1974 1.8L engine fast idle then stalls, Fuel injection issues |
|
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. |
|
1974 1.8L engine fast idle then stalls, Fuel injection issues |
tshih914 |
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?
|
Geezer914 |
Feb 20 2023, 06:48 AM
Post
#2
|
Geezer914 Group: Members Posts: 1,754 Joined: 18-March 09 From: Salem, NJ Member No.: 10,179 Region Association: North East States |
1+ on the AFM not being connected. Check for vacuum leaked. The intake boot may have a crack.
|
tshih914 |
Feb 20 2023, 11:02 AM
Post
#3
|
Member Group: Members Posts: 79 Joined: 17-July 05 From: central NJ Member No.: 4,426 |
1+ on the AFM not being connected. Check for vacuum leaked. The intake boot may have a crack. I assure all that the AFM is plugged in and my fuel pressure gauge reads 28psi. One other piece of info is when the engine is "idling" at 3000 rpm I placed my hand to cover the nozzle of the air box housing feeling for vacuum from the air passing through the air filter into the AFM and felt little air flow! This means that there is an air leak (like when you adjust the idle by opening the screw at the base of the throttle to bypass the AFM). I had replaced the intake boot when the initial problems showed up. When searching for vacuum leaks there are lots of hoses and connections and even the O-ring gasket under the oil filler cap to check. Also is there an auxiliary air flow sensor in the 1974 1.8L FI system? |
Van B |
Feb 20 2023, 02:51 PM
Post
#4
|
Senior Member Group: Members Posts: 1,618 Joined: 20-October 21 From: WR, GA Member No.: 26,011 Region Association: None |
1+ on the AFM not being connected. Check for vacuum leaked. The intake boot may have a crack. I assure all that the AFM is plugged in and my fuel pressure gauge reads 28psi. One other piece of info is when the engine is "idling" at 3000 rpm I placed my hand to cover the nozzle of the air box housing feeling for vacuum from the air passing through the air filter into the AFM and felt little air flow! This means that there is an air leak (like when you adjust the idle by opening the screw at the base of the throttle to bypass the AFM). I had replaced the intake boot when the initial problems showed up. When searching for vacuum leaks there are lots of hoses and connections and even the O-ring gasket under the oil filler cap to check. Also is there an auxiliary air flow sensor in the 1974 1.8L FI system? You covered the snorkel completely and the car kept running?? Here check this out to help you at least get a baseline on your connections: https://youtu.be/ToxifurNXXg https://www.youtube.com/watch?v=ToxifurNXXg |
Lo-Fi Version | Time is now: 11th November 2024 - 04:01 AM |
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 ... |