Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

 
 Reply to this topicStart new topic
> Ot 74 911 no spark help..
mb911
post Apr 9 2017, 02:29 PM
Post #1


914 Guru
*****

Group: Members
Posts: 7,422
Joined: 2-January 09
From: Burlington wi
Member No.: 9,892
Region Association: Upper MidWest
So a while ago I posted about taking on a basket case 911 project that had the engine out for a long time..

Well engine is in everything is hooked up but trying to fire this thing up and am having very intermittent spark.. The cdi box was a no go and hooked up a used msd box and now I see spark every once and a while. Looking for a little advice.. What should I check next.. Points hanging up ?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Dave_Darling
post Apr 9 2017, 04:15 PM
Post #2


914 Idiot
***************

Group: Members
Posts: 15,075
Joined: 9-January 03
From: Silicon Valley / Kailua-Kona
Member No.: 121
Region Association: Northern California
Definitely check for the points opening and closing. Make sure you have a good ground path for them, as well as for the spark.

--DD
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
infraredcalvin
post Apr 9 2017, 09:31 PM
Post #3


Distracted Member
***

Group: Members
Posts: 1,581
Joined: 25-August 08
From: Ladera Ranch, CA
Member No.: 9,463
Region Association: Southern California
QUOTE(Dave_Darling @ Apr 9 2017, 03:15 PM) *

Definitely check for the points opening and closing. Make sure you have a good ground path for them, as well as for the spark.

--DD


EDIT: looks like you have points per Dave mentions above, I'll leave my comments below for posterity in case you have a later dizzy...


Im guessing, but, does that have the star magnetic pickup inside the dizzy? If so check that the arms aren't bent, it happens pretty easy if the cap clips get caught up inside.

Then check the signal wire (green wire). Those are known cause weird issues.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mb911
post Apr 10 2017, 01:54 PM
Post #4


914 Guru
*****

Group: Members
Posts: 7,422
Joined: 2-January 09
From: Burlington wi
Member No.: 9,892
Region Association: Upper MidWest
Ok have decent enough spark now and got it to fire up.. Really didn't get it to run longer then about 15 seconds before it dies. Thinking points are a bit of an issue still and considering pertronix as I want to be done with this car.. And then it's tweaking the fuel injection..
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Jeffs9146
post Apr 10 2017, 03:17 PM
Post #5


Ski Bum
****

Group: Members
Posts: 4,062
Joined: 10-January 03
From: Discovery Bay, Ca
Member No.: 128
FI or Carbs?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mb911
post Apr 10 2017, 04:27 PM
Post #6


914 Guru
*****

Group: Members
Posts: 7,422
Joined: 2-January 09
From: Burlington wi
Member No.: 9,892
Region Association: Upper MidWest
QUOTE(Jeffs9146 @ Apr 10 2017, 01:17 PM) *

FI or Carbs?



Cis..
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Jeffs9146
post Apr 11 2017, 12:06 AM
Post #7


Ski Bum
****

Group: Members
Posts: 4,062
Joined: 10-January 03
From: Discovery Bay, Ca
Member No.: 128
Check for vacuum leaks. When I installed my motor it would use the cold start injector to run for a few seconds and the more leaks the shorter it would run!

The vacuum lifts the AFR plate to increase the fuel to the injectors.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mb911
post Apr 11 2017, 07:22 PM
Post #8


914 Guru
*****

Group: Members
Posts: 7,422
Joined: 2-January 09
From: Burlington wi
Member No.: 9,892
Region Association: Upper MidWest
QUOTE(Jeffs9146 @ Apr 10 2017, 10:06 PM) *

Check for vacuum leaks. When I installed my motor it would use the cold start injector to run for a few seconds and the more leaks the shorter it would run!

The vacuum lifts the AFR plate to increase the fuel to the injectors.




I was manually lifting the plate etc but I still think I have air to bleed out.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Jeffs9146
post Apr 11 2017, 08:03 PM
Post #9


Ski Bum
****

Group: Members
Posts: 4,062
Joined: 10-January 03
From: Discovery Bay, Ca
Member No.: 128
QUOTE(mb911 @ Apr 11 2017, 06:22 PM) *

QUOTE(Jeffs9146 @ Apr 10 2017, 10:06 PM) *

Check for vacuum leaks. When I installed my motor it would use the cold start injector to run for a few seconds and the more leaks the shorter it would run!

The vacuum lifts the AFR plate to increase the fuel to the injectors.




I was manually lifting the plate etc but I still think I have air to bleed out.


Check the fuel pressures.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mepstein
post Apr 11 2017, 08:15 PM
Post #10


914-6 GT in waiting
***************

Group: Members
Posts: 19,702
Joined: 19-September 09
From: Landenberg, PA/Wilmington, DE
Member No.: 10,825
Region Association: MidAtlantic Region
Tony Danato (on pelican) will rebuild a WUR and fuel dist but it costs about $800. Text me if you need his number.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mb911
post Apr 12 2017, 06:52 AM
Post #11


914 Guru
*****

Group: Members
Posts: 7,422
Joined: 2-January 09
From: Burlington wi
Member No.: 9,892
Region Association: Upper MidWest
QUOTE(mepstein @ Apr 11 2017, 06:15 PM) *

Tony Danato (on pelican) will rebuild a WUR and fuel dist but it costs about $800. Text me if you need his number.



Hoping I won't need him.. I will get fuel pressures this weekend. Gotta get this car out of my pole barn.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mb911
post Jun 17 2017, 05:45 AM
Post #12


914 Guru
*****

Group: Members
Posts: 7,422
Joined: 2-January 09
From: Burlington wi
Member No.: 9,892
Region Association: Upper MidWest
So update on this project is that finally got it running well.. Excited to get it out of my shop.. Will be leaving at the end of the month. Currently try to figure out why there is no voltage regulator, and why the silicone valve cover gaskets on passenger side are leaking..

User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mark Henry
post Jun 17 2017, 06:23 AM
Post #13


that's what I do!
***************

Group: Members
Posts: 20,065
Joined: 27-December 02
From: Port Hope, Ontario
Member No.: 26
Region Association: Canada
QUOTE(mb911 @ Jun 17 2017, 07:45 AM) *

Currently try to figure out why there is no voltage regulator, and why the silicone valve cover gaskets on passenger side are leaking..

No voltage regulator or the VR is not working?
There is internal and external VR's
No idiot light is a big cause of issues as it needs the idiot light to excite the field in the alternator. Some of the Bosch 911 alternator's are very sensitive to having the correct matching Bosch VR.

Other causes are wiring connections, ground issues, brushes, dead VR, wrong VR.

Silicone valve cover gaskets, I bet they are cranked on too hard. You have to use nyloc nuts and less than factory torque, almost half.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mb911
post Jun 17 2017, 07:29 AM
Post #14


914 Guru
*****

Group: Members
Posts: 7,422
Joined: 2-January 09
From: Burlington wi
Member No.: 9,892
Region Association: Upper MidWest
QUOTE(Mark Henry @ Jun 17 2017, 04:23 AM) *

QUOTE(mb911 @ Jun 17 2017, 07:45 AM) *

Currently try to figure out why there is no voltage regulator, and why the silicone valve cover gaskets on passenger side are leaking..

No voltage regulator or the VR is not working?
There is internal and external VR's
No idiot light is a big cause of issues as it needs the idiot light to excite the field in the alternator. Some of the Bosch 911 alternator's are very sensitive to having the correct matching Bosch VR.

Other causes are wiring connections, ground issues, brushes, dead VR, wrong VR.

Silicone valve cover gaskets, I bet they are cranked on too hard. You have to use nyloc nuts and less than factory torque, almost half.



Yup no voltage regulator.. I see the wires double blue, black , and brown. I have an extra regulator so i will have to try it..

I will try to loosen the valve covers a bit and see what happens.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
« Next Oldest · 914World Garage · Next Newest »
 

Reply to this topicStart new topic
2 User(s) are reading this topic (2 Guests and 0 Anonymous Users)
0 Members:

 

Display Mode: Standard · Switch to: Linear+ · Switch to: Outline

Track this topic · Email this topic · Print this topic · Subscribe to this forum

- Lo-Fi Version Time is now: 15th January 2025 - 12:39 AM
Invision Power Board v9.1.4 © 2025  IPS, Inc.
All rights reserved 914World.com © since 2002
914World.com is the fastest growing online 914 community!
We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ...