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 Technical BBS > 1- Porsche Technical Forums > Porsche 928 Technical Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Engineer of profanity
 
924CarreraGTP's Avatar
 
Join Date: Apr 2011
Location: BFE
Posts: 1,283
Garage
I'm going to get on the leak down test soon. I do now know that the car is firing on all cylinders. The spark plugs were dry though, so I'm guessing it may very well be a fuel problem. I'm going to pull the injectors and try to have them cleaned and flow tested locally, but I may try to see what I can do to clean them myself if I can't find a local place. I do have good fire to the plugs. I will do another compression test when I'm doing the injectors.
Old 04-04-2017, 06:16 PM
  Pelican Parts Technical Article Directory    Reply With Quote #41 (permalink)
Registered User
 
JK McDonald's Avatar
 
Join Date: Oct 2003
Location: Texas
Posts: 835
Garage
Spark and Fuel + Compression

Hey 924 - Sorry, but I was going on the assumption that you were now past the spark and fuel testing at the cylinders.

Quote:
Originally Posted by 924CarreraGTP;
Also the spark plugs had gasoline on them so I was getting some fuel spray from the injectors before the LH was sent out.
Quote:
Originally Posted by 924CarreraGTP;
I'm going to get on the leak down test soon. I do now know that the car is firing on all cylinders.
Usually once the cams and crank are all properly timed up, squirting oil into the cylinders would bring your compression back enough on a long hibernating motor to get you started - even with stuck piston rings.

In rereading over your posting from the beginning again, it appears that we should be leaning toward solving the "Low Compression" issue at this point. With a solid consistent spark, if it wont try to start on something as volatile as starter fluid only a very low compression seems to be remaining. One other possibility - Could you have the cam timing set slightly off since all the cylinders appear to be low on compression ?

Please keep us posted, Michael
__________________
1984 928S - "Miss Purdy"
1987 911SC - "Frau Helga"
1986 930 - "Well Hung"

Last edited by JK McDonald; 04-05-2017 at 09:02 AM..
Old 04-05-2017, 07:41 AM
  Pelican Parts Technical Article Directory    Reply With Quote #42 (permalink)
Registered User
 
JK McDonald's Avatar
 
Join Date: Oct 2003
Location: Texas
Posts: 835
Garage
Leak Down Test Results -

Hey 924 - With all the ups and downs you've already worked your way through on this motor and with over 1,600 hits, it is obvious that there is a lot of interest from everyone in following your progress. The more difficulty in resolving a "No Start" problem the more we all learn. Have you had an opportunity to get any results from a Leak Down Test ?

Perhaps someone can suggest what the best next step should be if the Leak Down Numbers come back good and it turns out NOT to be the reason for the No Start issue. I'm about ready to warm up my Ouija Board while twirling a dead cat over my head to help in diagnosing this problem.

Good Luck, Michael
__________________
1984 928S - "Miss Purdy"
1987 911SC - "Frau Helga"
1986 930 - "Well Hung"
Old 04-07-2017, 07:18 AM
  Pelican Parts Technical Article Directory    Reply With Quote #43 (permalink)
Registered User
 
JK McDonald's Avatar
 
Join Date: Oct 2003
Location: Texas
Posts: 835
Garage
Running Fine Now -

Hey 924 - How did your troubleshooting results come out ? Where you able to determine the reason for your "No Start" status or did you take out a full coverage replacement policy with Hagerty Classic Car Insurance, only to discover your car totally engulfed in flames ?

Michael
__________________
1984 928S - "Miss Purdy"
1987 911SC - "Frau Helga"
1986 930 - "Well Hung"
Old 04-16-2017, 07:46 AM
  Pelican Parts Technical Article Directory    Reply With Quote #44 (permalink)
Registered User
 
stepson's Avatar
 
Join Date: Mar 2010
Location: Texas
Posts: 1,483
JK-
Last week, we determined that his injectors were not injecting and from his and my "discussion," we both decided that although they may be "firing", they may be clogged, and therefore not introducing fuel into the equation.

I have a jig for cleaning injectors that is currently on loan. I will attempt to secure that this week for 924, and I also have an extra set of 84 Euro injectors. Once I get my jig back and find the injectors in my spare parts stash, I can test the injectors I have, then send them to him. He will have to get new O rings and mounting rubbers, and after swapping injectors, can just send me his old ones.

All in the name of reanimating an 84 Euro.
__________________
John Curry (Drift King) 928OC member
Grand Prix White 1994 GTS AT (The GTS)
Cobalt Blue 1989 S4 AT (The Blue Car)
Indishrot 1984 Euro S AT (The Stepson)
Black Metallic 1984 Euro S 5 speed (The Schwartz)
Old 04-16-2017, 06:31 PM
  Pelican Parts Technical Article Directory    Reply With Quote #45 (permalink)
Network Native
 
Danglerb's Avatar
 
Join Date: Jan 2007
Location: SoCal
Posts: 10,194
Electrically plug in one known good injector and listen for it clicking, or just use a noid light and see if it flashes.
Old 04-17-2017, 11:02 PM
  Pelican Parts Technical Article Directory    Reply With Quote #46 (permalink)
 
Now Available for Ordering:   101 Projects For Your BMW 3 Series 1982-2000  [more info]
Registered User
 
stepson's Avatar
 
Join Date: Mar 2010
Location: Texas
Posts: 1,483
Danglerb,

Wouldn't the noid light/clicking just tell you that the solenoid internal to injector was working? It wouldn't actually tell you that any liquid would pass through the injector, would it?
__________________
John Curry (Drift King) 928OC member
Grand Prix White 1994 GTS AT (The GTS)
Cobalt Blue 1989 S4 AT (The Blue Car)
Indishrot 1984 Euro S AT (The Stepson)
Black Metallic 1984 Euro S 5 speed (The Schwartz)
Old 04-18-2017, 08:19 AM
  Pelican Parts Technical Article Directory    Reply With Quote #47 (permalink)
Network Native
 
Danglerb's Avatar
 
Join Date: Jan 2007
Location: SoCal
Posts: 10,194
I"ve seen a car with all 8 injectors clogged and not flowing, but they also IIRC didn't click. The much more frequent issue though is no electrical pulse, so its a good place to start looking.
Old 04-22-2017, 04:42 AM
  Pelican Parts Technical Article Directory    Reply With Quote #48 (permalink)
Engineer of profanity
 
924CarreraGTP's Avatar
 
Join Date: Apr 2011
Location: BFE
Posts: 1,283
Garage
Sorry this is taking so long to determine. In the past I've removed those fuel rails in an afternoon, but my wife just got a night job and I've had very little time to mess with the shark until tomorrow. I'm going to pull the rails and injectors tomorrow. Oddly before the LH was rebuilt I measured a pulse on one injector connector, but since the LH was rebuilt I have tested it again and didn't record a pulse. Unfortunately I know that it's hard to measure the voltage at the connector with a voltage meter, and I don't have a noid light. I do know that before the LH rebuild I did get a 12 volt pulse from one of them. Also the spark plugs are mostly all dry. So I'm leaning toward clogged injectors at this time as Stepson said. I'm fixing to find out what's going on though.
I have had some time to start working on a test rig to pressurize B12 into each injector for cleaning. I'll post a picture here soon. Let me know if you guys think it will work. Basically I'm going to toggle 12 volts to the injector connection, and spray pressurized B12 into the injector with a spray needle from a can glued through a tire valve stem cap and stuck into a piece of fuel hose that's going to go on the injector spigot. Sound dangerous? I may end up as JK McDonald said engulfed in flames. We'll see, but I'll post the picture anyway of my test rig. See what you guys think.

Last edited by 924CarreraGTP; 04-27-2017 at 09:18 PM..
Old 04-27-2017, 08:33 PM
  Pelican Parts Technical Article Directory    Reply With Quote #49 (permalink)
Engineer of profanity
 
924CarreraGTP's Avatar
 
Join Date: Apr 2011
Location: BFE
Posts: 1,283
Garage
Test rig. The spray needle is hot glued and plastic glued through a very small drilled hole in a valve stem cap. The cap is pressed top side into the fuel hose. I saw this type of setup on a Youtube video, but designed it a little differently for the 928 injector. I'm going to use this old 914 switch to toggle 12V into each injector one by one and clean them. I may need more Berryman's, but I know where to get these cans locally. So will this work?




__________________
1970 Porsche 911T Black
1990 Porsche 944 S2 Red on cashmere
1984 Porsche 928S Euro ROW GP white on black

Last edited by 924CarreraGTP; 04-27-2017 at 09:10 PM..
Old 04-27-2017, 09:01 PM
  Pelican Parts Technical Article Directory    Reply With Quote #50 (permalink)
Registered User
 
JK McDonald's Avatar
 
Join Date: Oct 2003
Location: Texas
Posts: 835
Garage
Fuel Injector Testing -

Hey 924 - The fuel injectors all have +12 volts constantly applied to one of their electrical pins (you mentioned seeing this earlier) - the other pin has a burst of millisecond GROUND pulses applied that controls the firing time from the computer. Don't forget to check the vital grounds on the right hand cam cover and above the fuse panel.

There are a couple of good write-ups on this site and others on cleaning and testing fuel injectors. Just be very careful in applying power to their internal coil. The electrical winding inside each injector can over heat if they are energized too long. Here is a very basic video that demonstrates a set up using a tire air valve with it's center removed as a test jig or holder.

https://www.youtube.com/watch?v=rUUgR94drxg

Once you have verified the injectors are capable of passing fuel - you will need to then use a "NOID Test Light" to verify the wiring harness from the computer is good.

Have you had the opportunity to retest your compression ? You might let the cylinders set with some "Marvel Mystery Oil" or equivalent to try and free up the piston rings a bit - if this could be part of your low compression readings.

Good Luck, Michael
__________________
1984 928S - "Miss Purdy"
1987 911SC - "Frau Helga"
1986 930 - "Well Hung"

Last edited by JK McDonald; 04-28-2017 at 06:23 AM..
Old 04-28-2017, 06:17 AM
  Pelican Parts Technical Article Directory    Reply With Quote #51 (permalink)
Registered User
 
stepson's Avatar
 
Join Date: Mar 2010
Location: Texas
Posts: 1,483
924,
The way I do it is to use a Mityvac to put a vacuum on the fuel rail side of the injector, drop the injector into a cup of B12 and activate the injector(switching it on and off frequently and quickly) When the injector draws B12 through the injector because of the vacuum, you know it will inject fuel also.

This alleviates the need for atomized flammables coming into contact with an electrical source.

(But I DO keep a fire extinguisher handy)
__________________
John Curry (Drift King) 928OC member
Grand Prix White 1994 GTS AT (The GTS)
Cobalt Blue 1989 S4 AT (The Blue Car)
Indishrot 1984 Euro S AT (The Stepson)
Black Metallic 1984 Euro S 5 speed (The Schwartz)

Last edited by stepson; 04-28-2017 at 01:34 PM.. Reason: safety
Old 04-28-2017, 01:32 PM
  Pelican Parts Technical Article Directory    Reply With Quote #52 (permalink)
Engineer of profanity
 
924CarreraGTP's Avatar
 
Join Date: Apr 2011
Location: BFE
Posts: 1,283
Garage
Okay question, just so I know. Which injector pin should I put 12 volts to? So I should toggle ground to the other side then? Gotcha! I have already cleaned the camshaft housing grounds. I did a once over on the grounds above the fuse box, but will double check them as well. It of course poured rain here today so I got delayed again. I need to move the old car into my garage and put my 944 in the barn so I can keep the 928 dry and work on it. Rain has been a constant setback for me lately.
Marvel mystery oil. Great idea! I will do just that.
One more question though. I'm assuming the car would fire even if the injectors were not pulsing ground and receiving 12 volts at the connector? I'm saying the car is firing. Does it or does it not need an injector signal to fire?

Last edited by 924CarreraGTP; 04-28-2017 at 06:23 PM..
Old 04-28-2017, 06:11 PM
  Pelican Parts Technical Article Directory    Reply With Quote #53 (permalink)
Registered User
 
JK McDonald's Avatar
 
Join Date: Oct 2003
Location: Texas
Posts: 835
Garage
Injector Testing -

Hey 924 - There are lots of more experienced experts than me on this site but - the two electrical pins on each injector are simply an external connection point to each end of a coil of wire. It doesn't matter which pin receives the +12 volts and ground for the coil to become a magnet. Once magnetized, the internal pintal is lifted a fraction off it's seat to pass fuel. The important factor is for the fuel to be atomized in a very fine cone shaped mist when power is applied and the injector only passes fuel when the coil is energized.

As far as the ignition computer and it's spark circuitry - it is independent of the fuel computer. Once you are satisfied with the external injector operation - you may still need a "NOID Test Light" to answer the final fuel delivery question. The third leg of the (making it run) stool is compression.

Good Luck, Michael
__________________
1984 928S - "Miss Purdy"
1987 911SC - "Frau Helga"
1986 930 - "Well Hung"

Last edited by JK McDonald; 04-29-2017 at 06:38 AM..
Old 04-29-2017, 06:32 AM
  Pelican Parts Technical Article Directory    Reply With Quote #54 (permalink)
Registered User
 
stepson's Avatar
 
Join Date: Mar 2010
Location: Texas
Posts: 1,483
Quote:
Originally Posted by JK McDonald View Post
Hey 924 - There are lots of more experienced experts than me on this site but - the two electrical pins on each injector are simply an external connection point to each end of a coil of wire. It doesn't matter which pin receives the +12 volts and ground for the coil to become a magnet. Once magnetized, the internal pintal is lifted a fraction off it's seat to pass fuel. The important factor is for the fuel to be atomized in a very fine cone shaped mist when power is applied and the injector only passes fuel when the coil is energized.

As far as the ignition computer and it's spark circuitry - it is independent of the fuel computer. Once you are satisfied with the external injector operation - you may still need a "NOID Test Light" to answer the final fuel delivery question.
+1 But again, the noid light only tells you that the circuitry is working(ie, that the solenoid has power to it), it can't tell you if fuel is passing through the opening.
__________________
John Curry (Drift King) 928OC member
Grand Prix White 1994 GTS AT (The GTS)
Cobalt Blue 1989 S4 AT (The Blue Car)
Indishrot 1984 Euro S AT (The Stepson)
Black Metallic 1984 Euro S 5 speed (The Schwartz)
Old 05-01-2017, 07:49 AM
  Pelican Parts Technical Article Directory    Reply With Quote #55 (permalink)
Engineer of profanity
 
924CarreraGTP's Avatar
 
Join Date: Apr 2011
Location: BFE
Posts: 1,283
Garage
Alright, that's what I thought. I was just making sure so I could go about cleaning the injectors without messing up the injectors. I will try to pick up a noid light and Marvel Mystery oil sometime this weekend.
__________________
1970 Porsche 911T Black
1990 Porsche 944 S2 Red on cashmere
1984 Porsche 928S Euro ROW GP white on black
Old 05-01-2017, 01:24 PM
  Pelican Parts Technical Article Directory    Reply With Quote #56 (permalink)
Registered User
 
Join Date: Feb 2011
Location: denver
Posts: 718
Garage
hey 924 - i used a similar setup to blow out my injectors - they weren't totally clogged but the setup worked great - if you aim the injector into a can there won't be much flammable stuff blowing around
__________________
84 928 S
Old 05-02-2017, 04:30 PM
  Pelican Parts Technical Article Directory    Reply With Quote #57 (permalink)
Engineer of profanity
 
924CarreraGTP's Avatar
 
Join Date: Apr 2011
Location: BFE
Posts: 1,283
Garage
Honerboys, thanks! I was going to spray them into a baby food jar. I have like 100 of them. Time to use some and get rid of them. That is if it ever stops raining. I may be fashioning the shark as a row boat soon if we don't get some sunshine. Half of my state is under water right now. Lucky for me I live just off the side of a mountain.

Last edited by 924CarreraGTP; 05-03-2017 at 09:44 PM..
Old 05-03-2017, 09:41 PM
  Pelican Parts Technical Article Directory    Reply With Quote #58 (permalink)
Registered User
 
stepson's Avatar
 
Join Date: Mar 2010
Location: Texas
Posts: 1,483
Quote:
Originally Posted by 924CarreraGTP View Post
I was going to spray them into a baby food jar. I have like 100 of them. Time to use some and get rid of them.
Are you talking 100 baby food jars? or 100 injectors? Just to clarify....
__________________
John Curry (Drift King) 928OC member
Grand Prix White 1994 GTS AT (The GTS)
Cobalt Blue 1989 S4 AT (The Blue Car)
Indishrot 1984 Euro S AT (The Stepson)
Black Metallic 1984 Euro S 5 speed (The Schwartz)
Old 05-03-2017, 09:51 PM
  Pelican Parts Technical Article Directory    Reply With Quote #59 (permalink)
Engineer of profanity
 
924CarreraGTP's Avatar
 
Join Date: Apr 2011
Location: BFE
Posts: 1,283
Garage
Quote:
Originally Posted by stepson View Post
Are you talking 100 baby food jars? or 100 injectors? Just to clarify....
Yes, baby food jars. If I had 100 of these 928 injectors I'd be rich.

So here's the pictures of the removal of one rail and surgical removal of the original rail hoses. My phone died before I could take photos of the actual injector cleaning, but to make a long story short my original tester did not work because the B12 melted the glue. Then it melted super glue. So I designed a better tool to pressurize the injectors. Basically I plugged one end of a hose, and then gouged a small hole in the side just large enough to tightly push a B12 straw into. This tool worked perfectly to pressurize the injectors and I got all 4 of the left bank injectors clean and atomizing perfectly. I will remove the other side for cleaning tomorrow, but after getting this side back in the car and the system back pressurized I'm now leaning toward no power to the injectors, and/or no ground. The cleaning of the injection on the left bank made no difference. The car still will not start and in all actuality the injectors were not even clogged. I bought a new Dremel (my old one blew up). So I'm going to clean the grounds above the fuse box, and keep digging.
Photo of new pressurization tool.




__________________
1970 Porsche 911T Black
1990 Porsche 944 S2 Red on cashmere
1984 Porsche 928S Euro ROW GP white on black

Last edited by 924CarreraGTP; 05-08-2017 at 12:32 AM..
Old 05-08-2017, 12:25 AM
  Pelican Parts Technical Article Directory    Reply With Quote #60 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 11:18 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2017 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.