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Fuel injector servicing


Alex

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Hi guys...another tech service question which will probably lead to yet another project!

Has anybody either cleaned and serviced or replaced fuel injectors on their 3.0L SC's lately? Was it worth the time and money spent?.....improved performance?

 

Alex

Alex

 

1980 911SC Targa "turbo" - Light Blue Metallic

2007 997TT Coupe - black/black and black - now wrapped Gloss Red Metallic

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Hi Alex

 

Couple of questions first.

 

How many miles on the engine in question?

What grade of gasoline have you been using in the car?

 

In general ... if the car starts easily and idles smoothly there is likely little gain to be made by removing and cleaning the injectors manually.

 

If you believe the injectors or fouled or the car does not idle well or pull strongly you will likely get reasonably good results running an injector formuilation through the fuel system.

 

rgds;

 

Rick

Edited by Rick
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Hi Rick:

 

The engine has about 125K in total and about 75K since the PO had an engine rebuild. The car starts easily and idles well but runs rough above 4000 RPM (hesitation/surging). So far I've:

- cleaned and lubed the distributor "a la Gunter" method (PelicanParts)

- checked and confirmed vacuum advance

- checked timing

- changed spark plugs and spark plug wires (leads)

- changed the fuel filter

- adjusted valve clearances

 

My thought was that there must be some restriction on fuel flow...and, besides, I'm not really sure when the injectors were replaced last, if at all. I've though about pulling them out and verifying the spray pattern....but?

 

It was a pleasure to finally have met you in person, along with the better half, at the blast off party.

 

Thanks!

 

Alex

Alex

 

1980 911SC Targa "turbo" - Light Blue Metallic

2007 997TT Coupe - black/black and black - now wrapped Gloss Red Metallic

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Sorry, I should add...I use only Premium fuel...

Alex

 

1980 911SC Targa "turbo" - Light Blue Metallic

2007 997TT Coupe - black/black and black - now wrapped Gloss Red Metallic

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  • 3 weeks later...

Hi Alex

 

Nice to have met you and your wife during the party as well.

 

If I remember correctly, your car is running an aftermarket turbo-charger .... correct?

 

When the car is running well, I will assume the turbo isn't spooled up until around 3500 - 4000 rpm. If this is true, then I will ask if you have verified if the waste gate is functioning properly. By this I mean, does it close fully when not protecting the engine from over boost. Waste gates are notorious for seizing up (due to condensation and corrosion) if they aren't allowed to clear themselves at least once during any given outing. If your waste gate is siezed open, it will be defeating the boost effect the turbo is trying to produce and this could well manifest as surge or hesitation

 

f.y.i.: The Porsche Owners manual for 930's (old school turbo's ... like yours) recommends full throttle runs in first or second gear to force the waste gate to open and thereby blow out any accumulated moisture. This is to be done at least once during every outing once the engine has reached full operating temperature.

 

Look forward to your reply.

 

sincerely;

 

Rick

Edited by Rick
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