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 )

> 1974 1.8L engine fast idle then stalls, Fuel injection issues
tshih914
post Feb 19 2023, 11:45 PM
Post #1


Member
**

Group: Members
Posts: 79
Joined: 17-July 05
From: central NJ
Member No.: 4,426



My 1.8L 914-4 with stock Bosch L?-Jetronic FI after being stored several years started to develop a hard to start problem. When finally started would stall when I give the gas pedal any input to raise the revs. I suspect there was some kind of intake air leak and while fiddling around had a backfire which blew the AF meter which I had Pelicanparts repaired. After replacing the fuel lines with the stainless ones from Tangerine Racing and flushing out the fuel system with Techron the engine started to run normally for a short time. Now the engine can be started and fast idles at 3000 rpm but again any input to rev up the engine results in stalling. The idle adjustment screw at the base of the throttle housing is fully closed. Any suggestions on how to fix?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
 
Reply to this topicStart new topic
Replies
wonkipop
post Feb 25 2023, 08:56 PM
Post #2


Advanced Member
****

Group: Members
Posts: 3,938
Joined: 6-May 20
From: north antarctica
Member No.: 24,231
Region Association: NineFourteenerVille



i just watched your video @Van B .
your decel is rigged right or at least same as diagrams and how it is normally done.

i'm looking at his and it looks the same.
from what i can see of it.
but it would be nice to see a close in photo just to be sure.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
tshih914
post Feb 26 2023, 07:57 AM
Post #3


Member
**

Group: Members
Posts: 79
Joined: 17-July 05
From: central NJ
Member No.: 4,426



I have every vacuum hose hooked up the same as the diagram that wonkipop posted. My photo show the 2 plugged ports to the side of decel valve and the t leading to the boot (I will be ordering a new one from AutoAtlanta as the one currently in the car is an old used one from eBay that I got when the AFM explosion triggered the search for cause of stalling after starting). I have also removed the hose connecting the two ports
as instructed for this test. The idle adjustment screw at the base of the throttle valve was adjusted 2 turns from fully closed. I did mention that while the engine was idling at 2500-3000rpm I did try to cover the air filter box's snorkel with my hand and the engine did not stall indicating that there must be a vacuum leak. When I get the new boot installed I will hunt for the source of air leak with the Smoke in a can used to test fire alarm smoke detectors.
I just reattached the hose and started the engine after many cranks to get it idling at 2800 rpm before repeating test3 and 5 (wonkipop's earlier posts). When hose to side port of decel valve was pinched closed RPM dropped by 400-500 rpm. When AAV hose was pinched rpm dropped by 800-1000rpm. The smoke in a can wasn't useful in finding the source of air leaking pass the AFM pathway.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Posts in this topic
tshih914   1974 1.8L engine fast idle then stalls   Feb 19 2023, 11:45 PM
Van B   Check to make sure your AFM is plugged in first.   Feb 20 2023, 01:28 AM
wonkipop   Check to make sure your AFM is plugged in first. ...   Feb 20 2023, 01:38 AM
Geezer914   1+ on the AFM not being connected. Check for vacu...   Feb 20 2023, 06:48 AM
tshih914   1+ on the AFM not being connected. Check for vac...   Feb 20 2023, 11:02 AM
wonkipop   1+ on the AFM not being connected. Check for va...   Feb 20 2023, 02:33 PM
Van B   [quote name='Geezer914' post='3059382' date='Feb ...   Feb 20 2023, 02:51 PM
wonkipop   1+ on the AFM not being connected. Check for va...   Feb 20 2023, 05:11 PM
dr914@autoatlanta.com   for the hell of it check the throttle body boot fo...   Feb 20 2023, 11:17 AM
r_towle   for the hell of it check the throttle body boot f...   Feb 28 2023, 08:57 PM
tshih914   for the hell of it check the throttle body boot ...   Feb 28 2023, 09:13 PM
rhodyguy   Would a vacuum leak down stream of AFM result in a...   Feb 20 2023, 01:22 PM
wonkipop   Would a vacuum leak down stream of AFM result in ...   Feb 20 2023, 02:17 PM
Van B   @wonkipop What alerts me is the no change in idle...   Feb 20 2023, 02:57 PM
wonkipop   [b]@[url=http://www.914world.com/bbs2/index.php?s...   Feb 20 2023, 03:20 PM
Van B   Yeah, I know, but I don’t care about California ...   Feb 20 2023, 03:33 PM
wonkipop   Yeah, I know, but I don’t care about California...   Feb 20 2023, 03:49 PM
jim_hoyland   All the above; L-Jet requires that there are no va...   Feb 20 2023, 03:52 PM
wonkipop   @Van B thinking about his problem there are two ...   Feb 20 2023, 04:13 PM
tshih914   @[url=http://www.914world.com/bbs2/index.php?show...   Feb 22 2023, 07:36 PM
Van B   Boy does that all sound familiar. I’d still lik...   Feb 20 2023, 04:24 PM
wonkipop   Boy does that all sound familiar. I’d still li...   Feb 20 2023, 04:39 PM
porschetub   Boy does that all sound familiar. I’d still l...   Feb 20 2023, 08:34 PM
wonkipop   [quote name='Van B' post='3059531' date='Feb 20 ...   Feb 21 2023, 02:57 AM
Van B   @wonkipop . What he described is exactly what hap...   Feb 20 2023, 06:45 PM
wonkipop   [b]@[url=http://www.914world.com/bbs2/index.php?s...   Feb 20 2023, 06:52 PM
wonkipop   @Van B which is to say as i suspected that high ...   Feb 20 2023, 06:56 PM
Geezer914   Go to Jeff Bowlsby's web site and get the Ljet...   Feb 20 2023, 07:13 PM
JeffBowlsby   You might also check the quality of the contacts i...   Feb 20 2023, 11:58 PM
wonkipop   You might also check the quality of the contacts ...   Feb 21 2023, 03:05 AM
Van B   Whatever you have back there by the batter near wh...   Feb 22 2023, 08:19 PM
tshih914   Whatever you have back there by the batter near w...   Feb 23 2023, 04:46 AM
Van B   Ok. Glad that thing wasn't some decel valve ri...   Feb 23 2023, 05:54 AM
Geezer914   Got rid of all that shit, the decel valve and the ...   Feb 23 2023, 08:45 AM
rjames   Got rid of all that shit, the decel valve and the...   Feb 23 2023, 11:50 AM
wonkipop   Got rid of all that shit, the decel valve and th...   Feb 23 2023, 11:54 AM
rhodyguy   Curious. What kind of condition are the oil fill t...   Feb 23 2023, 11:58 AM
wonkipop   ok @tshih914 [b]@[url=http://www.914world.com/...   Feb 23 2023, 12:00 PM
tshih914   ok [b]@[url=http://www.914world.com/bbs2/index.p...   Feb 23 2023, 07:58 PM
tshih914   ok [b]@[url=http://www.914world.com/bbs2/index....   Feb 23 2023, 08:16 PM
Van B   @wonkipop if the decel valve is full flow, it cou...   Feb 23 2023, 02:50 PM
wonkipop   [b]@[url=http://www.914world.com/bbs2/index.php?s...   Feb 23 2023, 03:58 PM
wonkipop   ok @Van B and [b]@[url=http://www.914world.com/...   Feb 23 2023, 06:50 PM
wonkipop   wow @tshih914 that was a quick test and reply. ...   Feb 23 2023, 09:01 PM
Van B   Definitely sounds like the AFM is doing stuff… b...   Feb 23 2023, 09:41 PM
tshih914   Definitely sounds like the AFM is doing stuff… ...   Feb 25 2023, 04:35 PM
tshih914   Definitely sounds like the AFM is doing stuff…...   Feb 25 2023, 04:36 PM
wonkipop   @tshih914 we are getting somewhere. this time it...   Feb 25 2023, 05:56 PM
Van B   @tshih914 The decel valve is on the other side. ...   Feb 25 2023, 06:45 PM
Van B   Yeah this is all wrong. You’ve got the wrong par...   Feb 25 2023, 06:49 PM
wonkipop   @Van B . i think he has got it right. he seems to...   Feb 25 2023, 07:22 PM
wonkipop   i think he has pulled this hose out and capped the...   Feb 25 2023, 07:26 PM
wonkipop   where i am going with my thinking @Van B is 1. ...   Feb 25 2023, 07:44 PM
Van B   Looks to me then like the decel valve is connected...   Feb 25 2023, 07:54 PM
wonkipop   @Van B . yes i noticed that kink in the small vac...   Feb 25 2023, 08:29 PM
wonkipop   i just watched your video @Van B . your decel is ...   Feb 25 2023, 08:56 PM
tshih914   I have every vacuum hose hooked up the same as the...   Feb 26 2023, 07:57 AM
wonkipop   I have every vacuum hose hooked up the same as th...   Feb 26 2023, 12:53 PM
Van B   I have every vacuum hose hooked up the same as th...   Feb 26 2023, 12:58 PM
wonkipop   I have every vacuum hose hooked up the same as t...   Feb 26 2023, 01:03 PM
r_towle   When I am hunting for a failure in the vacuum syst...   Feb 25 2023, 09:03 PM
Van B   74 L-Jetronic needs the distributor vacuum for any...   Feb 25 2023, 09:19 PM
wonkipop   74 L-Jetronic needs the distributor vacuum for an...   Feb 26 2023, 12:37 AM
nihil44   I've come in late here and haven't read al...   Feb 26 2023, 01:43 AM
wonkipop   I've come in late here and haven't read a...   Feb 26 2023, 01:54 AM
Geezer914   Last resort is to do a smoke test. Search on you ...   Feb 26 2023, 06:12 AM
Geezer914   I had a hell of a time finding a vacuum leak. It ...   Feb 26 2023, 09:39 AM
Van B   Ok so, I checked my AFM to see what I settled on f...   Feb 26 2023, 12:50 PM
wonkipop   ps in addition to blocking off snorkel the only ot...   Feb 26 2023, 12:58 PM
Van B   ps in addition to blocking off snorkel the only o...   Feb 26 2023, 01:00 PM
wonkipop   two suggestions by other members re injector seals...   Feb 26 2023, 01:58 PM
tshih914   two suggestions by other members re injector seal...   Feb 26 2023, 03:23 PM
wonkipop   two suggestions by other members re injector sea...   Feb 26 2023, 03:50 PM
wonkipop   direct link to AA vac hose kit. http://www.autoat...   Feb 26 2023, 03:58 PM
tshih914   direct link to AA vac hose kit. http://www.autoa...   Feb 26 2023, 05:18 PM
wonkipop   [quote name='wonkipop' post='3061145' date='Feb 2...   Feb 26 2023, 06:36 PM
nihil44   Here is the gasket on the AFM connector which wasn...   Feb 26 2023, 05:47 PM
nihil44   I have been pursuing running issues and vac leaks ...   Feb 26 2023, 06:28 PM
wonkipop   love your work @nihil44   Feb 26 2023, 06:39 PM
tshih914   love your work @[url=http://www.914world.com/bbs...   Feb 27 2023, 09:45 PM
wonkipop   love your work [b]@[url=http://www.914world.com...   Feb 28 2023, 02:26 AM
Van B   See the little hole near the front right off the A...   Feb 28 2023, 06:51 AM
tshih914   See the little hole near the front right off the ...   Feb 28 2023, 07:44 PM
wonkipop   See the little hole near the front right off the...   Feb 28 2023, 07:51 PM
tshih914   [quote name='tshih914' post='3061665' date='Feb 2...   Feb 28 2023, 08:47 PM
tshih914   [quote name='tshih914' post='3061665' date='Feb ...   Feb 28 2023, 09:10 PM
wonkipop   [quote name='tshih914' post='3061665' date='Feb ...   Feb 28 2023, 10:40 PM
Van B   Have you adjusted the decel valve or tested it to ...   Feb 28 2023, 08:07 PM
Van B   @wonkipop quit being so scared to that mean AFM. ...   Feb 28 2023, 08:09 PM
wonkipop   [b]@[url=http://www.914world.com/bbs2/index.php?s...   Feb 28 2023, 10:23 PM
Van B   Thats too low IMO. I posted the link to my thread ...   Feb 28 2023, 08:53 PM
Van B   Diaphragm is rubber. It gets hard and less flexibl...   Feb 28 2023, 09:58 PM
wonkipop   @tshih914 i knew i had this filed away but could...   Mar 2 2023, 09:55 PM
wonkipop   here is the rest of it. its an idiots guide. which...   Mar 2 2023, 10:15 PM
tshih914   here is the rest of it. its an idiots guide. whic...   Mar 3 2023, 10:11 PM
tshih914   [quote name='wonkipop' post='3062180' date='Mar 2...   Mar 3 2023, 10:12 PM
tshih914   [quote name='wonkipop' post='3062180' date='Mar ...   Mar 3 2023, 10:13 PM
tshih914   [quote name='tshih914' post='3062427' date='Mar 3...   Mar 3 2023, 10:18 PM
Van B   When you pinch the AAV hose, and the rpm drops to ...   Mar 3 2023, 10:42 PM
Van B   One other thing, I’m not understanding how you j...   Mar 3 2023, 10:43 PM
3 Pages V  1 2 3 >


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: 10th December 2023 - 05:37 AM