MarkGolf

Hi Guys,

I recently got my 964 back on the road after some work due to a failing FPR. A fair few parts were changed in the run up to this and after. O2 sensor, Coils (Bosch 964 versions), Caps, arms, dizzy drive belt, plugs, injectors refurbished, new fuel lines and FPR (From 928sRUS)

The car has pretty much sat in my garage over winter since the above changes, battery disconnected but started up and run every few weeks.. Last week, I fired it up and took it for a drive to get it's MOT (road safety check here in UK). Drove perfectly, faith restored! Covered approx 15 miles, few stops along the way, behaved perfectly.

Last night, there was a Porsche meet, so I took the car for a 5 mile drive where it then sat for 4 hours. I then set off to the meet through rush hour traffic, still behaving perfectly, just prior to arriving at the meet, I felt some "bumps" through the car, these bumps felt the same as quickly dipping the clutch pedal and releasing it back up, this would happen a few times but 20-40 seconds a apart. This was while cruising at 70mph. Once in town, the car just lost drive for 2 seconds before coming back to life and carrying on, when stopped, still in D, the car stalled and kept stalling after being stopped at idle, even in N, while waiting to park every 10 seconds or so.

Parked for 4 hours at the meet, home time and I set off, bumping is back and worse, loosing drive for longer while doing 70, if I planted the accelerator, it wouldn't really go anywhere and the revs would fly up as drive was lost, the rev gauge even decided to freeze. I pulled over, car stalled. restarted, gauge came back to life and off I limped home, bumping still occurring, this bumping was just drive coming and going for a flash second or 2. When stopping for traffic lights, car just stalled out.

So, now I just have zero faith in the car, there is no way I will take my wife/son out for a drive in it as I can't risk breaking down with them in the car, after the FPR failure fire, now this.

One thing I noticed when I got home was some oil leaking from the top of the intake, where the ISV joins. Oil vapour I'm guessing but this could indicate an air leak after the MAF which may have resulted in the stalling. I had wiped it prior to taking the picture. Also, I did unplug the ISV and the idle did change and did go on to stall as it was doing. So I know the ISV is working.



Does anyone have any thoughts on what could be the trouble? I am aware that I should get a system adaptation done and have been offered help there previously, I just never had the car out to go and get it done, that may resolve the stalling but the loss of drive is what is puzzling me, maybe it's connected. I need to get under and check the fluid level, it has not been changed in a number of years. Would low fluid cause my loss of drive? I can't drive the car anywhere until resolved as it just isn't safe.

The engine itself sounds sweet and when it does idle, idles perfectly, fires up instantly and is generally perfect. I do have a ticking from the coils but guessing that is normal and just the spark inside.

Any help is much appreciated!

Thanks,
Mark

Silvertarga

Odds are the coils are the culprit (and they are silver Bosch) I had many issues with those coils and a brand new set caused my to call the flatbed for the first time in over 20 years of ownership.

Cools will work intermittently and fail when they get hot, once cooled they will work again

The fact that you hear a ticking means its shorting out (could be the connector as well)

Consider doing the 993 coil swap out...you will need to sooner or later

Laurus

I installed 993 coils and now I have ticking too.
I had to swap again to 964 silver coils.
Likely my 993 coil are bad quality .
I can not to claim the coils , because I bored hole for bracket.
I am going to buy new 993 coils and will install it again.

MarkGolf

Ah that's frustrating!

I am hoping I have some codes when I plug the Hammer in.

Here is a clip showing what the engine is doing, just as I pressed stop, the car stalled totally.

MarkGolf

Found my problem, positive terminal on one of the coils was sparking, tried various things but it just kept happening, swapped coils and bingo, no more. No more engine dying and engine feeling great.

Then used the hammer to clear codes, had a code for Hall Sensor, which basically means spark problem.

Took car for a drive and then did an adaptation. Car feeling great!

Advman89

I upgraded to the 993 coils after a similar issue...never ran better.