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Fix for a lumpy, rough engine idling...

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Old 05-17-2010, 07:01 PM
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w00tPORSCHE
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Default Fix for a lumpy, rough engine idling...

So my car is just back from it's first trip to the Porsche mechanic's shop. The PPI stated that the things that needed fix were:
1. A/c not cold. 2. Brake hose needing replacement. 3. Heater fan noisy.
4. Front left sway bar bushing cracked. 5. Engine idling rough/lumpy.

Car spent three days in the shop and had the following done:

1. A/C unit recharged. 2. Brake hoses replaced, system bled with Castrol LMA fluid . 3. Heater fan checked out okay. 4. Worn bushing replaced (although the mechanic said that the car had turbo size larger bushings sway bar (20mm, 76) which have been ordered and can come back at my convenience to have it installed. 5. Wow this was a big item (close to $900.00)...Fuel mixture was found incorrect, idle reset, fuel injectors sent out for testing and cleaning. Car had wrong type spark plugs which were replaced with the right type, new fuel filter and injectors then installed and tested. There was big "oil leak" during inspection under the a/c compressor, I spent a sleepless night only to find out that there was no leak on close inspection and that it was likely an oil spill It was cleaned up, oil (Shell Rotella T) and filter (OC 54) replaced but that required two hours of labor to diagnose or "not" diagnose a leak.

End result: What a difference with the smooth transition from idle to throttle pick up. Feels like a brand new car, unbelievable. Spent 2K for parts/labor. I know, I know the DIY's guys are

One huge regret/question: PPI said fuel lines looked okay but just was reading Pete Z's book which stated that many of the 3.2's have seeping fuel lines in the engine compartment after several years as the rubber on the hose shrinks/cracks with time/heat. Although both the PPI and mechanic did not suggest a new fuel line, should I have had them replace the fuel line anyway as it looks like that's an item that would need replacment soon and then the fuel mixture needs to be rechecked after the fuel lines replacement and boy that is an expensive item that I just paid for ?

Need your thoughts? Sorry if I am boring you all with these small details of my car. You are all such great educators/mentors for hopefully future DIY'ers like me.
Old 05-17-2010, 08:32 PM
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rusnak
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#5 makes your eyes bug out of your face. Get your injectors back and put them in a vacuum sealer if you can get one. You might want to re-use them later. You can send them to witchhunter.com for cleaning and testing. You absolutely do not want to let someone else have them.
Old 05-17-2010, 09:42 PM
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w00tPORSCHE
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Rusnak, just looked at the repair sheet. It says electric rebuild on the fuel injectors (sublet) for $185.00.
Old 05-17-2010, 09:56 PM
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I see. I wonder what they fixed?

As for the fuel lines, opinions differ on what to do. Almost no one recommends leaving the old ones unchanged however.
Old 05-17-2010, 10:06 PM
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ivangene
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OH the stress of it all !!

your story makes me wonder so many things! I need a beer....

on a side note, the wamer weather today was so fun in the 86' I gotta say I almost all but forgot the 996 I am starting to really enjoy the 915 - hope you are too !!
Old 05-17-2010, 11:31 PM
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Ed Hughes
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My guess is nothing was rebuilt on the injectors. It costs about $120 to have a set cleaned and tested, so the $185 is probably that along with a mark-up.

I'd drive the car for a while and see if anything else shows up. I'm not sure if a clutch is needed in the near future, but if the engine comes out for anything, the high pressure fuel lines are a no-brainer then. They can also be done with a partial engine drop, and you could have the "triangle of death" oil goodies redone, as well as the oil cooler seals and the intake manifold re-sealed at the same time. Probably another $2K.

Last edited by Ed Hughes; 05-17-2010 at 11:47 PM.
Old 05-17-2010, 11:45 PM
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ivangene
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gawd Ed - you're just full of good warm fuzzy news

Old 05-17-2010, 11:52 PM
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Ed Hughes
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Even a fully original, pristine and well cared for 911 has a lot of potential maintenance items it could benefit from, unless said items have been replaced or addressed recently. Let's face it, many parts are working on the 25 year mark, if not older. Not all have to be done at once, spreading them out keeps prolonging the enjoyment of ownership.

Besides, I've done my part in spending this economy out of recession. I just want to spread the load.
Old 05-18-2010, 12:11 AM
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rusnak
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I agree with this, it's rational advice.

Originally Posted by Ed Hughes
My guess is nothing was rebuilt on the injectors. It costs about $120 to have a set cleaned and tested, so the $185 is probably that along with a mark-up.

I'd drive the car for a while and see if anything else shows up. I'm not sure if a clutch is needed in the near future, but if the engine comes out for anything, then (1) the high pressure fuel lines are a no-brainer then. They can also be done with a partial engine drop, and you could have the (2) "triangle of death" oil goodies redone, as well as the (3) oil cooler seals and the (4) intake manifold re-sealed at the same time. Probably another $2K.

Note: 12 intake manifold seals needed. They are cheap. I think with the exception of the fuel lines, you are probably talking about less than a few hundred dollars of parts for 2-4. Its the fuel lines that cost a bundle. "Triangle of death" items are the thermostat O-ring, oil pressure light switch, and breather cover gasket. Again, these three are all very cheap items.
Old 05-18-2010, 12:12 AM
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Originally Posted by Ed Hughes
Even a fully original, pristine and well cared for 911 has a lot of potential maintenance items it could benefit from, unless said items have been replaced or addressed recently. Let's face it, many parts are working on the 25 year mark, if not older. Not all have to be done at once, spreading them out keeps prolonging the enjoyment of ownership .
Unbelievably accurate remark that sums up my car. I am so lucky to learn about 911's on a daily basis thanks to such a distinguished group of people. Ed, the clutch was brand new (only 1K miles and feels great). I am hoping to get another two more years at the very least for my fuel lines before I need to fix the "triangle of death". For sure at that time I'll have them replace the fuel lines. I also feel that rebuild is just the lingo they use for cleaning. But Ed, the car just feels brand new after they did what they did. How come it makes such a big difference in the throttle response and smooth transition from idling to the first two gears.
Old 05-18-2010, 12:14 AM
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clean injectors send a fog or mist of fuel. To properly burn, gas needs to be mixed with air (atomized), or it simply won't have the punch needed.
Old 05-18-2010, 12:28 AM
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My .02. I bought a nice 9 out of 10 car and came in with my eyes opened that I'm likely to spend $2-2.5K per year on maintenance and upgrades until I get the whole thing exactly where I want it.

Just got done spending almost $6K restoring a 28 year old bmw aircooled motorcycle that I only paid $5K for a few years ago. That was my labor and $6K in parts and a very few services like bead blasting and powdercoating that I can't do. I just wanted to do it and know that I could never get the value out if I ever sold it. But it was a labor of love and allowed my OCD to run wild. I know every single nut, bolt, seal, and part on that bike as I've held each one in my hands. It's a very fulfilling feeling.

My goal is to have the same experience with my 88 but over a 10 year span.

Tom
Old 05-18-2010, 12:37 AM
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Originally Posted by w00tPORSCHE
Unbelievably accurate remark that sums up my car. I am so lucky to learn about 911's on a daily basis thanks to such a distinguished group of people. Ed, the clutch was brand new (only 1K miles and feels great). I am hoping to get another two more years at the very least for my fuel lines before I need to fix the "triangle of death". For sure at that time I'll have them replace the fuel lines. I also feel that rebuild is just the lingo they use for cleaning. But Ed, the car just feels brand new after they did what they did. How come it makes such a big difference in the throttle response and smooth transition from idling to the first two gears.
Injectors and plugs are two very important components to making an engine run well. Enjoy it!
Old 05-18-2010, 12:52 AM
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Makes absolute sense. It's interesting how these items ie. lumpy idling are unknowingly billed as aah..just a small adjustment in the engine by sellers when it comes to a discussion on the final price after the PPI. Not a big deal for me spending 1K on this but for somebody on a tight budget, one could make a strong case for bargaining a little more on the final sale price. But one can turn around and say that someone on a tight budget has no business doing Porsche shopping.
Old 05-18-2010, 01:02 AM
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That is why many older Porsches get into a downward spiral. This has been particularly evident with 928's and 944's. Guys find examples that look OK, and think that "hey, I can buy a Porsche for $7000" or whatever the price may be. Then they find out what a set of new brake rotors can cost. Then a set of sparkplug wires. Next, you have a "$7000" car being unloaded for $3 or 4 thousand, and maybe another round of shock. The fact that 911's have stayed relatively stable in price has helped keep many 911's in more capable hands.


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