964 C4 light refurb
01-17-2016, 07:26 PM
#241
Rennlist Member
Thread Starter
A consolation. The box rebuilder lent me a fully caged road legal C2 for the local Porsche Festival weekend.
Last edited by John McM; 01-18-2016 at 01:01 AM.
01-17-2016, 07:28 PM
#242
Rennlist Member
Thread Starter
That meant I could participate in regularity trials (only event for non race cars) and the track record attempt (402 Porsches on the track at one time)
01-17-2016, 11:38 PM
#243
Burning Brakes
01-28-2016, 12:01 AM
#250
Rennlist Member
Oh many sorry for the box problems. That cup car is what I'm going for with mine :-)
02-20-2016, 04:54 AM
#252
Rennlist Member
Thread Starter
Latest update.
The selector rod was replaced with a used one and the box reassembled. It failed the test drive and was dismantled again. Apparently the rod breakage ruined the 3/4 gear guide sleeve and a syncro.
Luckily I had spares so the box could be reassembled albeit the replacement guide sleeve was a good used one ex 993 (from Cogs Cogs) not the brand new one that was ruined. The mechanic now thinks the box is sorted.
Other items revealed in what has become the shakedown were a leaking power steering hose, a leaking slave actuator, a cv clip that came undone and a bad coil.
The latter was interesting as it means that the car has been running on one set of plugs which affects power and may be a reason why the car has been running a black exhaust for the last year. I have asked the mechanic to run the car with an Innovate AFR logger as I have an aftermarket ECU.
It is now close to 7 months since I started this light refurb and it has tested my patience lately, plus my wallet. Right now I just want to drive it and regain the love of piloting an air cooled classic.
The selector rod was replaced with a used one and the box reassembled. It failed the test drive and was dismantled again. Apparently the rod breakage ruined the 3/4 gear guide sleeve and a syncro.
Luckily I had spares so the box could be reassembled albeit the replacement guide sleeve was a good used one ex 993 (from Cogs Cogs) not the brand new one that was ruined. The mechanic now thinks the box is sorted.
Other items revealed in what has become the shakedown were a leaking power steering hose, a leaking slave actuator, a cv clip that came undone and a bad coil.
The latter was interesting as it means that the car has been running on one set of plugs which affects power and may be a reason why the car has been running a black exhaust for the last year. I have asked the mechanic to run the car with an Innovate AFR logger as I have an aftermarket ECU.
It is now close to 7 months since I started this light refurb and it has tested my patience lately, plus my wallet. Right now I just want to drive it and regain the love of piloting an air cooled classic.
03-25-2016, 05:23 PM
#253
Rennlist Member
Thread Starter
The car was picked up from the mechanic with an uneventful 140km drive home. I then took it for small local drives and a shortish B road run with other air cooled owners
03-25-2016, 05:38 PM
#254
Rennlist Member
Thread Starter
While the car is running strongly there are two things annoying me.
1. The warm start takes an embarrassing number of engine turns and
2. The exhaust is still black and sooty.
The mechanic tested the afr and it seemed fine with mid 13s at idle and high 12s at 5,000 rpm. However I'm not convinced it is sorted, even though the engine power seems fat.
Searching through the net for hot start issues I happened to see a FB post about the fuel pressure regulator. Two symptoms of a bad one are:
1. Sooty exhaust due to over fueling and
2. Hard warm start.
The fuel pressure regulator is designed to supply a desired pressure to the injectors. It does this with input from an intake fed vacuum line that adjusts a diaphragm in the regulator. If the diaphragm splits then the regulator won't work properly and fuel will be sucked back into the intake, enriching the mixture. This leads to a sooty exhaust and higher than normal fuel consumption.
The diaphragm split also allows fuel pressure to bleed out of the system when stopped for a while meaning a harder start as pressure needs to be built up.
There is also a possibility that the fuel accumulator is bad causing the same pressure issue but Im only going to do that if replacing the regulator doesn't fix this problem.
I wish I had known about testing this before I put the engine back in as its a big job to do with the engine in place.
1. The warm start takes an embarrassing number of engine turns and
2. The exhaust is still black and sooty.
The mechanic tested the afr and it seemed fine with mid 13s at idle and high 12s at 5,000 rpm. However I'm not convinced it is sorted, even though the engine power seems fat.
Searching through the net for hot start issues I happened to see a FB post about the fuel pressure regulator. Two symptoms of a bad one are:
1. Sooty exhaust due to over fueling and
2. Hard warm start.
The fuel pressure regulator is designed to supply a desired pressure to the injectors. It does this with input from an intake fed vacuum line that adjusts a diaphragm in the regulator. If the diaphragm splits then the regulator won't work properly and fuel will be sucked back into the intake, enriching the mixture. This leads to a sooty exhaust and higher than normal fuel consumption.
The diaphragm split also allows fuel pressure to bleed out of the system when stopped for a while meaning a harder start as pressure needs to be built up.
There is also a possibility that the fuel accumulator is bad causing the same pressure issue but Im only going to do that if replacing the regulator doesn't fix this problem.
I wish I had known about testing this before I put the engine back in as its a big job to do with the engine in place.
03-25-2016, 05:44 PM
#255
Rennlist Member
Thread Starter
One way to test for a split diaphragm is to disconnect the vacuum line from the intake, run the engine and see if gas/petrol leaks out. I'm not keen to risk fuel running on my engine and the regulator may only leak at higher revs which is difficult to diagnose with just myself in the garage.
If you do want to test yours this way the intake position differs based on the model.
In the metal intake version the off take is under the throttle cable mechanism (just visible in my photo)
In the plastic version it is far more accessible as shown by the red arrow.
If you do want to test yours this way the intake position differs based on the model.
In the metal intake version the off take is under the throttle cable mechanism (just visible in my photo)
In the plastic version it is far more accessible as shown by the red arrow.