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Old 06-29-2011, 01:17 PM   #96 (permalink)
MetroMPG
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,527

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 54.46 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)

Appliance car - '14 Mitsubishi Mirage ES (base)
90 day: 65.39 mpg (US)
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groundskeeping

Insight's chassis ground strap problem...

I removed, tested (for resistance) cleaned & reinstalled the two chassis-to engine/transmission ground straps yesterday. The mating surfaces at the bolts & terminals were pretty corroded & cruddy. The wiring itself checked out OK.

Also cleaned some corrosion from the negative 12v battery-to-chassis cable, and from the positive 12v terminal & battery cable connector.

These can cause some problems when they start to corrode and resistance increases. Corroded ground straps are apparently a fairly common problem on these cars (at least those that live where corrosion is a part of life). Some Insight owners report they have to change the straps themselves because the wires have corroded to the point of actually breaking.

Insight's redundant 12v starter

With the IMA switch in the OFF position, the car should revert to using its redundant, conventional 12 volt starter instead of the faster, quieter, 144v IMA motor which normally spins up the ICE when you turn the key.

(With IMA in normal working order, the 12v starter is also called into action by the computer when the hybrid battery is either too cold or too warm.)

I have the IMA switch turned "OFF" to protect the worn out pack from further damage, and I was having trouble starting the car via the 12v starter:
  • Sometimes when I turned the key there was a mad buzzing sound coming from an unidentified relay under the dash, and no 12v starter action.
  • Sometimes with the key held at "start", the 12v starter seemed to engage and disengage randomly as though the key switch was being jiggled.
  • Sometimes there was a several second delay before the 12v starter would go.
  • Sometimes nothing would happen at all.
A couple of times, I got stuck at a stop with an unresponsive 12v starter. Had to go to IGN off, reach back and flip the IMA switch back "ON" to use the 144v IMA starter to refire the ICE.

But the good news: cleaning up the ground straps seems to have fixed all this. The 12v starter comes to life reliably when the key is turned.

Interestingly, the ICE now seems to run slightly smoother, though I'm doubting my perception. (Might be a case of "I got brand new sneakers and feel like I can run faster!")
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Project MPGiata! Mods for getting 50+ MPG from a 1990 Miata
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: 70 MPG in my ecomodded, dirt cheap, 3-cylinder Mirage.
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
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