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Old 09-27-2017, 02:23 PM   #19
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Join Date: Jan 2011
Posts: 295

2001 SL1
Default Re: hard starting 2001 SL1

Well this is new one. here is what happened today in order.

I used the Snap on MT-2500 scanner, STFT was a little negative, and LTFT was a little positive, not huge way off numbers. The first (pre cat) o2 sensor was switching correctly, the post cat sensor was parked at about .395V, but the emissions monitors were not locked in yet (I cleared them last time, restart the relearn....0, and the engine was running in open loop, and was running very well, no surge, BUT!!!!

When I checked the battery voltage, and then used my multi meter to verify the SnapOn reading of the battery voltage I found a wandering battery voltage, and low system voltage with all loads on, brake lights, head lights, AC and blower on Max,... etc, it was cycling to 11.9 (lowest I saw) to 13.9 volts when all the loads were on when the engine rpm fell.

As a side note, the MT-2500 has many data outputs on the saturn I have not seen before, COLL beans!!!! Future project...

So I went to AZ, to test the bat-Alt-Starter system expecting the voltage regulator/alternator to show as bad.

Silly me, the battery tested the battery was BAD!!!! Did not even suggest charging it.....I still had reservations about the Alternator VR..... and the battery was only 2 years old

Got a new free (warranty) battery from AZ!!!

So, as expected the codes got cleared again, disconnecting the battery.

But here is the crazy news!!!!!

the OBD-II code scanner showed the system switched to a green light, all sensors and emmisions monitor locked in, in a 3 minute (or less?) drive!!! WTF???? Now a happy rig running closed loop.

Even the 5 year old P0401 and P0410 codes are gone????

I must add I did check the vac lines, the PCV valve got wiggled, the CTS and AIT sensor connectors got wiggled, but I doubt that did anything.

I have no doubt this is too good to be true, so I will be monitoring it with scanners 93 rigs I have) for several days.

But in 10 years and 100,000 miles I have never seen this rig go to a closed loop green scanner (OBD-II) ready for inspection operation in less than 30 minutes of painful drive relearn process.

I have seen very odd battery behavior, but in 45 years I have never seen this version. So far the rough engine cycling with all loads on max is gone. I still need to check the peak load battery voltage, will post up when i have more data. thanks for all the feed back folks!!!


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