FAS'ing and engine temps - Fuelly Forums

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Old 06-07-2006, 04:01 PM   #1
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FAS'ing and engine temps

I'm been trying out FAS'ing lately and have a couple of questions. Since starting a cold engine is one of the hardest things you can do to your engine. Do you wait until engine temperature is at normal operating temp before shutdown. It takes about 3-5 miles to get up to normal engine temp but there are a couple of spots before then that I could get a good 10-40 second FAS out of. Also a couple of light that I could shut down at also. Thoughts?
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Old 06-07-2006, 04:29 PM   #2
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On the way to work, my first FAS is after about 10 seconds, just long enough to get up my driveway and to the peak on my street. Then bump start and then 20 seconds of hill climbing before my second FAS. At that point I am at .66 kilometers and .066 liters used. That second FAS lasts about 2.5 km and then two more FAS's by the time I am 4 km into the drive to work. Then no FAS's for the next 5 km when my engine finally reaches normal operating temp.

On the way home, my first FAS is after 5 seconds, then a bump start and burst to build up speed for 10 sec then another FAS for about 1 km. Then a quick bump for 3 sec then a FAS for another km, after which I'm at 2.65 km with only .044 liters used. Another 2 FAS's by the time I am at 5 km. Then 5 miore km with no FAS when my engine reaches operating temps.

In all cases except for the initial starts, I am able to bump start as long as I time things correctly. At low speeds I bump start in 3rd and drop to 2nd for accelerating.

I use Mobil1 0W-20. No apparent issues yet.
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Old 06-07-2006, 04:46 PM   #3
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I also typically kill the engine within either 5 seconds or about 20 seconds after a cold start, depending on which way I turn out of the driveway.

If I'm not mistaken, the wear of a cold start is caused mainly by lack of oil (which has drained down while parked for an extended period). So while all starts are technically cold until the engine reaches operating temps, only the very first one has the oil issue.

I'm also running full synthetic.
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Old 06-07-2006, 05:01 PM   #4
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Quote:
Originally Posted by MetroMPG
I If I'm not mistaken, the wear of a cold start is caused mainly by lack of oil (which has drained down while parked for an extended period). So while all starts are technically cold until the engine reaches operating temps, only the very first one has the oil issue.
That is my understanding also. That is why I am not concerned.

Damn you Metro! I thought that I was the only one FASing so often. I have no tricks left up my sleeve. Looks like I need to remove my alternator belt also. One advantage you have is your kill switch and you dont have to turn the key off and on again to restart the fuel pump. I loose prolly 1/2 to 1 mile per day while I ign off long enough for the engine to die and the VSS isnt outputting a signal. But that is just a small thing. You will not see a 100 MPG segment out of the Del Sol. Methinks my low 80's segment is the wall. I just have one cylinder too many. I would love to get my hands on the Blackflea for a shot at a 110 MPG segment.
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Old 06-07-2006, 05:15 PM   #5
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Dan, why don't you do the kill switch? I'm telling you that the fuel pressure stays for much time after the engine is shut off, so you don't need to worry about that.
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Old 06-07-2006, 05:26 PM   #6
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Quote:
Originally Posted by SVOboy
Dan, why don't you do the kill switch? I'm telling you that the fuel pressure stays for much time after the engine is shut off, so you don't need to worry about that.
I did the kill switch. The engine would not bump start unless I keyed off and back on again. I read that the fuel pump is shut off as soon as the ECU senses that the engine has stopped turning. That defeats the purpose of a kil switch so I removed it. Is it different with yours? Maybe it is a OBD1 thing?
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Old 06-07-2006, 05:38 PM   #7
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Eh, I've been obd1 for a long while, I dunno, we'll see, I guess, but whatev even so.
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Old 06-07-2006, 06:51 PM   #8
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Quote:
Originally Posted by krousdb
Damn you Metro! I thought that I was the only one FASing so often.
I told you: I've been driving like a crazy person.

Though you're still likely a bigger nutbar, and I would only be mildly surprised to see 110 on the old ScanGauge with you piloting the Flea and FASing it mercilessly.

As for alternator belt - I got the data today, and it's pretty much what I thought.

EDIT: actually, it's better than I thought, now that I've looked at the numbers closer. See the alternator experiment thread: Alternator v. no alternator
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Old 06-07-2006, 07:32 PM   #9
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While fas'ing in my 91 civic hatch std, my power brakes went out.

Only happened once.

Did it happen because of a certain time window, or

Because I was using the brakes while fas'ing more than usual?
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Old 06-07-2006, 07:37 PM   #10
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Could have been either, budomove.

Eventually the vacuum will be lost if the engine is off for a long time. How long probably depends on how well sealed the plumbing is in each particular car.

If you brake while FASing, you use up the reserve eventually. On the rare occasions that I have to brake several times with the engine off (you notice it as the pedal firms up), I'll re-start it to "recharge" the vacuum, then kill it again.
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