911E Erratic Engine
Thread Starter
Instructor
Joined: Sep 2019
Posts: 242
Likes: 89
From: Greensboro, NC
911E Erratic Engine
I have a 1972 911E Targa in mostly original condition. The engine has developed a problem which exhibits itself by cutting out, stumbling, coughing, spitting, and almost dying when throttle is depressed rapidly, with engine at normal operating temperatures. I have done the following, but none has helped:
- Replaced fuel filters (2) and drained fuel tank (it's clean)
- Replaced fuel pump and lines
- Replaced all electrical parts (coil, dist cap, rotor, points, plug wires, connectors and plugs)
- The MFI pump was rebuilt and calibrated a few years ago; have not had any issues
- The ignition timing is spot on
I have gone through most of the issues addressed in Rennlist in this forum but cannot find any applicable solution. Would appreciate any information that can shed some light on this issue.
18 W. Mountain Street, Kernersville, NC 27284
- Replaced fuel filters (2) and drained fuel tank (it's clean)
- Replaced fuel pump and lines
- Replaced all electrical parts (coil, dist cap, rotor, points, plug wires, connectors and plugs)
- The MFI pump was rebuilt and calibrated a few years ago; have not had any issues
- The ignition timing is spot on
I have gone through most of the issues addressed in Rennlist in this forum but cannot find any applicable solution. Would appreciate any information that can shed some light on this issue.
18 W. Mountain Street, Kernersville, NC 27284
Last edited by Bahman; Jan 14, 2021 at 12:10 PM.
Three Wheelin'
Joined: Aug 2009
Posts: 1,334
Likes: 340
From: Denver
There could be dirt or rust in the hard lines running through the tunnel, which are very difficult to plumb or replace. Though you have gone through all the usual suspects, to quote Sherlock Holmes, "Eliminate all other factors, and the one which remains must be the truth."
Thread Starter
Instructor
Joined: Sep 2019
Posts: 242
Likes: 89
From: Greensboro, NC
raspritz
I have replaced all rubber/flexible fuel lines, but not the solid ones in the floor. Good suggestion. Will check and update the post.
Spyerx
Fuel pressure and injectors are good. There is not grounding of the fuel pump, except for the sealed harness (2-wires) that plugs into it for power. The connection is good.
Thank yo both for suggestions.
I have replaced all rubber/flexible fuel lines, but not the solid ones in the floor. Good suggestion. Will check and update the post.
Spyerx
Fuel pressure and injectors are good. There is not grounding of the fuel pump, except for the sealed harness (2-wires) that plugs into it for power. The connection is good.
Thank yo both for suggestions.
Thread Starter
Instructor
Joined: Sep 2019
Posts: 242
Likes: 89
From: Greensboro, NC
911E Erratic Engine Running
“Thank you” to all who helped by providing advice & suggestions.
I narrowed the problem to a faulty ignition combo of points, coil and CDI box. CDI was the culprit, but I replaced the points and coil again.
the engine now runs flawlessly, as it used to.
Thanks again. 😊
I narrowed the problem to a faulty ignition combo of points, coil and CDI box. CDI was the culprit, but I replaced the points and coil again.
the engine now runs flawlessly, as it used to.
Thanks again. 😊
Trending Topics
Burning Brakes
Joined: Mar 2004
Posts: 767
Likes: 16
From: Texas
Glad you found it !!
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
Stunning Porsche 356A Super GT Speedster Auction Fails to Meet Reserve
Verdad Gallardo
Every Era of 911 Owner Explained in One Sentence
Verdad Gallardo
Thinking of Buying a Porsche? Do These 10 Things First
Joe Kucinski
Pixar Pals Turned Into 1-of-1 Porsches!
Michael S. Palmer
Theon Goes Full Carbon Fiber With Stunning New Build
Verdad Gallardo
Genius Porsche-Themed Gifts That'll Make Any Dad or Grad Smile
Joe Kucinski
10 Used Porsches Are Selling for Way Too Cheap
Joe Kucinski
Tuner Is Converting Porsche 911s Into Shooting Brakes
Verdad Gallardo
This Coachbuilt Creation Is A Modern Take on the Legendary Porsche 917
Verdad Gallardo
Thread Starter
Instructor
Joined: Sep 2019
Posts: 242
Likes: 89
From: Greensboro, NC
911E Erratic Engine
Super90,
25 years of my car’s 48 years were spent in Dallas area, and I came to recognize and appreciate Ed Mayo’s mastery of 911 expertise. It was he who guided me remotely (I now live in NC) to look at the ignition area, especially the CDI.
Comforting to know maestros like Ed exist, and generously share their knowledge.
Cheers,
Bahman
25 years of my car’s 48 years were spent in Dallas area, and I came to recognize and appreciate Ed Mayo’s mastery of 911 expertise. It was he who guided me remotely (I now live in NC) to look at the ignition area, especially the CDI.
Comforting to know maestros like Ed exist, and generously share their knowledge.
Cheers,
Bahman
