Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

2 Pages V  1 2 >  
 Reply to this topicStart new topic
> No Start, Swapped combo gauge and tach and now no start. Connection between the two?
Jim C
post Dec 3 2020, 11:36 AM
Post #1


Member
**

Group: Members
Posts: 192
Joined: 11-July 19
From: Texas
Member No.: 23,294
Region Association: Southwest Region
(IMG:style_emoticons/default/confused24.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
GregAmy
post Dec 3 2020, 11:41 AM
Post #2


Advanced Member
****

Group: Members
Posts: 2,311
Joined: 22-February 13
From: Middletown CT
Member No.: 15,565
Region Association: North East States
Check that you connected the tach wire correctly. Grounding the tach signal wire will cause a no-spark condition.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Jim C
post Dec 3 2020, 12:51 PM
Post #3


Member
**

Group: Members
Posts: 192
Joined: 11-July 19
From: Texas
Member No.: 23,294
Region Association: Southwest Region
QUOTE(GregAmy @ Dec 3 2020, 11:41 AM) *

Check that you connected the tach wire correctly. Grounding the tach signal wire will cause a no-spark condition.

Double checked connections. Even connected spare tach. Both of the tachs are/were good. Still no start.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
914forme
post Dec 3 2020, 12:55 PM
Post #4


Times a wastin', get wrenchin'!
****

Group: Members
Posts: 3,896
Joined: 24-July 04
From: Dayton, Ohio
Member No.: 2,388
Region Association: None
Tach or your hookup of the tach is questionable. Your signal wire is making it to ground some how. As stated before that will not allow the spark to work.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Chris H.
post Dec 3 2020, 01:05 PM
Post #5


Senior Member
****

Group: Members
Posts: 4,031
Joined: 2-January 03
From: Chicago 'burbs
Member No.: 73
Region Association: Upper MidWest
Does the GEN warning light in the combo gauge have to be connected correctly for the car to start?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Jim C
post Dec 3 2020, 01:37 PM
Post #6


Member
**

Group: Members
Posts: 192
Joined: 11-July 19
From: Texas
Member No.: 23,294
Region Association: Southwest Region
Should it start if I disconnect the tach?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Chris H.
post Dec 3 2020, 02:23 PM
Post #7


Senior Member
****

Group: Members
Posts: 4,031
Joined: 2-January 03
From: Chicago 'burbs
Member No.: 73
Region Association: Upper MidWest
I think so as long as the wire is not grounded on the engine side. Did you check your fuses just to be sure you didn't pop one? Check your combo gauge wiring as well if you swapped that out.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Spoke
post Dec 3 2020, 04:10 PM
Post #8


Jerry
*****

Group: Members
Posts: 6,986
Joined: 29-October 04
From: Allentown, PA
Member No.: 3,031
Region Association: None
QUOTE(Jim C @ Dec 3 2020, 02:37 PM) *

Should it start if I disconnect the tach?


The tach does not inhibit the engine from running, so yes, the engine can run w/o the tach connected.

Does the fuel pump run when you turn the key on? If you have FI, the FP will run for 2 seconds when you turn the key on.

You could always disconnect the tach at the ignition coil too. It's the black/purple wire. Then try starting the engine.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
surfdogskier
post Dec 3 2020, 05:53 PM
Post #9


Member
**

Group: Members
Posts: 164
Joined: 20-May 16
From: East TN
Member No.: 20,019
Region Association: None
I have been having the same issue with my tach. The only way I can start the car and run it is if if the purple and black wire at the ignition coil is unplugged. If the car is started and I plug this wire to the coil, she immediately dies and will not start. I have just been running without the tach until I could trace the issue.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
GregAmy
post Dec 3 2020, 06:11 PM
Post #10


Advanced Member
****

Group: Members
Posts: 2,311
Joined: 22-February 13
From: Middletown CT
Member No.: 15,565
Region Association: North East States
If you plug in the tach wire at the coil and the car dies, then that wire is connecting to chassis ground.

Could be it's plugged in the wrong place up front, could be that it has chafed to ground somewhere along the way. Could be the tach has failed internally.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Spoke
post Dec 3 2020, 06:40 PM
Post #11


Jerry
*****

Group: Members
Posts: 6,986
Joined: 29-October 04
From: Allentown, PA
Member No.: 3,031
Region Association: None
QUOTE(surfdogskier @ Dec 3 2020, 06:53 PM) *

I have been having the same issue with my tach. The only way I can start the car and run it is if if the purple and black wire at the ignition coil is unplugged. If the car is started and I plug this wire to the coil, she immediately dies and will not start. I have just been running without the tach until I could trace the issue.


The same thing happened on my 914. I found the tach wire in the engine wire harness was shorting out. I measured the resistance of the tach wire at the coil and when I unplugged the engine harness from the relay board and the short remained. I ran a new wire from the tach to the relay board and all was good.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
surfdogskier
post Dec 3 2020, 08:03 PM
Post #12


Member
**

Group: Members
Posts: 164
Joined: 20-May 16
From: East TN
Member No.: 20,019
Region Association: None
QUOTE(GregAmy @ Dec 3 2020, 07:11 PM) *

If you plug in the tach wire at the coil and the car dies, then that wire is connecting to chassis ground.

Could be it's plugged in the wrong place up front, could be that it has chafed to ground somewhere along the way. Could be the tach has failed internally.


I am figuring this is probably the case. What I intend to do is run new wire directly from the coil to the tach and see if the this will fix the issue and with a new ground and go from there. I don't know if the original poster of the thread has this issue as well but my gas gauge does not work either and I figure they share a bad wire between the 2 gauges.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
surfdogskier
post Dec 3 2020, 08:04 PM
Post #13


Member
**

Group: Members
Posts: 164
Joined: 20-May 16
From: East TN
Member No.: 20,019
Region Association: None
QUOTE(Spoke @ Dec 3 2020, 07:40 PM) *

QUOTE(surfdogskier @ Dec 3 2020, 06:53 PM) *

I have been having the same issue with my tach. The only way I can start the car and run it is if if the purple and black wire at the ignition coil is unplugged. If the car is started and I plug this wire to the coil, she immediately dies and will not start. I have just been running without the tach until I could trace the issue.


The same thing happened on my 914. I found the tach wire in the engine wire harness was shorting out. I measured the resistance of the tach wire at the coil and when I unplugged the engine harness from the relay board and the short remained. I ran a new wire from the tach to the relay board and all was good.

I am hoping that is the case with mine.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Jim C
post Dec 7 2020, 04:23 PM
Post #14


Member
**

Group: Members
Posts: 192
Joined: 11-July 19
From: Texas
Member No.: 23,294
Region Association: Southwest Region
An update. I triple checked all the gauge connections. Here is what's happening: The fuel pump activates when I turn the key, it has spark at the plugs, a refurbished ECU, a 123 distributor, and will turn over and start on starter fluid BUT it has no pulse at the injectors with a noid light. Could the ignition switch be a cause? It won't lock the wheel and never seemed to operate smoothly when turning the key.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
914forme
post Dec 8 2020, 07:09 PM
Post #15


Times a wastin', get wrenchin'!
****

Group: Members
Posts: 3,896
Joined: 24-July 04
From: Dayton, Ohio
Member No.: 2,388
Region Association: None
what year car what version of engine, what EFI is it running?

Then at least we will have a clear picture to help you figure this out.

D-Jet 1.7L and 2.0L use trigger points in the base of the distributor to tell the fuel injectors when to squirt gas towards the valves.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
JeffBowlsby
post Dec 8 2020, 07:11 PM
Post #16


914 Wiring Harnesses
*****

Group: Members
Posts: 8,523
Joined: 7-January 03
From: San Ramon CA
Member No.: 104
Region Association: None
Are the three pair of injector grounds connected?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Jim C
post Dec 9 2020, 10:31 AM
Post #17


Member
**

Group: Members
Posts: 192
Joined: 11-July 19
From: Texas
Member No.: 23,294
Region Association: Southwest Region
D jet 2.0 with 123 distributor. 3 trigger point wires connected.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
GregAmy
post Dec 9 2020, 11:11 AM
Post #18


Advanced Member
****

Group: Members
Posts: 2,311
Joined: 22-February 13
From: Middletown CT
Member No.: 15,565
Region Association: North East States
So...we're talking about all this other stuff but I have to go back to your topic title and first post...

Is **ALL** you did was swap the gauges, and now it won't start?

If so, swap it all back, see if it starts.

If not then you need to tell us what else you did.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Jim C
post Dec 9 2020, 02:26 PM
Post #19


Member
**

Group: Members
Posts: 192
Joined: 11-July 19
From: Texas
Member No.: 23,294
Region Association: Southwest Region
QUOTE(GregAmy @ Dec 9 2020, 11:11 AM) *

So...we're talking about all this other stuff but I have to go back to your topic title and first post...

Is **ALL** you did was swap the gauges, and now it won't start?

If so, swap it all back, see if it starts.

If not then you need to tell us what else you did.

That's all I did and I did swap them back and no start.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
ClayPerrine
post Dec 9 2020, 03:03 PM
Post #20


Life's been good to me so far.....
***************

Group: Admin
Posts: 15,493
Joined: 11-September 03
From: Hurst, TX.
Member No.: 1,143
Region Association: NineFourteenerVille
QUOTE(JeffBowlsby @ Dec 8 2020, 07:11 PM) *

Are the three pair of injector grounds connected?


QUOTE(Jim C @ Dec 9 2020, 10:31 AM) *

D jet 2.0 with 123 distributor. 3 trigger point wires connected.



You said it will start if you spray starting fluid into the intake, so the ignition is working. Leave it alone for now.

Jeff is trying to get you to check the injection ground point on the engine case.

The grounds are not the same as the connections for the trigger points. Look at the top of the enigne case, on the right side, just to the rear and below the intake plenum. There should be a 3 spade ground connector held on by the case through bolt. Check to make sure there are 3 connections there.. 2 should each have a pair of white wires connected together, and one should have a single white wire. If any of them are disconnected, then the car will not have an injector pulse.

Let us know what you find.

Clay
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
« Next Oldest · 914World Garage · Next Newest »
 

2 Pages V  1 2 >
Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 

Display Mode: Standard · Switch to: Linear+ · Switch to: Outline

Track this topic · Email this topic · Print this topic · Subscribe to this forum

- Lo-Fi Version Time is now: 29th May 2024 - 11:01 PM
Invision Power Board v9.1.4 © 2024  IPS, Inc.
All rights reserved 914World.com © since 2002
914World.com is the fastest growing online 914 community!
We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ...