Stalling but only with warm engine
10-05-2023 | 06:58 AM
#31
Instructor
Joined: Jan 2020
Posts: 178
Likes: 39
From: Potsdam / Germany
10-08-2023 | 07:38 AM
#32
Thread Starter
Instructor
Joined: Jul 2014
Posts: 134
Likes: 2
10-09-2023 | 05:02 AM
#33
Instructor
Joined: Jan 2020
Posts: 178
Likes: 39
From: Potsdam / Germany
There's this guy in Italy who resurrected a yellow 993 that was in a river for several years, interesting story. He might have contacts to Porsche mechanics in Italy.
https://rennlist.com/forums/993-foru...1-tribute.html
https://rennlist.com/forums/993-foru...1-tribute.html
Last edited by uli1266; 10-09-2023 at 05:16 AM.
10-09-2023 | 03:17 PM
#34
Thread Starter
Instructor
Joined: Jul 2014
Posts: 134
Likes: 2
Today the car was very reluctant to start even when cold. Amongst other things I had a good look at the coils and ignition modules.
On the multimeter the coils measured:
+ and - terminals 1.2 and 1.3 @200 Ω
+ and ht output 6.97 and 6.80 @20k Ω
Wheras the modules
+ on the coil and - on the module
pin 1 2.47 and 2.46 @ 20k Ω
pin2 0.07 and 0.08
pin 3 0.07 and 0.08
pin 4 2.42 and 2.32
pin 5 zero
pin 6 zero
The battery:
Engine off 12.59v
Engine on 13.44
So I think these items can be removed from the list of potential problem components.
On the multimeter the coils measured:
+ and - terminals 1.2 and 1.3 @200 Ω
+ and ht output 6.97 and 6.80 @20k Ω
Wheras the modules
+ on the coil and - on the module
pin 1 2.47 and 2.46 @ 20k Ω
pin2 0.07 and 0.08
pin 3 0.07 and 0.08
pin 4 2.42 and 2.32
pin 5 zero
pin 6 zero
The battery:
Engine off 12.59v
Engine on 13.44
So I think these items can be removed from the list of potential problem components.
10-15-2023 | 06:08 AM
#35
Banned
Joined: Oct 2023
Posts: 3
Likes: 0
Hi, somethings wrong with my 964. I’m so sad because it had been going very well😭
Today, about 10km after putting some fuel in it, when the engine is warm, but only in neutral, it stalls, but if I keep the clutch depressed it’s fine! I think it’s also ok coasting in gear. I’ve tried cleaning the idle control valve. So I was thinking it may be the throwout bearing?
Also of note, although I doubt it’s related, the car has an issue with what I believe to be the fuel pressure regulator because hot starts are getting progressively difficult.
The car has significant engine/drive train vibration, but I’ve been told that’s because of the cheap URO RS engine mounts.
Its a 90 C4 and the clutch was changed about 30,000km ago and the crank position sensor was changed about a year or two ago, as were the coils. The battery was also changed a month ago. It’s always been kept in a garage and has very rarely ever been driven in the rain.
However just a few weeks ago I let a friend who has a 993 drive it and he remarked on how heavy the clutch was, he’s actually a mechanic and said the clutch would soon need replacing even though it’s not slipping, so I was somewhat surprised with his opinion.
Any thoughts or suggestions would be much appreciated, thanks.
Today, about 10km after putting some fuel in it, when the engine is warm, but only in neutral, it stalls, but if I keep the clutch depressed it’s fine! I think it’s also ok coasting in gear. I’ve tried cleaning the idle control valve. So I was thinking it may be the throwout bearing?
Also of note, although I doubt it’s related, the car has an issue with what I believe to be the fuel pressure regulator because hot starts are getting progressively difficult.
The car has significant engine/drive train vibration, but I’ve been told that’s because of the cheap URO RS engine mounts.
Its a 90 C4 and the clutch was changed about 30,000km ago and the crank position sensor was changed about a year or two ago, as were the coils. The battery was also changed a month ago. It’s always been kept in a garage and has very rarely ever been driven in the rain.
However just a few weeks ago I let a friend who has a 993 drive it and he remarked on how heavy the clutch was, he’s actually a mechanic and said the clutch would soon need replacing even though it’s not slipping, so I was somewhat surprised with his opinion.
Any thoughts or suggestions would be much appreciated, thanks.
11-14-2023 | 04:14 PM
#36
Thread Starter
Instructor
Joined: Jul 2014
Posts: 134
Likes: 2
The nightmare continues…
For the past few weeks the car has been with my other independent specialist, who thought the crank sensor was the issue as the bolts were stripped and the sensor was moving around, so out came the engine for that.
Engine reinstalled but the symptoms remained. On the oscilloscope the signal is regular but at intervals goes all over the place (but the Hall sensor and the other one is stable all of the time) He’s checked the wiring harness and now thinks it’s the flywheel, so he’s going to take the engine out again.
This repair is adding up horrifically!
For the past few weeks the car has been with my other independent specialist, who thought the crank sensor was the issue as the bolts were stripped and the sensor was moving around, so out came the engine for that.
Engine reinstalled but the symptoms remained. On the oscilloscope the signal is regular but at intervals goes all over the place (but the Hall sensor and the other one is stable all of the time) He’s checked the wiring harness and now thinks it’s the flywheel, so he’s going to take the engine out again.
This repair is adding up horrifically!
Last edited by aldo964; 11-14-2023 at 11:29 PM.
11-24-2023 | 03:02 PM
#39
Thread Starter
Instructor
Joined: Jul 2014
Posts: 134
Likes: 2
Update: just had a call from the mecchanic, more bad news…
New flywheel installed, good signal on the oscilloscope but the car wouldn’t start… No signal to the coil modules he said.
So he then tried another ECU and it goes fine!
How can that be possible?!😵💫
New flywheel installed, good signal on the oscilloscope but the car wouldn’t start… No signal to the coil modules he said.
So he then tried another ECU and it goes fine!
How can that be possible?!😵💫
11-24-2023 | 03:33 PM
#40
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
Joined: Jul 2018
Posts: 856
Likes: 116
From: SoCal
The 964 DME ECM rarely if ever fails, unless damaged during troubleshooting.
__________________
Loren
Systems Consulting - Automotive Electronics
Specializing in Porsche cars
http://www.systemsc.com/
Loren
Systems Consulting - Automotive Electronics
Specializing in Porsche cars
http://www.systemsc.com/