Previous Thread
Next Thread
Print Thread
Page 2 of 2 1 2
Re: ECU Dead? Why? **UPDATE** [Re: cjskotni] #1322422
10/19/12 07:50 PM
10/19/12 07:50 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
R
RapidRobert Offline
Circle Track
RapidRobert  Offline
Circle Track
R

Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
Quote:

Any other ideas??? What else can stop a running motor except for a bad ignition circuit?


dist pickup. I'm assuming the bulkhead has been checked/brass terminals cleaned (small metal bristle brush on the male ones/725147 NAPA male brass 1/4" terminal to clean the female ones)


live every 24 hour block of time like it's your last day on earth
Re: ECU Dead? Why? **UPDATE** [Re: RapidRobert] #1322423
10/19/12 08:10 PM
10/19/12 08:10 PM
Joined: Jan 2003
Posts: 16,376
D
dogdays Offline
I Live Here
dogdays  Offline
I Live Here
D

Joined: Jan 2003
Posts: 16,376
It's either that or a grounding issue, or a broken wire somewhere, but I'd swap distributors or pickup coils because you've done about everything else.
What kind of slop in the distributor? Can you wiggle the reluctor sideways enough to cause a misfire situation?

I am currently fighting with a ford 400 engine that has a hard miss in the #3 hole, everything else is fine. I'm pretty sure it's either how I put the distributor in or else the pickup is somehow missing that particular tooth, maybe by a few thousandths of an inch.
It can be very irksome.

R.

Re: ECU Dead? Why? **UPDATE** [Re: dogdays] #1322424
10/19/12 08:42 PM
10/19/12 08:42 PM
Joined: Sep 2007
Posts: 14,889
up yours
Supercuda Offline
About to go away
Supercuda  Offline
About to go away

Joined: Sep 2007
Posts: 14,889
up yours
If you want to rule out most of the wiring as an issue, simply run a jumper from the battery + to feed side (switched 12V) of the ballast resistor.

This will eliminate everything from the battery to the the ballast. Heck, you could jumper out the ballast to eliminate that too as a temporary test.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
Re: ECU Dead? Why? **UPDATE** [Re: RapidRobert] #1322425
10/19/12 08:44 PM
10/19/12 08:44 PM
Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni Offline OP
pro stock
cjskotni  Offline OP
pro stock

Joined: Jul 2007
Posts: 1,526
North Carolina
Quote:

Quote:

Any other ideas??? What else can stop a running motor except for a bad ignition circuit?


dist pickup. I'm assuming the bulkhead has been checked/brass terminals cleaned (small metal bristle brush on the male ones/725147 NAPA male brass 1/4" terminal to clean the female ones)




How does one test a pickup to see if it's bad? Can I look at it and see or just odomething you have to swap to find out?

Re: ECU Dead? Why? **UPDATE** [Re: cjskotni] #1322426
10/19/12 09:24 PM
10/19/12 09:24 PM
Joined: Sep 2007
Posts: 14,889
up yours
Supercuda Offline
About to go away
Supercuda  Offline
About to go away

Joined: Sep 2007
Posts: 14,889
up yours
Quote:


How does one test a pickup to see if it's bad? Can I look at it and see or just odomething you have to swap to find out?




In order of best to worst.

If you have an oscilloscope, you can pull the distributor, hook the O scope up to the leads, rotate the distributor by hand, or with a drill at slow speeds and observe the output. Maybe heat it up with a hair drier to see if it fails when hot.

If you have an analog voltmeter you can put the range to it's lowest setting and do the same test only you will be looking at needle deflection.

You can ohm it out as well, maybe use the heat idea to see if the resistance changes substantially when hot.

If you have none of the above you can swap it out with a known good unit.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
Re: ECU Dead? Why? **UPDATE** [Re: Supercuda] #1322427
10/19/12 10:26 PM
10/19/12 10:26 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
R
RapidRobert Offline
Circle Track
RapidRobert  Offline
Circle Track
R

Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
You could ohm it at the pickup pull apart connector & do it fast while it's still hot. The spec is in the archives. Also put your VOM on low AC volts scale & see if the pickup will generate iirc ~1 volt AC while someone cranks it. Could sub in another pickup/plate or another dist depending on what you have available


live every 24 hour block of time like it's your last day on earth
Re: ECU Dead? Why? **UPDATE** [Re: RapidRobert] #1322428
10/20/12 09:09 AM
10/20/12 09:09 AM
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383 Offline
Too Many Posts
70Cuda383  Offline
Too Many Posts

Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
Ok, so you've replaced the ECU, the coil, the ballast, and are now checking the distributor.


any chance that this is NOT ignition related? maybe it's fuel related? is your tank vents plugged up putting a vacuum on the fuel system, which then causes air to suck in from the carb to relieve the vacuum in the tank. or maybe your carb is heating up too much and you're getting vapor lock?

next time it happens, quickly check for spark. if you have spark, then maybe your problem is not in the ignition system.


**Photobucket sucks**
Re: ECU Dead? Why? **UPDATE** [Re: RapidRobert] #1322429
10/20/12 09:39 AM
10/20/12 09:39 AM
Joined: Mar 2006
Posts: 9,791
MI, usa
dvw Offline
master
dvw  Offline
master

Joined: Mar 2006
Posts: 9,791
MI, usa
Quote:

You could ohm it at the pickup pull apart connector & do it fast while it's still hot. The spec is in the archives. Also put your VOM on low AC volts scale & see if the pickup will generate iirc ~1 volt AC while someone cranks it. Could sub in another pickup/plate or another dist depending on what you have available




Also swap the box and coil with your original parts during the time when it's failed. My bet is neither part will make it start but you should check. The resistance spec for the pick-up coil is aprox 270 ohms. Ohm testing wiring itself is a poor method. It puts no load on the circuit(amperage). Rig a simple tester with a new style head lamp bulb. Disconnect the circuit you want to test from both ends. Hook one end of the bulb to battery positive, the other end of the bulb/tester to one end of the circuit you want to test. Now ground the other end of the circuit you are testing, the bulb should light. I can't tell you how many wires I've found that went open circuit when heated or placed under load. You can check your entire key fed circuit by placing the bulb after the ballast resistor and grounding the other side of the bulb, then key on. Your problem really should be very easy to find. I bet less than 1 hour.
Doug

Re: ECU Dead? Why? **UPDATE** [Re: 70Cuda383] #1322430
10/20/12 09:42 AM
10/20/12 09:42 AM
Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni Offline OP
pro stock
cjskotni  Offline OP
pro stock

Joined: Jul 2007
Posts: 1,526
North Carolina
These are possibilities but I don't think this is fuel related. This is why:

- fuel bowls on the carb on a HOT (95 deg) day after running the motor in traffic 30+ minutes were maybe 145 degrees. I don't think that would be hot enough to boil the fuel? Maybe I am wrong here Either way, then it didn't make the motor die or hard to start...

- car was running fine for quite awhile and I have done NOTHING to the fuel system to cause this. Same tank/vents/carb/pump everything.

I can try to check for spark next time this happens on one of the plugs and see.


I have a new distriibutor pickup on the way. For $20 I will just get a new one and swap it in to see if that fixes my problem. I read some people online had the exact same problem as me ( car would run until warm then die until cool) and it was the dist pickup.

Worth a shot I guess. Any other ideas if this doesn't work?

Re: ECU Dead? Why? **UPDATE** [Re: cjskotni] #1322431
10/20/12 04:55 PM
10/20/12 04:55 PM
Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni Offline OP
pro stock
cjskotni  Offline OP
pro stock

Joined: Jul 2007
Posts: 1,526
North Carolina
I popped the distributor cap today and found this on the rotor. What would cause this to happen and do I need a new rotor now or can this clean up? Would this cause my warm engine dying issues?

Please advise me guys. I am still learning this car and ignition system!

Re: ECU Dead? Why? **UPDATE** [Re: cjskotni] #1322432
10/20/12 06:44 PM
10/20/12 06:44 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
R
RapidRobert Offline
Circle Track
RapidRobert  Offline
Circle Track
R

Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
The rotor looks bent in the pic. I had one like that & I believe it was caused by my carelessness in not setting the cap straight down. I tried to rebend it with no success. It was misfiring/snapping badly. New cap/rotor & all was good. Dont know if I needed to replace the cap as that violated my rule of only 1 part change at a time but I had one handy


live every 24 hour block of time like it's your last day on earth
Re: ECU Dead? Why? **UPDATE** [Re: RapidRobert] #1322433
10/20/12 07:35 PM
10/20/12 07:35 PM
Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni Offline OP
pro stock
cjskotni  Offline OP
pro stock

Joined: Jul 2007
Posts: 1,526
North Carolina
Quote:

The rotor looks bent in the pic. I had one like that & I believe it was caused by my carelessness in not setting the cap straight down. I tried to rebend it with no success. It was misfiring/snapping badly. New cap/rotor & all was good. Dont know if I needed to replace the cap as that violated my rule of only 1 part change at a time but I had one handy




I think you are on to something. I looked in the cap and the button is all chewed up, thats what those filings are all over the rotor it looks like. I am guessing the bent rotor sanded the button down and maybe enlarged the gap to where the spark couldn't arc across it?

I am guessing maybe when hot, this enlarged gap got wide enough to cause this?

I popped the cap a month or so ago (before this started happening) and the rotor was squeaky clean. I guess I got a bit over excited when I put the cap back on.

I have a new cap/rotor on order so we will see if this fixes the problem.

Page 2 of 2 1 2






Powered by UBB.threads™ PHP Forum Software 7.7.1