Notices
928 Forum 1978-1995
Sponsored by:
Sponsored by: 928 Specialists

***No start/No Spark Ran Fine last Night***

Thread Tools
 
Search this Thread
 
Old 03-28-2017 | 06:45 PM
  #31  
G8RB8's Avatar
G8RB8
Nordschleife Master
 
Joined: Feb 2011
Posts: 8,200
Likes: 407
Default

Pretty much the same as my problem. Watching
Old 03-28-2017 | 08:21 PM
  #32  
dr bob's Avatar
dr bob
Chronic Tool Dropper
Lifetime Rennlist
Member
 
Joined: Oct 2001
Posts: 20,506
Likes: 549
From: Bend, Oregon
Default

So...

Fuel pressure is confirmed OK with a pressure gauge?

Then on to ignition, where we suspect that X is causing no spark. Actually a list of X's.

----

What was worked on last? That's often a good place to start if it's all all even remotely related to symptoms. The RL jury can help you decide what's related.

After that, it comes down to some basic electrical troubleshooting, either to make the fuel pressure come up, or get a spark. In either case, start at one end and work towards the other end of the system. Go from the "underperforming" end if you wish. I like to start in the middle of each system under question, halving the list of probable causes with each test. For the fuel system with no pressure for instance, I check to see if there's full voltage at the fuse with the key on and cranking. There's a tiny hole in the back of the fuses that will take a needle probe. Use that to test the circuits without disturbing anything. Test both sides of each fuse for voltage to ground. If voltage is low, work towards the battery. If voltage is OK, work towards the pump. If the relay doesn't pull in, troubleshoot back through the LH towards the EZF. Does the tach bounce as you crank on the starter? Bouncing suggests that the CPS is OK, no movement points to not. You get the idea. Diagnosing is the logical process of systematically eliminating things it might be. Each step narrows the remaining options by half if you do it right.
Old 03-28-2017 | 08:39 PM
  #33  
buccicone's Avatar
buccicone
Thread Starter
Rennlist Member
 
Joined: Oct 2010
Posts: 2,062
Likes: 471
From: Centerburg, OH
Default

He's replacing the 7 year old battery that test weak also.
Old 03-28-2017 | 09:26 PM
  #34  
buccicone's Avatar
buccicone
Thread Starter
Rennlist Member
 
Joined: Oct 2010
Posts: 2,062
Likes: 471
From: Centerburg, OH
Default

Originally Posted by dr bob
So...

Fuel pressure is confirmed OK with a pressure gauge?

Then on to ignition, where we suspect that X is causing no spark. Actually a list of X's.

----

What was worked on last? That's often a good place to start if it's all all even remotely related to symptoms. The RL jury can help you decide what's related.

After that, it comes down to some basic electrical troubleshooting, either to make the fuel pressure come up, or get a spark. In either case, start at one end and work towards the other end of the system. Go from the "underperforming" end if you wish. I like to start in the middle of each system under question, halving the list of probable causes with each test. For the fuel system with no pressure for instance, I check to see if there's full voltage at the fuse with the key on and cranking. There's a tiny hole in the back of the fuses that will take a needle probe. Use that to test the circuits without disturbing anything. Test both sides of each fuse for voltage to ground. If voltage is low, work towards the battery. If voltage is OK, work towards the pump. If the relay doesn't pull in, troubleshoot back through the LH towards the EZF. Does the tach bounce as you crank on the starter? Bouncing suggests that the CPS is OK, no movement points to not. You get the idea. Diagnosing is the logical process of systematically eliminating things it might be. Each step narrows the remaining options by half if you do it right.
Dr. Bob: Forgot about the tach bounce to check spark. I was just informed with the new battery in, there is NO tach bounce. Getting new CPS tomorrow. We shall see.
Old 03-29-2017 | 12:20 AM
  #35  
Mrmerlin's Avatar
Mrmerlin
Team Owner
 
Joined: May 2004
Posts: 28,620
Likes: 2,654
From: Philly PA
Default

its also possible that the low battery has damaged the running relays with undervoltage.

If the CPS is old then the connector will probably fall apart.
it would also be wise to replace the TPS short harness this is near the test port Roger sells them.
Note the TPS connector is made of the same material as the CPS connector
Old 03-29-2017 | 09:06 AM
  #36  
buccicone's Avatar
buccicone
Thread Starter
Rennlist Member
 
Joined: Oct 2010
Posts: 2,062
Likes: 471
From: Centerburg, OH
Default

Stan, the CPS is relatively new ( within 7 yrs.). Connector not crumbling. Is it possible to test the CPS with a VOM?
Old 03-29-2017 | 12:19 PM
  #37  
Landseer's Avatar
Landseer
Rennlist Member
 
Joined: Sep 2007
Posts: 12,155
Likes: 371
From: Johnson City, TN
Default

CPS failures are quite common. I've not gotten 7 years from one yet. Of course, my cars are driven. As I recall, the manufacturing process shifted to China. The old and new ones looked similar but the plastic wasn't well bonded to the metal sensor on one of them I inspected.
Old 03-29-2017 | 06:00 PM
  #38  
buccicone's Avatar
buccicone
Thread Starter
Rennlist Member
 
Joined: Oct 2010
Posts: 2,062
Likes: 471
From: Centerburg, OH
Default

There are two out there. Bosch & FAE Do you think both are from China?
Old 03-29-2017 | 09:18 PM
  #39  
Mrmerlin's Avatar
Mrmerlin
Team Owner
 
Joined: May 2004
Posts: 28,620
Likes: 2,654
From: Philly PA
Default

only use bosch for electric parts
Old 03-29-2017 | 10:48 PM
  #40  
buccicone's Avatar
buccicone
Thread Starter
Rennlist Member
 
Joined: Oct 2010
Posts: 2,062
Likes: 471
From: Centerburg, OH
Default

Update tonight: New CPS still no spark or tach bounce. Told him to check voltage at EZK term 30.
Old 03-29-2017 | 10:52 PM
  #41  
SeanR's Avatar
SeanR
Rennlist Member
 
Joined: Apr 2006
Posts: 35,700
Likes: 503
Default

Do you have an extra ignition switch hanging around that you can test with? If so unhook the connector from the switch in the car, plug spare one in and use a screw driver to crank it over.
Old 03-30-2017 | 07:59 AM
  #42  
buccicone's Avatar
buccicone
Thread Starter
Rennlist Member
 
Joined: Oct 2010
Posts: 2,062
Likes: 471
From: Centerburg, OH
Default

Sean: That was his next step. He was looking for a new spare he had lying around.
Old 03-30-2017 | 10:17 AM
  #43  
checkmate1996's Avatar
checkmate1996
Rennlist Member
 
Joined: May 2002
Posts: 2,478
Likes: 195
From: Columbus, Oh
Default

Hey battery voltage been confirmed from from battery -- > starter -- > alternator -- > t14 connector?
Old 03-30-2017 | 08:40 PM
  #44  
G8RB8's Avatar
G8RB8
Nordschleife Master
 
Joined: Feb 2011
Posts: 8,200
Likes: 407
Default

Mine's running, but I'm not that happy because I still don't really know what it was. I pulled the CEP and looked for anything loose behind it. It was out to fix the recirc flap and replace the fan motor. Then I pulled the EZK connector which hadn't been touched and hit it with some DO100 and plugged it back in. Started in four turns and after a short drive idles nice.

Cross posted in case it gives you any ideas.
Old 03-31-2017 | 10:51 AM
  #45  
buccicone's Avatar
buccicone
Thread Starter
Rennlist Member
 
Joined: Oct 2010
Posts: 2,062
Likes: 471
From: Centerburg, OH
Default

We will be putting the heads together tomorrow to see if we can make some progress.


Quick Reply: ***No start/No Spark Ran Fine last Night***



All times are GMT -3. The time now is 01:38 AM.