1973 1.7L bucking skipping backfiring thru engine, 1973 1.7L bucking skipping backfiring thru engine |
|
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. |
|
1973 1.7L bucking skipping backfiring thru engine, 1973 1.7L bucking skipping backfiring thru engine |
johnoscar |
Jul 6 2022, 05:15 PM
Post
#1
|
Newbie Group: Members Posts: 11 Joined: 23-May 22 From: Westfield, Massachusetts Member No.: 26,569 Region Association: North East States |
Hi all...my first post. ***** (07-10-2022)Updated at bottom
Original owner 1973 1.7 914 now having engine issues. Engine rebuilt top end at Tangerine Racing 2008-2009. The only real new added different part was pop-up pistons 91mm. Slight bucking since then, but never before. Now gotten significantly worse with skipping and backfiring back thru engine. Car will do 80mph on the highway. Probably still skipping, but too fast to feel. Car is bucking. Most felt when feathering throttle under even small load, Also skipping and backfiring while static and under load So......what have I done............ Replaced throttle switch with new from AA Removed electric connection to throttle switch and drove without change Checked Head temp sensor ohms cold 3600-3700 hot 80-90 Replaced Head Temperature Sensor new from AA without change Trigger points cleaned/lubed replaced without change Swapped trigger points with used without change Replaced distributor cap, points, rotor and reset dwell to 48.5 degrees all new from AA Replaced distributor with 123 ignition without change Timing adjusted to 27 Degrees BTDC Replaced all air hoses new from AA without change Replaced ignition wires new from AA without change Checked all ground wires and connections Ignition harness is original but very flexible without brittle wires Replaced push rod tube seals new from AA Reset valve adjustment to .006 in Swapped ECU with used and drove without change. Swapped MPS with used and drove without change Rebuilt MPS with new beryllium copper diaphragm and drove without change Swapped coil with used and drove without change Fuel pump and hose visually checked with nothing compromised. Stainless steel fuel lines installed with rebuild. Disconnected tach from coil and ran without change Disconnected alternator from relay board and ran without change Fuel filter changed within last 2000 miles New Bosch Ignition condenser wire too short on replacement part (not replaced) All above is done and results are totally without change in the issues I'd be interested in anyone's thoughts. I feel the list is extensive and I have had help with this project from a 50 year experience 914 guy. What have I not done? Where else could the issues be generated? Please feel free to comment on anything within the post!!! ***** Clarification within post Cylinder compression 1=158 2=155 3=165 4=154 (all cold) Don't know what the compression ratio is. Fuel injectors cleaned and measured by Dr Injector and are not the problem according to him. The backfiring is thru the intake. Intermittent. On increase in rpm's even in static position |
ChrisFoley |
Jul 10 2022, 08:57 AM
Post
#2
|
I am Tangerine Racing Group: Members Posts: 7,958 Joined: 29-January 03 From: Bolton, CT Member No.: 209 Region Association: None |
ctc911ctc has a 2L engine. The 1.7L plenum is different, and not prone to cracking as the 2L unit is.
|
Lo-Fi Version | Time is now: 22nd September 2024 - 12:38 PM |
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 ... |