Hello! Log in or Register   |  Help  |  Donate  |  Buy Shirts  See all banner ads | Advertise on TheSamba.com  
TheSamba.com
 
Intermittent starting issues, potentially bad wiring harness
Forum Index -> Type 3 Share: Facebook Twitter
Reply to topic
Print View
Quick sort: Show newest posts on top | Show oldest posts on top View previous topic :: View next topic  
Author Message
vwmattm
Samba Member


Joined: August 16, 2015
Posts: 10
Location: Detroit, MI
vwmattm is offline 

PostPosted: Sat Dec 05, 2015 11:15 pm    Post subject: Intermittent starting issues, potentially bad wiring harness Reply with quote

My 1970 FI Squareback has recently had some issues starting, maybe trouble 1 out of 5 times; not always the first start of the day either. I've experienced it while starting even after having been out and about.

The symptom is: it'll turn over after a bit, then run for maybe 30 secs, then putter out. repeat.

Background: Recently (Sept), the car has been thoroughly gone through by my mechanic, and some connectors were replaced -- PO had the wiring badly spliced and not protected -- so I think its not all that bad.

But I do suspect the white connector to the ECU to be making a poor connection. When I experience the issue, if I jiggle/reorient the ECU, it usually starts just fine. Except, this past Tues, no amount of repositioning was helping. It was also very humid / foggy outside (crazy GA weather) and I'm wondering if that could have made a poor connection even worse.

See my images, it appears that the connection points for the #24 wire are awfully shorter then the others; could it be too short to be in constant contact with the ECU? I attempted to push it further into the connector, but it I suspect those legs are a part of the connector itself, is that right?

Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.


Of course, the one other time this week I tried starting it, it fired right up... I've been reading a bunch of FI related posts here, but I'm a bit overwhelmed with where and how to start diagnosing this issue; seems like its a little particular Wink Anyone have any thoughts?
_________________
70 FI M/T Squareback
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Bobnotch
Samba Member


Joined: July 06, 2003
Posts: 18128
Location: Kimball, Mi
Bobnotch is offline 

PostPosted: Sun Dec 06, 2015 10:12 am    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

vwmattm wrote:
My 1970 FI Squareback has recently had some issues starting, maybe trouble 1 out of 5 times; not always the first start of the day either. I've experienced it while starting even after having been out and about.

The symptom is: it'll turn over after a bit, then run for maybe 30 secs, then putter out. repeat.

Background: Recently (Sept), the car has been thoroughly gone through by my mechanic, and some connectors were replaced -- PO had the wiring badly spliced and not protected -- so I think its not all that bad.

But I do suspect the white connector to the ECU to be making a poor connection. When I experience the issue, if I jiggle/reorient the ECU, it usually starts just fine. Except, this past Tues, no amount of repositioning was helping. It was also very humid / foggy outside (crazy GA weather) and I'm wondering if that could have made a poor connection even worse.

See my images, it appears that the connection points for the #24 wire are awfully shorter then the others; could it be too short to be in constant contact with the ECU? I attempted to push it further into the connector, but it I suspect those legs are a part of the connector itself, is that right?


Of course, the one other time this week I tried starting it, it fired right up... I've been reading a bunch of FI related posts here, but I'm a bit overwhelmed with where and how to start diagnosing this issue; seems like its a little particular Wink Anyone have any thoughts?


You might want to go over the entire wiring harness, and maybe see about carefully tightening up all of the connectors. I only say that, as moving the harness around indicates that something is loose with it causing an intermittant.

I was going to suggest contacting Joe and having a new harness made, but his web site is currently down, and he hasn't been in the forums much lately.
_________________
Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
mark tucker wrote:
dont the youthinasisa make all our vw stuff? Shocked
Tram wrote:
People keep confusing "restored" and "restroyed".
Back to top
View user's profile Send private message Gallery Classifieds Feedback
KTPhil Premium Member
Samba Member


Joined: April 06, 2006
Posts: 26335
Location: Conejo Valley, CA
KTPhil is offline 

PostPosted: Sun Dec 06, 2015 10:49 am    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

"Reorienting the ECU" could indicate a flakey electrical connection in the harness, as you suggest. It also could be something loose inside the ECU. It may be worth taking it out and shaking it, and perhaps opening it to see if a heavy component like an output transistor has a loose solder connection. Rare, but possible.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
vwmattm
Samba Member


Joined: August 16, 2015
Posts: 10
Location: Detroit, MI
vwmattm is offline 

PostPosted: Sun Dec 06, 2015 1:00 pm    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

KTPhil

Quote:
something loose inside the ECU.


Funny you mention that; the ECU I've got now is actually a replacement from the one that came with the car, since that one had broken solder joints! I'll double check, but it was fine when installed a few months ago.

Bobnotch: is Joe, JSMskater on here? I've seen him in a lot of harness related threads.

Does my ECU connector look like perhaps the #24 connection is not like it should be? It just looks to be shorter, maybe a loose connection over the years has burnt up the legs in there to be shorter?

Is there any recommended way to test for that condition? I did include a multimeter in my travel toolbox, but I've never really done any tests on a car before (I've only had the square since Sept even).
Is it possible to find a new replacement connector? I understand this wiring is pretty old at this point, but I'm pretty far from home to try and replace the whole harness.


thanks for the replies so far!
_________________
70 FI M/T Squareback
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Bobnotch
Samba Member


Joined: July 06, 2003
Posts: 18128
Location: Kimball, Mi
Bobnotch is offline 

PostPosted: Sun Dec 06, 2015 8:58 pm    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

vwmattm wrote:

Bobnotch: is Joe, JSMskater on here? I've seen him in a lot of harness related threads.

Does my ECU connector look like perhaps the #24 connection is not like it should be? It just looks to be shorter, maybe a loose connection over the years has burnt up the legs in there to be shorter?

Is there any recommended way to test for that condition? I did include a multimeter in my travel toolbox, but I've never really done any tests on a car before (I've only had the square since Sept even).
Is it possible to find a new replacement connector? I understand this wiring is pretty old at this point, but I'm pretty far from home to try and replace the whole harness.

thanks for the replies so far!


Yes, Joe is JSMskater.
I can't really say that it looks shorter. It might be, or it might be just right, but is moving in the plastic piece.
To test the harness, here's a link to Russ's FI pages. You can open the diagram for your year and use the ohm meter to check the harness itself (from the white ECU plug to the component).
http://classicvw.org/gallery2/v/Fuel-Injection-Manual/
It might help you out looking for a particular problem as well. Wink
_________________
Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
mark tucker wrote:
dont the youthinasisa make all our vw stuff? Shocked
Tram wrote:
People keep confusing "restored" and "restroyed".
Back to top
View user's profile Send private message Gallery Classifieds Feedback
raygreenwood
Samba Member


Joined: November 24, 2008
Posts: 15924
Location: Oklahoma City
raygreenwood is offline 

PostPosted: Mon Dec 07, 2015 7:21 am    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

The length of the connectors in the ECU plug are not important in themselves. They can vary in their position in the plug by a small amount. This is usually because of differences in the position of the locking tang.

The ONLY portions of these connectors that make contact are the pads at the tips of the forks. They make contact on the top and bottom of the circuit board edge.

I have written so much about these and the female connectors over the past 15 years that I am tired of it. The ECU connectors are less problematic than the female component ned connectors but they have the same issue. If you repeatedly remove and replug the connector.....it gets spread and makes less secure contact.

If you remove one from the plug...you can see how it works. It is a tin plated phosphor bronze fork with very little "spring" ability.
There are three potential problems a with these...and are fairly easy to fix.

1. On the fork connectors themselves....clean then with an oxidizing style circuit cleaner like pro-gold.....then use the pro-gold type circuit electrolyte upon reconnection (works wonders...one of the best products I have ever found). The issue is to remove deposits from the electrolytically oxidized tin plating to prevent tin whiskers from growing.

2. The copper pads on the edge of the circuit board get oxidized as well. Oxidized copper....meaning copper patina...whether its dark penny colored or green corroded.....is a non-conductor. I used to polish these with a pink eraser....but the pro-gold product does this better with less wear and the electrolyte creates a better connection and protects from future oxidization.

3. Bend the tips of the forks inward slightly so they make better contact. Unlike modern fuel injection connectors......there are no actual springs built into these card edge connectors so over time with plugging and unplugging cycles...they get loose.

Also.....your plug looks filthy. Make sure that the gray sliding dust cover is installed once you reassemble the plug to the ECU....and lastly make sure the strain relief clamp is installed on the wire on the outside of the ECU. It cuts down oncplug vibration and connector wear.

I would get a new harness if you can. Ray
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
vwmattm
Samba Member


Joined: August 16, 2015
Posts: 10
Location: Detroit, MI
vwmattm is offline 

PostPosted: Fri Dec 18, 2015 1:08 pm    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

Finally getting back to this... So, I got the DeoxIT cleaners as you suggested Ray, the board edge connectors look nice and shiny now. I got the spray version of their product, and so I sprayed the crap (hit it from the top and bottom) out of the big ECU plug to get everything. But, I don't have anything small enough to fit in there and really wipe the surface of those legs down with. Any suggestions? I did bend them back towards each other, and the plug is noticeably tighter now.

Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.



After all that, it still didn't want to stay running. It was getting dark, so I stopped. Next day, fired right up?! Drove/start it a few times, no problem. Yesterday I went to drive, same symptoms. Starts ok, runs for maybe 30 secs, then sputters out; even with the accelerator pedal to the floor.

I'm trying to make sense of what the brown Bentley book says.
The fuel pump relay (under drivers side dash) clicks every time I turn the key, and its getting ground, so I think its ok. I followed the harness through the engine bay, and just using my fingers, ensured that all the component connections are at least tight; they all were. (I know that doesn't necessarily equal good contact though)

Going through the first row in "table a" on pg. 21 ch. 4:
My shop recently replaced the MPS (along with the ECU), so I wanna think that hasn't died already. At that time, we also replaced the points with Pertronix ignition.

Are there any common things I should be checking? Still swimming in information-overload between threads here and the Bently Confused
_________________
70 FI M/T Squareback
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Mike Fisher
Samba Member


Joined: January 30, 2006
Posts: 16408
Location: Eugene, OR
Mike Fisher is offline 

PostPosted: Fri Dec 18, 2015 2:04 pm    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

Do you have 30 lbs fuel pressure & 13.5V+ charging power?
_________________
http://s169.photobucket.com/albums/u236/mr_bojangles500/
69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
two 57 oval ragtops sold
'68 Karmann Ghia sold

Society is like stew. If you don't keep it stirred up you end up with a lot of scum on the top! - Russ_Wolfe/Edward Abbey
Back to top
View user's profile Send private message Send e-mail Facebook Gallery Classifieds Feedback
vwmattm
Samba Member


Joined: August 16, 2015
Posts: 10
Location: Detroit, MI
vwmattm is offline 

PostPosted: Fri Dec 18, 2015 6:12 pm    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

hey Mike- I don't have a way to measure the fuel pressure at the moment (don't have a gauge). Something I should look into getting. But, I'm guessing that, it usually runs ok, so pressure must not be so bad. I'm sure that comment will come back to bite me. Also, when it was in the shop around Sept, they had a gauge on there while diagnosing other things and it was good.
Voltage is good. The battery was ~12.2 before starting, then with a little throttle, got up to ~14.1. Yes, it started this evening...

How many times should the main relay under the back-seat click while starting/cranking? Swear I heard it click a few times while testing the battery. I assume it should only click once, when the key is in the first position.
_________________
70 FI M/T Squareback
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Mike Fisher
Samba Member


Joined: January 30, 2006
Posts: 16408
Location: Eugene, OR
Mike Fisher is offline 

PostPosted: Fri Dec 18, 2015 8:13 pm    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

I'm guessing crap in your gas tank is sloshing/clogging up your fuel sock inside the tank. I made a fuel pressure gauge out of a water gauge from Home Depot. It hooks up the the capped off test port between the 3-4 or 1-2 injectors with clamped on 5/16" fuel hose. The adjustable fuel pressure regulator is on the right hooked to the fuel return line.
_________________
http://s169.photobucket.com/albums/u236/mr_bojangles500/
69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
two 57 oval ragtops sold
'68 Karmann Ghia sold

Society is like stew. If you don't keep it stirred up you end up with a lot of scum on the top! - Russ_Wolfe/Edward Abbey
Back to top
View user's profile Send private message Send e-mail Facebook Gallery Classifieds Feedback
vwmattm
Samba Member


Joined: August 16, 2015
Posts: 10
Location: Detroit, MI
vwmattm is offline 

PostPosted: Fri Dec 18, 2015 8:58 pm    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

Quote:
I'm guessing crap in your gas tank is sloshing/clogging up your fuel sock inside the tank.


Would that present itself even if the car hasn't moved, with the same fuel level, between a non-start and a start? I'm not sure of the condition of the tank, so it could be rusty in there.
_________________
70 FI M/T Squareback
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Tram
Samba Socialist


Joined: May 02, 2003
Posts: 21654
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
Tram is offline 

PostPosted: Fri Dec 18, 2015 9:56 pm    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

raygruenwald hates it when I do this, and any day I can piss somebody off is a good day, so let's do this!!!:

Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.


I'll take "What are trigger points" for $500, Trebeck!!!

Image may have been reduced in size. Click image to view fullscreen.

_________________
Give A Pal a Hand!
www.happytrailsfarm.org

vwfye wrote:
Oh the joy of custom things...



RIPRW

"I'm very fond of long walks, especially when taken by those who annoy me."- Fred Allen
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Mike Fisher
Samba Member


Joined: January 30, 2006
Posts: 16408
Location: Eugene, OR
Mike Fisher is offline 

PostPosted: Fri Dec 18, 2015 10:02 pm    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

It is a lot more likely than the ECU running/quitting/running again! Pull the fuel gauge and shine a flash light down into the tank. Pull the supply line & drain the gas filtering it through a T shirt. Unbolt the supply line to remove/clean or replace the fuel sock. Pour the filtered gas back in the tank & repeat as long as necessary. Keep looking into the tank with your flashlight & you can see the crud if there is any when it is empty. If there is a lot of rust/crud in the tank you might have to remove it for more thorough cleaning.
_________________
http://s169.photobucket.com/albums/u236/mr_bojangles500/
69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
two 57 oval ragtops sold
'68 Karmann Ghia sold

Society is like stew. If you don't keep it stirred up you end up with a lot of scum on the top! - Russ_Wolfe/Edward Abbey
Back to top
View user's profile Send private message Send e-mail Facebook Gallery Classifieds Feedback
ddare
Samba Member


Joined: January 10, 2005
Posts: 581
Location: Cypress, CA
ddare is offline 

PostPosted: Sat Dec 19, 2015 7:21 am    Post subject: Re: Intermittent starting issues, potentially bad wiring har Reply with quote

Hows the wire in the engine bay that goes from the rear harness to the FI harness? I think it is wire 19 on the d-jet connector. I would ohm that out just to be sure. I have also had issues with my voltage supply relay and/or pump supply relay grounds coming loose, so make sure those have good connections. When I had the cold start relay installed, sometimes that injector would stay open and flood the engine. I live in CA so I just took mine out but you probably need yours!

If you prefer flowcharts, I scanned this Robert Bosch d-jet manual. What I like is that it actually has the specs for each test so you don't have to flip back and forth as much. Kinda hard to read unless you view it two pages side by side though.

http://document.li/96pA
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Bobnotch
Samba Member


Joined: July 06, 2003
Posts: 18128
Location: Kimball, Mi
Bobnotch is offline 

PostPosted: Sat Dec 19, 2015 10:54 am    Post subject: Re: intermittent starting issues, potentially bad wiring har Reply with quote

vwmattm wrote:

I'm trying to make sense of what the brown Bentley book says.
The fuel pump relay (under drivers side dash) clicks every time I turn the key, and its getting ground, so I think its ok. I followed the harness through the engine bay, and just using my fingers, ensured that all the component connections are at least tight; they all were. (I know that doesn't necessarily equal good contact though.


The rear under seat relay should click once every time the key is moved to the "on" position. If it's clicking, then the ground screw holding the relay in place is loose.
_________________
Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
mark tucker wrote:
dont the youthinasisa make all our vw stuff? Shocked
Tram wrote:
People keep confusing "restored" and "restroyed".
Back to top
View user's profile Send private message Gallery Classifieds Feedback
blues90
Samba Member


Joined: March 14, 2009
Posts: 1367
Location: Hollywood ,CA
blues90 is offline 

PostPosted: Sat Dec 19, 2015 3:29 pm    Post subject: Re: Intermittent starting issues, potentially bad wiring har Reply with quote

vwmattm wrote:
My 1970 FI Squareback has recently had some issues starting, maybe trouble 1 out of 5 times; not always the first start of the day either. I've experienced it while starting even after having been out and about.

The symptom is: it'll turn over after a bit, then run for maybe 30 secs, then putter out. repeat.

Background: Recently (Sept), the car has been thoroughly gone through by my mechanic, and some connectors were replaced -- PO had the wiring badly spliced and not protected -- so I think its not all that bad.

But I do suspect the white connector to the ECU to be making a poor connection. When I experience the issue, if I jiggle/reorient the ECU, it usually starts just fine. Except, this past Tues, no amount of repositioning was helping. It was also very humid / foggy outside (crazy GA weather) and I'm wondering if that could have made a poor connection even worse.

See my images, it appears that the connection points for the #24 wire are awfully shorter then the others; could it be too short to be in constant contact with the ECU? I attempted to push it further into the connector, but it I suspect those legs are a part of the connector itself, is that right?

Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.


Of course, the one other time this week I tried starting it, it fired right up... I've been reading a bunch of FI related posts here, but I'm a bit overwhelmed with where and how to start diagnosing this issue; seems like its a little particular Wink Anyone have any thoughts?


In your very first post , the second photo down . I can clearly see the one connector , the first wire on the left , is not pushed in the white housing all the way . It needs to be . You can also see it in the third photo in your first post . There is a small prong that holds the connector itself in the white plug. Wire # 24 and #16 on the white plug to the ECU are the wires that supply voltage to the ECU . It's the voltage supply relay , the one under the rear seat which supplies the ECU with battery voltage , in turn the ECU supplies and powers up the fuel pump relay. You need both #24 and #16 to supply power to the ECU and from what it looks like #24's connector is not fully seated in the white connector .

Now in your post after you cleaned the white plug it looks like #24 connector is seated fully . Is it possible the #24 connector is not making good contact with the wire itself , where the #24 two prong connector is crimped to the wire itself?
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Display posts from previous:   
Reply to topic    Forum Index -> Type 3 All times are Mountain Standard Time/Pacific Daylight Savings Time
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

About | Help! | Advertise | Donate | Premium Membership | Privacy/Terms of Use | Contact Us | Site Map
Copyright © 1996-2018, Everett Barnes. All Rights Reserved.
Not affiliated with or sponsored by Volkswagen of America | Forum powered by phpBB