Car will not start?

Tiny
JIMEL48
  • MEMBER
  • 1996 TOYOTA TACOMA
  • 2.4L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
The car was running good and just stopped. Pulled and checked No 4 plug and it was not firing. Visual inspection of distributor cover and rotor looked good so started looking at coil. I hooked voltmeter to positive terminal on coil and ground on Battery and got 12 volts. Hooked meter to negative terminal on coil and battery ground and also got 12 volts. Checked secondary resistance and it was within specs. Checking primary resistance, I hooked meter to positive terminal and negative terminal on coil and got 0.9 ohms. Specs call for 0.45 to 0.65 ohms. I thought it was out of range, so I purchased a new coil. However, the new coil did not solve the problem and the primary resistance was 0.9 ohms also. Since I seem to have voltage to coil do I need to check CPS or should I look elsewhere?
Wednesday, February 21st, 2024 AT 4:39 PM

10 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

The crankshaft position sensor is a good suspect. To check it, try this. First, if there is a tachometer in the vehicle, see if it moves a bit when cranking. Or, if you have a live data scan tool, see if there is an RPM signal when cranking.

Take a look through this link and let me know if it seems to mirror what you are experiencing:

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

Let me know.

Take care,

Joe
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Wednesday, February 21st, 2024 AT 8:28 PM
Tiny
JIMEL48
  • MEMBER
  • 32 POSTS
It cranks 218 RPM to 223 RPM consistently.
I got a P1300 code after cranking.
For clarification the truck stopped running. Started after a couple days and I would let it idle, sounded very good, did this for two days. Tried on third day and would not start and has not started since.
I have not ruled out coil so would like to ask a couple questions.
1. Referring to my first post, the primary resistance of coil reads 0.9 ohms (specs call for 0.45 to 0.65 ohms). Is this enough difference to replace coil. Already replaced once.
2. I am getting about 12 volts at both the negative and positive terminals of the coil with key on. Is this normal?
3. Since I have voltage at coil with key on and no spark at plug when cranking does that denote the problem lies between coil and plugs?
Thanks for your time, it is greatly appreciated.
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Thursday, February 22nd, 2024 AT 9:04 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

The resistance cold should be between 0.36 and 0.55 ohms. When it is hot, it can reach up to 0.85 ohms. That is close if you are checking it hot (which I doubt since it won't run).

The 0.90 resistance is high and could prevent it from working. It wouldn't hurt to replace it and see if that makes a difference. I say that because it is beyond the specs and likely will need to be replaced soon if it hasn't already failed.

As far as the power question, if the key is on, yes, both sides will have power. Power enters through the positive and exits at the negative. The ignition system is what controls spark by providing and on/off ground.

I would replace the coil based on the resistance. Let's see if that resolves the issue.

Take care,

Joe

See pics below for testing resistance.
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Thursday, February 22nd, 2024 AT 8:01 PM
Tiny
JIMEL48
  • MEMBER
  • 32 POSTS
Thanks for your input, Joe,
I misread primary resistance for a hot coil which is not the case. You are right resistance cold (under 122F) max is 0.55 ohms. So, getting 0.9ohms is even high for a hot coil. What is confusing to me is I have gotten 2 new Delphi coils. The original coil and two new ones all show primary resistance of 0.9 ohms. I will go to a local auto store and try a different brand.
The image you sent is for checking secondary resistance. I checked it and it was within specs.
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Thursday, February 22nd, 2024 AT 9:06 PM
Tiny
JIMEL48
  • MEMBER
  • 32 POSTS
Hello Joe,

I checked the primary resistance on a Duralast coil today and it was 0, 9 ohms. So, I have checked original Toyota coil, two Delphi and one Duralast coils with resistance of 0.8 to 0.9 ohms. Auto parts place said Duralast coil specs was 0.2 to 0.9 ohms. I do not understand the difference in specs, but I think we have to assume the coil is good.
I also checked pickup coil today and it was good at 227 ohms. Any way I can check wires going to pickup coil for voltage etc.
I have to remove alternator and bracket to check crankcase position sensor. Do you feel that needs to be done considering what I have already told you?
Again, thanks for any insight you can give me.
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Friday, February 23rd, 2024 AT 4:47 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

I'm not sure what to say about the coils. I checked two manuals, and both are the same. As far as the crankshaft position sensor, were you able to confirm if there is an RPM signal? If there is one, it should be working.

Do me a favor. I attached diagnostics below specific to the P1300 code you have. Take a look through them and let me know if you are comfortable performing them.

Let me know.

Joe

See pics below.
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Friday, February 23rd, 2024 AT 8:39 PM
Tiny
JIMEL48
  • MEMBER
  • 32 POSTS
It has turned cold here, and I probably will not work at truck for a week or so.
Yes, I accessed the ECM years ago and I plan to do that after going over everything again.
Again, I appreciate your input and your prompt responses. I will keep you updated on any developments, and I may ask your opinion again as I continue to work on the truck.
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Saturday, February 24th, 2024 AT 10:34 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Sounds like a plan. Take your time and let me know how things turn out for you.

Take care of yourself,

Joe
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Saturday, February 24th, 2024 AT 7:44 PM
Tiny
JIMEL48
  • MEMBER
  • 32 POSTS
Hello Joe,

I got lucky and found no continuity between the igniter connector and 2 wires running to it. Fixed connection and is running fine.
That Toyota manual must be a misprint stating the primary coil resistance is maximum.65 ohms. I reinstalled the original Toyota coil and it works fine with a resistance of.90 ohms.
Again, I appreciate your input in this repair.
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Thursday, March 7th, 2024 AT 3:55 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

Thanks for the update. I'm glad to hear you found the issue and were able to repair it. They can be difficult at times. LOL

Regardless, take care of yourself and feel free to come back anytime in the future.

Joe
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Thursday, March 7th, 2024 AT 5:17 PM

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