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 > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Apr 2007
Location: wisconsin
Posts: 2,539
quick question on checking CIS pressures...any risk of flooding the cylinders?

Plan to do this weekend, weather permitting. I have the workshop manual, read the threads, and watched you tube videos.

Here is what I don't understand.

If you hook up the guages between the fuel distributor and the WUR, remove the plug to the metering plate (so the pumps run), remove the plug to the WUR (so its cold), and the turn the key to measure...

Won't the engine flood???

The pumps are running, so there is pressure to the fuel injectors, right?

In the videos, the guys check the cold pressure, then the system pressure, then the warm pressure. The pumps are running for 10 minutes or so...

Is that right?

What am I missing here? I don't want to hydrolock the motor.

Bo

Old 11-07-2014, 11:27 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 14,101
Garage
As long as you do not depress the air meter plate the injectors will not fire. Best to put a battery charged on if running the pumps to get true values at 13V
Old 11-07-2014, 12:14 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
Join Date: Apr 2007
Location: wisconsin
Posts: 2,539
Thanks. Thats very helpful! I figured that had to be the case but wanted to make sure.

What confused me was that I thought depressing the metering plate, OR disconnecting the hookup to the metring plate both make the pumps run. I though the down stream result was the same (IE. Fuel flows everywhere it was supposed to).

Bo

Last edited by bpu699; 11-07-2014 at 12:26 PM..
Old 11-07-2014, 12:23 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
dos531's Avatar
 
Join Date: Apr 2014
Location: Los Angeles
Posts: 758
Garage
Quote:
Originally Posted by bpu699 View Post
Thanks. Thats very helpful! I figured that had to be the case but wanted to make sure.

What confused me was that I thought depressing the metering plate, OR disconnecting the hookup to the metring plate both make the pumps run. I though the down stream result was the same (IE. Fuel flows everywhere it was supposed to).

Bo
The pumps run to provide the fuel pressure, but that pressure is not released to the injectors unless the air meter is depressed.
__________________
'86 930 Guards Red - EFI MS3Pro, 80lb inj, 3.4, GT35R, Tial 46, Bosch 044, B&B Headers, 3.2 carrera manifold, Turbokraft Full bay IC
'12 Gallardo LP-570-4 Performante
'01 996tt
Ducati 748R
Old 11-07-2014, 12:55 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
Join Date: Jul 2006
Location: S. Florida
Posts: 7,289
The best way for you to understand it is simple.
Using two 14mm or 9/16" open end wrenches use one to hold the injector from turning and the other to loosen the injector line.. remove an injector line from an easy to reach injector and do your test.

CIS injectors shouldn't open or even dribble until something like 35 psi is put to them and no fuel should come out of the injector line until the metering plate is pushed down a little. If it does something is wrong.
You'll never really understand it until you do it yourself and watch what happens.
Old 11-07-2014, 01:34 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered User
 
Join Date: Apr 2013
Posts: 18
can happen ...

i broke my 91 3.3 this way. fuel head was bad and fluted one cylinder. cranking lead to a bent rod and defective cam and rockers. fuel head was not totaly shot. had some hot start issues. preasure test was fine, preasure after shut down fine for 30 minutes. and this little bit fuel that found its wrong way was enough. so next time i try, i will crank w/o ignition after this test. in my case it fired up and locked then. much $...
Old 11-07-2014, 01:55 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Registered User
 
Join Date: Apr 2007
Location: wisconsin
Posts: 2,539
Quote:
Originally Posted by peterpullin View Post
i broke my 91 3.3 this way. fuel head was bad and fluted one cylinder. cranking lead to a bent rod and defective cam and rockers. fuel head was not totaly shot. had some hot start issues. preasure test was fine, preasure after shut down fine for 30 minutes. and this little bit fuel that found its wrong way was enough. so next time i try, i will crank w/o ignition after this test. in my case it fired up and locked then. much $...
Thanks for the warning. I will spin the motor by hand before firing up.

Bo

Old 11-07-2014, 02:05 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 06:57 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2020 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.