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 Technical BBS > 1- Porsche Technical Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Jan 2009
Location: DC
Posts: 1,170
Garage
930 Permatune CDI/Coil Idle skip

Has any body experienced this before?
The car starts fine cold,warm and hot to a smooth idle, drives fine with no misfire as far as I can tell.

But some times when driving and come to a stop light the Idle skips but not all the time.

I installed new plugs , cap and rotor, but not the spark plug wires.

Could it be that I,m getting a voltage drop to the Permatune. Could it be that the Permatune needs a relay ?
__________________
1986 944 turbo -first car
1997 993 Cab 6 speed-sold
1992 964 C2 turbo
SOLD, 911GT ,CIS, 428 fwhp 450 trq, Carrillo rods, 964 cams, TT retainers,7.5 comp 1.1 bar boost 320 ml black fuel head 009 injectors, 044 pumps, 60-1 T4/T3 dual scroll turbo
Old 06-02-2011, 06:57 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered User
 
HFR_Racer's Avatar
 
Join Date: Sep 2005
Location: Indiana
Posts: 546
Garage
Sounds like you've got a handle on it.. It sounds like plug wires to me. How old are your wires? Are you running OEM type 7mm wires with the grounding braid?
__________________
Thank you,
HFR_Racer

'87 930, 3.3 liter, K27 hybrid, Kokeln IC, Andial, B&B, Borla, 17" Supercups.
Old 06-02-2011, 06:34 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
PrimeMvr's Avatar
 
Join Date: Dec 2010
Location: Iowa
Posts: 370
Garage
Quote:
Originally Posted by heliolps2 View Post
Could it be that I,m getting a voltage drop to the Permatune. Could it be that the Permatune needs a relay ?
You shouldn't need a relay if you wired it to the starter power lug with at least 12 gauge wire. It could be a loose or bad plug wire. If you can replicate it in your garage, you could pull wires one at a time. If you pull one and it doesn't get any worse, that's your culprit.

Get in a very dark place and watch for any arcing. Also pull your cap and see if there are any black signs of arching.

Could be an intermitent vacuum leak. Do you have an AFR gauge?

Do you have any vertical play in your dizzy (pull up and down on the rotor). This can cause the timing to bounce around, but you probably would have seen this before the CDI swap.
__________________
87 930 - Black - 3.4L/964 cams/K29/Powerhaus IC/6AL-2/B&B dual exhaust/MTX-L/235-315 Toyo R888/18" Kinesis wheels/Big Red brakes/LSD
10 997.2 Cab - Speed Yellow
83 SC Cab - Guards Red [SOLD]
17 NSX - Nouvelle Blue
Old 06-02-2011, 08:58 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Jan 2009
Location: DC
Posts: 1,170
Garage
DISTRIBUTOR TRIGGER SIGNAL

The second most common cause of 930 engine ignition failure is the ignition trigger circuit. Since the ignition box is controlled by the magnetic pulse generator located inside the distributor, any disruption in the triggering signal will cause ignition problems. Full disassembly and inspection of the distributor is highly recommended due to the intermittent nature of triggering problems. Pay special attention to the distributor trigger shielded cable ( green wire ), magnetic pulse generator magnet and magnetic pulse generator winding connection as these parts are known to fail in combination. An especially common problem is a broken magnet pole.

Evidence of arching between the magnetic pulse generator magnet points indicates a defective rotor. In this case replace the rotor, magnetic pulse winding, green wire and ignition box. The Perma-Tune high performance triggering is so accurate that worn out distributor shaft bearings can be detected by the tachometer. This is indicated by the tachometer needle slightly bouncing at idle and is usually accompanied by excessive end play of the distributor shaft. Trigger signal problems can cause double triggering which results in a weak ignition spark. Due to the lower triggering resolution of the stock ignition box, some symptoms of trigger signal problems can be more evident after the Perma-Tune is installed. Refer to the vehicle maintenance manual for triggering signal waveform specifications and distributor repair instructions.

To quickly test the triggering circuit without the use of an oscilloscope: Unplug the harness connector from the ignition box. Refer to the 930 6 pin Installation Instructions diagram; connect an Ohmmeter between pins 3 and 6 of the harness connector. To prevent the possibility of misdiagnosis, tug on the green triggering signal wire located at the base of the distributor while viewing the meter. The published specification for the magnetic pulse generator is 600 Ohms +- 100. Our experience has shown that a variation of +- 25 Ohm indicates a need to repair defective connections or to replace the magnetic pulse generator windings.

In my case the green wire behind the connector is coming loose, Pin 6

BENCH CHECK OF THE IGNITION BOX.

1 = System ground
4 = Coil + Hot (coil - to ground)
2 = Tachometer signal
5 = Power
3 = Signal ground (distributor pin B) Green wire shield
6 = Signal (distributor pin A) Green wire center conductor
__________________
1986 944 turbo -first car
1997 993 Cab 6 speed-sold
1992 964 C2 turbo
SOLD, 911GT ,CIS, 428 fwhp 450 trq, Carrillo rods, 964 cams, TT retainers,7.5 comp 1.1 bar boost 320 ml black fuel head 009 injectors, 044 pumps, 60-1 T4/T3 dual scroll turbo
Old 06-03-2011, 07:50 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
PrimeMvr's Avatar
 
Join Date: Dec 2010
Location: Iowa
Posts: 370
Garage
heliolps2: Great post, I tend to overlook the obvious at times Beautiful car!!
__________________
87 930 - Black - 3.4L/964 cams/K29/Powerhaus IC/6AL-2/B&B dual exhaust/MTX-L/235-315 Toyo R888/18" Kinesis wheels/Big Red brakes/LSD
10 997.2 Cab - Speed Yellow
83 SC Cab - Guards Red [SOLD]
17 NSX - Nouvelle Blue
Old 06-03-2011, 08:11 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered User
 
TurboKraft's Avatar
 
Join Date: Mar 2005
Location: Phoenix, AZ
Posts: 2,484
distributor pulse generator

Unfortunately, the distributor pulse generator is NLA, and no longer produced by Bosch. If you are lucky, you can find a NOS one.
The green trigger wire is still offered.
__________________
Chris Carroll
TurboKraft, Inc.
Tel. 480.969.0911
email: info@turbokraft.com
http://www.facebook.com/TurboKraft - http://www.instagram.com/TurboKraft
Old 06-03-2011, 10:03 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
Brando
 
quattrorunner's Avatar
 
Join Date: May 2006
Location: Las vegas
Posts: 5,671
Garage
Quote:
Unfortunately, the distributor pulse generator is NLA, and no longer produced by Bosch. If you are lucky, you can find a NOS one.

The green trigger wire is still offered.
What are the options if it's in need of replacement?
Old 12-11-2011, 10:48 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Registered User
 
HFR_Racer's Avatar
 
Join Date: Sep 2005
Location: Indiana
Posts: 546
Garage
The pulse generator coil is surely available. Napa, Delco... Use the search.
Old 12-11-2011, 04:35 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Registered User
 
Join Date: Jan 2009
Location: DC
Posts: 1,170
Garage
thats good to know, thanks
__________________
1986 944 turbo -first car
1997 993 Cab 6 speed-sold
1992 964 C2 turbo
SOLD, 911GT ,CIS, 428 fwhp 450 trq, Carrillo rods, 964 cams, TT retainers,7.5 comp 1.1 bar boost 320 ml black fuel head 009 injectors, 044 pumps, 60-1 T4/T3 dual scroll turbo
Old 12-13-2011, 01:42 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Brando
 
quattrorunner's Avatar
 
Join Date: May 2006
Location: Las vegas
Posts: 5,671
Garage
I just thought I needed one of them but I tested the plug/wire that the green wire plugs into in the wire harnss and it was short or faulty, so I replaced that plug and rewired it into the harness and have spark again. Test that wire with an ohm meter.
Old 12-13-2011, 01:51 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 11:07 AM.


 
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.