To bump or key start?

[GRU]

Originally Posted by HilseeJ

Maybe going key-off at a red light is more common than I originally presumed.

I still can't say I'm convinced it's a good idea though.



I'm confused here. Are you saying that you bump start 5-10 seconds BEFORE coming to a complete stop? As in coasting for 5-10 seconds before a stop but after a bump start?

Yes, i bump start it at about 20mph so by the time i get to a full stop at the light my engine has been idling for about 5-10 seconds.

[Frank Lee]

Could very well be that IF a starter issue develops, you don't need to replace the whole thing. I have found a new set of brushes ($5-$20 for my stuff) to cure all my starter ills so far. However I am willing and able to put them in myself.

[HilseeJ]

Originally Posted by GRU

Yes, i bump start it at about 20mph so by the time i get to a full stop at the light my engine has been idling for about 5-10 seconds.

Am I missing something or could you simply just wait longer before bumping? It might result in a more erratic/sudden stop but it should cut down on idling a teensy bit.

For me, if I'm EOC'ing up to a red light I bump it right before I have to stop. That would leave an estimated 3 seconds of idling maximum.

This is a bit of a side step from the original topic but I'm still interested as to whether I might be doing something wrong.

[pete c]

At most lights you can see the reflection of the other directions yellow light in the light shade. I look for this and start my car as soon as I see yellow for the other direction.

[SiVX]

I don't know much about starters so I've been hesitant to cut off at lights. Sadly, my kill switch broke already I used a cheapy. I think this time I'm gonna get a push button, buy a cruise control plate and hide it behind there. Kill switch plus a true security mod... forget that switch out in the open thing lol.

[PaleMelanesian]

Originally Posted by HilseeJ

Am I missing something or could you simply just wait longer before bumping? It might result in a more erratic/sudden stop but it should cut down on idling a teensy bit.

For me, if I'm EOC'ing up to a red light I bump it right before I have to stop. That would leave an estimated 3 seconds of idling maximum.

This is a bit of a side step from the original topic but I'm still interested as to whether I might be doing something wrong.

My thoughts as well. I can reliably bump start below 5 mph. I do it regularly at certain stop signs.

My key-start with a warm engine is fast. If I'm watching the cross lights I can usually be the first one off the line.

Oh, and I'm on my original starter at 194,000 miles. The first 150k was "normal" driving. At 1 key start per 10 miles that's 15,000 starts. 44k miles hypermiling at maybe 1 key start every 2 miles is another 22,000 starts, for a total of (very approximately) 37,000 starts.

[user removed]

If you need to bump start just before the light changes, why not use DFCO to slow down a little faster and avoid the whole shut down restart scenario altogether.

I know every one of the 46 lights I go through regularly, and I know when they are about to change to green. The Fiesta downshifts nicely to maintain DFCO down to very low speeds and it's the automated manual transmission.

Out of the 46 lights there are a couple new ones that are triggered, by cross traffic, and not synchronized. Those are the one that catch me occasionally, and in a few more months the city will get it's act together and fix their timing.

If I was going to restart, I would avoid key starts as much as possible since they may also include temporary enrichment. On the VX a key restart kills lean burn for something like 30 seconds.

regards
Mech

[NeilBlanchard]

I'll throw in another tidbit to consider: bump starting will use less energy overall, so all else being equal, it is better to bump start. If you use the starter, you have the losses of the starter motor itself (minimal) and the losses of using the alternator to replenish the charge on the battery, etc. which are somewhat greater. Bump starting has only some mechanical losses.

So, I bump start when I can (with less than about 15s of idling) or use the starter when I can sit for longer than ~15s.

[HilseeJ]

Originally Posted by Old Mechanic

If you need to bump start just before the light changes, why not use DFCO to slow down a little faster and avoid the whole shut down restart scenario altogether.

I know every one of the 46 lights I go through regularly, and I know when they are about to change to green. The Fiesta downshifts nicely to maintain DFCO down to very low speeds and it's the automated manual transmission.

I don't have any instrumentation to confirm that my car is in DFCO. Would a vacuum gauge do the trick?

I delivery drive and am afraid that someone might just reach in and take my scan gauge.

[California98Civic]

Originally Posted by HilseeJ

I don't have any instrumentation to confirm that my car is in DFCO. Would a vacuum gauge do the trick?

I don't think knowing vacuum could tell you anything for this purpose. If you could read data from the O2 sensor...

Originally Posted by HilseeJ

I delivery drive and am afraid that someone might just reach in and take my scan gauge.

Why not mount it with velcro, take it off the dashboard when you do a delivery and have a separate velcro mounting spot under the dash somewhere out of sight? You wouldn't even need to unplug it probably.