96 Gst Spyder getting code p0340

[9699 RS]

I have had this 96 Eclipse GST Spyder for awhile now and I am having some issues with it. I did a head gasket job on it over this last winter and got it together running great. I put a new water pump and all new timing components as well. Additionally I put in new cam position sensor and crank angle sensor both brand new from expsi. Now I had an issue where it wasn't wanting to stay running on startup and would just die a few seconds after running. Usually would only happen after I had been driving it. I can clear the code and it comes back with the p0340. I have tried testing the cam position sensor with a volt meter. When the sensor is unplugged and the key on I am only getting 3.72v on the signal wire. I believe it is supposed to be 5v? I tested the wire from the sensor plug to the ecu and it is fine. It seems like this issue is only happening when the car is warm. If i just let it sit it will start up and run no issues. I have also had this issue happen once when driving down the road the car would just shut off and do the same thing not wanting to start issue.

So I tore the timing side of the motor apart and put in a 2nd BRAND NEW cam position sensor from expsi and it is doing the EXACT same thing.

I did try a spare ecu I had lying around and it was doing the same thing.

Only mods are valve springs and head studs. Stock turbo stock injectors etc.

Any help is greatly appreciated

 

[spyderdrifter]

Well this is about a month old, so if you're still having issues, here's a link to read if you want: https://www.engine-codes.com/p0340_mitsubishi.html
Might be worth inspecting all the wires for damage. How did you actually test the cam sensor and wires?

Here are some images I took screenshots of from the Service Manual I have on my phone.

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[luv2rallye]

Usually would only happen after I had been driving it.... It seems like this issue is only happening when the car is warm. If i just let it sit it will start up and run no issues....So I tore the timing side of the motor apart and put in a 2nd BRAND NEW cam position sensor from expsi and it is doing the EXACT same thing.

Spyderdrifter: Thanks for the factory procedures. I as an electrical engineer easily understand all those waveforms, however 99% of home car owners don't have an oscilloscope (even I don't) nor would understand them. So please don't take offense when I offer some more practical, home car owner info they can use.

Sounds like you MAY have a heat related issue with the Cam sensor using an after market part (and if so, buying another same new after market brand part won't help). Not unusual at all - I see it all the time. That's why internal critical engine parts are always best spending the extra money to use factory OEM which are designed way better in this area.

When warm and have the problem, try measuring voltage on the signal wire with it connected. It is a pulse but the voltmeter reads the average value which should be in the 0.4-3.0v range while cranking (0.5-2.0v when running). {The voltage when unconnected and on means nothing since it goes through a 5v pullup voltage divider inside the ECU and can easily read your 3.72v. But the fact you read something then is good.}

Another thing you can try (to prove it's a heat related issue) is when cold and it runs fine, heat the CAM sensor with a hair dryer. If it now starts failing you found your problem. Then try a real factory OEM part (can use Beck-Arnley sold at some auto stores which is a real factory OEM part). Note: many auto stores (and after market parts) claim OEM but OEM and factory OEM are not the same. OEM just means it will fit and function correctly but you still often have heat issues and long term reliability issues.

Of course you always may just have an intermittent bad connection on a wire and so should check that out first.