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
> Starting question 73 1.7
rosenfe
post Jun 7 2024, 03:17 PM
Post #1


Senior Member
***

Group: Members
Posts: 564
Joined: 14-October 13
From: northern california
Member No.: 16,512
Region Association: None



When I turn key I get intermittent response from starter. Sometimes nothing, other times barley cranks. Rebuilt starter from bruce. New battery jumping posts with key on or off only spins starter motor. Bad starter?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Ishley
post Jun 7 2024, 03:50 PM
Post #2


Member
**

Group: Members
Posts: 148
Joined: 4-October 21
From: Clarendon Hills Il
Member No.: 25,957
Region Association: Upper MidWest



Start with the basics… is the transmission ground strap connected and giving a good ground?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rosenfe
post Jun 7 2024, 03:53 PM
Post #3


Senior Member
***

Group: Members
Posts: 564
Joined: 14-October 13
From: northern california
Member No.: 16,512
Region Association: None



QUOTE(Ishley @ Jun 7 2024, 02:50 PM) *

Start with the basics… is the transmission ground strap connected and giving a good ground?

Yes. I checked grounds
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
emerygt350
post Jun 7 2024, 04:03 PM
Post #4


Advanced Member
****

Group: Members
Posts: 2,470
Joined: 20-July 21
From: Upstate, NY
Member No.: 25,740
Region Association: North East States



Jump the solenoid not just the starter. Does that work?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rosenfe
post Jun 7 2024, 04:07 PM
Post #5


Senior Member
***

Group: Members
Posts: 564
Joined: 14-October 13
From: northern california
Member No.: 16,512
Region Association: None



I’m jumping the two posts
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Ishley
post Jun 7 2024, 04:24 PM
Post #6


Member
**

Group: Members
Posts: 148
Joined: 4-October 21
From: Clarendon Hills Il
Member No.: 25,957
Region Association: Upper MidWest



Battery good and charged? I assume if you got it from Bruce the starter was checked and is good… sounds like a power or solenoid issue. Is the supply positive good and connection is good?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rosenfe
post Jun 7 2024, 04:48 PM
Post #7


Senior Member
***

Group: Members
Posts: 564
Joined: 14-October 13
From: northern california
Member No.: 16,512
Region Association: None



I’ve been jumping wrong part on starter. Should be positive lead to spade terminal. Now starter engages. I will test voltage of switch at starter. Pretty sure it’s a bad switch
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
emerygt350
post Jun 7 2024, 05:22 PM
Post #8


Advanced Member
****

Group: Members
Posts: 2,470
Joined: 20-July 21
From: Upstate, NY
Member No.: 25,740
Region Association: North East States



It could just be the normal "time to put a Ford solenoid on there". The original is picky about 12v. Google it. I will be heading for the door before the purists get here....
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
SirAndy
post Jun 7 2024, 05:32 PM
Post #9


Resident German
*************************

Group: Admin
Posts: 41,854
Joined: 21-January 03
From: Oakland, Kalifornia
Member No.: 179
Region Association: Northern California



QUOTE(emerygt350 @ Jun 7 2024, 04:22 PM) *

It could just be the normal "time to put a Ford solenoid on there". The original is picky about 12v. Google it. I will be heading for the door before the purists get here....

IMHO, running a relay is a good idea regardless.

There's really no need to run all that current through the starter switch.
(IMG:style_emoticons/default/popcorn[1].gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Superhawk996
post Jun 8 2024, 12:16 PM
Post #10


914 Guru
*****

Group: Members
Posts: 6,502
Joined: 25-August 18
From: Woods of N. Idaho
Member No.: 22,428
Region Association: Galt's Gulch



QUOTE(emerygt350 @ Jun 7 2024, 07:22 PM) *

It could just be the normal "time to put a Ford solenoid on there". The original is picky about 12v. Google it. I will be heading for the door before the purists get here....

Ya’ gotta laugh how the solution is always to add weight to a 914 (IMG:style_emoticons/default/lol-2.gif)
User is online!Profile CardPM
Go to the top of the page
+Quote Post
emerygt350
post Jun 8 2024, 12:18 PM
Post #11


Advanced Member
****

Group: Members
Posts: 2,470
Joined: 20-July 21
From: Upstate, NY
Member No.: 25,740
Region Association: North East States



That Ford part probably adds at least 5 HP...
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Superhawk996
post Jun 8 2024, 12:23 PM
Post #12


914 Guru
*****

Group: Members
Posts: 6,502
Joined: 25-August 18
From: Woods of N. Idaho
Member No.: 22,428
Region Association: Galt's Gulch



QUOTE(rosenfe @ Jun 7 2024, 05:53 PM) *

QUOTE(Ishley @ Jun 7 2024, 02:50 PM) *

Start with the basics… is the transmission ground strap connected and giving a good ground?

Yes. I checked grounds

How?

You cannot tell the quality of a ground cable just by visual inspection.

The most reliable way to verify a ground cable is measure the voltage drop across the cable while simultaneously cranking.

This is because you’re trying to measure less than 1 ohm of resistance which many cheap o’ multimeters will struggle to do.
User is online!Profile CardPM
Go to the top of the page
+Quote Post
Superhawk996
post Jun 8 2024, 12:23 PM
Post #13


914 Guru
*****

Group: Members
Posts: 6,502
Joined: 25-August 18
From: Woods of N. Idaho
Member No.: 22,428
Region Association: Galt's Gulch



QUOTE(emerygt350 @ Jun 8 2024, 02:18 PM) *

That Ford part probably adds at least 5 HP...

(IMG:style_emoticons/default/laugh.gif)
User is online!Profile CardPM
Go to the top of the page
+Quote Post
Superhawk996
post Jun 8 2024, 12:28 PM
Post #14


914 Guru
*****

Group: Members
Posts: 6,502
Joined: 25-August 18
From: Woods of N. Idaho
Member No.: 22,428
Region Association: Galt's Gulch



Good reading regarding how to measure and judge acceptable voltage drop across a ground.

https://www.fenderbender.com/running-a-shop...ircuits-part-11

The most misunderstood aspect of the stater is that it typically draws 50-100 amps of current while cranking. This is in addition to the 25 amps of current that the Bosch starter solenoid needs to draw to pull in and operate the actual motor correctly.

It only takes a minute amount of resistance in the ground cable to cause HUGE problems due to the high current draw.

As an example .01 ohms of resistance in a ground cable will drop 1.25 volts (way too much) if drawing 125 amps of current while cranking.
User is online!Profile CardPM
Go to the top of the page
+Quote Post
dtmehall
post Jun 8 2024, 08:38 PM
Post #15


Newbie
*

Group: Members
Posts: 35
Joined: 21-December 23
From: Farmington Hills, Michigan
Member No.: 27,808
Region Association: Upper MidWest



QUOTE(Superhawk996 @ Jun 8 2024, 12:28 PM) *

Good reading regarding how to measure and judge acceptable voltage drop across a ground.

https://www.fenderbender.com/running-a-shop...ircuits-part-11

The most misunderstood aspect of the stater is that it typically draws 50-100 amps of current while cranking. This is in addition to the 25 amps of current that the Bosch starter solenoid needs to draw to pull in and operate the actual motor correctly.

It only takes a minute amount of resistance in the ground cable to cause HUGE problems due to the high current draw.

As an example .01 ohms of resistance in a ground cable will drop 1.25 volts (way too much) if drawing 125 amps of current while cranking.

User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 30th October 2024 - 09:44 PM