Starts then stalls - after car wash - car is in a show tomorrow and won't start :/
11-08-2018, 06:44 AM
#46
The membrane gets weaker over the years. if you dismantle the fuel head you wil find it no longer flat. i never found a broken one (hole in it or similar). i had an issue with the fuel head on my 91 turbo. the little orings that seal the plungers case to the fuel head were hard - one was broken. so fuel was able to find another way. this happened using poor fuel in the past. the previous owner drove fuel with ethanol on the x33 car. this damaged not only the fuelhead - more parts were involved. it was #5 in my case too......
so find one that can proof everything. can be very pricy to drive in this condition. check if it keeps system preasure first. mine dropped fuel so it did not.
so find one that can proof everything. can be very pricy to drive in this condition. check if it keeps system preasure first. mine dropped fuel so it did not.
11-08-2018, 09:30 AM
#47
Rennlist Member
The membrane gets weaker over the years. if you dismantle the fuel head you wil find it no longer flat. i never found a broken one (hole in it or similar). i had an issue with the fuel head on my 91 turbo. the little orings that seal the plungers case to the fuel head were hard - one was broken. so fuel was able to find another way. this happened using poor fuel in the past. the previous owner drove fuel with ethanol on the x33 car. this damaged not only the fuelhead - more parts were involved. it was #5 in my case too......
so find one that can proof everything. can be very pricy to drive in this condition. check if it keeps system preasure first. mine dropped fuel so it did not.
so find one that can proof everything. can be very pricy to drive in this condition. check if it keeps system preasure first. mine dropped fuel so it did not.
Over on Pelicanparts there's been a few cars that have ruptured membranes duel to age and abuse but the WUR dumps lots of fuel to the air cleaner housing so it's obvious what has happened.
All fuels today have some ethanol. Ordinarily, the legacy materials in our cars and indeed the materials used in new cars can tolerate 10% ethanol. However, those materials are degrading on our old cars due to age, prolonged fuel exposure and ozone damage.
Running E85 in a car of any age that is not built to handle flex fuel is asking for trouble.
To run E85 safely requires a complete rebuild of the fuel system and I'm not even sure you could get everything you need to truly do it right on an old 930 or 965. On top of that, the mixture would have to be re-tuned and ethanol doesn't have the energy density of gasoline.
Modern flex-fuel capable cars use a lot of stainless steel, special nylons and other exotic materials in the fuel systems as E85 can be very corrosive if it's sours or absorbs water. They also have a sensor so the engine management knows what fuel is being run.
11-08-2018, 09:33 AM
#48
Rennlist Member
...The membrane material (a bit hangs out the side and is strong) and the o-rings on the regulator seem to be unaffected by the carb cleaner, so I'm thinking the FD is maybe OK. Want to get it on a proper test rig...anyone in the LA area have one? There don't appear to be filter screens under the banjos, are there supposed to be on a 145 unit? Was gonna pull those.
Any other ideas why cylinder 5 would be failing to fire? Air, fuel, spark, air fuel spark...
Any other ideas why cylinder 5 would be failing to fire? Air, fuel, spark, air fuel spark...
Check for spark and check for cracks.
11-08-2018, 01:26 PM
#49
Rennlist Member
Thread Starter
Have visually verified spark the old fashioned way. Have a kit en route, will see if it's any of those o-rings soon...
How do we try to find the least ethanol gas? I usually only fuel up at 76 or Shell.
How do we try to find the least ethanol gas? I usually only fuel up at 76 or Shell.
11-08-2018, 02:57 PM
#50
Rennlist Member
Thread Starter
FD rebuild seems to have been successful. She idles nice n smooth on all cylinders now. Starts quickly. But, still doesn't run properly, misfirey and such running her up in the RPMs. Set the AFR to 14.3, took a whole turn in to get there at idle.
System pressure tested at 6.7 BAR, and I was unable to get a control pressure. Opening the gauge valve to let fuel pass gave no drop on the pressure. There may seem some weirdness with this fuel pressure gauge setup, first time using it (from HF, the one people have mentioned removal of the little insert valves in the couplings, though I couldn't get mine to read anything but zero with those removed.
In the Bosch CIS book, misfiring up the range no power troubleshoots to "control pressure too high", and that traces to bad WUR - so maybe I am back to bad WUR, now that my damage to the FD seems fixed.
I need to study up a bit and also make sure nothing in the air meter is thrown off by the height of the plunger - I set plunger back to exactly the bottom drop limit it had before. But, maybe something is off with how FD is oriented now and maybe that has something to do with above bad running. I did the basic exams again on air meter and test passed. Not sure how mixture screw adjustments effect the rest of the running range of the air lever and plunger.
(Re FD - the o-rings seem to have survived the carb cleaner well, but the diaphragm was looking very bad/crinkled, like what carb cleaner does to your rubber gloves. I replaced everything the kit came with and cylinder 5 came back alive (and dieseling is gone), but unable to test the rest of it's functioning due to above).
None of this experience, though, explains why the car wouldn't even start (start, immediate stall) after last Friday perfect test drives and then cash wash.
System pressure tested at 6.7 BAR, and I was unable to get a control pressure. Opening the gauge valve to let fuel pass gave no drop on the pressure. There may seem some weirdness with this fuel pressure gauge setup, first time using it (from HF, the one people have mentioned removal of the little insert valves in the couplings, though I couldn't get mine to read anything but zero with those removed.
In the Bosch CIS book, misfiring up the range no power troubleshoots to "control pressure too high", and that traces to bad WUR - so maybe I am back to bad WUR, now that my damage to the FD seems fixed.
I need to study up a bit and also make sure nothing in the air meter is thrown off by the height of the plunger - I set plunger back to exactly the bottom drop limit it had before. But, maybe something is off with how FD is oriented now and maybe that has something to do with above bad running. I did the basic exams again on air meter and test passed. Not sure how mixture screw adjustments effect the rest of the running range of the air lever and plunger.
(Re FD - the o-rings seem to have survived the carb cleaner well, but the diaphragm was looking very bad/crinkled, like what carb cleaner does to your rubber gloves. I replaced everything the kit came with and cylinder 5 came back alive (and dieseling is gone), but unable to test the rest of it's functioning due to above).
None of this experience, though, explains why the car wouldn't even start (start, immediate stall) after last Friday perfect test drives and then cash wash.
Last edited by wicks; 11-09-2018 at 01:30 AM.
11-09-2018, 03:00 AM
#52
may be the car wash was not the reason. your distributor llok usual. no visual defects. orings are fine so far, membrane as usual.
now there is the wur left so far. i went through this years ago. often an easy solution but a long way there....
now there is the wur left so far. i went through this years ago. often an easy solution but a long way there....
11-09-2018, 09:09 AM
#53
Rennlist Member
FD rebuild seems to have been successful. She idles nice n smooth on all cylinders now. Starts quickly. But, still doesn't run properly, misfirey and such running her up in the RPMs. Set the AFR to 14.3, took a whole turn in to get there at idle.
System pressure tested at 6.7 BAR, and I was unable to get a control pressure. Opening the gauge valve to let fuel pass gave no drop on the pressure.
In the Bosch CIS book, misfiring up the range no power troubleshoots to "control pressure too high", and that traces to bad WUR - so maybe I am back to bad WUR, now that my damage to the FD seems fixed.
System pressure tested at 6.7 BAR, and I was unable to get a control pressure. Opening the gauge valve to let fuel pass gave no drop on the pressure.
In the Bosch CIS book, misfiring up the range no power troubleshoots to "control pressure too high", and that traces to bad WUR - so maybe I am back to bad WUR, now that my damage to the FD seems fixed.
Congratulations on successfully rebuilding your fuel distributor.
Warm control pressure spec is 4.5 bar (I'm set to 4.3 but my engine isn't stock. When it was, 4.5 bar worked fine). You are not even close.
Calling Brian Leask.....or Flowtech http://www.cisflowtech.com/
11-09-2018, 12:36 PM
#54
Rennlist Member
Thread Starter
Thanks. Once more thing in the car is new...I've replaced or rebuilt about everything but the crank now.
Paul, is there another way to test the WUR? Or is it pretty standard that if the WUR is dead, system pressure becomes the control pressure? I thought it was the other way - bad WUR = fuel pressure too low. I'm concerned my pressure test rig isn't doing what it's supposed to since there is no change when I open the gauge valve...or maybe my WUR is somehow blocked and that indicates I need to clear something out of the path?
Paul, is there another way to test the WUR? Or is it pretty standard that if the WUR is dead, system pressure becomes the control pressure? I thought it was the other way - bad WUR = fuel pressure too low. I'm concerned my pressure test rig isn't doing what it's supposed to since there is no change when I open the gauge valve...or maybe my WUR is somehow blocked and that indicates I need to clear something out of the path?
Last edited by wicks; 11-09-2018 at 01:07 PM.
11-09-2018, 06:00 PM
#55
Rennlist Member
Wicks
Wow the diaphragm looks bad, Is it ok ? What does it look like new ?
Next step is to make your WUR adjustable. at least the control pressure side of it. Drill a 5mm hole under WUR in the center of the circular part of the WUR, then use a 4 or 4.5 mm allen wrench, left to lower the pressure(rich) and right to raise it (lean) no way to mess this up, pretty simple I did it to my 930 years ago. I'll text you pic's
Good luck
Wow the diaphragm looks bad, Is it ok ? What does it look like new ?
Next step is to make your WUR adjustable. at least the control pressure side of it. Drill a 5mm hole under WUR in the center of the circular part of the WUR, then use a 4 or 4.5 mm allen wrench, left to lower the pressure(rich) and right to raise it (lean) no way to mess this up, pretty simple I did it to my 930 years ago. I'll text you pic's
Good luck
11-10-2018, 08:41 AM
#56
Rennlist Member
Paul, is there another way to test the WUR? Or is it pretty standard that if the WUR is dead, system pressure becomes the control pressure? I thought it was the other way - bad WUR = fuel pressure too low. I'm concerned my pressure test rig isn't doing what it's supposed to since there is no change when I open the gauge valve...or maybe my WUR is somehow blocked and that indicates I need to clear something out of the path?
11-12-2018, 01:26 PM
#59
Rennlist Member
Thread Starter
Oh, yes this is the next test after cold control pressure. Hot control pressure is supposed to be an increase from cold. So, if cold control pressure is the same as system pressure, it would be pointless to check hot given that cold control is as high as system pressure already.
I need to find out what would cause cold control pressure to remain the same as system pressure. I'm planning to remove the WUR and aux air valve and clean/inspect those next.
I need to find out what would cause cold control pressure to remain the same as system pressure. I'm planning to remove the WUR and aux air valve and clean/inspect those next.
Last edited by wicks; 11-12-2018 at 03:26 PM.
11-12-2018, 04:46 PM
#60
Burning Brakes
So bizarre. Driving fine one day than bam! Not. And needing all this stuff done. I'm scratching my head. Wish I could have been more help.
Brandon
'91 911 Turbo
Brandon
'91 911 Turbo