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Ask Tim Mohr Your Own Question
Tim Mohr
Tim Mohr, ASE Certified Technician
Category: Saturn
Satisfied Customers: 15121
Experience:  30 YRS EXPERIANCE, AUTO AND TRUCK,FOREIGN AND DOMESTIC, GAS AND DEISEL
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I need help trouble shooting my 02 Saturn L300 with the 3.0

Customer Question

I need help trouble shooting my 02 Saturn L300 with the 3.0 V6 35,000 miles
I got it from a family member and the car sat a couple of years. when I started the car it ran (not good) but was leaking fuel from the top of the tank, I dropped the tank and replaced the fuel pump assembly and the fuel filter. cleaned out the tank and the car was running fine. I had to leave on military duty and the car sat 9 months.
here's my problem.:
First-- Alt not charging battery light on dash is on. tested with my Fluke shows battery voltage.at any RPM. Changed Alternator still not charging. Checked the fusible link power wire and it is good and have 12V going to the alternator.
Second -- the car starts then dies immediately. will start every time but dies. but if I hold at 2k and above it stays running, ( and runs great no misses or stumbles) let off the pedal and it dies.
I checked all the fuses and the relays, did not find anything bad. replaced with the known horn working relay just to try. nothing. the fuel pump does not come on with the key in the on position . but does when cranking or started. I can hear it when the car dies. hooked up a fuel pressure gauge nothing at key on, 45 when it starts, when it dies holds at 42. jumped pins 87 and 30 and the pump comes on and has pressure. left the pins jumped and started the car and still dies.
no codes
security light comes on then goes out.
CPS OHMED out at 946
all lights and gauges seem to be functioning correctly
new battery
new alternator
I have 20 + mechanic exp in the military.
I have the snap on 2500 scanner and access to a Versus D10 snap on if needed
I have most test equipment if needed.
Just can't figure this one out.
thanks for your help
Mark
Submitted: 11 months ago.
Category: Saturn
Expert:  Tim Mohr replied 11 months ago.

Hi, my name is ***** ***** is caused by the computer not recognizing the signal from the key, and will not let it run, what was the actual code you got from the computer?

Customer: replied 11 months ago.
P1107
Customer: replied 11 months ago.
Are you referring to the charging problem or not staying running? or is the signal from the key affecting both?
Expert:  Tim Mohr replied 11 months ago.

they both could be related, if the alternator is not charging, and the battery gets low, it could lose the programming for the key, is the battery fully charged up right now?

Customer: replied 11 months ago.
it is, fully charged.
Expert:  Tim Mohr replied 11 months ago.

ok, if you start it and it dies, if the key is left in the run position, is the antitheft light on?

Customer: replied 11 months ago.
no it is off
Expert:  Tim Mohr replied 11 months ago.

ok, you said it had a P1107, there is no P1107 code for this vehicle, how are you pulling codes?

Customer: replied 11 months ago.
Key on the security light comes on then goes out. when it dies the light stays off. when I keep it above 2K RPM the car stays running. no light. as soon as I let off the pedal it dies
Customer: replied 11 months ago.
I was using my Snap on 2500 scanner. it was a code for low voltage Map sensor.
Customer: replied 11 months ago.
I apologize if the number was wrong, but it was in reference to low voltage Map sensor.
I'm not at home right now, at work I'll rescan if that will help
Customer: replied 11 months ago.
but I cleared that code and it hasn't returned, that's why I said no codes at the present time.
Expert:  Tim Mohr replied 11 months ago.

ok, it very well could be a bad MAP sensor, but that would not have anything to do with the alternaor not charging, so right now , you are not at the vehicle?

Customer: replied 11 months ago.
No sir I'm not. I will be home around five. It's 2:53 here in Florida
Is there some I can do when I get home?
Would the alternator affect the dying? I leave the charger on it while I'm troubleshooting it.
when I keep it above 2K RPM the car stays running. let off and it dies. starts right back up.
Customer: replied 11 months ago.
the fuel pump does not come on with the key in the on position . but does when cranking or started.
Expert:  Tim Mohr replied 11 months ago.

if the battery egts low, the computer can lose its adaptive memory, and the idle is the first one effected, when you get hon=me and are at the vehicle, just come back to this question, and we can test the alternator inputs and outputs, do you have a multi meter?

Customer: replied 11 months ago.
I do. this week end I tested and it was 12.3 going to the battery post. its a two wire Alt. battery wire and the small post for the dash light. 12.3 going to the Alt. nothing coming out. Battery light on the dash.
the new Alternator came from NAPA.
Customer: replied 11 months ago.
When I'm testing the car running I keep the battery charger on it at all times. stays above 12V. he doesn't stay running long enough to drain the battery.
Expert:  Tim Mohr replied 11 months ago.

there should be 2 wires, the red one should have 12 volts when running, with the connector disconnected, and it should then drop to .5 volts when hooked up to the alternator, does it?

Customer: replied 11 months ago.
just to be clear. which connector disconnected are you talking about? the big post or small post?
Customer: replied 11 months ago.
its very hard to get to the back of the alternator when its hooked up in the car. just want to be clear on what I'm testing.
Expert:  Tim Mohr replied 11 months ago.

there are actually 3 wires on the alternator, one large one going to the battery, then 2 smaller wires, a red and a grey wire, they both go to the PCM, the main computer, the red wire should have 12 volts when running, if disconnected, and then when attached, should drop to about.5 volts,Tim

Customer: replied 11 months ago.
Mine has two wires. the battery fusible link (RED) and a small red wire for the battery light on the dash. just want to make sure we are testing for the right application
Customer: replied 11 months ago.
I'm not trying to be a pain, just want to be correct.
Expert:  Tim Mohr replied 11 months ago.

yes, I was looking at the 2.2 engine diagram, I apologize for the confusion, there are 2 red wires , the large post goes to the battery, via the fusible link, the small post is the one going to the computer, with the key on, and engine off, it should have 12 volts, check this with the wire off the computer, if it does have 12 volt, then connect the wire, and the voltage should drop to .5 volts, if it does not, then the alternator, if the wire does not have 12 volts wih the key on, then you need check the wire between the alt and the computer for a short to ground or an open, if the wire is good, then replace the computer, the comuter also controls the idle circuit, and could also cause the other problems,Tim

Customer: replied 11 months ago.
Thank you Tim, I just wanted to make sure. I will check tonight weather permitting and get back to you.
Thank you
Mark
Expert:  Tim Mohr replied 11 months ago.

Anytime my friend, let me know,Tim