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Idle improvement: new FPR


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Idle improvement: new FPR
pontifex4
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#1

08-07-2012, 10:28 AM
My suspicions about the rough idle and loud fuel pump were confirmed when I installed a new fuel pressure regulator this weekend. Both are cured!



[Image: 7721469902_b34f2cf970_c.jpg]



As I see it, I'm halfway there, because it's no longer rough, but it hunts a little (~800-950RPM), warm or cold. Think it's a vacuum leak? I almost can't believe how simple the vacuum system is compared to my 951, but I also don't know where to look or how to test for leaks. Can I pressurize it?
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Charlie

1992 968 (Now Road + Track)
(This post was last modified: 08-07-2012, 10:28 AM by pontifex4.)
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DaveN
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#2

08-07-2012, 02:37 PM
If it hunts a little clean your <acronym title='mass air flow'>MAF</acronym> first with the proper cleaner and give it another look. It's the easy FIRST step <img src="/forum/images/smilies/968/wink.png" class="smilie" alt="" />
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Dave



'93 968SC Nachtblau Metallic Coupe

'89 944 S2 Zermatt Silber Sold

'87 944 Silber Rose in colour only Sad Sold
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pontifex4
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#3

08-07-2012, 03:43 PM
[quote name='DaveN' timestamp='1344361045' post='130668']

If it hunts a little clean your <acronym title='mass air flow'>MAF</acronym> first with the proper cleaner and give it another look. It's the easy FIRST step <img src="/forum/images/smilies/968/wink.png" class="smilie" alt="" />

[/quote]



Interesting. What's an approved cleaner that we can get in Canada?
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Charlie

1992 968 (Now Road + Track)
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flash
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#4

08-07-2012, 04:30 PM
CRC MAF cleaner should be available
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



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mbardeen
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#5

08-07-2012, 05:06 PM
And if one can't get <acronym title='mass air flow'>MAF</acronym> cleaner? Is there any alternatives that could be used? I've searched high and low here and no <acronym title='mass air flow'>MAF</acronym> cleaner to be found.
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-Matt

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tamathumper
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#6

08-07-2012, 05:37 PM
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mbardeen
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#7

08-07-2012, 05:55 PM
Unfortunately they won't (knowingly) ship that via air, means that neither Amazon nor my reshipper can get it to me (hazardous materials or some such). I probably couldn't even bring that with me in my luggage if I traveled. Same with lots of fun stuff, like paint, electroplating solution, etc...



Oh to live in the USA again...
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-Matt

1993 Midnight Blue Porsche 968 Cabriolet (toy! Currently under restoration)

1995 Jeep Cherokee (war wagon, Zombie Apocalypse Response Vehicle)

2015 Mazda 3 (my reliable, nice car)

 
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John
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#8

08-07-2012, 09:06 PM
"... but I also don't know where to look or how to test for leaks. Can I pressurize it?"



Check out "Vacuum Leak Tester" in topic "Testing 1-2-3"
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tamathumper
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#9

08-07-2012, 09:24 PM
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pontifex4
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#10

08-07-2012, 10:55 PM
Great -- thank you!
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Charlie

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968Syncro
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#11

08-08-2012, 01:20 AM
[quote name='pontifex4' timestamp='1344346087' post='130642']

My suspicions about the ..... loud fuel pump were confirmed when I installed a new fuel pressure regulator this weekend.

[/quote]

Wow, I am interested in the loud fuel pump symptom. How does the FPR cause a loud fuel pump? My 968 has had a loud fuel pump for many years, so this sounds interesting. But it has always run fine. As a matter of fact the fuel pump recently failed. Any insights on how the FPR might affect the fuel pump noise would be much appreciated. Thank you.



Roland
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Roland

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flash
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#12

08-08-2012, 10:44 AM
if it is jammed up, it would cause the pump to back up.
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



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DaveN
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#13

08-08-2012, 04:53 PM
<acronym title='mass air flow'>MAF</acronym> cleaner should be everywhere. I bought it under the Brakeclean logo I think but CRC and others have it as well.
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Dave



'93 968SC Nachtblau Metallic Coupe

'89 944 S2 Zermatt Silber Sold

'87 944 Silber Rose in colour only Sad Sold
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pontifex4
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#14

09-18-2012, 08:04 PM
[quote name='DaveN' timestamp='1344455618' post='130725']

<acronym title='mass air flow'>MAF</acronym> cleaner should be everywhere. I bought it under the Brakeclean logo I think but CRC and others have it as well.

[/quote]



CRC is what I found -- now at Canadian Tire in my area. For the record, I don't believe that it made a difference as far as the idle was concerned, but it was an inexpensive test!



I'm still getting some fuel pump noise, so I have ordered a fuel pump check valve, and will pick it up tomorrow. Might be too big a job to do in the three hour window I have tomorrow afternoon, but we'll see!
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Charlie

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DaveN
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#15

09-19-2012, 01:04 PM
The fuel pump check valve is in the 3 hour window if you have done it before. It took me a while as you have to jack up the car and block, remove tire. Remove the fuel tank cover which has a tricky bolt to get at. Crimp the fuel line and drop the pump and fuel filter, remove the fuel line and power connectors. I changed the fuel filter at the same time as I had to remove everything to get a good purchase on the valve as it was really tight in the pump. Then reverse the whole process.
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Dave



'93 968SC Nachtblau Metallic Coupe

'89 944 S2 Zermatt Silber Sold

'87 944 Silber Rose in colour only Sad Sold
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Lear35A
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#16

09-19-2012, 03:26 PM
Maybe FPRs are more vulnerable than we think. On BMWs (at least some) the FPR is integral with the fuel filter. The fuel filter is huge, but when you change it you get a new FPR as part of the deal. Interest approach I thought.
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kwikt
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#17

09-19-2012, 07:11 PM
You are correct. Like on my 330i.
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pontifex4
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#18

09-19-2012, 10:30 PM
[quote name='DaveN' timestamp='1348070681' post='132930']The fuel pump check valve is in the 3 hour window if you have done it before. It took me a while as you have to jack up the car and block, remove tire. Remove the fuel tank cover which has a tricky bolt to get at. Crimp the fuel line and drop the pump and fuel filter, remove the fuel line and power connectors. I changed the fuel filter at the same time as I had to remove everything to get a good purchase on the valve as it was really tight in the pump. Then reverse the whole process.[/quote]



That should be just the push I need to take Friday morning off and go for it! I'll watch for the tricky bolt.
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Charlie

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vliegwielolaf1234
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#19

09-20-2012, 06:57 AM
Don't all these cars hunt the idle a bit ??

I have seen many of them but never seen one keeping a 100% steady idle .

Also with the fuel pump noise ,i can hear mine now and then when the car idles , i did change pump and check valve , no difference , and old pump seemed still in great shape .

I think some pump noise will always be there .



One thing did your FPR leak fuel at the vacuum side ?
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(This post was last modified: 09-20-2012, 12:44 PM by vliegwielolaf1234.)
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Cloud9...68
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#20

09-21-2012, 01:07 AM
[quote name='vliegwielolaf1234' timestamp='1348135073' post='132953']

Don't all these cars hunt the idle a bit ??

I have seen many of them but never seen one keeping a 100% steady idle .

[/quote]

I think you're right - I've never heard of a 968 with a rock steady idle, but maybe there's one out there.
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