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#1077554 - 10/09/11 11:46 PM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: Strawdawg]
451Mopar Offline
master

Registered: 05/19/08
Posts: 5053
Loc: Aurora, Colorado
Right, not an easy test to rig up and test by yourself. I just checked my DMM (a Greenlee #93-606 I bough at the hardware store several years ago), and the continuity buzzer would sound even with 33+ ohms of resistance (I put 3 100-Ohm resistors in parallel.) The buzzer did not sound at 50-Ohms FWIW.
But we are looking for bad connections / grounds that are closer to 1-ohm, so checking the voltage drop across the suspect connection points at high current draw works better than testing with the meters continuity buzzer or ohms range.

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#1077555 - 10/10/11 06:32 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: 451Mopar]
Oyvind Mopar Offline
mopar

Registered: 07/04/09
Posts: 410
Loc: Norway (old world)
Hi, just want to give you a link for problem solving same problem earlier on Moparts.
Hope you fix it. Annoying problem.
http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=5616001&Main=5611904

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#1077556 - 10/10/11 06:33 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: 451Mopar]
mopar_man Offline
master

Registered: 01/19/03
Posts: 4664
Loc: Newfoundland
Too bad he dosen't have a point distributor to drop in for a minute . he would at least know if the wiring harness , ballast , and cranking voltages were ok .
Like i said in previous posts, this looks to be ECM issue.
There is only one thing I can think of that has not been addressed .......is it possible that the ignition switch housing is worn and when in starting mode he has the key twisted beyond the contacts and that only the starter is cranking and no ignition? But isn't the ignition being fed from the relay ?

I don't know whats wrong why this car is not starting and I see no reasons why it won't at present time and what been tried .

This is not rocket science, i know its difficult for someone who is just learning but for us seniors who have 40 -50 yrs at this stuff, it bugs me to no end .


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#1077557 - 10/10/11 09:32 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: mopar_man]
Strawdawg Offline
member

Registered: 10/01/10
Posts: 183
Loc: Eden, Texas
LOL...you are right...for those of us that starting off building crystal set radios 60 years ago, using a meter and checking circuits was just part of growing up. It's frustrating to try to help someone and not being able to show them how to do it.

This one is crazy because it does not work when everything is bypassed, but, we know the components work because it does start and run. Going to an extreme and powering it from a separate battery may seem uncalled for, but, it seems we have to prove it will work when it gets the right voltage.

The anomaly in this set up is the ignition box mounted inside the car...we may ultimately discover that the quality of ground is turning it off when the current draw increases.
_________________________
Steve

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#1077558 - 10/10/11 09:51 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: Strawdawg]
451Mopar Offline
master

Registered: 05/19/08
Posts: 5053
Loc: Aurora, Colorado
I think it may still be a grounding problem?
The issue may be that differences between the engine block ground and chassis ground may cause the reference point of the magnetic pickup trigger to change where the ECU is not sensing the pulses from the distrubitor. Which leads back to replace battery cables, and add grounds from ECU to engine block, and battery to chassis.

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#1077559 - 10/10/11 09:57 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: 451Mopar]
Strawdawg Offline
member

Registered: 10/01/10
Posts: 183
Loc: Eden, Texas
Quote:

I think it may still be a grounding problem?
The issue may be that differences between the engine block ground and chassis ground may cause the reference point of the magnetic pickup trigger to change where the ECU is not sensing the pulses from the distrubitor. Which leads back to replace battery cables, and add grounds from ECU to engine block, and battery to chassis.




sure would not bet against it
_________________________
Steve

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#1077560 - 10/11/11 07:00 PM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: Strawdawg]
MONC Offline
master

Registered: 04/08/04
Posts: 3037
Loc: The Historic Hudson Valley
I am hoping to work on the car tomorrow, at least for a little while.
I am going to take the glove box out again (and leave it out) so I can have easier access to the ECU for testing.

Mopar man, can you explain more about your theory of the ignition switch being worn out? With the replacement of the switch, what exactly would be worn?
The key goes in the cylinder and all that does is allow it to move the switch into the various positions, right?
Or am I missing something?

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#1077561 - 10/11/11 07:02 PM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: MONC]
MONC Offline
master

Registered: 04/08/04
Posts: 3037
Loc: The Historic Hudson Valley
And BTW I built those crystal radios too when I was a kid, problem is, it was about 35 years ago, and my memory ain't so good now .


Besides , I was never any good at diagnosing electrical problems..

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#1077562 - 10/11/11 09:14 PM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: MONC]
mopar_man Offline
master

Registered: 01/19/03
Posts: 4664
Loc: Newfoundland
Quote:

I am hoping to work on the car tomorrow, at least for a little while.
I am going to take the glove box out again (and leave it out) so I can have easier access to the ECU for testing.

Mopar man, can you explain more about your theory of the ignition switch being worn out? With the replacement of the switch, what exactly would be worn?
The key goes in the cylinder and all that does is allow it to move the switch into the various positions, right?
Or am I missing something?




Monc, I never said the ignition switch would be worn out . I was wondering about the housing . I am not sure of the configuration , did you replace the whole unit including the cylinder and keys ? Even if you replaced the switch and never replaced the rest of the ignition it may be possible that the key could be turning the switch beyond the contacts that energize the ECM. I really don't know if thats possible but at this point most of us are just grasping for straws.
This engine should be running long ago .
How about twisting the key very slowly and don't twist all the way, just enough for the starter to engage and see what happens. It just may be that your twisting beyond the starter contacts .

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#1077563 - 10/11/11 10:19 PM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: MONC]
Strawdawg Offline
member

Registered: 10/01/10
Posts: 183
Loc: Eden, Texas
Quote:

I am hoping to work on the car tomorrow, at least for a little while.
I am going to take the glove box out again (and leave it out) so I can have easier access to the ECU for testing................






Is it bolted to the firewall? Thinking of a means to run a ground strap from the mounting bolt to the engine to cover that base

I find it much easier to troubleshoot than try to give clear instructions on how to do it
_________________________
Steve

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#1077564 - 10/12/11 12:25 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: Strawdawg]
magnum440 Offline
enthusiast

Registered: 11/28/06
Posts: 347
Loc: texas
last time my challenger had that symptom or it would kick the engine over for a second on key release it was ecu...always good idea to carry a spare ecu anyways...one way to do a quick test it is to just turn ign. on unplug dist connector,,and on the harness side the male terminal just touch it to ground for a second you should hear it spark every time you ground it...if it sparks problem probably in dist,,,if it doesnt spark then problem is in the car,,had a bad dist connector on harness side once even though it looked good it wasnt...


Attachments
6867471-70blckcuda.jpg (82 downloads)


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#1077565 - 10/12/11 06:10 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: magnum440]
63stabamatic Offline
enthusiast

Registered: 09/11/06
Posts: 277
Loc: Palmyra, NY
FWIW A guy at last nights cruise said he had this problem, said the DC wires to the coil were somehow reversed. This was a standard original points system though.

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#1077566 - 10/13/11 10:31 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: mopar_man]
MONC Offline
master

Registered: 04/08/04
Posts: 3037
Loc: The Historic Hudson Valley
Quote:

Quote:

I am hoping to work on the car tomorrow, at least for a little while.
I am going to take the glove box out again (and leave it out) so I can have easier access to the ECU for testing.

Mopar man, can you explain more about your theory of the ignition switch being worn out? With the replacement of the switch, what exactly would be worn?
The key goes in the cylinder and all that does is allow it to move the switch into the various positions, right?
Or am I missing something?




Monc, I never said the ignition switch would be worn out . I was wondering about the housing . I am not sure of the configuration , did you replace the whole unit including the cylinder and keys ? Even if you replaced the switch and never replaced the rest of the ignition it may be possible that the key could be turning the switch beyond the contacts that energize the ECM. I really don't know if thats possible but at this point most of us are just grasping for straws.
This engine should be running long ago .
How about twisting the key very slowly and don't twist all the way, just enough for the starter to engage and see what happens. It just may be that your twisting beyond the starter contacts .




I was just trying to understand where these contacts are so I can check them. I did not replace the lock cylinder , only the ignition switch.
I will try your suggestion though, easy enough to do.

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#1077567 - 10/13/11 10:34 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: Strawdawg]
MONC Offline
master

Registered: 04/08/04
Posts: 3037
Loc: The Historic Hudson Valley
Quote:

Quote:

I am hoping to work on the car tomorrow, at least for a little while.
I am going to take the glove box out again (and leave it out) so I can have easier access to the ECU for testing................






Is it bolted to the firewall? Thinking of a means to run a ground strap from the mounting bolt to the engine to cover that base

I find it much easier to troubleshoot than try to give clear instructions on how to do it




The ECU is not bolted to the firewall it is bolted to the dash frame.

I didn't get a chance to do anything the other day, will have to wait until Saturday.

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#1077568 - 10/22/11 09:28 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: MONC]
MONC Offline
master

Registered: 04/08/04
Posts: 3037
Loc: The Historic Hudson Valley
Ok, finally got some time to work on car again.

I checked the lock cylinder, while the housing is a little loose I could not detect any changes as I turn the key in different positions.

I dismounted the ECU , but left it hooked up to see if there was any change in the starting issue.

With it unmounted and hooked up the car cranks but does not start.
I interpreted that to mean I have no ground, which tells me it had a good ground before.

Regardless, I am going to clean up the areas where it grounds to the frame and reinstall right now and see what happens.

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#1077569 - 10/22/11 09:39 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: MONC]
JohnRR Offline
I Win

Registered: 01/20/03
Posts: 73560
Loc: U.S.S.A.
Do you have another ECU to try ?

also do you have a helper to crank the car over while you check to see that you have voltage at the positive side of the coil ? Not sure if you did that already ?

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#1077570 - 10/22/11 10:07 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: JohnRR]
MONC Offline
master

Registered: 04/08/04
Posts: 3037
Loc: The Historic Hudson Valley
Just changed the ECU on the odd chance the generic replacement was no good.

No helpers , unfortunately.

Going to go back in the post and look at the ECU tests now that I have it accessible . ( mounted behind glove box - no I did not put it there...)

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#1077571 - 10/22/11 10:09 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: MONC]
JohnRR Offline
I Win

Registered: 01/20/03
Posts: 73560
Loc: U.S.S.A.
Quote:


Going to go back in the post and look at the ECU tests now that I have it accessible . ( mounted behind glove box - no I did not put it there...)




Since you have it unbolted now might be the time to move it to a place more accessible ? But out of sight?

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#1077572 - 10/22/11 10:13 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: JohnRR]
MONC Offline
master

Registered: 04/08/04
Posts: 3037
Loc: The Historic Hudson Valley
Yeah, I was thinking about that. Was trying to figure out how to route the wiring to a place inside I could mount it to , or through the firewall


Between posts, I just remounted a new ECU after thoroughly sanding the mounting area and the ECU and the bolts for a good ground.

I remounted it, and it STARTED IN THE START POSITION !!!!!!

Not sure if this is the end of my troubles though.

The car would idle fine for 20 minutes or more, but when I get on the road and drive, it would stall after about a mile or 2.

I am hoping this is a related issue, only 1 way to find out...

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#1077573 - 10/22/11 10:41 AM Re: Car starts when key is RELEASED, why? * UPDATE* [Re: MONC]
Strawdawg Offline
member

Registered: 10/01/10
Posts: 183
Loc: Eden, Texas
Hey!!! It is undoubtedly progress...that has to be a good feeling. Sounds like it may have been suffering a big voltage drop across the ground when the starter was engaged.

I would try to insure a good ground path back to the engine to optimize it.

Keeping my fingers crossed that it keeps running!!!!!!!!!!!!!
_________________________
Steve

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