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 )

> Could a vacuum leak or poor ground be a starting killer?, 73 914 2.0 - EARLY Sept 72 VIN4732901102
avidfanjpl
post Apr 7 2010, 08:57 AM
Post #1


914 Hemophiliac
***

Group: Members
Posts: 720
Joined: 6-April 10
From: Bear, Delaware
Member No.: 11,566
Region Association: MidAtlantic Region



I am having a world of hurt. Car ran on Saturday. Drove it an hour. Got slightly warm and it ran rich the whole time. Crack in the dual tube elbow into the Manifold corrected last night.

Gapped at .017 to start. Waiting for dwell/vacuum/fp gauge/timing light in mail.

Backfires and will not start. I have the ecu at 11, all electrical checks out, changed ht sensor and manifold sensor last night.

Have one chinese relay but the rest are wehrle and good

chinese one ran the fan so it seems OK All hoses new. Fuel hoses too. How serious is a poorly adjusted fps on the drivers side? I am sure mine is not on 29psig.

I am wearing out my solenoid and maybe my ignition switch!

Thanks!

John

Any ideas? (IMG:style_emoticons/default/WTF.gif) (IMG:style_emoticons/default/wacko.gif) (IMG:style_emoticons/default/hissyfit.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
 
Reply to this topicStart new topic
Replies(1 - 4)
Root_Werks
post Apr 7 2010, 10:02 AM
Post #2


Village Idiot
*****

Group: Members
Posts: 8,456
Joined: 25-May 04
From: About 5NM from Canada
Member No.: 2,105
Region Association: Pacific Northwest



Check your points again. Make 100% sure the little ground strap in the dizzy isn't broken or the green wire didn't rub up against something grounding out. Sounds like that might have happened.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
realred914
post Apr 7 2010, 11:30 AM
Post #3


Senior Member
***

Group: Retired Members
Posts: 1,086
Joined: 1-April 10
From: california
Member No.: 11,541
Region Association: None



whats the fps you refer to? duel tube elbow?

rich running on a D-jet (stock 2 liter system) can be worn trigger points that are bouncing, high resistance head temp sendor or wire / resistor that conects to it, defective manifold pressure sendor or some bad wires to the sendors and brain.
the ecu know that I think you refer to with the 11 shoudl be basically be set at the mid range, it has only a small effect on mixture however.

aslo supper rich could be fromt eh cold start injector being on, dissconnect it to be sure that is not it either. your ignition switch shoudl have no effect on the mixture as it energizes a relay to run teh injection electrical so long as th ekey switch trips the relay it is not a problem

sine you say it was running prior to doing some work suggest you look carefully at wires and vacuum hoses in areas you did work for broken connections and leaks

good luck (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving-girl.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
avidfanjpl
post Apr 7 2010, 11:51 AM
Post #4


914 Hemophiliac
***

Group: Members
Posts: 720
Joined: 6-April 10
From: Bear, Delaware
Member No.: 11,566
Region Association: MidAtlantic Region



Thanks Root Werks and RealRed!

I meant the Manifold Pressure Sensor, and later I was talking about stupidly messing with the Fuel Pressure Regulator. Dope that I was, I have to wait for my fuel pressure meter to arrive and undo my work from Saturday.

Replacing the dual elbows into the MPS may have worked, but the backfire last night was so loud I have to wait till this afternoon to try again.

Root Werks - The green wire seems intact. Rechecking the gap to .17 later today.

Checked all hoses, cut some for tighter fits, but I think I may have a bad trigger.

It sends out some spurious signals when testing with a continuity tester when cranking, but the damn thing ran rich but pretty well on Saturday before I messed with it.

Truly, as it warmed up in SoCal, it starting messing up.

THANKS!

John
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Rand
post Apr 7 2010, 11:57 AM
Post #5


Cross Member
*****

Group: Members
Posts: 7,409
Joined: 8-February 05
From: OR
Member No.: 3,573
Region Association: None



QUOTE(avidfanjpl @ Apr 7 2010, 10:51 AM) *
Root Werks - The green wire seems intact. Rechecking the gap to .17 later today.

Be sure and check the other wire Dan mentioned. It's a little braided wire that connects between the advance plates inside the distributor. Sometimes one of the ends will come loose where it's soldered to the plate, and it will cause your exact symptoms. (Spark will be super weak, it won't start, and when it tries you'll get a nasty loud backfire. Happened to me.)
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: 31st October 2024 - 05:52 PM