Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > Porsche 911 Technical Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
muck-raker
 
kidrock's Avatar
 
Join Date: Jan 2009
Location: Coastal PNW
Posts: 3,059
3.2 is dead at work....need help.

Scenario:

3 days ago, drove to work during the recent cold snap (0 degrees fahrenheit). Drove perfect as usual, except while idling, idle would drop from 900 rpm to around 600-700 rpm. Figured it was due to the extreme cold weather, in conjunction with a small vacuum leak I've been hunting down.

After work, car would not start. Temperatures were still in the single digits. Battery is new and strong, with no slow turning issues (12.7 volts). Replaced DME relay to no avail. ICV is vibrating with ignition on. Injected "quick start" (ether) into both the ICV and AFM sleeve....not even a cough or sputter. Spark issue, I assume. I go home and bring back the Fluke meter.

Pull spark plug wire at #4 and put in good plug, grounding it to the motor. Yes, I have decent spark.

Proceed to test coil, although I'm no expert at this. With the meter connected to Terminal 15 (+) and the black to ground, the coil reads 12+ volts. However, voltage across both terminals with ignition on reads .001 volts. What does this mean?

Move on to check TDC & RPM sensors at the DME harness. Pins #8 & #27 for the RPM sensor read 916 ohms, whether ignition is on or off. Pins #25 & #26 for the TDC sensor read exactly the same as the RPM sensor....well within the 600-1600 ohm range.

I have not tested the CHT sensor....but it is only 2 years old, as is the fuel pump, O2 sensor and ICV valve (all replaced during the last "no-start" episode).

Any and all suggestions are appreciated....I just want to get my baby home again.

__________________
STONE
'88 Cabriolet, using EP Slick 20w50 partial synthetic Snake Oil...just as Rommel intended.

Deny Everything; Admit Nothing; and Always Make Counter-accusations

Last edited by kidrock; 02-06-2011 at 09:31 AM..
Old 02-06-2011, 09:29 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered
 
Join Date: May 2002
Location: St Louis
Posts: 4,211
These two don't add up
  1. Quote:
    Originally Posted by kidrock View Post
    Injected "quick start" (ether) into both the ICV and AFM sleeve....not even a cough or sputter.
  2. Quote:
    Pull spark plug wire at #4 and put in good plug, grounding it to the motor. Yes, I have decent spark.
Quote:
Proceed to test coil, although I'm no expert at this. With the meter connected to Terminal 15 (+) and the black to ground, the coil reads 12+ volts. However, voltage across both terminals with ignition on reads .001 volts. What does this mean?
I have been told by the experts on this board that the firmware in the DME does not charge the coil until rotation is detected so this would be normal. Under this condition both terminals should be at 12 volts referenced to ground.
__________________
Rick
88 Cab
Old 02-06-2011, 09:45 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered
 
Join Date: Oct 2004
Posts: 15,612
what is the voltage at the injector connection? I'm wondering if there is enough voltage to open the injectors.
Old 02-06-2011, 10:40 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered
 
Join Date: Oct 2001
Location: San Carlos, CA US
Posts: 5,523
Do you have fuel?
__________________
Porsche 2005 GT3, 2006 997S with bore-scoring
Exotic: Ferrari F360F1 TDF, Ferrari 328 GTS
Disposable Car: BMW 530xiT, 2008 Mini Cooper S
Two-wheel art: Ducati 907IE, Ducati 851
Old 02-06-2011, 10:45 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
RETIRED
 
Joe Bob's Avatar
 
Join Date: Jul 1999
Location: BOULDER Colorado
Posts: 39,412
Garage
With a good fat spark, my first guess as above is fuel....
__________________
1983/3.6, backdate to long hood
2012 ML350 3.0 Turbo Diesel
Old 02-06-2011, 10:52 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Grappler
 
Rodsrsr's Avatar
 
Join Date: Jul 2006
Location: Nor Cal
Posts: 5,858
Garage
I had cold start issues with my 3.2 and it turned out to be head temp switch.
__________________
Grappler
Know Gi / No Gi

1976 RSR Backdate (Turbo 3.2)
Old 02-06-2011, 11:11 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Member 911 Anonymous
 
DRACO A5OG's Avatar
 
Join Date: Sep 2007
Location: Rancho Palos Verdes
Posts: 14,329
Garage
Send a message via Skype™ to DRACO A5OG
Hey Kidrock,

Good Grief, So you baby cranks but does not engage?

Do you smell unburnt fuel?

Jim
__________________
'85 Carrera Targa
Factory Marble Grey/Black * Turbo Tail * 930 Steering Wheel* Sport Seats * 17" Fuchs (r) * 3.4 * 964 Cams * 915 * LSD * Factory SS * Turbo Tie Rods * Bilsteins * Euro Pre-Muff * SW Chip on 4K DME * NGK * Sienes GSK * Targa Body Brace
PCA/POC
Old 02-06-2011, 11:18 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Burn the fire.
 
Brando's Avatar
 
Join Date: May 2003
Location: Land of Liberty, NH
Posts: 6,501
Garage
+1 for fuel here. Are you getting pressure at the rail? Pulled an injector and checked for spray?
__________________
[x] Working | [_] Broken: 2017 Victory Octane
[x] Working | [_] Broken: 2005 Ram 1500 SLT w/5.7L Hemi

"Drive it like you stole it."
Old 02-06-2011, 11:34 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
RETIRED
 
Joe Bob's Avatar
 
Join Date: Jul 1999
Location: BOULDER Colorado
Posts: 39,412
Garage
Tow her home, if you don't have AAA, you should. Heated garage and fire it up. "typically" the shot of ether rules out fuel....but not always.
__________________
1983/3.6, backdate to long hood
2012 ML350 3.0 Turbo Diesel
Old 02-06-2011, 11:44 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
muck-raker
 
kidrock's Avatar
 
Join Date: Jan 2009
Location: Coastal PNW
Posts: 3,059
Quote:
Originally Posted by Joe Bob View Post
With a good fat spark, my first guess as above is fuel....
Maybe I should back up a bit. I have a spark, but it's not as good as I would like to see it. I figure as long as I have some spark, that would be enough to fire up.

I haven't checked any injectors yet. I do smell unburnt fuel. I even smell ether through the pipe during testing.

What's the easiest procedure for testing the CHT sensor? For volts or ohms, and how much?

I have AAA. I've just tried some of the "quick and easy" stuff at work in hopes that it would fire, and I wouldn't need to tow. I'll probably have her towed tomorrow on my day off....I've been working midnights and sleeping during the day.
__________________
STONE
'88 Cabriolet, using EP Slick 20w50 partial synthetic Snake Oil...just as Rommel intended.

Deny Everything; Admit Nothing; and Always Make Counter-accusations
Old 02-06-2011, 01:54 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
Grappler
 
Rodsrsr's Avatar
 
Join Date: Jul 2006
Location: Nor Cal
Posts: 5,858
Garage
Tow it home and let it sit in a nice warm gargae. If it starts it is more than likely the CHT sensor.
__________________
Grappler
Know Gi / No Gi

1976 RSR Backdate (Turbo 3.2)
Old 02-06-2011, 03:02 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)
muck-raker
 
kidrock's Avatar
 
Join Date: Jan 2009
Location: Coastal PNW
Posts: 3,059
meh....I guess I'll get her home Monday and break open the Bentley. I'll keep y'all posted.
__________________
STONE
'88 Cabriolet, using EP Slick 20w50 partial synthetic Snake Oil...just as Rommel intended.

Deny Everything; Admit Nothing; and Always Make Counter-accusations
Old 02-06-2011, 06:07 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)
Registered
 
Join Date: Oct 2004
Posts: 15,612
Quote:
Originally Posted by kidrock View Post
Maybe I should back up a bit. I have a spark, but it's not as good as I would like to see it. I figure as long as I have some spark, that would be enough to fire up.

I haven't checked any injectors yet. I do smell unburnt fuel. I even smell ether through the pipe during testing.

What's the easiest procedure for testing the CHT sensor? For volts or ohms, and how much?

I have AAA. I've just tried some of the "quick and easy" stuff at work in hopes that it would fire, and I wouldn't need to tow. I'll probably have her towed tomorrow on my day off....I've been working midnights and sleeping during the day.
You could just use a paper clip and jumper the two ends on the cht connector. If it starts up, then it was the cht sensor. Or you can use a nice clip, jumper wire and a good ground just to be sure.
Old 02-06-2011, 10:27 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #13 (permalink)
muck-raker
 
kidrock's Avatar
 
Join Date: Jan 2009
Location: Coastal PNW
Posts: 3,059
Quote:
Originally Posted by rusnak View Post
You could just use a paper clip and jumper the two ends on the cht connector. If it starts up, then it was the cht sensor. Or you can use a nice clip, jumper wire and a good ground just to be sure.
rusnak, I'm not the smartest peanut in the turd....I know the sensor goes into the white connector on the harness in the engine compartment. How the heck do I "jumper" that stuff? Forgive me, it's hard for me to visualize exactly what you're suggesting.

Just called the tow, I'm bringing her to my garage this morning. If the CHT theory doesn't pan out, I'll be pulling the hoses to the fuel filter and the fuel rail if necessary.

Man, this is pissing me off
__________________
STONE
'88 Cabriolet, using EP Slick 20w50 partial synthetic Snake Oil...just as Rommel intended.

Deny Everything; Admit Nothing; and Always Make Counter-accusations
Old 02-07-2011, 07:54 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #14 (permalink)
Sultan of Sawzall
 
rouxroux's Avatar
 
Join Date: Oct 2004
Location: Louisiana "Take me to 'da bridge"
Posts: 4,806
Send a message via AIM to rouxroux
(In best "Carl" voice from the movie "Slingblade"):


"mmmmmppphhhh, needs gas mmmmmmppphh"
__________________
Gruppe B #319
2 '86 911 Carrera coupes (red & white)
'66 Corsa convertible 140/4(red)
'66 Monza coupe 110/PG(white)
'95 993 cabriolet (wife's)
Old 02-07-2011, 08:33 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #15 (permalink)
French Import
 
zippy_gg's Avatar
 
Join Date: Jul 2009
Location: Kennesaw, GA, USA
Posts: 2,047
Garage
Quote:
Originally Posted by rouxroux View Post
(In best "Carl" voice from the movie "Slingblade"):


"mmmmmppphhhh, needs gas mmmmmmppphh"
Not sure it applies here...
Quote:
Originally Posted by kidrock View Post
I haven't checked any injectors yet. I do smell unburnt fuel. I even smell ether through the pipe during testing.
__________________
Gilles & Kathy

Happiness is not having a Porsche in the garage... Happiness is having a Porsche on the road!
86 Porsche 911 Cabriolet, 2011 BMW 1200RT, 03 Saab 93 Cabriolet, 06 MB E350 Estate
Old 02-07-2011, 11:14 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #16 (permalink)
muck-raker
 
kidrock's Avatar
 
Join Date: Jan 2009
Location: Coastal PNW
Posts: 3,059
Update:

disconnected lines from fuel filter....OK.

disconnected lines to fuel rail....OK.

checked fuel injectors....OK.

All tests done by jumping the DME relay harness, reconnecting relay, then turning ignition key. Pump is running fine and supplying plenty of fuel.

I even tried to "jumper" the CHT sensor by running a jumper wire on both ends of the CHT connector (leading to the DME), as suggested by Rusnak. I tested the CHT sensor for resistance (3.74 K ohms), which I believe is within spec according to my Bentley.

I even went back and checked again for spark at cyl. #1, which produces an orange spark.

I am freaking STUMPED.
__________________
STONE
'88 Cabriolet, using EP Slick 20w50 partial synthetic Snake Oil...just as Rommel intended.

Deny Everything; Admit Nothing; and Always Make Counter-accusations
Old 02-07-2011, 04:14 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #17 (permalink)
I'm here to cause trouble
 
jimbauman's Avatar
 
Join Date: Mar 2005
Location: CA
Posts: 935
My 2 pfennig's worth....

1. pop the distributor cap just to make sure all is well under there.
2. the easiest way to test for a bad DME relay is to run a jumper wire from the fuel pump fuse to another "hot" lead. The fuel pump will run constantly when you do that. Jump in the car and see if it starts.

JB
__________________
'86 Carrera Cabriolet '73 911T Sporto (RIP)
'90 Miata LeMons Contender! '71 Datsun 510 (RIP)
'67 Fiat 124 Sedan (RIP) '72 Ford Pinto (RIP)
'62 Plymouth Valiant '60 Ford Galaxy 500 (RIP)
Old 02-07-2011, 05:17 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #18 (permalink)
 
muck-raker
 
kidrock's Avatar
 
Join Date: Jan 2009
Location: Coastal PNW
Posts: 3,059
Hi Jim,

yeah, the first thing I did was pop the cap and check it, along with the rotor. Everything looked good, everything only has about 20 K miles on them. I still kept the old, good cap and rotor so I'll go out and try your suggestions first thing in the morning. I'll try the jumper at the fuel pump fuse as well.

Right now, I just need to take a break. My tools are about to sprout wings.
__________________
STONE
'88 Cabriolet, using EP Slick 20w50 partial synthetic Snake Oil...just as Rommel intended.

Deny Everything; Admit Nothing; and Always Make Counter-accusations
Old 02-07-2011, 06:31 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #19 (permalink)
Registered
 
Join Date: Oct 2004
Posts: 15,612
When the key is on, the icv should vibrate. That tells you the dme relay is powering the system. Also, you'll feel a click in the relay when you turn the key on. Since you have fuel pressure, you know the fuel pump is running. Make sure you have at least 12v to the fuel injector connectors.

Old 02-07-2011, 06:58 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #20 (permalink)
Reply


 


All times are GMT -8. The time now is 11:37 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.