Parts Catalog Accessories Catalog Tech Info Tech Forums
 
  Search our site:    
 Cart  | Project List | Order Status | Help    
  We salute a legendary member of the community.
Thank you for selflessly sharing your wisdom with us...
Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > Porsche 912 Technical Forum

Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Nov 2001
Location: Port Washington, New York
Posts: 76
Hard to start when hot.

My 67 with original solex carbs (rebuilt) and inline fuel filter runs great but after a long run she wont start up when hot. Give her a while to cool off and she starts right up with an occasional backfire. I guess its vapor lock from the fuel getting hot but are there any solutions to this problem any suggestions or comments.
Old 07-23-2002, 07:27 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #1 (permalink)
Registered User
 
Join Date: Nov 2001
Location: arlington,va USA
Posts: 180
Hello Alex

Check your timing.
I too, run solex carbs(one NEEDS rebuilding) with inline(before pump) filter. It been very hot in the DC area and I havent had a problem one with hot starts. Funny sometimes looking at the filter and seeing no gas, wonder how she runs.

Also, I have a 1/4 bakelite between carb and intake, stock??


GoodLuck
Brett
Old 07-24-2002, 03:37 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #2 (permalink)
Registered User
 
Duke's Avatar
 
Join Date: Nov 2000
Location: Redding,CA USA
Posts: 282
Porsche Crest

This has been an ongoing problem with these cars since day one. I had the same problem after a long trip-car would not start. I fixed the problem by installing a separate solenoid mounted away from the starter (behind the right rear passenger seat). These are inexpensive & are available from most auto parts stores & are basically a Ford solenoid. See Dave's web site for info on mounting these. WWW.bay912.org
Old 07-24-2002, 11:07 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Nov 2001
Location: arlington,va USA
Posts: 180
Hey Alex

Maybe Im running up the the wrong tree. Im thinking that it turns over,just wont start. ALSO, NEVER had hot start problems with stock starter. Just lucky I guess, once in my life.

Brett
Old 07-24-2002, 11:37 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #4 (permalink)
Registered User
 
Join Date: Feb 2002
Location: Winchester, MA
Posts: 42
http://www.allzim.com/cgi-bin/zim/gettip.pl?tip=07249816974

I don't know if it will fix your problem.

This has been covered before, pretty recently. Do a search. The owner with the same problem may be able to give you more insight into what fixed it.

Mark
__________________
'68 912
Old 07-24-2002, 11:40 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #5 (permalink)
Registered User
 
Join Date: Aug 2001
Location: Las Vegas, NV USA
Posts: 552
Garage
I am with Duke on the "hot start" relay.

I bought a Bosch relay kit at Bugformance for $8.00 and it has not reared its ugly head since installing and I was having a hell of time with it. I have a web page saved at home that talks about this kit specifically. Installed in 30 minutes including the time to jack the car and take it down.

Craig
Old 07-24-2002, 11:56 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #6 (permalink)
Registered User
 
Join Date: Nov 2001
Location: arlington,va USA
Posts: 180
Quote
" Secondly, a word about "start booster relays". These relays are added to control the starter solenoid control circuit, and be controlled by the ignition key "start" switch. They are like painting over rust. They will often "patch" the system into operating, but they are a band-aid approach that covers up a real problem in the starter control circuit of the car. If your car has all parts correct, and all connections clean, then you do not need this relay. I donít, and I can start my car just find when itís near freezing outside, or in a Mojave Desert summer. My best advice: If your car wonít start, find the problem and fix it... donít paper it over."

http://www.pelicanparts.com/techarticles/mult_starter_diag/mult_starter_diag.htm

Brett
Old 07-24-2002, 12:45 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #7 (permalink)
abit off center
 
cgarr's Avatar
 
Join Date: Feb 2002
Location: At the Airport Kentwood, MI
Posts: 6,557
Garage
Send a message via Yahoo to cgarr
I dont think alex67 is talking about the starter relay problem? I think I have the same problem he has when hot but not quite as bad, if I try to start when setting for 5 or 10 min after hot it seems flooded and will not fire for quite a while but if you let it set for 30 min its ok I also notice a lot of bubbling in my fuel filter when it gets hot after I shut it down.

Craig
Old 07-24-2002, 12:47 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #8 (permalink)
Registered User
 
Duke's Avatar
 
Join Date: Nov 2000
Location: Redding,CA USA
Posts: 282
Porsche Crest

I installed mine in 1979 & have not had a hot start problem since. The problem is caused by excessive heat which causes the solenoid to fry-move it away from the starter & problem is solved if this is your problem. You may also have a fuel pump going bad. There are one way check valves in the fuel pump & if one is failing it will cause this problem too. Solution: new fuel pump.
Old 07-24-2002, 01:44 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #9 (permalink)
Registered User
 
Join Date: Nov 2001
Location: Port Washington, New York
Posts: 76
Cgarr my problem sounds like yours but i have not checked to see if there is any bubbling at the fuel filter. I will next run. My problem is if the car is cool she starts right up but when she is hot she turns over but real slow like my battery is going dead. After a while and she is cool she starts right up.

Last edited by Alex 67; 07-28-2002 at 08:02 PM..
Old 07-28-2002, 07:51 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #10 (permalink)
Registered User
 
Join Date: Nov 2001
Location: arlington,va USA
Posts: 180
Hey Alex

Sounds like starter/solenoid trouble or timing. Somewhere I saw "NEW" starter for about 125. The relay might help if money is tight. Checking the timing is free

GoodLuck
Brett
Old 07-29-2002, 04:01 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #11 (permalink)
Registered User
 
Join Date: Aug 2001
Location: Las Vegas, NV USA
Posts: 552
Garage
Alex,

I have to agree with Brett, sounds like the start of a hot start problem. I would try the relay fix first as it is about $10 or replacing the solenoid, cheaper than a new starter.

I am in the midst of tracking down all my ground points and cleaning them an making sure I have good contacts. I am noticing improvments in lighting and some signal indicator behaviors. So check those while you are at it.

Craig
69-912
Old 07-29-2002, 06:01 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #12 (permalink)
Registered User
 
Join Date: Nov 2001
Location: Port Washington, New York
Posts: 76
I want to thank everyone for their advice and will be trying some of the suggestions this weekend. Ill let you all know how it works out.
Alex
Old 07-31-2002, 04:38 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #13 (permalink)
Registered User
 
Join Date: Nov 2001
Location: Port Washington, New York
Posts: 76
hard start when hot

I first want to thank all of you for your advice. I first tried to
clean all points of ground and connections that I could find that would cause this problem. After this did not work I installed a Ford two ton truck relay and it seems to have solved the problem.
It is sooooo nice not to have to push start your car after driving her for a while. It always seems to happen when someone is admiring your car.
Old 09-16-2002, 12:31 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #14 (permalink)
Registered User
 
Join Date: Apr 1999
Location: Baltimore/DC area
Posts: 119
does it crank?

I'm confused. Is the problem that the car will not crank? Or is the problem that the car cranks and cranks but does not fire?

I have the same problem if it is the later. When it's really hot it will crank and crank but not fire up. I have Solexes. I figured it was vapor lock. How does the a beefed up starter relay fix this problem if the starter is already cranking?

thanx.
Old 09-16-2002, 04:40 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #15 (permalink)
abit off center
 
cgarr's Avatar
 
Join Date: Feb 2002
Location: At the Airport Kentwood, MI
Posts: 6,557
Garage
Send a message via Yahoo to cgarr
Enrique,,, I had the same problem you have, I have weber 44's, I did a test on one carb, I have always had fuel seeping down the side of the carbs. When hot it always felt as if it was flooding when trying to start. I took off one carb and lapped in the needle and seat (I am ordering new ones) and it stopped the seeping fuel and it already starts much better. I have outlets tapped into my manifold for vacuum lines to help sink the carbs and when I pulled the rubber plugs off there was always raw fuel.

Craig
Old 09-16-2002, 05:01 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #16 (permalink)
Registered User
 
Join Date: Nov 2001
Location: Port Washington, New York
Posts: 76
The car did crank but with not enough force to turn the starter over. Whenever the car was cold it would turn more freely and start right away. When hot it cranked slowly. Carbs were fine checked those also. I also checked the fuel pump. With this relay I guess it is sending more power to the starter. The relay is positioned as far as I could get it away from the heat of the enginewhich I believe was causing the problems.
Old 09-16-2002, 05:08 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #17 (permalink)
Registered User
 
Duke's Avatar
 
Join Date: Nov 2000
Location: Redding,CA USA
Posts: 282
Porsche Crest

Alex: Glad to hear the relay solved your problem. It has worked for me for 23 years.
Old 09-16-2002, 07:06 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #18 (permalink)
Registered User
 
Join Date: Nov 2001
Location: Port Washington, New York
Posts: 76
Enrique:
It might be wrong but I read and was told that sometimes the heat from the engine might cause the starter to not get the proper amount of juice. This is because it has an effect on the
internals and the solenoid. By using the relay it allows for better
distribution of the juice or more direct hence the starter working the way it should. So far this relay has worked drove the car 150 miles turned her off and she started right up. If I tried this before I would need to wait till the car cooled down. I thought it was vapor lock at first also.
Old 09-16-2002, 08:56 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #19 (permalink)
Registered User
 
Join Date: Nov 2001
Location: Port Washington, New York
Posts: 76
Article in the Nov 2002 excellence pg 131 regarding relay kits for 356. I am sure this information could also pertain to our 912's
Old 09-24-2002, 09:11 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #20 (permalink)
Old 09-24-2002, 09:11 PM
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 11:38 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - 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.