|
|
|
|
| Author |
|
|
Recreational User
|
Engine Died: Early 911
This is in regards to my '71 T...
As I went to start the car after not driving it for a week, the engine struggled more than usual and gave-out an unusually loud backfire. Nevertheless, the car started and I took it out for a spirited cruise. It was driving great, as usual. About 11 miles into it, I came upon a stop light. As I pushed in the clutch and the RPMs dropped, the engine backfired again - louder than usual - and the engine died. When I attempted to restart it, the engine turned but would not fire... as if it was out of gas (but isn't.) I've got power and I can hear the familiar buzz from the engine compartment. The cap and rotor appear to be in good condition as well (they were replaced, along with the plugs, within the past year.) Where else should I look? I've read about SCs having similar issues when their pop-off value wasn't seated properly. Of course, the early air cleaner is different... but maybe there's something there to look at? 
__________________
'88 924S - Stone Grey Metallic |
||
08-25-2010, 08:45 AM
|
|
|
Registered
|
Does the car still have points?
__________________
72 911 Although it is done at the moment, it will never be finished. |
||
|
08-25-2010, 08:48 AM
|
|
|
Registered
|
Quote:
__________________
SWB 911S 1967 307653S in my fathers garage now LWB 911T 1971 9111120264 Back in my garage after a lenghty stay in Oregon |
||
|
08-25-2010, 09:55 AM
|
|
|
Registered
Join Date: Mar 2009
Location: a quiet beach town in Florida
Posts: 430
|
Check to see if the fuel pump is pumping. Doesn't usually cause backfires but a burp in the fuel pressure could cause it to backfire. Try tapping the side of the fuel pump with the end of a wrench. Might have a clog or dissconect the hose that feeds the injection and see if it's pumping.
__________________
Bill B. 63 Little B Coupe 67 SWB 3.63 Hotrod 08 Cayenne S 65 F100 |
||
|
08-25-2010, 10:31 AM
|
|
|
muck-raker
Join Date: Jan 2009
Location: Coastal PNW
Posts: 3,059
|
I'm with tobluforu and dhrcr911s on this one...if it's still got points, it'd be the first thing I'd check.
__________________
STONE '88 Cabriolet, using EP Slick 20w50 partial synthetic Snake Oil...just as Rommel intended.  Deny Everything; Admit Nothing; and Always Make Counter-accusations 
|
||
|
08-25-2010, 11:20 AM
|
|
|
Recreational User
|
Quote:
__________________
'88 924S - Stone Grey Metallic |
||
|
08-25-2010, 12:05 PM
|
|
|
|
Registered
Join Date: Aug 2009
Location: Sweden
Posts: 58
|
Pretty much the same for me and it was the CDI box.
__________________
911 1966 untuched exept 2,2E MFI -70 engine |
||
|
08-25-2010, 12:12 PM
|
|
|
Bandwidth AbUser
Join Date: Nov 2001
Location: SoCal
Posts: 29,522
|
I think it's most likely the Pertronix (if that's what you have in it now), the coil, or the CDI box. That loud backfire sounds like un-ignited fuel finally detonating due to the engine's heat. Of course I could be FOS. Good luck with the troubleshooting, Davie.
__________________
Jim R. |
||
|
08-25-2010, 12:15 PM
|
|
|
JOT MON ABBR OTH
Join Date: Feb 2001
Location: USA
Posts: 3,238
|
Davie,
You sound as if the backfiring has been going on for some time? This is not a normal occurance. Can you think of when the backfiring started? Was there another event in the same time frame (new plugs, new CDI, timing advanced/retarded)? The guys above have some good hints. Here is hoping you are home with the baby safe and sound!!
__________________
David '83 SC Targa (sold  ) MANLY babyblue honda '00 F250 7.3L (MINE!)'15 F250 Gas (Her Baby) '95 993 (sold )I don't take scalps. I'm civilized like white man now, I shoot man in back. |
||
|
08-25-2010, 12:19 PM
|
|
|
Recreational User
|
Quote:
I've owned the car for about a year and half now. At the time I bought it, it backfired quite a bit. After I replaced the plugs, cap, rotor, air and fuel filters, and got the carbs dialed in, things improved a lot. Still, it continues to backfire every now and again, especially when it's cold. To be honest, I did think it was normal for an older car. I guess that was naive of me. I'll be checking the coil and CDI, and let you all know. Thanks for your help.
__________________
'88 924S - Stone Grey Metallic |
||
|
08-25-2010, 01:33 PM
|
|
|
N-Gruppe doesn't exist
Join Date: Jun 2005
Location: *%@#ing GPS, where am I? Oh wait I see the Space Needle.
Posts: 4,394
|
exact same issue i have a month or so ago...turned out to be the small switched red wire to the MSD box. make sure your connections are good at the ignition switch and at the cdi box in back.
__________________
Ted '70 911T 3.0L "SKIPPY" R-Gruppe #477 '73 914 2.0L SOLD bye bye "lil SMOKEY" "Silence is Golden, but duct tape is SILVER.” other flat fours:'77 VWBus 2.0L & 2002 ImprezaTS 2.5L |
||
|
08-25-2010, 03:02 PM
|
|
|
UNDER CONSTRUCTION!
Join Date: Jul 2008
Location: ALASKA
Posts: 1,508
|
have you checked to see if your distributer is tightened down and hasn't moved? if it has it will give you the labored start you speak of and back fire as well. all good suggestions above to check out.
ed
__________________
Sometimes the first thing that comes to mind should be the last thing that you do!
|
||
|
08-25-2010, 03:58 PM
|
|
|
Registered
|
Sorry but I can't help it: Responses that start out with: "That's exactly what mine did, and it was....blah blah" are entertaining at best but might set you on a ghoose hunt.
You need to DIAGNOSE the issue systematically. An engine is either missing spark or fuel or air in the right amount and at the right time when it doesn't start. Once you have determined which is missing start looking for the root cause: To check for missing fuel you could simply introduce some by spraying starter fluid into the intake and see if it starts when cranking. If yes you can assume the no-start was due to a lack of fuel or bad mixture. If fuel is dripping out of the tail pipe that is a clear sign there was too much and the engine is flooded. To check for spark, get an old spark plug, disconnect one spark plug wire from the engine side and connect it to the single old plug. Ground the plug to something metalic on the engine while an assistant cranks. See if you get sparks Ingo
__________________
1974 Targa 3.6, 2001 C4 (sold), 2019 GT3RS, 2000 ML430 I repair/rebuild Bosch CDI Boxes and Porsche Motronic DMEs Porsche "Hammer" or Porsche PST2, PIWIS III - I can help!! How about a NoBadDays DualChip for 964 or '95 993 |
||
|
08-25-2010, 05:28 PM
|
|
|
Recreational User
|
And the winner is!?!?!?!
It was the CDI box. Thanks for your help. 
__________________
'88 924S - Stone Grey Metallic |
||
|
09-03-2010, 02:09 PM
|
|
|
Registered
Join Date: Jan 2002
Location: Long Beach CA, the sewer by the sea.
Posts: 37,803
|
Quote:
I can't believe Ingo, of all people, didn't cite the CDI directly as a possible cause. |
||
|
09-03-2010, 02:29 PM
|
|
|
N-Gruppe doesn't exist
Join Date: Jun 2005
Location: *%@#ing GPS, where am I? Oh wait I see the Space Needle.
Posts: 4,394
|
Quote:
__________________
Ted '70 911T 3.0L "SKIPPY" R-Gruppe #477 '73 914 2.0L SOLD bye bye "lil SMOKEY" "Silence is Golden, but duct tape is SILVER.” other flat fours:'77 VWBus 2.0L & 2002 ImprezaTS 2.5L |
||
|
09-03-2010, 02:37 PM
|
|
|
Recreational User
|
Quote:
__________________
'88 924S - Stone Grey Metallic |
||
|
09-03-2010, 08:47 PM
|
|
Linen (Sold)
The T (Sold)
The 2-4 #2
Zed (Sold)
The 2-4 #1 (Totaled)
Tobluforu
1967 Porsche 911S 2.0 S
1971 911T
1974 Porsche 911 Targa 3.6
