the tube and banjo bolt clean with brake cleaner or similar. From the overboost protector you will find a tube that runs to the back of the intake manifold where it is connected with another banjo bolt. Repeat the removal and cleaning procedure as before. You may also want to blow the cleaner through the overboost protector, although I have no idea if this affects the reliability of the unit. Replace banjo bolts and lines.

There is no guarantee of power increase, however, for these 617 engines fitted with the EGR, soot often chokes off this VITAL passage and decreases the power. These lines are meant to transmit the increase in manifold pressure created by the turbo to the IP via the ALDA. So when the lines get choked off, turbo boost is not recognized by the IP and fuel flow does not increase with the air intake pressure boost provided by the turbo. The increase in power that some of us realize is because the tubes and/or the banjo bolts and/or the overboost protector were clogged. We clean them and all of a sudden we go from a 300D to a 300DT.

I've had my banjo bots totally clogged. One was caked full of crap 6 inches up the line. Ran like a new car with this simply cleaning feature.

Don

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DAILY DRIVERS:
'84 300DT 298k (Aubrey's)
'99.5 Jetta TDI IV 251k (Julie's)
'97 Jetta TDI 127k (Amber's)
'97 Jetta TDI 186k (Matt's)
'96 Passat TDI 237k (Don's
'84 300D 211k Mint (Arne- Undergoing Greasecar Conversion)

SOLD:
'82 240D 229k (Matt's - Converted-300DT w/ 4 speed

We dipped my intake manifold and crossover pipe in a parts cleaning tank when I changed my timing chain.. it was caked with soot and oil.. got it totally clean.. I noticed zero performance increase.

Just wondering what causes the build up of soot and oil in this banjo bolt by the intake manifold?



David

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1985 300D Turbo

[Just wondering what causes the build up of soot and oil in this banjo bolt by the intake manifold?]

The Exhaust Gas Recirculator was installed in th eearly 80's. As the name implies, the EGR regulates the introduction of exhaust into the intake manifold for the purpose of cooking off a higher percentage of pollutants. In a diesel system this pushes soot into the intake manifold. By virtue of it's location on the back of the intake manifold, the banjo bolt tends to vacuum up bits of this soot until things get choked off. In the movie City Slickers, the old trail boss dies and somebody comments that "... he ate bacon at every meal, you just can't do that." Kinda like that.


Many of us plug the EGR.