Firstly, Hello!

I'm new to the Camry forums and recently joined in order to elicit help fixing my mom's '91. I hope that I'm not stepping on any toes by jumping right in. I've searched extensively both here and on the internet at large and I can't seem to find anything to help with this particular issue.

As the title says, I'm dealing with a '91 Camry with the 3sfe engine. In the last few months I had lots of problems with burning out ignition coils and finally had a mechanic work on it. He determined that "you're right, it's the coil again... it seems that the water temp sensor was pulling current off of that circuit and overloading the primary". I'm not sure I believe his conclusion based on my understanding of the wiring diagrams but he managed to get it to start when I couldn't so I didn't argue.

Now fast forward a few days and it's down again, this time with a different symptom. The car starts up fine. You might even say it starts "eagerly" but that could be me projecting. But, as soon as it's started, it instantly dies. Blipping the throttle has NO effect so it's not that it's laboring to run. It just straight up dies right away.

So far I've tried a number of things to resolve this.

1) I unplugged the AFM to see if it would run in "limp mode". No difference. Starts then dies.

2) I thought it might be a fuel pump issue like maybe it's priming but then shutting off the pump. I jumped FP to B+ to "hotwire" the pump. No difference, except that now I can hear the pump any time the key is on. I can also hear fuel in the rail so if it probably isn't a clogged filter.

3) I thought it might be that the primary injectors weren't getting a signal. So I unplugged the cold-start injector which I reasoned might be starting the engine and then shutting down. No difference. So the injectors are getting a signal, at least initially.

4) I put a timing light on the plug wires to watch what was happening. The light shows spark during the whole event, even as the engine is coasting down after the initial start. So, I don't think it's an ignition issue. I supposed it COULD be timing related but it came on suddenly and given how easily it starts I suspect that the timing is at least close to spec.

After all of this I can only reason that the ECU is shutting the injectors off after the initial startup. I can't understand why it would do that. There are no error codes, just a solid CEL with the key in the on position (indicating functional ECU with no errors).

So, that's as far as I've gotten and I wold REALLY appreciate any input/advice/speculation as to what the problem might be or other troubleshooting that I can do.

Thanks,

-Roger

 

Don't know. Have you asked at the Toyotanation website?

Did the mechanic replace the coil? If so did this issue start after the coil was replaced?

Fuel system would not be covered by the trouble code system.

Use a section of hose as a stethoscope and determine if the injectors are still making a clicking noise as the engine shuts down.

Thought the cold start injector ran some time based on a timer when coolant was cold, is it working?

There is a fuel pressure regulator system that routes excess fuel back to the tank via a second line. Maybe pressure to low, to high. The regulator reacts to manifold pressure via a hose. Make sure the hose is not damaged, etc. The regulator should be mounted on the fuel rail some place.

Not sure how a bad water temp sensor can cause coil failure. Might look at the ign system parts-cap, rotor, wires, plugs. If these are breaking down (failing with age and use) they will cause a strain on coil.

Is the coil putting out a hot spark, should be able to gap 1/2 inch?

Have you checked for diagnostic info at the Autozone website? They often have detailed info to check various components, look in the sites vehicle repair guides. You will need to sign up but free to use.