Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical chat

Reply
 
LinkBack Thread Tools Display Modes
Old 03-17-2018, 07:18 AM   #1
Registered User
 
geraintthomas's Avatar
 
Join Date: Nov 2015
Location: South Wales, UK
Posts: 843
Bogging while pulling away?

Seem to have another problem. The car bogs when pulling away to the point where it's stalled once or twice if I don't compensate it with revs.

https://youtu.be/aaWPUa50EkY

Recently replaced a very bad air oil separator and thought it may have dirtied the MAF. Cleaned the MAF, still no good. Maybe it's ruined the MAF and needs replacing?

This has only happened since I've had a bad AOS.

Help!

__________________
Porsche Boxster S Type 986

Bi-xenon Headlight Upgrade | 987 S 18" Anthracite Alloys | Android Head Unit | 5000k 55w HID's | 5000k Cree DRL's | 5000k Cree number plate lights | Cree LED Indicators | One-touch roof operation | Bypass exhaust pipes | Parking sensors | Ambient footwell lighting
geraintthomas is offline   Reply With Quote
Old 03-17-2018, 07:54 AM   #2
Boxster 986
 
Wolf's Avatar
 
Join Date: Oct 2017
Location: Nebraska
Posts: 28
I want to say it could be a vacuum leak, have you checked your lines to make sure none are cracked?
Wolf is offline   Reply With Quote
Old 03-17-2018, 10:36 AM   #3
Artist, 986S tinkerer
 
NewArt's Avatar
 
Join Date: Aug 2013
Location: Montreal, Canada
Posts: 1,632
To properly diagnose a problem like this, a scanner, preferably a Durametric, would be invaluable.
__________________
James
2004 986 S
987 air intake TB and plenum, Mantissport 2 litre sump, UDP, Bilstein B6 with H&R lowering spings, re71-rs for track, other stuff.
https://www.youtube.com/user/12shoes2
NewArt is offline   Reply With Quote
Old 03-17-2018, 10:58 AM   #4
Registered User
 
Join Date: Sep 2016
Location: Stow, MA
Posts: 895
Garage
Another possibility, but you should check codes first, is misfires at low to medium throttle. The resistance of the mixture between the points is highest at those throttle settings and the spark will tend to go through cracks in the coils when you are there and then when you give more throttle the mixture resistance decreases and the spark starts jumping between the points. I had a really bad case of this many years ago.
__________________
2004 Boxster S Silver - FUNTOY
2002 Boxster Base Guardsy Red - FUNBOX
1987 Caterham Super 7 1700 Supersprint
2009 Mercedes Benz CLK 350 convertible
1941 Dodge Luxury Liner Coupe
Anker is offline   Reply With Quote
Old 03-17-2018, 11:05 AM   #5
Registered User
 
geraintthomas's Avatar
 
Join Date: Nov 2015
Location: South Wales, UK
Posts: 843
No codes, after pulling off the performance is fantastic. It's just that initial load on the engine/throttle.
__________________
Porsche Boxster S Type 986

Bi-xenon Headlight Upgrade | 987 S 18" Anthracite Alloys | Android Head Unit | 5000k 55w HID's | 5000k Cree DRL's | 5000k Cree number plate lights | Cree LED Indicators | One-touch roof operation | Bypass exhaust pipes | Parking sensors | Ambient footwell lighting
geraintthomas is offline   Reply With Quote
Old 03-17-2018, 12:26 PM   #6
Artist, 986S tinkerer
 
NewArt's Avatar
 
Join Date: Aug 2013
Location: Montreal, Canada
Posts: 1,632
I've found that a simple way to search for vacuum leaks is to use a can of throttle body cleaner. With the straw you can spray various locations fairly accurately. If the car stumbles or increases in revs, you've found your problem.
__________________
James
2004 986 S
987 air intake TB and plenum, Mantissport 2 litre sump, UDP, Bilstein B6 with H&R lowering spings, re71-rs for track, other stuff.
https://www.youtube.com/user/12shoes2
NewArt is offline   Reply With Quote
Old 03-17-2018, 02:21 PM   #7
Registered User
 
geraintthomas's Avatar
 
Join Date: Nov 2015
Location: South Wales, UK
Posts: 843
There's no vacuum leaks. Have checked lots before changing the AOS, and checked afterwards. The car went back to normal after changing the AOS but has slowly developed this bogging about a week or so after it. If there was a vacuum I'd at least get P0171 or P0174 codes.but it's all fine.

I'm more inclined to think it's a bad MAF as, doing a bit of research, they can go bad after having a bad AOS due to it being contaminated with oil.

Any way to test a MAF?
__________________
Porsche Boxster S Type 986

Bi-xenon Headlight Upgrade | 987 S 18" Anthracite Alloys | Android Head Unit | 5000k 55w HID's | 5000k Cree DRL's | 5000k Cree number plate lights | Cree LED Indicators | One-touch roof operation | Bypass exhaust pipes | Parking sensors | Ambient footwell lighting
geraintthomas is offline   Reply With Quote
Old 03-18-2018, 12:22 PM   #8
Registered User
 
geraintthomas's Avatar
 
Join Date: Nov 2015
Location: South Wales, UK
Posts: 843
Have been told by the guys over on Boxa.net that it could be residual oil in the throttle body from the bad AOS, causing the throttle body to not let the correct air flow when it starts to open (because of the oil on the valve), which is why it's poor at low revs (where it's only just opening) and fine afterwards when it's fully open.

Makes sense, will clean it when I get a spare hour.
__________________
Porsche Boxster S Type 986

Bi-xenon Headlight Upgrade | 987 S 18" Anthracite Alloys | Android Head Unit | 5000k 55w HID's | 5000k Cree DRL's | 5000k Cree number plate lights | Cree LED Indicators | One-touch roof operation | Bypass exhaust pipes | Parking sensors | Ambient footwell lighting
geraintthomas is offline   Reply With Quote
Old 03-18-2018, 02:59 PM   #9
Artist, 986S tinkerer
 
NewArt's Avatar
 
Join Date: Aug 2013
Location: Montreal, Canada
Posts: 1,632
Cleaning the TB is pretty easy and you'll see it as soon as it's opened. A fouled TB could possibly cause low rev breathing problems. I don't think MAFs go wonky as often as people think. Often it's a cleaning problem but I'm not sure how a MAF can get contaminated due to a bad AOS. (feel free to correct me here). The air just goes the other way! A MAF could suffer physical damage or maybe die of natural causes, but if it's dirty, a good cleaning should remedy the situation. Good luck, and let us know what you find!
__________________
James
2004 986 S
987 air intake TB and plenum, Mantissport 2 litre sump, UDP, Bilstein B6 with H&R lowering spings, re71-rs for track, other stuff.
https://www.youtube.com/user/12shoes2
NewArt is offline   Reply With Quote
Old 03-18-2018, 03:14 PM   #10
Registered User
 
geraintthomas's Avatar
 
Join Date: Nov 2015
Location: South Wales, UK
Posts: 843
Thanks

I actually read it on PelicanParts that a MAF can go bad after a bad AOS, but not sure how.

I've cleaned the throttle body about a year ago as part of maintenance, so I'm accustomed to taking it apart. Will take the plenum off too and give that a good scrub.

I've got two brand new lambda sensors waiting to go in. I'm tempted to buy a MAF as well just so that there's all new sensors, clean the TB, and even service the car at the same time. All fresh then.
__________________
Porsche Boxster S Type 986

Bi-xenon Headlight Upgrade | 987 S 18" Anthracite Alloys | Android Head Unit | 5000k 55w HID's | 5000k Cree DRL's | 5000k Cree number plate lights | Cree LED Indicators | One-touch roof operation | Bypass exhaust pipes | Parking sensors | Ambient footwell lighting
geraintthomas is offline   Reply With Quote
Old 03-19-2018, 12:26 AM   #11
still plays with cars...
 
BoxsterSteve's Avatar
 
Join Date: May 2011
Location: Baden, ON, Canada
Posts: 1,079
Garage
Does it bog badly until 2500 or so and then start to pull strongly again?
Mine did this a couple of years back.
Turns out it was a faulty MAF that didn’t set a CEL.
Try unplugging your MAF and see how it runs.
The car will revert to the factory programmed fuel map and throw a CEL, but if it runs like a champ again, you’ve found the problem part and you aren’t replacing things you don’t need to.
__________________
Six speed 2000 Boxster S
Arctic Silver on Metropol Blue | LN Dual Row IMSR | Arctic Silver console, spoiler frame & bumperettes | Crios mod | Technobrace | RoboTop module & modified convertible top relay for one-touch roof operation
BoxsterSteve is offline   Reply With Quote
Old 03-19-2018, 06:34 AM   #12
Registered User
 
geraintthomas's Avatar
 
Join Date: Nov 2015
Location: South Wales, UK
Posts: 843
Quote:
Originally Posted by BoxsterSteve View Post
Does it bog badly until 2500 or so and then start to pull strongly again?
Mine did this a couple of years back.
Turns out it was a faulty MAF that didnít set a CEL.
Try unplugging your MAF and see how it runs.
The car will revert to the factory programmed fuel map and throw a CEL, but if it runs like a champ again, youíve found the problem part and you arenít replacing things you donít need to.
That's exactly how it feels. Feels like driving a turbo where there's a little bit of lag, and then it really gives it the beans.

I'll try unplugging it later, thank you!
__________________
Porsche Boxster S Type 986

Bi-xenon Headlight Upgrade | 987 S 18" Anthracite Alloys | Android Head Unit | 5000k 55w HID's | 5000k Cree DRL's | 5000k Cree number plate lights | Cree LED Indicators | One-touch roof operation | Bypass exhaust pipes | Parking sensors | Ambient footwell lighting
geraintthomas is offline   Reply With Quote
Old 03-19-2018, 09:00 AM   #13
Registered User
 
oldskool73's Avatar
 
Join Date: May 2015
Location: Sydney, Australia
Posts: 335
Mine also did something like that. replaced the AOS, cleaned the TB & MAF etc... all with no codes... replacing the MAF was the final part of the puzzle that got everything working nicely again.

FWIW, I put in one of the cheapo $30 chinese knockoffs that you can find on ebay as a test, and it was so much better than the 'real' one in there I'm still running it, though not sure how long it'll last.
oldskool73 is offline   Reply With Quote
Old 03-19-2018, 01:24 PM   #14
Registered User
 
geraintthomas's Avatar
 
Join Date: Nov 2015
Location: South Wales, UK
Posts: 843
So... Just took the throttle body and plenum out.



And have a look inside:



Soaked with oil. Cleaned and as good as new.



The throttle body also had a load of gunk. See the black rim?



Much better



Also gave the connecting hose a good clean, and cleaned out the pipes in the intakes.



Car is 100% better thanks everyone who helped!
__________________
Porsche Boxster S Type 986

Bi-xenon Headlight Upgrade | 987 S 18" Anthracite Alloys | Android Head Unit | 5000k 55w HID's | 5000k Cree DRL's | 5000k Cree number plate lights | Cree LED Indicators | One-touch roof operation | Bypass exhaust pipes | Parking sensors | Ambient footwell lighting
geraintthomas is offline   Reply With Quote
Old 03-19-2018, 02:31 PM   #15
2003 S, Arctic Silver, M6
 
paulofto's Avatar
 
Join Date: Oct 2014
Location: Winnipeg, MB, Canada
Posts: 1,067
Garage
Now your car is very clean INSIDE as well as outside!

paulofto is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 12:47 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page