volt problem HELP

[jarredsoon]

PLease help.....

My cars batery gauge and the scan master show about 9 volts!!!!

I place a volt meter to the battery and it has 12.5

I check the alternator with car running and it is 14, battery with car running is 14 too.

I probed the harness to the ecm and it is 12.5 with motor off, key on.

Car wont start unless I put a battery charger on it, and then even when it does start the scanmaster tells me the bat is at 9 volts???? But I know the bat has 14 when car running????????

I checked the grounds by the battery and they seem good, grounds to the engine seem good, all tight and clean.????

Please help????

Thanks, Jarred.
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[Razor]

On your ECM there are two plugs. A long one and a short one. The short one in the middle has a pink/black wire that is your Ignition sense input. Check your voltage at that pin. Technically that pin is labeled A6. It has two 12 pin rows.

If the voltage there is 12.5 and your scanmaster reads 9, then you may have a bad ECM.

 

[Chuck Leeper]

"Car wont start unless I put a battery charger on it,"..
Sounds to me as tho the starter solenoid/ cable connection could be fubar.
If the solenoid pulls the starter into the flexplate, and the engine won't turn over w/o a booster, I'd be looking closely at the connections at the starter. [Including the fuseable links]
Another possibility is the battery has a bad cell. As long as there's no load, you get good volt readings. Load it w/ a starter, and the ign system, the cell goes away and you are at 9+ volts.
12 v at the batt is too low. A fully charged batt should be 12.9, or better.
The reason you have 14 with the engine running, is the alt is working, and the reading across the batt is showing that value.
Take the batt to the AP store, and have them load test it...

 

[jarredsoon]

Razor I will check that, Thanks,

CHuck, I know the bat is good I put in a known good bat from another car and have a new one for the car. I will investigate the starter seleniod, but would that explain why my IP displays low volts???

Thanks guys,

Jarred

 

[jarredsoon]

Razor, the A6 is reading 9 volts on the volt meter, so my ecm is ok then right?? what would be causing poor voltage to the A6 pin?? I checked the C16 pin (Battery) and it is good at 12.5.

Also the starter and its connections all check out good. I can hear the starter engage the motor but that is all, and only if I turn the key all the way and hold it there for a few seconds.

I am sure that this is a voltage problem.

I looked for a wire touching some metal like the exhaust but I am not sure whick wires to check and what I am really doing??

Thanks, Jarred.

 

[Chuck Leeper]

"Also the starter and its connections all check out good. I can hear the starter engage the motor but that is all".
The solenoid requires a lower power level to engage the flexplate. Once the sol strokes, it should close the hi load contact, and the starter should run. I'd take the starter off, and look at the solenoid...

 

[jarredsoon]

I am going to remove the starter tonight, I began last night but am having trouble getting ahold of one bolt. My tool collection is poor, but I have a friend who can help me out. We'll see what happens tonight.

 

[Razor]

Razor, the A6 is reading 9 volts on the volt meter, so my ecm is ok then right?? what would be causing poor voltage to the A6 pin?? I checked the C16 pin (Battery) and it is good at 12.5.

Also the starter and its connections all check out good. I can hear the starter engage the motor but that is all, and only if I turn the key all the way and hold it there for a few seconds.

I am sure that this is a voltage problem.

I looked for a wire touching some metal like the exhaust but I am not sure whick wires to check and what I am really doing??

Thanks, Jarred.

That typically comes from the ignition switch. The ignition switch gets power from the fuse box. The fuse box gets power from the fusible link at the starter.

If you see 9volts.. that "is" the problem. You need that voltage to be up at least 2.5-3volts.

Some chips wont fire injectors when voltage is low. Thrashers where known for this.

 

[jarredsoon]

Volt problem FIXED

OK so volt problem is fixed thanks to everyone on this board!!!!!! It was the connection on the starter, I cleaned it up and tightened it up really really well and all is well.......

So then I am happy and go to the gas station, car goes good....

shut off car, fill with gas........

start car and the SES is flashing rapidly in my face!!!! and car idles like GARBAGE!!! I checked for loose connections again under the hood, unplugged the MAF, tried that, then plugged it back in, no change, still garbage. I drive it to a parking stall and barley made it there. The scanmaster is reading Mal 51 and 22. I call my buddy for a ride and he shows up, we look again under the hood and see nothing out of the ordinary, he brought me a couple other proms to try if that is the problem.

After all this looking and doing nothing I start the car up and it idles GREAT, no SES, nothin!! so I drive it home. I look up mal 51 and it is bad chip so I change the chip with the one my friend gave me, (a known good stock chip). NOw the car is back to garbage and the scanmaster won't even turn on, the SES light is flashing rapidly again, and I think the ECM is shot....

But I have 14 volts on the IP and the car starts every time......

UGHhhhhh...... one thing after the next and probably all my doing too...... AHH....

Jarred.

Th

 

[Razor]

May also be dirty pins on chip socket. But dead scanmaster=bad ecm.

make sure the ecm socket has no corrossion where the two plugs go into it.

 

[jarredsoon]

where can I get a good ecm. I have heard that good ones are tough to get, should I get a gm one or an aftermarket one???

THanks, Jarred.

 

[TTA1326]

where can I get a good ecm. I have heard that good ones are tough to get, should I get a gm one or an aftermarket one???

I would stick with the GM ECM. I spent 7 years in 3 different GM dealers in my youth as a technician (including 2 Pontiac dealers) and we fixed a lot of cars that had been previously "fixed" by aftermarket ECMs. Maybe the aftermarket pieces have caught up a lot in the past 10+ years, but I wouldn't bet on it with an ECM. Find a wholesaler in your area that stocks AC\Delco parts. They are much more affordable than the typical dealer retail.

 

[Razor]

Go to the parts wanted section and put a post.. WTB stock ECM.

Make sure its not a reman.

HTH

 

[jarredsoon]

Got an ecm from my uncle and all is good to go now
Thanks you all for your help. Jarred.