Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > Porsche 911 Technical Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Dec 2014
Location: Sweden
Posts: 290
Garage
Ok we now checked the accumulator, we took off the hose under it and turned on the ignition, a faulty one should leak when we do this apparently but it didn't. That means the fuel check valve is ok, the accumulator is ok, the wur i checked and was ok. Fuel distributor is next to check i guess.
We also suspect a blown air box, not sure tho.
Old 02-08-2016, 01:12 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #21 (permalink)
Registered User
 
Join Date: Mar 2002
Location: Philadelphia, PA
Posts: 9,444
Garage
Wrong test procedure........

Quote:
Originally Posted by Porscher View Post
Ok we now checked the accumulator, we took off the hose under it and turned on the ignition, a faulty one should leak when we do this apparently but it didn't. That means the fuel check valve is ok, the accumulator is ok, the wur i checked and was ok. Fuel distributor is next to check i guess.
We also suspect a blown air box, not sure tho.


Porscher,

When you turned the ignition switch to ON position, the FP should no run at all unless the AFS (air flow sensor) switch was disconnected. Was the FP running? It did not leak because the FP was not activated (?). If the pump was running, fuel would coming out from the disconnected return line from the fuel accumulator. Is your mechanic familiar with CIS? Keep us posted.

Tony
Old 02-08-2016, 02:06 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #22 (permalink)
Registered User
 
Join Date: Dec 2014
Location: Sweden
Posts: 290
Garage
Quote:
Originally Posted by boyt911sc View Post
Porscher,

When you turned the ignition switch to ON position, the FP should no run at all unless the AFS (air flow sensor) switch was disconnected. Was the FP running? It did not leak because the FP was not activated (?). If the pump was running, fuel would coming out from the disconnected return line from the fuel accumulator. Is your mechanic familiar with CIS? Keep us posted.

Tony
I would say non of us are mechanics, home diy:ers with little experience of 911:s. Bit like 2 blind persons trying to cross a street.
I activated fp by pushing sensor plate then fuel came out of the accumulator, is this right?
Old 02-08-2016, 06:20 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #23 (permalink)
Registered User
 
Join Date: Aug 2013
Location: Grand Junction, Co
Posts: 129
Garage
Does my 78 have a fuel pump check valve? And it's in the pump itself? And it is fixable, or replaceable?
__________________
Jimmy Foster
78 911 SC
Old 02-08-2016, 06:28 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #24 (permalink)
Registered User
 
Join Date: Dec 2014
Location: Sweden
Posts: 290
Garage
Quote:
Originally Posted by 2stroke View Post
Does my 78 have a fuel pump check valve? And it's in the pump itself? And it is fixable, or replaceable?
Mine is 78 and it has the check valve and as far as i know there should be no problem replacing if faulty, cheap and easy I've heard. Mine is checked and was ok.
Old 02-08-2016, 06:59 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #25 (permalink)
Registered User
 
Join Date: Mar 2002
Location: Philadelphia, PA
Posts: 9,444
Garage
Time for a new fuel accumulator.........

Quote:
Originally Posted by Porscher View Post
I would say non of us are mechanics, home diy:ers with little experience of 911:s. Bit like 2 blind persons trying to cross a street.
I activated fp by pushing sensor plate then fuel came out of the accumulator, is this right?
Porscher,

If fuel came out from the bottom port of the fuel accumulator with the FP running, it would confirm that the diaphragm inside the FA is ruptured or broken. With a defective FA, the residual pressure is not holding to facilitate the start up. Time to replace it.

Tony
Old 02-08-2016, 08:03 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #26 (permalink)
 
Registered User
 
Join Date: Dec 2014
Location: Sweden
Posts: 290
Garage
Quote:
Originally Posted by boyt911sc View Post
Porscher,

If fuel came out from the bottom port of the fuel accumulator with the FP running, it would confirm that the diaphragm inside the FA is ruptured or broken. With a defective FA, the residual pressure is not holding to facilitate the start up. Time to replace it.

Tony
That's great news! Tnx! Then we know what to do, then we only have the cold start issues left. Tnx again
Old 02-08-2016, 08:20 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #27 (permalink)
Registered User
 
Join Date: Mar 2002
Location: Philadelphia, PA
Posts: 9,444
Garage
Fuel injectors........

Quote:
Originally Posted by Porscher View Post
That's great news! Tnx! Then we know what to do, then we only have the cold start issues left. Tnx again



Porscher,

After you replaced the FA, test the residual fuel pressure. You might as well investigate the conditions of the 7 fuel injectors for leak. Yes, you have seven (7) fuel injectors in your engine including the CSV. Pull the six (6) injectors out with the fuel lines and CSV too. Run the FP for several seconds and observe for any fuel leak or delivery. They should not be leaking at all with the FP running and the FD plunger at rest.

Next, test the spray patterns or shapes of the injected fuel from the injectors. They should look like a smooth V-shape spray patterns. In spite of these, the engine might not start at all if you have unmetered air going into system. Stop guessing and do a pressure test. Keep us posted.

Tony
Old 02-09-2016, 06:08 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #28 (permalink)
Registered User
 
Join Date: Apr 2014
Location: Georgia
Posts: 17
Garage
I had almost the exact same symptoms as you. Figured fuel pump. replaced it and same issue. would fire for a split second the first time I turned the key, then nothing. Pulled the plunger on side of the fuel distributor, and fuel WAS indeed getting delivered. Pulled the air filter and noticed my pop-off valve was ill-seated. the epoxy had let go after 25 years. Cleaned it and re-installed with gorilla glue (don't laugh). Waited a day for it to set. Turned the key and it fired up. Ran rough for a few minutes, but cleared out and have had zero problems for the last 300 miles. Good Luck. These issues can be head bangers.
Old 02-09-2016, 07:45 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #29 (permalink)
Registered User
 
Join Date: Dec 2014
Location: Sweden
Posts: 290
Garage
Quote:
Originally Posted by boyt911sc View Post
Porscher,

After you replaced the FA, test the residual fuel pressure. You might as well investigate the conditions of the 7 fuel injectors for leak. Yes, you have seven (7) fuel injectors in your engine including the CSV. Pull the six (6) injectors out with the fuel lines and CSV too. Run the FP for several seconds and observe for any fuel leak or delivery. They should not be leaking at all with the FP running and the FD plunger at rest.

Next, test the spray patterns or shapes of the injected fuel from the injectors. They should look like a smooth V-shape spray patterns. In spite of these, the engine might not start at all if you have unmetered air going into system. Stop guessing and do a pressure test. Keep us posted.

Tony
Funny you wrote about the injectors cause that was my next question, they're just finger tightened to our engine, is that correct? Should you be able to move them with just your fingers. .?

Actually we(a mechanic) already tested the fuel pressure, and it did drop the pressure after turning engine off but the mechanic thought it was the fuel distributor. But I lost my faith in him for a couple reasons so i brought it home and now just me and my college working on it. Sadly we don't have the equipment for testing the pressure ourselves.

Can you reach the CSV? Thought it was impossible without removing engine?

Thank you for your inputs.

/Ola
Old 02-10-2016, 12:42 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #30 (permalink)
Registered User
 
Join Date: Dec 2014
Location: Sweden
Posts: 290
Garage
Quote:
Originally Posted by betiller View Post
I had almost the exact same symptoms as you. Figured fuel pump. replaced it and same issue. would fire for a split second the first time I turned the key, then nothing. Pulled the plunger on side of the fuel distributor, and fuel WAS indeed getting delivered. Pulled the air filter and noticed my pop-off valve was ill-seated. the epoxy had let go after 25 years. Cleaned it and re-installed with gorilla glue (don't laugh). Waited a day for it to set. Turned the key and it fired up. Ran rough for a few minutes, but cleared out and have had zero problems for the last 300 miles. Good Luck. These issues can be head bangers.


Interesting because we just found that the lid(!!??) on the popup valve is cracked, it backfired bad a couple of times and now it's cracked. We also suspect the airbox is cracked, because the screw right of the popup valve is just spinning when trying to fastened it. This is not good, big job getting it out I've heard and also expensive but its good to hear that it made a big difference for you, then it probably will for us aswell.
Old 02-10-2016, 12:49 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #31 (permalink)
Registered User
 
Join Date: Dec 2014
Location: Sweden
Posts: 290
Garage
God news!! After changing fuel accumulator, fuel filter and fixing popupvalve lid the Engine started up and ran REALLY GOOD after som finetuning airmix. Such a relief, now lets hope it stays that way. Tnx for your help guys, specially Boyt911sc! We'll se if we test the injectors(dont fix whats not broken!?). Have plenty of other stuff to do on the car.
Old 03-19-2016, 04:51 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #32 (permalink)
Registered User
 
Join Date: Dec 2014
Location: Sweden
Posts: 290
Garage
I'm just gonna ad in this thread that we now know what was the issue on this car.
First of all we had a faulty accumulator as I wrote before but we also had a faulty WUR. Now it's a racer!!!
Old 06-05-2016, 10:45 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #33 (permalink)
Registered User
 
Join Date: Mar 2002
Location: Philadelphia, PA
Posts: 9,444
Garage
CIS troubleshooting........

Quote:
Originally Posted by Porscher View Post
I'm just gonna ad in this thread that we now know what was the issue on this car.
First of all we had a faulty accumulator as I wrote before but we also had a faulty WUR. Now it's a racer!!!


Porscher,

Good to hear the news. If you had a pressure gauge kit, it would take a few mins. of troubleshooting to determine the root cause/s of your CIS woes. The pressure tests would have directed your attention to control and residual fuel pressures. Right now, I don't see how you were able to identify the WUR fault without knowing the control fuel pressures. Do you even know your system fuel pressure? Keep us posted.

Tony
Old 06-06-2016, 04:33 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #34 (permalink)
Registered User
 
Join Date: Dec 2014
Location: Sweden
Posts: 290
Garage
Quote:
Originally Posted by boyt911sc View Post
Porscher,

Good to hear the news. If you had a pressure gauge kit, it would take a few mins. of troubleshooting to determine the root cause/s of your CIS woes. The pressure tests would have directed your attention to control and residual fuel pressures. Right now, I don't see how you were able to identify the WUR fault without knowing the control fuel pressures. Do you even know your system fuel pressure? Keep us posted.

Tony
We took it to some aircooled experts, didnt take them long to identify the problem. Sent the WUR to UK for renovation and tnx to brexit the sterling was really cheap, thx Brexit(I Think...).
Old 06-28-2017, 05:39 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #35 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 12:53 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.