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Toyota Service
Toyota Service, Toyota Expert
Category: Toyota
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Experience:  30+ Yrs of auto experience, Award Winning Svc. Manager; Just Answer Customer's Choice Award Winner
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91 Toyota pick up 4x4 3.0 intermittent no start. Cranks just

Customer Question

91 Toyota pick up 4x4 3.0 intermittent no start. Cranks just fine and doesn't lose any power after multiple cranks. Almost seems like a fuel or ignition issue. Got codes 25 -43 from obd1. Replaced EFI relay already but it's aftermarket and not denso so maybe it's not reading well
JA: How many miles are on the car? Has the car been starting normally?
Customer: 163k. Starts normally here and there
JA: What is the model of your '91 Toyota?
Customer: Standard pickup v6 3.0
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: That's the plan for now. So far I replaced the EFI relay
JA: Anything else you want the mechanic to know before I connect you?
Customer: That's about it. Thank you!
Submitted: 10 months ago.
Category: Toyota
Expert:  Toyota Service replied 10 months ago.

Hello. Welcome to Just Answer. Please allow me to assist you. In order to get to the cause of this issue, we need to know a couple things. First, we need to know if the spark plugs are wet with fuel when it will not start. Can you check that please?

Customer: replied 10 months ago.
As far I know they aren't wet. I'll try to pull a plug right after an attempt at starting
Expert:  Toyota Service replied 10 months ago.

Ok. That would be critical information. We will also be needing to do a quick test when it does not start. We will need a piece of wire that is bared at both ends, or a paper clip.

Customer: replied 10 months ago.
I already pulled the obd1 codes. Got 25 and 43
Customer: replied 10 months ago.
I don't have the correct tools to remove a plug right now unfortunately
Expert:  Toyota Service replied 10 months ago.

Code 25 is an oxygen sensor code. You can disconnect the oxygen sensor on this truck and it should still start.

The code 43 is the STA (starter) signal. This comes from the crank angle sensor in the distributor. This is most likely the problem. Without the STA Signal (Read at over 800 RPM), the computer will not cause the injectors to fire. That would explain the plugs not being wet.

Expert:  Toyota Service replied 10 months ago.

Most likely, you will need to replace the distributor. The crank angle/STA signal is critical to the operation of the vehicle. Perhaps your next step is to pull the cap off an examine the interior of the distributor for corrosion , loose wire connections, or a wobbly distributor shaft. Any of these issues will compromise the STA signal.

Customer: replied 10 months ago.
Ok I'm going to pull the cap off the distributor real quick and inspect it. Where do I unplug the o2 sensor
Expert:  Toyota Service replied 10 months ago.

Don't worry about the O2 Sensor at the moment. It needs replaced, or it is already disconnected. The O2 sensor is not the cause of the intermittent no start.

Customer: replied 10 months ago.
Ok. I removed the distributor cap and nothing appears to be damaged or corroded. Is there a specific thing part I should be looking directly at? Or a tall tell sign of a failing distributor
Expert:  Toyota Service replied 10 months ago.

In the center of the distributor (under the rotor, close to the bottom of the distributor casting, there should be a silver disc. This is the crank angle sensor. The part that reads the disc is a black thing that the disc passes thru. If the disc is bent, cracked, or warped, this will require a new distributor. We have had no start issues with these units form temperature changes. When the engine was hot, the sensor failed. When it cooled off, it worked again. Also, check the shaft endplay by moving the rotor laterally. If the shaft moves at all the bushings are worn out; this can compromise the crank sensor readings.

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