1972 Starting Problems - Chevelle Tech
Electrical & Wiring Troubleshooting electrical problems.

 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 11 (permalink) Old Apr 12th, 14, 5:25 PM Thread Starter
John
 
Join Date: Mar 2003
Location: Virginia
Posts: 26
1972 Starting Problems

Not my car (I have a 1971 Vette but I wish I did own it.) but my cousins. He has a 350 Malibu Convertible and it won't start.
Mallory Unilite distributor (not new, been in the car for some time and the module has not been replaced).
New Plug wires
New Plugs
New cap and rotor
New coil
All this was done about 8 to 10 months ago.

Being the family mechanic I went over a few weeks ago and I managed to get it started. I checked for voltage at the coil (9 volt, is this correct because of the resistor wire, if a resistor wire was used in these cars or should it be battery voltage). and various other places and everything looked good. I fixed a suspect ground wire. Ohm'd out the coil and it is good (static).
Was a resistor wire installed on these cars or did they use a ballast resistor between the ignition switch and the coil? If a ballast resistor was used from the factory then maybe my cousins unilite module is burned up since there is not a resistor installed at this time. The thing is with this is he's had this car for over 10 years in this configuration and has never had any ignition problems before. This is why I think the ignition wire is a resistor wire.

Put my timing light on #1 plug wire and it wouldn't fire the strobe. Put the timing light clamp on the coil to cap wire and still nothing until I was pulling the timing light clamp off the coil wire and it fired up. I pulled the coil wire off and checked continuity and it was intermittent at one of the ends. Fixed that and when I left his house that evening it would start every time.
The next day he calls me and says it's doing the same thing. He bought a new coil wire and coil but it still won't start.
I don't think it's the NSS switch because the engine turns over on the starter until the battery goes dead.
My question is could it be the ignition switch on the steering column or the key switch rod out of adjustment slightly or both?
Thanks in advance guys. Let's get this thing started……it's convertible weather again!!

Last edited by theandies; Apr 12th, 14 at 6:10 PM.
theandies is offline  
Sponsored Links
Advertisement
 
post #2 of 11 (permalink) Old Apr 12th, 14, 8:17 PM
Senior Tech Team
Eric
 
Join Date: Aug 2011
Location: Poteau, Ok
Posts: 4,104
Re: 1972 Starting Problems

You failed to mention what year his Malibu is. If his car came with a points style ignition then it had a resistor wire. Since you are reading 9v at the coil with the ignition on, I'd say it's still there. If you have 12v at the coil while cranking and 9v in run, then the ignition switch is doing its job.

I'd replace the coil HV wire.

Your just jealous because you can't hear the voices!

1967 Olds Cutlass 468 BBC/T400
1963 Plymouth Fury 440/Torqueflite
2007 Ford Mustang GT (momma's car)
oldcutlass is offline  
post #3 of 11 (permalink) Old Apr 12th, 14, 9:39 PM Thread Starter
John
 
Join Date: Mar 2003
Location: Virginia
Posts: 26
Re: 1972 Starting Problems

Well I did say 1972 in the tread title. I guess I should have in the body as well.
Thanks for the information.

Since GM didn't come out with electronic ignition until 1975 my instinct tells me the wire is still a resistor wire. The unilite was on the car when he bought it. He changed the HV coil lead along with the coil and it's doing the same thing.

I'm going to look at the ignition switch/rod setup then go to the unilite module itself.

I'm still open to any suggestion of things to check that I may be overlooking.
Thanks
theandies is offline  
 
post #4 of 11 (permalink) Old Apr 12th, 14, 10:27 PM
Senior Tech Team
Eric
 
Join Date: Aug 2011
Location: Poteau, Ok
Posts: 4,104
Re: 1972 Starting Problems

Sorry I overlooked that, you did. If there is voltage to the coil, then I'm assuming the switch is ok. You can try and run a jumper from the battery directly to the coil and see if it will start.

Your just jealous because you can't hear the voices!

1967 Olds Cutlass 468 BBC/T400
1963 Plymouth Fury 440/Torqueflite
2007 Ford Mustang GT (momma's car)
oldcutlass is offline  
post #5 of 11 (permalink) Old Apr 13th, 14, 8:13 PM
Gold Member
Joe
 
Join Date: Aug 1998
Location: Lincoln, NE
Posts: 4,477
Re: 1972 Starting Problems

John,

I would focus on the ignition connections and components. Don't focus the car's electrical system at this point.

If this is the set-up, follow the wiring:

http://www.mastercraft.com/teamtalk/...t=48341&page=7

The system needs a good power and ground. You are correct. These cars left the factory with a resistance wire built into the wiring harness to limit current to the ignition coil. This resistance wire is also combined at the coil's (+) terminal with a 'bypass relay' wire that comes from the factory starter's "R" terminal. This provides non-resistance power to aid in starting when cranking. The picture's factory wire colors are incorrect. The bypass wire from the starter is YELLOW. The resistance wire is has a woven cloth appearance.

You'll notice the the input power (RED) to the unilite needs full 12 volts apparently. Is this how the car is set-up???


**EDIT**

Read through this, apparently the system would "prefer to see 12 volts"....but is "do-able" with the resistance wire...

http://prestoliteperformance.com/med...7_38_45_47.pdf

-If you don't stand for something, you'll fall for anything.
Coppertop is offline  
post #6 of 11 (permalink) Old Apr 16th, 14, 1:03 PM Thread Starter
John
 
Join Date: Mar 2003
Location: Virginia
Posts: 26
Re: 1972 Starting Problems

Awesome information everyone. Thanks
As soon as I'm able to get back over there I'll put all the good info to use unless my cousin gets off the couch and figures it out before I can get over there.
I'll keep everyone posted as to what we find/do.

Joe - I downloaded Mallory's instructions the other day. I sent them to my cousin too. Hope he looks at them.

Again, thanks. This is why I love the car hobby so much.

John
theandies is offline  
post #7 of 11 (permalink) Old Apr 19th, 14, 6:40 PM Thread Starter
John
 
Join Date: Mar 2003
Location: Virginia
Posts: 26
Re: 1972 Starting Problems

UPDATE:
He changed the ignition switch today and still won't start. I'm now thinking it's a bad Mallory module since we've checked everything but that. I also told him to check his ground from the block to the frame and the battery to the frame and to clean them up even it the appear to be good and OHM out ok. I'm going to try to get over there soon and perform the module test spelled out in the Mallory instructions.

Have I missed anything?
theandies is offline  
post #8 of 11 (permalink) Old Apr 21st, 14, 10:34 PM
Gold Member
Joe
 
Join Date: Aug 1998
Location: Lincoln, NE
Posts: 4,477
Re: 1972 Starting Problems

Quote:
Originally Posted by theandies View Post
UPDATE:
He changed the ignition switch today and still won't start. I'm now thinking it's a bad Mallory module since we've checked everything but that. I also told him to check his ground from the block to the frame and the battery to the frame and to clean them up even it the appear to be good and OHM out ok. I'm going to try to get over there soon and perform the module test spelled out in the Mallory instructions.

Have I missed anything?
He should not have spent time and $ on the switch....

Oh well. Don't know where you/he are/is on this but getting back to basics...

Battery (-) should have 2 connections. One to body via the little pigtail bolted to the fender and one to the engine. There is no sense spending time grounding the frame (unless he has a trunk mounted battery and using the frame as the main battery (-), but I think you would have mentioned that).

There should be 3 Mallory wires. Brown, green, red. Unplug the distributor connector. With the other half of the connector in your hand, take a test light and see if it lights up with probing the red wire with the key "on". The other test lead should be stuck in the brown connector pin. This will tell you, you have both power and ground at the connector. The test light should also be lit when cranking the engine.

If that's okay, reconnect the 2 halves of the Mallory distributor connector.

Disconnect the green wire from the coil. Connect one test lead of your test lamp to the green wire. Connect the other end ( probe) of the test light to where the red wire connects (or try to stab it where the connection is made on the back side of the connector). When cranking, the light should be flashing as this indicates the module is switching ground on and off to trigger the coil.

If connections ok, but no flash, suspect module.

Let us know.

-If you don't stand for something, you'll fall for anything.
Coppertop is offline  
post #9 of 11 (permalink) Old Apr 24th, 14, 10:32 PM Thread Starter
John
 
Join Date: Mar 2003
Location: Virginia
Posts: 26
Re: 1972 Starting Problems

Thanks again guys.
I didn't know he was going to buy the ignition switch. I had mentioned it to him but he pulled the trigger. Oh well, at least I didn't have to change it. After the switch didn't work he finally checked the module and sure enough it is DEAD! He has one on order. From what he was telling me I think he may a burned it out himself. He said he was using his charger/starter and in the Unilite instructions it says NOT to use a battery starter as it can damage the module just like welding can do with it connected. Since the staring circuit is so simple (at least to some Ha Ha) and I went through it all except for checking the module I think this is the problem. I'll keep ya posted.
theandies is offline  
post #10 of 11 (permalink) Old Apr 28th, 14, 7:01 PM Thread Starter
John
 
Join Date: Mar 2003
Location: Virginia
Posts: 26
Re: 1972 Starting Problems

Module did it. He's happy. I'm happy and now when I go over there we can go play golf instead of messing with his car.
Thanks everyone!
theandies is offline  
post #11 of 11 (permalink) Old Apr 28th, 14, 7:04 PM
Gold Member
Joe
 
Join Date: Aug 1998
Location: Lincoln, NE
Posts: 4,477
Re: 1972 Starting Problems

Quote:
Originally Posted by theandies View Post
Module did it. He's happy. I'm happy and now when I go over there we can go play golf instead of messing with his car.
Thanks everyone!


-If you don't stand for something, you'll fall for anything.
Coppertop is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in









Old Thread Warning
This Thread is more than 1941 days old. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
If you still feel it is necessary to make a new reply, you can still do so though.

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome