Major service complete - still stalling!

 Welcome to lockdown #5 in Victoria, thanks to Glady's royal f#ckup with NSW "gold standard" contact tracing and quarantine.

Anyway, done some minor work in the last few weeks.

Pulled both exhausts off in preparation to a major service - replacing spark plug tubes, spark plugs and coilpacks. Might as well polish the exhaust tips while mufflers are off. Easy to remove - 17mm bolts on the cross pipe, and 13mm bolts x3 holding the muffler on.

Polished with 400-3000 sandpaper, then an orange cutting pad and wool fine pad with metal polishing compound. Nice!

Pulled off the old coilpacks - very old 996 items, plus some pretty well used NGK spark plugs.

Spark plug tubes are a fiddly and annoying thing to remove. I made a little tool with a long bolt and washer to tug the spark plugs tubes out, also had a 1" boat plug with sandpaper wrapped around it. A combination of both tools was able to remove all the spark plug tubes.

A view through cyl 1.

New coils are a Beru coil, comes with new E10 bolts.

Bought some spark plug tubes from ebay delivered from USA, did take ages to arrive. Cheap though.

Finally, some Bosch FGR6KQE spark plugs

Installed tubes, spark plugs and coils. Fitted up the original heat shields, using some new spare M8 rivets to space the heatshield away from the new coil packs.

Started everything up - had a great super smooth idle for 2 minutes... then it stalled. Restarted and stalled again immediately.

Tomorrow.... smoke test the intake system looking for leaks. If that's good, then go back a step of two - swap in another battery, then byopass fuel pump relay and check again.  If still no good, will remove fuel injectors and check for any clogging (eg if the old old fuel lines are perishing internally and blocking up the injectors)

Getting closer to a solution for a 911 966 that stalls at idle - bad electrical wiring somewhere! And start motor replaced.

 So today I finished off replacing the starter motor - pulled the thorttle body and plenum a week or so ago, then got distracted.

Anyway, also tested my Y cable (alternator-starter-battery) which I replaced around 2018. Cable is good, but there's a short somewhere in the cable to the battery, as there's some continuity with the engine block! 

Anyway, I'm OK with car electrics but not a pro, so if there's anyone smart out there let me know how to investigate further!

Starter motor is done at least.

Yanked the old starter out. 13mm bolt for the Y cable, 10mm bolt for the starter wire, and 15mm bolts hold that actual starter to the engine.

Nothing wrong with the old starter, but I'd bought a new starter on sale a few years back and lockdown #4 is a good opportunity to fit it.

Did some testing - this is with battery disconnected from the car. Continuity between ground terminal and ground bolt is perfect.

However this is the weird problem - from positive terminal, there's some continuity to ground as well! Suspect a short in the positive cable somewhere.

There's also a bit of continuity between the ground and positive terminals, which I don't think is good!

At the back of the car, I disconnected Y cable from the battery cable. 

Y cable has perfect internal continuity and no continuity to engine block.

Battery cable has some continuity to engine block.

Task for tomorrow - jack up the car, and trace/test the battery cable.

Still working our way through problems with the 911 - attempted starter motor replacement but....

 One thing I've learned is that an old 911 can test your patience!

What I've learned recently is that if I start the car dead cold, it will start no problem, and run with a slightly high idle of 1000rpm. During this time, everything is perfect - no smoke from exhaust, no misfiring or vibration, all is good. After 3 minutes, or 3:30, then problems will set in. Idle with drop, pops and misfires, vibrations. So WTF is going on here?

Anyway, now Victoria is in it's FOURTH COVID19 lockdown (due to massive incompetence from Scott Morrison, Greg Hunt, and basically all of Federal government by not managing hotel quarantine or the vaccination rollout) I have a few days to spare. Thought I might as well put in a new starter motor I bought years ago, and also check the Y cable and vacuum lines while I'm in there.

As usual - disconnect battery. Remove airbox. Dropped drive belt. Here's the throttle body.

Easy to remove, just four 10mm bolts. Disconnect the Idle Air Control Valve, and the Throttle position Sensor on the left, and unhook cable throttle on right.

Four hose clamps to loosen, plus disconnect hose from AOS to remove plenum.

Plenum removed. A little oily on the inside, but nothing major.

New alternator installed, still stalling!

 So here in Australia, labour costs are pretty high - was planning to get my alternator tested and rebuilt, and most were charging a big assessment fee jsut to look at the thing.

Bought an aftermarket unit on Ebay and it took the seller a week to tell me it was out of stock, so got a refund and bought a Bosch unit 0 124 515 042, which was a direct replacement for the alternator alrady in the car.

Changed it over this evening - I can do the job in well under an hour now with my eyes shut!

No improvement. Still low idle, stalling.

Since I've already narrowed it down to an electrical problem (car runs perfectly with alternator disconnected and everything else connected as usual) the next step is to trace back connections from the alternator. Will remove the Y cable which I installed a couple of years ago to make sure it looks good still, 

I might even replace the starter motor while I'm in there - I'm pretty sure I bought a replacement starter when there was a huge ebay sale a while ago!

Thankfully with winter setting in, I'm not missing driving the car anyway - it hasn't been convertible weather for ages. But I want it fixed before spring 2021!

Porsche 996 911 - bad alternator causing stalling, misfires, backfiring!

 Super weird problems to have, but a neglected 22 year old 911 with nearly 260,000km will be that way I guess.

Anyway, this morning removed the airbox, belt and alternator (this time only took 15 minutes now I've done it a few times!). Unplugged the electrical connections from the alternator, and reinstalled everything.

Car runs fine, perfect idle, not a problem. This isolates the problem to the alternator/charging circuit, and everything else is good.

Removed alternator again, and used a spare old voltage regulator (I'd put a newregulator in this alternator in 2018). Refitted everything, and same old problems arise - low revs, misfires, backfires, lots of motor rocking, eventually stalling. 

While the alternator was out, I rechecked the new Y cable (all connections appear good), checked all vacuum connections (again seem fine).

Next step? I'll probably remove the alternator and send it to an auto electrician for testing. Possible issue - alternator has some crazy internal fault that only shows up at idle? Voltage fluctuations, other things causing engine to run poorly. Hopefully a good auto elec will be able to bench test, simulate load etc. Then get alternator rebuilt, reinstall, and hope it works.

Was thinking of selling the 911 once all these issues are fixed - but I still like driving the car!

Making progress - removing the serpentine belt and the engine runs fine!

 Thought I might try a few random experiments today - removed the airbox and serpentine belt (let it dangle underneath the car) and tried starting it up.

Guess what - engine runs perfectly with the belt disconnected!

And when I replaced the belt, back to stalling immediately and idling terribly.

All the pulleys and tensioners seem fine.

So it comes down to a component driven by the belt causing the problem

1. water pump (unlikely? only replaced 2000km ago, mid 2020)
2. alternator (seems most likely to me, i did change the regulator in it in 2018)
3. power steering pump (hopefully not)
4. airconditioner compressor (unlikely, as it freewheels and disengaged/not turned on)

Tomorrow will remove the alternator electrical harness at the back, and see if the car runs OK with the serpentine belt on, but alternator disconnected. If so, then further investigate the alternator, the regulator, and all electrical connections from alternator.

Porsche 996 - continuing the saga of stalling and misfires. Replacing the fuel pump

Was psoting about these problems on FB, and Jake Raby thought it'd be worth changing out the fuel pump. Why not - pretty cheap part for $150 (non OEM) part.

Remove the battery and unbolt the battery plate to reveal the fuel pump cover.

Remove the locking ring (I used a rubber mallet and wooden stake), lift off the top plate and disconnect the two fuel lines (press in the little black tab) and remove the electrical connections.

Fuel level sender removed

Removing the old fuel pump was a little tricky - in theory, just grab it and rotate counterclockwise. Mine was stuck fast, I wrapped an old belt around it and yanked it counterclockwise to loosen it.

The new pump didn't come with any connecting pipes or connectors. I removed the swaged metal bands holding the original fuel lines in, and used new stainless fuel clips to lock them into place ont he new pump.

Reinstallation is pretty straightforward. Threw some fuel in and started the car up....

.... only a slight improvement. Car doesn't stall completely and die, revs hunt up and down, few pops from the left tailpipe.

More to come!