Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Ruff1's Avatar
 
Join Date: Jan 2005
Location: Canada
Posts: 174
loss of power under boost!!!!!

hi i have an 89 3.3l turbo and i started it up today after the winter sleep. i fully charged the battery and started her up and after warming up for about 10 mins i went for a drive. i went to punch it and i had a loss of power at about 3500 rpm. almost a hesitation or bucking and if i kept the pedal stable it pick up again at 4200 rpm and on. i was in 3rd it started bucking at 3500rpm shifted to 4rth it ran fine and then bucked again at 3500 to 4000 and the took of after 4000 with no problem could it be the WUR i check all the hoses they seemed fine. please help before i go get rocked by the local mechanic!
Old 04-06-2007, 09:41 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered User
 
9dreizig's Avatar
 
Join Date: Jul 2005
Location: Reno NV, Bay Area during most weeks,, Kids still in NH
Posts: 5,777
Send a message via AIM to 9dreizig
I"ve got the same problem. Seems to be one of a couple of things.. a) over boost switch is kicking in too early or b) problem with the waste gate not opening and holding causing over boost,, hence the ob switch kicking in.. ..
As soon as my car gets here from the east coast I'm going to diagnose it
__________________
"Todd"
98 Tahoe ,2007 Saturn Vue
86 930 black and stock, 80 930 blue tracdog
91 Spec Miata (yeah I race a chick car)
"life"ll kill ya" Warren Zevon
Old 04-06-2007, 09:47 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
Ruff1's Avatar
 
Join Date: Jan 2005
Location: Canada
Posts: 174
please let me know when u find out something. is it as easy as replaceing the switch and where is the switch and how do u tast the waste gate should i go to an aftermarket bov?
Old 04-07-2007, 08:18 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
9dreizig's Avatar
 
Join Date: Jul 2005
Location: Reno NV, Bay Area during most weeks,, Kids still in NH
Posts: 5,777
Send a message via AIM to 9dreizig
will do !
__________________
"Todd"
98 Tahoe ,2007 Saturn Vue
86 930 black and stock, 80 930 blue tracdog
91 Spec Miata (yeah I race a chick car)
"life"ll kill ya" Warren Zevon
Old 04-07-2007, 08:22 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered
 
Join Date: Sep 2004
Location: Tonawanda NY
Posts: 789
Guys,
When gasoline sits it loses octane (even breaks down or gels if not treated at all) I suggest running the old gas out or mixing it with high octane so you don't experience detonation. This could be the cause or your rough running.
__________________
82 930 Pearl White 3.3 964 cams, K27 HF, Kokeln, fuel enriched, IA fuel head mod, wur mod, crankfire, 2X plug, Aase worked heads. 1bar, GHL, zork, 23/33 bars, low, loud
Old 04-08-2007, 03:23 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered User
 
9dreizig's Avatar
 
Join Date: Jul 2005
Location: Reno NV, Bay Area during most weeks,, Kids still in NH
Posts: 5,777
Send a message via AIM to 9dreizig
not my problem here, the boys bringing it west probably have 10 tanks of 93 throught it
__________________
"Todd"
98 Tahoe ,2007 Saturn Vue
86 930 black and stock, 80 930 blue tracdog
91 Spec Miata (yeah I race a chick car)
"life"ll kill ya" Warren Zevon
Old 04-08-2007, 03:35 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
Registered
 
Join Date: Sep 2004
Location: Tonawanda NY
Posts: 789
930, you may simply have a bad switch, disconnect it, be careful when you run the car up. The cars will see serious bucking and undulating if the fuel isn't flowing as well (kinked line, old pumps etc.) Ruffs car might have a fuel issue considering it was just pulled from storage.
__________________
82 930 Pearl White 3.3 964 cams, K27 HF, Kokeln, fuel enriched, IA fuel head mod, wur mod, crankfire, 2X plug, Aase worked heads. 1bar, GHL, zork, 23/33 bars, low, loud
Old 04-08-2007, 03:47 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Registered User
 
9dreizig's Avatar
 
Join Date: Jul 2005
Location: Reno NV, Bay Area during most weeks,, Kids still in NH
Posts: 5,777
Send a message via AIM to 9dreizig
I agree,, but how will I know that it's a bad switch and not a bad waste gate and it truly is overboosting ??
__________________
"Todd"
98 Tahoe ,2007 Saturn Vue
86 930 black and stock, 80 930 blue tracdog
91 Spec Miata (yeah I race a chick car)
"life"ll kill ya" Warren Zevon
Old 04-08-2007, 03:55 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Registered
 
Join Date: Sep 2004
Location: Tonawanda NY
Posts: 789
Disconnect the wg boost line and run .8 bar (11-12 lb for a stock spring) compressed air throgh the line, if it's working you can hear the wg open up. If not you may have found your problem.
__________________
82 930 Pearl White 3.3 964 cams, K27 HF, Kokeln, fuel enriched, IA fuel head mod, wur mod, crankfire, 2X plug, Aase worked heads. 1bar, GHL, zork, 23/33 bars, low, loud
Old 04-08-2007, 04:04 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Registered
 
Join Date: Sep 2004
Location: Tonawanda NY
Posts: 789
My apologies. I should ask, what spring/WG are you running? Headers? Turbo?
__________________
82 930 Pearl White 3.3 964 cams, K27 HF, Kokeln, fuel enriched, IA fuel head mod, wur mod, crankfire, 2X plug, Aase worked heads. 1bar, GHL, zork, 23/33 bars, low, loud
Old 04-08-2007, 04:09 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
Registered User
 
9dreizig's Avatar
 
Join Date: Jul 2005
Location: Reno NV, Bay Area during most weeks,, Kids still in NH
Posts: 5,777
Send a message via AIM to 9dreizig
KT27-7200 , Euro engine, 964 cams, 0,8 bar spring ...
I believe my buddy did check the waste gate as you suggested.. guess that points to the switch huh ??
__________________
"Todd"
98 Tahoe ,2007 Saturn Vue
86 930 black and stock, 80 930 blue tracdog
91 Spec Miata (yeah I race a chick car)
"life"ll kill ya" Warren Zevon
Old 04-08-2007, 07:38 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)
Registered
 
Join Date: Sep 2004
Location: Tonawanda NY
Posts: 789
If you're boost is at .8 +/- and the switch is faulty grounding the switch should alleviate the problem or at least tell you to look elsewhere. Lot of guys keep them disconnected, I personally leave mine in place even with a 1 bar tial, GHL headers and a hi flow. (switch=inexpensive, melted piston=expensive)
__________________
82 930 Pearl White 3.3 964 cams, K27 HF, Kokeln, fuel enriched, IA fuel head mod, wur mod, crankfire, 2X plug, Aase worked heads. 1bar, GHL, zork, 23/33 bars, low, loud
Old 04-08-2007, 07:53 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)
 
Registered User
 
Ruff1's Avatar
 
Join Date: Jan 2005
Location: Canada
Posts: 174
does anyone know were the switch is? or have any pics on it?
Old 04-20-2007, 03:45 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #13 (permalink)
Registered User
 
Join Date: Jul 2003
Location: Glorious Pac NW
Posts: 2,831
Quote:
Originally posted by Ruff1
does anyone know were the switch is? or have any pics on it?
Part #13 on this diagram: http://www.pelicanparts.com/PartsLookup/HTML/911_USA_87_89_KATALOG/107-30-Frame3.htm
__________________
'77 S with '78 930 power and a few other things.
Old 04-21-2007, 12:35 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #14 (permalink)
Registered User
 
Join Date: Dec 2004
Location: Danville - CA
Posts: 1,259
Three things I have run into that are create somewhat similar symptoms.

1. Boost leak at the throttle body... one of my intercooler bolts loosened up and allowed the neck of the IC to almost seperate from the TB.

2. Overly rich situation on initial startup / warm up.

3. Bad plugs essentially allowing the engine to flood under boost/enrichment.
__________________
Rob Montgomery
'88 Blk/Blk 930 ('Lucy') - Not Stock & Not Running
Old 04-23-2007, 11:21 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #15 (permalink)
Registered User
 
Ruff1's Avatar
 
Join Date: Jan 2005
Location: Canada
Posts: 174
what part is this pic of? were on the motor?
Old 04-25-2007, 10:06 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #16 (permalink)
Registered User
 
Join Date: Jul 2003
Location: Glorious Pac NW
Posts: 2,831
Quote:
Originally posted by Ruff1
what part is this pic of? were on the motor?
It's the picture of the boost pressure switch you asked for.

This thread has a discussion and pictures of the boost pressure sensor (drives the gauge) and boost pressure switch (overboost protection):

The little yellow box

From your description of the symptoms, it doesn't sound like the boost switch - because if it were killing the motor at 3500-4000, it would surely be in the loop over 4200, where you say it runs OK again.

For the same reason, fuel starvation from a bad pump or kinked/blocked line seems unlikely to me - as I can't see how that would improve at higher RPM.
__________________
'77 S with '78 930 power and a few other things.
Old 04-26-2007, 01:08 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #17 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 07:49 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization 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
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.