Parts Catalog Accessories Catalog Tech Info Tech Forums
 
  Search our site:    
 Cart  | Project List | Order Status | Help    
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Mar 2009
Location: West Virginia
Posts: 25
Question 87 944 NA Starter Solenoid Signal - No connection pins 50 to 4

I have an 87 944 NA with a no-start issue.

No spark, no pulse from the injectors. I have no voltage coming across the coil when in the ON or START positions. I do, however get 12+ volts at pin 86 on the fuse panel for the DME Relay. I have 12+ volts on pins 18 and 35 on the DME connector, so I know there's power coming through the system from the ignition switch.

Here's what I've found so far:

The resistance checks out good on the coil (about 6200K Ohms). The car cranks fast, the tach bounces, the reference sensor is brand new (both the reference and speed sensor test with almost the exact same resistance).

The battery is new with 805 CCA, the fuel pump is new, the plugs are clean, the wires are all good, the distributor cap and rotor are fine and fitted snugly, the engine ground is good, there is a known-good computer in the car (I also have the original to test), the DME kicks the fuel pump on when starting (the DME is like new with perfect solder joints, and I've even tried jumpering the pins on the board - it runs the pump fine, but the car still doesn't start).

The wiring in the car looks good and is still pliable (I have found no notable corrosion, breakage, or fraying anywhere - the car was garage kept for years), there are no secret ignition switches for security purposes, there is no water leakage into the cabin, the car has never been in an accident, the intake is not blocked, the fuel lines are good, the fuel filter is new, and the car ran fine when it was stored 8 years ago.

With that out of the way, can anyone tell me a good way to test the coil? The clarks garage coil spark test procedure kinda confused me a bit on which ground wire to connect to what, so any kind of clarification would help me see if I'm doing it right.

I followed the IGN-04 Ignition Systems Troubleshooting on Clark's Garage, and I found in my car there is no connection (infinite resistance) between pin 50 on the ignition switch connector and pin 4 on the DME connector. Does that mean I have a broken wire from the ignition switch to the DME, or does that have something to do with the wire to the starter solenoid?

What should I be looking for? Can I run a new wire? Is that test accurate?

Any information is greatly appreciated.
Old 07-11-2009, 09:24 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #1 (permalink)
1984 porsche 944 na
 
ballysdad's Avatar
 
Join Date: Aug 2008
Location: Westfield NJ
Posts: 306
PM me your email address I will send you a pinout of your dme plug and if you want you can call me and we can walk through some tests.
__________________
1984 Red NA/Sold
1984 Gray NA/Sold
1986 Red NA
1986 Gray NA
Old 07-11-2009, 11:26 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #2 (permalink)
Registered User
 
Join Date: Mar 2009
Location: West Virginia
Posts: 25
Testing, testing ...

Here's a bit of an update.

Today, I tested the car for fuel over-pressure at the rail by disconnecting one of the injectors to reduce the load on the injector driver.

Still no change while using either DME computer I have. The car doesn't generate a spark or pulse on the injectors - there's not so much as even a residual fuel odor in the exhaust pipe.

I'm still wondering how the circuit between pin 50 on the ignition switch connector and pin 4 on the DME computer could factor in.
Old 07-11-2009, 06:09 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #3 (permalink)
1984 porsche 944 na
 
ballysdad's Avatar
 
Join Date: Aug 2008
Location: Westfield NJ
Posts: 306
There is a 14 pin plug that is in between the ignition switch pin 50 and the dme plug pin 4 there should be 12v starter trigger when you turn the key at pin 4. Check for continuity. The wire should be red/black from pin 50 to the 14 pin dme pin 7 to the 36 pin main dme plug on pin 4
__________________
1984 Red NA/Sold
1984 Gray NA/Sold
1986 Red NA
1986 Gray NA
Old 07-11-2009, 07:35 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #4 (permalink)
Registered User
 
Join Date: Mar 2009
Location: West Virginia
Posts: 25
Smile 14 pin plug

Thanks for the info. Is that 14 pin plug anywhere near the DME Computer? Any idea where it is located?

When I tested pin 4 on the DME connector, I also tested it while having someone crank the car. There was no voltage on pin 4 to ground while the starter was cranking the engine.

Thanks, again, for the help.

Last edited by memoriter; 07-12-2009 at 08:28 AM.. Reason: added information
Old 07-12-2009, 08:27 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #5 (permalink)
1984 porsche 944 na
 
ballysdad's Avatar
 
Join Date: Aug 2008
Location: Westfield NJ
Posts: 306
can you locate the red/black wire that goes into the dme plug? If you can open it little bit and check for crank voltage to ground there with a exposed wire. It may be the pin that is bad. If you still have no voltage check for crank voltage at the switch on pin 50 if you have it there run a jumper from the switch pin 50 wire to the exposed red/black wire at pin 4 of the dme and see if she starts. In the mean time I will try and locate the 14 pin dme plug.
__________________
1984 Red NA/Sold
1984 Gray NA/Sold
1986 Red NA
1986 Gray NA
Old 07-12-2009, 08:53 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #6 (permalink)
1984 porsche 944 na
 
ballysdad's Avatar
 
Join Date: Aug 2008
Location: Westfield NJ
Posts: 306
In theory if there is no crank voltage detected by the computer when the engine turns while cranking the reference sensors are supposed to take over tdc reading and engine revolution.
__________________
1984 Red NA/Sold
1984 Gray NA/Sold
1986 Red NA
1986 Gray NA
Old 07-12-2009, 08:57 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #7 (permalink)
Registered User
 
Join Date: Mar 2009
Location: West Virginia
Posts: 25
Question

Yeah, and that's why I'm lost at this point, because both my reference sensor and speed sensor test out to be good. I also have several other known-good sensors from E30's that I've tried.

I'll try making a jumper wire from the red/black wire on the ignition connector (50) to the red/black on the DME (4) and see what happens.

At the worst it'll either not start, catch fire, or explode. It won't make much difference at this point, since all I have is a comatose piece of metal that takes up space.

Maybe I've just somehow overlooked some kind of secret switch somewhere. Is there a general place people wire them in, or maybe some kind of connector (like that 14 pin connector you were making reference to) people disconnect to keep the car secure while in storage? I've already checked under the dash, the fender wells, under the hood, and in the cabin. Is there any chance people rig one up in the rear compartment?

Also, I found this group of wires under the edge of my carpet in the driver's foot well. Any ideas what that stray yellow wire should go to? There's been a cellular phone installed years ago in the car, and I'm suspecting that it has something to do with the factory phone wiring being tapped into.



Thanks again for all the help. I really appreciate it. The reason I'm in this predicament is because I took the previous owner's word on the fuel pump being the only issue with the car. I realized, after a very cold winter of waiting to tinker with it, that was only part of the problem.

Also, I just thought I'd mention that I know the timing belt isn't broken and the camshaft is rotating. I've watched it turn when having the engine cranked.

Last edited by memoriter; 07-12-2009 at 09:31 AM..
Old 07-12-2009, 09:12 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #8 (permalink)
1984 porsche 944 na
 
ballysdad's Avatar
 
Join Date: Aug 2008
Location: Westfield NJ
Posts: 306
I wouldn't worry about putting 12v where it should be anyway just make sure it is only crank voltage (trigger) not 12v constant. Did you replace the ignition switch? or check for resistance between the pins?
__________________
1984 Red NA/Sold
1984 Gray NA/Sold
1986 Red NA
1986 Gray NA
Old 07-12-2009, 09:42 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #9 (permalink)
1984 porsche 944 na
 
ballysdad's Avatar
 
Join Date: Aug 2008
Location: Westfield NJ
Posts: 306
I think you said you don't get 12v to the coil(black wire)
remove the dme relay. At pin 86 you should have 12v when cranking the motor. Do you have 12v at this pin? If not then jumper the alarm module and check again.
__________________
1984 Red NA/Sold
1984 Gray NA/Sold
1986 Red NA
1986 Gray NA
Old 07-12-2009, 09:49 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #10 (permalink)
Registered User
 
Join Date: May 2009
Location: Hawkinsville / Perry, Ga.
Posts: 1,157
It sounds as if you have done plenty of wire checking. My "no start, no spark" engine turned over fine. I ended up replacing the ignition switch modual forward of the key switch. Car starts every time. I also had to replace the fuel check valve at the fuel pump as it was stuck closed, so no fuel at the fuel rail. I hope you get your car running soon.

Cheers, Larry
Old 07-12-2009, 10:07 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #11 (permalink)
Registered User
 
Join Date: Mar 2009
Location: West Virginia
Posts: 25
Well, I have 12+ volts on pin 86 for the DME Relay when the key switch is in the ON position, but I haven't tested it for voltage while the car is being cranked. I'll have to try that, I suppose.

I pulled up a Clark's Garage manual for the appropriate resistances for the ignition switch. I'll go test that as soon as possible, as it points out the correct resistance between pin 30 and 50 on the ignition switch as being 0 (when turning it to the start position).

Oh, and my car doesn't have an alarm system.

I've also loosened the fuel rail bolt at the end to bleed any trapped air out of the rail. Quite a few bubbles flowed out at first, but then eventually it was only pressurized fuel. I did this while I had the DME Relay pins jumpered for the fuel pump to run continuously, but I do know for certain the pump runs while the car is being cranked.

The main issue is getting no power to the coil and no activity from the injectors at all. I thought maybe the regulator was bad, causing too high of pressure - which led me to disconnecting the injector (and injectors) to reduce load on the driver. But of course, that didn't change anything.

Could a bad electrical portion of the ignition switch cause this problem while still supplying voltage appropriately to pin 86 at the DME Relay, as well as pins 18 and 35 on the DME computer connector?

Thanks again.

Last edited by memoriter; 07-12-2009 at 12:15 PM..
Old 07-12-2009, 11:53 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #12 (permalink)
1984 porsche 944 na
 
ballysdad's Avatar
 
Join Date: Aug 2008
Location: Westfield NJ
Posts: 306
Yes you need primary coil voltage at crank on pin 86 of the dme relay. Did you ever supply 12v cranking voltage to pin 4 on the dme?
__________________
1984 Red NA/Sold
1984 Gray NA/Sold
1986 Red NA
1986 Gray NA
Old 07-12-2009, 12:35 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #13 (permalink)
Registered User
 
Join Date: Mar 2009
Location: West Virginia
Posts: 25
Unhappy Ready to push my 944 into the lake ...

Here's what I did this afternoon:

I tested the resistance on my ignition switch between pins 50 and 30. The resistance is absolutely 0 when I turn the key to the start position, so I'm guessing that rules the switch out.

I removed the front bumper to trace the wiring that travels along underneath. I could see no damage to the wires - it looked in great condition. I can't find any grounds that are broken, or any that are notably corroded or rusted.

I created a jumper wire from pin 50 on the ignition switch to a slightly stripped section of the red/black wire on the DME, going to pin 4. Nothing happened when I cranked the car other than it just doing what it's always done - continuously turn over - but I was definitely getting 12 volts across that wire when cranking.


Here's a recap of most of the things I've tried so far:

1. I am getting 12 volts to my injectors using the DME Relay or jumpered.

2. I get no power to the coil (no power on the black wire +).

3. The injectors are not firing.

4. The ignition switch has tested good in the starting position.

5. I have 12 volts at pin 86 for the DME relay while cranking.

6. I get 12 volts at pin 18 and 35 on the DME connector when cranking.

7. I have no voltage on DME connector pin 4 when cranking.

8. I have good/tested speed and reference sensors.

9. Jiggling the speed/ref sensor wires does nothing.

10. I just replaced the fuel pump with one from a running car.

11. There is fuel at the rail, and the filter is new.

12. Disconnecting an injector does not make them pulse while cranking.

13. I have a known-good DME computer.

14. I have no alarm module or alarm system.

15. The timing belt is not broken.

16. I'm certain there is compression, because I can feel the compression strokes as the engine turns over.

17. The battery is 805 CCA, a 550 CCA battery has also been tested in the car.

18. I have ran a jumper from the positive terminal on the battery to the positive terminal on the coil while cranking the car - still not firing.


Anyway, I'm pretty much dumbfounded as to what is wrong. Anyone have any ideas?

Thanks for any help, ahead of time, because I know this is one is a doozie.
Old 07-12-2009, 07:32 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #14 (permalink)
1984 porsche 944 na
 
ballysdad's Avatar
 
Join Date: Aug 2008
Location: Westfield NJ
Posts: 306
The biggest problem I would have with this would start at the ignition switch. I know it passed the resistance check but the hot lead from the battery goes there then to the G5 relay to power the coil and send 12v to injectors and the trigger voltage to the dme brain (red/black). If this were my car I would order a new switch. Too much rides on that circuit and it is inexpensive.
Check for 12v at the dme relay term 30 (dme primary supply) what is the resistance between + and - at the coil? Is it in spec? Do you get 12v at pin 1 on the dme connector plug 12v to ign pulse /ign coil it is the green wire that goes to pin 1 on plug. May sound dumb but also check set screw on camshaft that holds rotor on.
__________________
1984 Red NA/Sold
1984 Gray NA/Sold
1986 Red NA
1986 Gray NA
Old 07-12-2009, 08:06 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #15 (permalink)
Registered User
 
Join Date: Mar 2009
Location: West Virginia
Posts: 25
Okay ... I get 12 volts at pin 30 and 86 at the DME relay. Otherwise I couldn't use the three wire jumper method to do testing with, since 30 is power from the battery. I get 12 volts of power at the injectors with the DME relay installed and the key on START.

The rotor is securely fastened on, and the cap is on firmly as well.

I have tested the resistance on the coil. I know off the top of my head the secondary resistance (between the wires and the center) is 6200K Ohms, which is well within spec. I don't remember what the primary was (between the green and black wires). I'll retest the next time I have a chance. But still, I'm getting no power to the coil. I can't find a break anywhere, and I've swapped relays in the ignition several times with known-good ones without a change.

I also pulled the fuse box up, and it looks practically brand new underneath.

I have not tested pin 1 on the DME yet, but I will do that as soon as I can. I can't keep the car where I live, so I have to drive 12 miles each time to where I have it stored.
__________________
1987 Porsche 944 NA
1987 BMW 325e Coupe
Old 07-12-2009, 08:43 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #16 (permalink)
1984 porsche 944 na
 
ballysdad's Avatar
 
Join Date: Aug 2008
Location: Westfield NJ
Posts: 306
When you jumpered the coil with 12v right from the battery you bypassed that part of the ignition sequence 12v to pin 1. You would still need to have jumpered pin 50 to 4 on the dme plug at the same time to activate the dme signals to the injectors and fuel pump to have something to spark. I would do that and put a spark tester in line and noid light on the injectors. While you at it you may as well have the 3 way jumper in the dme relay slot then you have bypassed the entire switch except pin 50 trigger voltage.
I have read every detail you have tested and my vote is still the ignition switch and trigger signal. I started another no start thread so others may chime in and help with their experiences.
__________________
1984 Red NA/Sold
1984 Gray NA/Sold
1986 Red NA
1986 Gray NA
Old 07-12-2009, 09:10 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #17 (permalink)
Registered User
 
Join Date: Mar 2009
Location: West Virginia
Posts: 25
Here's an update - I DO have 12v on DME Computer's pin 4 while cranking the car.

However, I DO NOT get 12v on pin 1 of the DME Computer's connector. I get around 3v, not 12v, while cranking the car.

I removed the cover on the DME Computer's connector and found all the wires are in great shape, and there is no damage, melting, or corrosion on any of the connections going into the pins.
__________________
1987 Porsche 944 NA
1987 BMW 325e Coupe
Old 07-17-2009, 06:13 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #18 (permalink)
 
Now Available for Ordering:   101 Projects For Your BMW 3 Series 1982-2000  [more info]
1984 porsche 944 na
 
ballysdad's Avatar
 
Join Date: Aug 2008
Location: Westfield NJ
Posts: 306
Looking now at the electrical diagram brb.

What voltage do you get at the coil on the Green wire (-) when the key is on? test to ground. This is the ground path from the negative back to pin #1 at the dme connector. It does go to the 14 pin dme plug and right to the coil.

Pin 15 from the ignition switch should supply 12v to the black wire on the ignition coil. The green (neg) should have 12v and go back through 14pin dme connector to the dme pin #1 (green) for ignition pulse.
__________________
1984 Red NA/Sold
1984 Gray NA/Sold
1986 Red NA
1986 Gray NA

Last edited by ballysdad; 07-17-2009 at 06:34 PM..
Old 07-17-2009, 06:17 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #19 (permalink)
Registered User
 
Join Date: Mar 2009
Location: West Virginia
Posts: 25
Question

On the DME Computer's PIN 1 to ground, I was getting an odd reading of around 2.5 to 3 volts.

I remember, before, I was getting no voltage at the coil. So, after I found voltage on pin 4 (and the odd reading on pin 1), I retested my coil and found there was no voltage on either side of it.

Would running a test replacement wire from DME PIN 1 to the coil be a good idea?

It seems like a logical step, after having looked at the electrical schematics. The wire apparently goes straight from DME PIN 1 to the coil.
__________________
1987 Porsche 944 NA
1987 BMW 325e Coupe
Old 07-17-2009, 07:00 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #20 (permalink)
Reply

Tags
coil, pin, solenoid, start

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 08:21 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - 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.