Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Boxster General Discussions

Reply
 
LinkBack Thread Tools Display Modes
Old 01-01-2018, 11:40 PM   #1
Registered User
 
Badboybox's Avatar
 
Join Date: Oct 2017
Location: Los Angeles
Posts: 50
help needed

Was out driving my 1998 boxster drove great .when I got home pulled in my driveway
Got out to open garage the car started to run rough then turned off.tried to restart , it would start
But only run for maybe 3 to 5 seconds then turn off.if I touched the gas pedal it would turn right off.
Had to push it into my garage as it would not stay running long enough or let me hit the gas with out it turning off .it turns over no problem.i have no check engine light on at all and have no codes.i pulled the MAF sensor and cleaned it now the car turns over but will not come on at all.does anyone have any ideas of what it could be.it just seems so random that one second its running great the next its not wanting to run at all.Thanks again for any help.

Badboybox is offline   Reply With Quote
Old 01-02-2018, 12:19 AM   #2
Registered User
 
Join Date: Jun 2016
Location: England
Posts: 178
Hi Badboy
I had a similar problem when I removed the throttle body and cleaned it. It would turn over and fire but turn off straight away.

Has to get it trailer to a garage. The fault was I hadn't attached one of the plenum chamber tubes back on properly so it was drawing air.

Your sound like a very similar fault.

Its definitely nothing serious

Peter
YellowS2000 is offline   Reply With Quote
Old 01-02-2018, 12:22 AM   #3
Registered User
 
Badboybox's Avatar
 
Join Date: Oct 2017
Location: Los Angeles
Posts: 50
Quote:
Originally Posted by YellowS2000 View Post
Hi Badboy
I had a similar problem when I removed the throttle body and cleaned it. It would turn over and fire but turn off straight away.

Has to get it trailer to a garage. The fault was I hadn't attached one of the plenum chamber tubes back on properly so it was drawing air.

Your sound like a very similar fault.

Its definitely nothing serious

Peter
Hi thanks for the reply.i didn't remove anything on the engine when it started running bad.
Just started out of no were.
Badboybox is offline   Reply With Quote
Old 01-02-2018, 05:23 AM   #4
Registered User
 
husker boxster's Avatar
 
Join Date: Sep 2006
Location: Omaha
Posts: 2,219
Sounds like it could be the crankshaft position sensor.
__________________
PCA National HPDE Instructor
2008 Boxster S Limited Edition #005
2007 Cayman S - SOLD on Valentine's Day 2013
2008 Cayman S Sport - Signal Green
husker boxster is offline   Reply With Quote
Old 01-02-2018, 06:42 AM   #5
Registered User
 
Badboybox's Avatar
 
Join Date: Oct 2017
Location: Los Angeles
Posts: 50
Quote:
Originally Posted by husker boxster View Post
Sounds like it could be the crankshaft position sensor.
Do they go out like that.one second running next not.? What are the symptoms of it going out.how can I tell if it's the crankshaft position sensor or MAF sensor or fuel pump.when I crank it over I can smell fuel like it's getting gas.so I don't think it's the fuel pump.its weird I'm not getting the check engine light.
Badboybox is offline   Reply With Quote
Old 01-02-2018, 07:16 AM   #6
Beginner
 
Jamesp's Avatar
 
Join Date: Mar 2013
Location: Houston
Posts: 1,659
Garage
Crank it and watch the tachometer. If the tachometer does not move while cranking, change the CPS.
__________________
2003 S manual
Jamesp is offline   Reply With Quote
Old 01-02-2018, 07:23 AM   #7
Registered User
 
Badboybox's Avatar
 
Join Date: Oct 2017
Location: Los Angeles
Posts: 50
Quote:
Originally Posted by Jamesp View Post
Crank it and watch the tachometer. If the tachometer does not move while cranking, change the CPS.
Ok im going to change it..I just went out there after the car sat over night.it started for 2 or 3 seconds then turned off.thanks for the help.
Badboybox is offline   Reply With Quote
Old 01-02-2018, 10:46 AM   #8
Registered User
 
Join Date: Aug 2005
Location: Sanford NC
Posts: 2,338
Fault codes read? Don't just go throwing parts at it. Doesn't the fact that it starts for 2-3 seconds point to a CPS working at least during that time. Fuel pressure?
mikefocke is offline   Reply With Quote
Old 01-02-2018, 11:07 AM   #9
Registered User
 
Join Date: Dec 2016
Location: Clifton, NJ
Posts: 782
when my cps was bad, the car shut right the hell off and would not restart until stone cold.

this seems more like a major vac leak.
Quadcammer is offline   Reply With Quote
Old 01-02-2018, 11:50 AM   #10
Registered User
 
Badboybox's Avatar
 
Join Date: Oct 2017
Location: Los Angeles
Posts: 50
No love..changed the crank position sensor still just turns over with no start.maybe the fuel pump or the relay.any ideas.Thanks.car is bone stock.ran perfect yesterday till I pulled in my driveway and it just turned off.
Badboybox is offline   Reply With Quote
Old 01-02-2018, 12:20 PM   #11
Registered User
 
Join Date: Dec 2016
Location: Clifton, NJ
Posts: 782
have you looked over the engine for obvious issues or vac leaks?
Quadcammer is offline   Reply With Quote
Old 01-02-2018, 12:42 PM   #12
Registered User
 
Join Date: Feb 2017
Location: CO
Posts: 939
Check this article for an easy way to test the fuel pump.

https://www.pelicanparts.com/techarticles/Boxster_Tech/22-FUEL-Fuel_Pump/22-FUEL-Fuel_Pump.htm
Geof3 is offline   Reply With Quote
Old 01-02-2018, 01:33 PM   #13
Registered User
 
Badboybox's Avatar
 
Join Date: Oct 2017
Location: Los Angeles
Posts: 50
Yes looked over the engine see nothing..i really think it's Electrical because it was running one minute turned off the next like something electrical went out.
Badboybox is offline   Reply With Quote
Old 01-02-2018, 02:10 PM   #14
Registered User
 
Join Date: Oct 2012
Location: Cincinnati, Ohio
Posts: 283
Garage
Check the MAS. I had a similar problem
Van914 is offline   Reply With Quote
Old 01-02-2018, 02:36 PM   #15
Registered User
 
Badboybox's Avatar
 
Join Date: Oct 2017
Location: Los Angeles
Posts: 50
Quote:
Originally Posted by Van914 View Post
Check the MAS. I had a similar problem
I took it out and cleaned it.but wont it still start and run with a bad MAS.?or if you disconnect
The MAS wont it run.my car is just cranking over with out much happening. And it was runjing perfect till I turned into my driveway when it just turned off.when I would turn it over it would act like it wanted to start but would just turn off after a second or 2.
Badboybox is offline   Reply With Quote
Old 01-02-2018, 10:18 PM   #16
Certified Boxster Addict
 
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,500
Disconnect the electrical connector to the MAS (or MAF) and try to start the car. The ECU will use the factory pre-programmed fuel map and the engine should start and be drivable (although it might run kind of rough). This won't harm anything.

If the engine runs and drives (even roughly) with the MAF disconnected, then replace the MAF. If the engine still won't start, then its not the MAF and you'll have to look elsewhere.

And yes, its fairly common for a car to run perfectly until they don't run at all since many components do not suffer a gradual degradation in performance, but instead fail like a light bulb.
__________________
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
POC Licensed DE/TT Instructor

Last edited by thstone; 01-02-2018 at 10:21 PM.
thstone is offline   Reply With Quote
Old 01-02-2018, 10:59 PM   #17
Registered User
 
Badboybox's Avatar
 
Join Date: Oct 2017
Location: Los Angeles
Posts: 50
Quote:
Originally Posted by thstone View Post
Disconnect the electrical connector to the MAS (or MAF) and try to start the car. The ECU will use the factory pre-programmed fuel map and the engine should start and be drivable (although it might run kind of rough). This won't harm anything.

If the engine runs and drives (even roughly) with the MAF disconnected, then replace the MAF. If the engine still won't start, then its not the MAF and you'll have to look elsewhere.

And yes, its fairly common for a car to run perfectly until they don't run at all since many components do not suffer a gradual degradation in performance, but instead fail like a light bulb.
I disconnected the MAF sensor still won't start. Im pretty sure I hear the fuel pump from behind
The dash.when I turn over the motor I can spell gas like its getting full but do spark.i changedvthe crank sensor today with no change.
Badboybox is offline   Reply With Quote
Old 01-02-2018, 11:19 PM   #18
Registered User
 
Join Date: Feb 2017
Location: CO
Posts: 939
Have you checked all of your fuses and relays? Mine died due to a failed (burned actually, longish story) wire harness section to the drivers side aft O2 sensor. It was shorting out and blowing the injector bank fuse. Look to see if all of your fuses are intact, if not it may have just been a fluke. But if you find a dead one, and replace it and it pops again you have a short or something somewhere. I would stop throwing parts at it until you check all the electrical pathways first.

I’m pretty sure all of the various sensors can be checked with a Durametric or pst at the dealer. You may have to bite the bullet and get some systemic diagnostics done.
Geof3 is offline   Reply With Quote
Old 01-03-2018, 04:10 AM   #19
Registered User
 
husker boxster's Avatar
 
Join Date: Sep 2006
Location: Omaha
Posts: 2,219
It may be time to invest in a code reader or find someone who has one. Pulling codes will help you zero in on the issue. A decent / adequate code reader runs $50-70. You will spend way more than that chasing and replacing parts.
__________________
PCA National HPDE Instructor
2008 Boxster S Limited Edition #005
2007 Cayman S - SOLD on Valentine's Day 2013
2008 Cayman S Sport - Signal Green
husker boxster is offline   Reply With Quote
Old 01-03-2018, 05:50 AM   #20
Registered User
 
Join Date: Dec 2016
Location: Clifton, NJ
Posts: 782
a $13 obd bluetooth dongle and a $3 obd fusion app will get the job done.

but I'm guessing he doesn't have any codes.

Definitely check fuses.

go back to the basics.

Does the car have spark?

Have you verified fuel pressure at the rail?

Quadcammer 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 02:00 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, 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