New member 1st time Porsche owner
#61
Instructor
Thread Starter
#62
Instructor
Thread Starter
Update- Advance Auto Parts 3/8 fuel injection hose will not hold the pressure... chasing leaks everywhere in the rear wheel house. On my way out to get some better hose...
Is the hose from the bottom of the filter to the hard line on the car a different size? I seem to recall reading somewhere that it is, but can't find detail. I used 3/8 everywhere, fit tight on all the barbs, have had clamps that weren't tight enough, hoses flying off of fittings, and now one that "blew out" below the fuel filter at the fitting. Ripped wide open. Somehow I'm pretty sure it wouldn't have leaked this much had I done nothing...
Is the hose from the bottom of the filter to the hard line on the car a different size? I seem to recall reading somewhere that it is, but can't find detail. I used 3/8 everywhere, fit tight on all the barbs, have had clamps that weren't tight enough, hoses flying off of fittings, and now one that "blew out" below the fuel filter at the fitting. Ripped wide open. Somehow I'm pretty sure it wouldn't have leaked this much had I done nothing...
#63
Instructor
Thread Starter
Update number 2: Replaced all fuel hoses with $6/ft Barricade 3/8 fuel injection hose.... no leaks! Started the car with its own fuel. Starts instantly, but won't stay running. I was occasionally able to let it idle for a while, but it won't take any throttle without stalling. What now? I haven't touched anything underhood except replacing the fuel feed and return soft lines. It acts like it is losing fuel pressure when it stalls. Any ideas from those of you who have done this to a car that sat for decades?
#64
Rennlist Member
Ok, so you now have the correct hose. The barricade hose is what you want, 30R9, I believe.
So, it's a cis system, and I am right behind you on my 79, and have been through this on my 78.
So many places to begin....there are little strainers on each hard line where they connect to the fuel distributor. Those need to be checked/replaced, I just took mine out (have replacement copper crush washers on hand), there is also a strainer at the large fuel inlet on the side of the fuel distributor, check / clean that (lots of peeps miss this one). There is a strainer on the fuel inlet of the WUR, check / clean that. I used B-12 chemtool to help clean the fuel injectors, and also Marvel Mystery Oil...poured both into the tank...
These are tough puppies to clean out....you may end up needing to rebuild the fuel distributor. Jim Doerr on the forums here http://928classics.com/index.html can rebuild it for you, if you want it right.
I rebuilt mine myself...took me five tries to get it right...but worth all the hassle, as now I have an additional level of knowledge...I found it fun but frustrating...
Sooo, in a nutshell....clean all those strainers out, pour in some chemtool and fresh gas, and keep playing. Lots of info in my 78 thread ...
https://rennlist.com/forums/928-foru...ue-thread.html
Good luck
So, it's a cis system, and I am right behind you on my 79, and have been through this on my 78.
So many places to begin....there are little strainers on each hard line where they connect to the fuel distributor. Those need to be checked/replaced, I just took mine out (have replacement copper crush washers on hand), there is also a strainer at the large fuel inlet on the side of the fuel distributor, check / clean that (lots of peeps miss this one). There is a strainer on the fuel inlet of the WUR, check / clean that. I used B-12 chemtool to help clean the fuel injectors, and also Marvel Mystery Oil...poured both into the tank...
These are tough puppies to clean out....you may end up needing to rebuild the fuel distributor. Jim Doerr on the forums here http://928classics.com/index.html can rebuild it for you, if you want it right.
I rebuilt mine myself...took me five tries to get it right...but worth all the hassle, as now I have an additional level of knowledge...I found it fun but frustrating...
Sooo, in a nutshell....clean all those strainers out, pour in some chemtool and fresh gas, and keep playing. Lots of info in my 78 thread ...
https://rennlist.com/forums/928-foru...ue-thread.html
Good luck
#65
Instructor
Thread Starter
Update- Starting to run much better. I put in more fresh fuel, let it run some more and it is starting to smooth out and let me give it a little throttle. Still not running on all 8 though. I did try pushing the big circular plate down a little, and it smooths out and idles great with a little pressure on it... mixture issue?
New problem -- I noticed water collecting down in the valley and originally assumed it was from when I cleaned the motor a week or 2 ago. Started adding antifreeze while the car was idling and noticed more water... coolant going everywhere and it seems to be coming out of the back side of the thermostat/ WUR housing. Is there a hose there? I can't see exactly where it is coming from due to the many hoses/ wires etc in that area, but if I grab a rad hose and squeeze it, coolant shoots out the back toward the underside of the spider. Ugh.
New problem -- I noticed water collecting down in the valley and originally assumed it was from when I cleaned the motor a week or 2 ago. Started adding antifreeze while the car was idling and noticed more water... coolant going everywhere and it seems to be coming out of the back side of the thermostat/ WUR housing. Is there a hose there? I can't see exactly where it is coming from due to the many hoses/ wires etc in that area, but if I grab a rad hose and squeeze it, coolant shoots out the back toward the underside of the spider. Ugh.
#66
Instructor
Thread Starter
Found the leak culprit. Small hose on the backside of the thermostat housing that attaches to a nipple on the underside of the crankcase ventilation hose. Should be an easy fix once I get the remnants of the old hose off of the nipple on the housing. It's hard to get at, and I can't seem to get any of the surrounding hoses loose to gain access. There is a LOT of rubber hose on too of this motor... Hope I don't have to replace all of it.
#67
Rennlist Member
Update- Starting to run much better. I put in more fresh fuel, let it run some more and it is starting to smooth out and let me give it a little throttle. Still not running on all 8 though. I did try pushing the big circular plate down a little, and it smooths out and idles great with a little pressure on it... mixture issue?
New problem -- I noticed water collecting down in the valley and originally assumed it was from when I cleaned the motor a week or 2 ago. Started adding antifreeze while the car was idling and noticed more water... coolant going everywhere and it seems to be coming out of the back side of the thermostat/ WUR housing. Is there a hose there? I can't see exactly where it is coming from due to the many hoses/ wires etc in that area, but if I grab a rad hose and squeeze it, coolant shoots out the back toward the underside of the spider. Ugh.
New problem -- I noticed water collecting down in the valley and originally assumed it was from when I cleaned the motor a week or 2 ago. Started adding antifreeze while the car was idling and noticed more water... coolant going everywhere and it seems to be coming out of the back side of the thermostat/ WUR housing. Is there a hose there? I can't see exactly where it is coming from due to the many hoses/ wires etc in that area, but if I grab a rad hose and squeeze it, coolant shoots out the back toward the underside of the spider. Ugh.
#68
Nordschleife Master
You have basically two choices.
Replace them all at once.
Replace them one at a time as they fail until you have replaced all of them.
#69
Rennlist Member
^^^^This. Also, the water leak is likely from the hose that connects into the back side of the water bridge. A head gasket leak would not do what you described. It sounds like a hose breach.
#70
Rennlist Member
given the age and condition of the vehicle, a full top-end refresh sounds in-order. Better to do all at once.
#72
Instructor
Thread Starter
Got it running way better now. Fixed water leak (small hose on back of water bridge), added more fuel, checked screens at fuel distributor inlet (cleaned it though it wasn't bad) cleaned and checked left bank of injectors ( sooty but not clogged, cleaned and blew air through them. Car still would start instantly, but idle falls way off and stalls... so, I adjusted the idle mixture screw 1/4 turn clockwise, and it smoothed out. Revved better but backfired a bit. Advanced the timing a couple of degrees because I noticed the distributor was fully retarded, and VOILA... runs like a champ. Idles too high now though, so I think there may be a vacuum leak somewhere. It's idling at about 1200 rpm, though I haven't run it long enough to thoroughly warm it up. I'm afraid to run it more than a couple of minutes at a time because I think there is likely some air in the system... temp gauge never really moves. I will be replacing the crusty plug wires next. I'm also tempted to put some clean brake fluid in the old master cylinders and try to bleed the brakes and clutch to see if I can test drive it a little.
#73
Shameful Thread Killer
Rennlist Member
Rennlist Member
If you turned the idle mixture screw CW, and it smoothed out, something is wacky with the CIS still. If it's like all other CIS systems in the world, it is an air bypass that goes around the throttle plate, and allows more or less air to enter the engine. In general, turning the idle air bypass CW will lower the air allowed, and reduce the idle speed. Turning CCW will increase the amount of air, and make the RPM increase.
The CIS mixture setscrew is the 3mm hex between the dist head, and the inlet port. Adjustment of this is tricky. Because the engine will run with a fairly wide range of air-fuel ratios, it's best to work from lean to rich. When rich, the unburnt fuel will remain in the engine, and clog up the spark plugs a bit.
Once you get the car up to operating temp, turn the 3mm screw CCW until the engine stumbles, don't worry about the idle speed yet, unless the engine dies. If the idle is around 1200, get the mixture very lean but still running. Now, without changing anything else, turn the idle air bypass screw CW to reduce the air bypassing the throttle plate. This may be where you were headed with your first adjustment. The engine will run a bit smoother and the idle should go DOWN as you turn the air bypass CW.
Once you get the target RPM of about 900, then you can go back and adjust the mixture slightly CW to get the mixture correct. Without the CO meter, you can check somewhat by smelling the exhaust. If it smells a bit sweet, and burns inside your nose a bit, that is too rich. Remember, the mixture screw is very sensitive. If the RPM changes, go back and set it again for ~900, then do the mixture and fine tune until you have a good idle speed, with a good mixture setting.
All this presumes you have NO vac leaks at the intake, which will allow air to bypass the throttle plate, and mess up your idle adjustment. The CIS metering pin, and arm, and mass air sensor(damper plate) are calibrated very carefully to provide about 14:1 ratio at idle, and progressively slightly richer as the throttle is opened. Getting it right at the idle is critical for CIS, as are the pressures. If you don't have a set of CIS gauges, you will be buying them eventually(or borrow).
The CIS mixture setscrew is the 3mm hex between the dist head, and the inlet port. Adjustment of this is tricky. Because the engine will run with a fairly wide range of air-fuel ratios, it's best to work from lean to rich. When rich, the unburnt fuel will remain in the engine, and clog up the spark plugs a bit.
Once you get the car up to operating temp, turn the 3mm screw CCW until the engine stumbles, don't worry about the idle speed yet, unless the engine dies. If the idle is around 1200, get the mixture very lean but still running. Now, without changing anything else, turn the idle air bypass screw CW to reduce the air bypassing the throttle plate. This may be where you were headed with your first adjustment. The engine will run a bit smoother and the idle should go DOWN as you turn the air bypass CW.
Once you get the target RPM of about 900, then you can go back and adjust the mixture slightly CW to get the mixture correct. Without the CO meter, you can check somewhat by smelling the exhaust. If it smells a bit sweet, and burns inside your nose a bit, that is too rich. Remember, the mixture screw is very sensitive. If the RPM changes, go back and set it again for ~900, then do the mixture and fine tune until you have a good idle speed, with a good mixture setting.
All this presumes you have NO vac leaks at the intake, which will allow air to bypass the throttle plate, and mess up your idle adjustment. The CIS metering pin, and arm, and mass air sensor(damper plate) are calibrated very carefully to provide about 14:1 ratio at idle, and progressively slightly richer as the throttle is opened. Getting it right at the idle is critical for CIS, as are the pressures. If you don't have a set of CIS gauges, you will be buying them eventually(or borrow).
#74
Instructor
Thread Starter
The idle was low because there was not enough fuel. It was barely running, say 400RPM. I could squirt starting fluid, and it would smooth out and idle comes up to 1200. It also wouldn't rev, partly I think to the timing being off. It doesn't seem to be running rich, no smoke, no burning eyes, no smell. I think I just need to adjust the idle at the throttle plate now. I can't overstate the fact that I haven't found varnish in any of the injectors or screens thus far.
#75
Shameful Thread Killer
Rennlist Member
Rennlist Member
Grrr. Once again, the idle adjust is NOT the throttle plate. The screw is an idle air bypass. The throttle plate should be completely closed at idle. CCW allows more air to enter, CW allows less air to enter. Somewhat counter-intuitive.
I didn't know you had to add fuel to get it to come up and run better. It sounds like it was very lean, and you got it into the stoich range. Which leads to another word of caution. If CIS is lean, and ignition is too far advanced, you can get serious detonation which will destroy an engine.
If you have a smog inspection near you, go ask if they can hook up their CO probe to your car for a test run. Offer a couple bucks. They may, or may not let you do it. If they do, get the car fully warm, go to the test station, hook up the CO probe, and set it for the book values of idle RPM and CO reading(I don't have them offhand).
I didn't know you had to add fuel to get it to come up and run better. It sounds like it was very lean, and you got it into the stoich range. Which leads to another word of caution. If CIS is lean, and ignition is too far advanced, you can get serious detonation which will destroy an engine.
If you have a smog inspection near you, go ask if they can hook up their CO probe to your car for a test run. Offer a couple bucks. They may, or may not let you do it. If they do, get the car fully warm, go to the test station, hook up the CO probe, and set it for the book values of idle RPM and CO reading(I don't have them offhand).