Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

Residual Pressure Mystery :0) HELP !

 
Post new topic   Reply to topic    924Board.org Forum Index -> General Discussions
View previous topic :: View next topic  
Author Message
Sndtech  



Joined: 23 Apr 2013
Posts: 59
Location: New York

PostPosted: Mon Jun 04, 2018 4:42 pm    Post subject: Residual Pressure Mystery :0) HELP ! Reply with quote

My 80 924 N/A has a residual pressure loss. After just 4 minutes it drops to almost zero.

As part of the restoraton of this car I replaced the below items
and the residucal pressure results are the same

1- New (Rebuilt) Control Pressure Regulator replaceed
2- New Fuel Pump and Check Valve Replaced.
3- New Fuel Accumulator Replaced.
4- New Injectors
5- New Cold Start Valve
6- Fuel Dizzy rebuilt
7- No visual fuel leaks as pressure drops
8- No leaky injctors or cold start valve they have been checked also.

System checked for ai/vacuam leaks and confirmed there are none.
It's a bizarre problem and my mechanic can't figure it out either.

Anyone any ideas as to where I can look for the prioblem ?

Please help ??

Thanks

Manny
_________________
Manny-
1977 924 Red "Wheeler Dealer Car" | 1977 924 Martini | 1979 Sebring |1979 924 N/A Dolomite Grey | 1980 924 N/A Minerva Blue
Back to top
View user's profile Send private message
morghen  



Joined: 21 Jan 2005
Posts: 8868
Location: Romania

PostPosted: Mon Jun 04, 2018 5:16 pm    Post subject: Reply with quote

The rebuild of the WUR (control pressure regulator) was done incorrectly and it is leaking fuel back to the tank.

Loads of people assume that "rebuilding" things makes them work better.
Unless you know what you're doing and using the right parts, it actually makes things worse.
_________________
https://www.the924.com
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
Fasteddie313  



Joined: 29 Sep 2013
Posts: 2596
Location: MI

PostPosted: Tue Jun 05, 2018 2:21 am    Post subject: Reply with quote

Pressure up and then pull the return to tank line banjo off the FD and see if anything is coming out that hole..

If yes then leak = FD or WUR returning fuel..
I suppose the frequency valve could leak by just as well as the wur can, you ever test that?

To test the check valve you could probably pressure up and then pull the fuel line before the main pump and see if you get a continuous leak there after the initial fuel spill..

The accumulator would hold what, a cup or so volume of fuel at pressure before it would leak completely to zero? Some decent little amount of volume you should be able to see go somewhere..
4 minutes should be enough time to pull this and that and see it go somewhere I would think..
_________________
80 Turbo - Slightly Modified
Back to top
View user's profile Send private message Yahoo Messenger
Sndtech  



Joined: 23 Apr 2013
Posts: 59
Location: New York

PostPosted: Wed Jun 06, 2018 1:16 pm    Post subject: Reply with quote

Thanks Morghen & Fasteddie313 for the advice. I got the Control Pressure Regulator rebuilt by http://fuelinjectioncorp.com/. They seem reputable. I'll try the steps outlined soon.
I just recently pulled another WUR from a perfectly starting 924 NA and will try that also.

Apppreciate the advice as always.. I'll let you know what happens.
_________________
Manny-
1977 924 Red "Wheeler Dealer Car" | 1977 924 Martini | 1979 Sebring |1979 924 N/A Dolomite Grey | 1980 924 N/A Minerva Blue
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> General Discussions All times are GMT + 10 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group