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> Engine barely turns over, need help
solex
post Jun 20 2020, 10:41 AM
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I have done a lot of work and had the car running fine for serveral but now I have an electrical problem that I cannot seem to find.

Symptoms:
Starter will turn a few degrees but will not turn over the engine when I release the key the starter will turn over a few more degrees as though I still have the key in the start position.

What I checked:
  1. Battery was tested and showing 12.58 volts
  2. Checked current draw looking for a dead short on negative side of battery (no current draw indicated)
  3. Also had a charger (in start mode) hooked up while starting
  4. The starter was rebuilt and a new solenoid was installed the starter was bench tested
  5. The starter relay was also removed and bench tested
  6. Visual inspection of the wiring in the engine bay and underneath the car, I could not see anything obvious

Recent work done (may not be relevant):
  1. Installed 123 D-Jet distributor (using curve D)
  2. Rebuild Fuel Injectors (Mr. Injector)
  3. Adjusted Fuel Pressure was 26 psi is now set at 28 psi
  4. New cap, rotor and wires
  5. New spark plugs W7C W175T2
  6. All new vacuum lines
  7. Compression checked #1:145 psi, #2:135 psi, #3:145 psi and #4:145 psi
  8. Replaced activated charcoal in charcoal canister (no more gas smell)
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Superhawk996
post Jun 20 2020, 02:00 PM
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0.1 ohm is too high of resistance

Ohms Law voltage = current x resistance

Stating can draw several hundred amps

Let’s use 100 amps to keep the math easy

100a x 0.1 ohm = 10 volt drop

You can see how even a 50a starter current will drop 5 volts across that strap. Not good.

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solex
post Jun 20 2020, 02:21 PM
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QUOTE(Superhawk996 @ Jun 20 2020, 04:00 PM) *

0.1 ohm is too high of resistance

Ohms Law voltage = current x resistance

Stating can draw several hundred amps

Let’s use 100 amps to keep the math easy

100a x 0.1 ohm = 10 volt drop

You can see how even a 50a starter current will drop 5 volts across that strap. Not good.



I just checked the specs on my meter and 0.1 is the lower limit of the meter so I would need to get a better meter to confirm the actual resistance of the strap but will order a new one
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Bartlett 914
post Jun 21 2020, 10:55 AM
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QUOTE(solex @ Jun 20 2020, 03:21 PM) *

QUOTE(Superhawk996 @ Jun 20 2020, 04:00 PM) *

0.1 ohm is too high of resistance

Ohms Law voltage = current x resistance

Stating can draw several hundred amps

Let’s use 100 amps to keep the math easy

100a x 0.1 ohm = 10 volt drop

You can see how even a 50a starter current will drop 5 volts across that strap. Not good.



I just checked the specs on my meter and 0.1 is the lower limit of the meter so I would need to get a better meter to confirm the actual resistance of the strap but will order a new one


I would agree with that. Measuring very low resistance has too many variables and is often unreliable. I am sure the cable is fine but the problem was properly cleaned and seated connections. Glad you are up and running
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