Speed Sensor Curcuit Malfunction

DEcosse said:

post image of the Diagnostic Screen on TuneECU with all the tabs on left margin open
(do ALT + Print Screen then 'paste' into a photo program and save image)

Also, while it's cranking, monitor the manifold pressure readings in the 'tests' screen and report what the three values are. (you MUST be at least cranking, if not actually running, to get these values)

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DEcosse said:

post image of the Diagnostic Screen on TuneECU with all the tabs on left margin open
(do ALT + Print Screen then 'paste' into a photo program and save image)

Also, while it's cranking, monitor the manifold pressure readings in the 'tests' screen and report what the three values are. (you MUST be at least cranking, if not actually running, to get these values)

Click to expand...

vocaldog said:

Pressure test reads at 960 on 1 &2 cylinders and 970 on cylinder 3. It's cranking at 275rpm. Speedo and tach hooked back up. Still getting 'speed sensor circuit malfunction' error code. But speedo connector has 2 pins broken off. I wonder if that's the source If all my problems?

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warp9.9 said:

I would bet that would create a problem also.

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vocaldog said:

Pressure test reads at 960 on 1 &2 cylinders and 970 on cylinder 3.

Click to expand...

DEcosse said:

Again - the speed sender issue will NOT cause any problem starting/running
You have something else causing the non-starting

But certainly if you have broken pins in the connector not much you can do about that & will have to replace speedo regardless




That is virtually atmospheric pressure and no vacuum at all
Were those readings WHILE it was actually cranking? (& they did not change at all?)
(I haven't specifically tested it during cranking as opposed to actually running - so maybe if someone else with access can take a look and see what it reports)

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DEcosse said:

You do not need the clocks connected (on a classic*) in order for it to start.
However that is indeed source of the 'speed sensor' error message you are getting - the power to the speed sensor actually originates from the gauge.
So now gauge connected means no power to the sensor means error detected by the ECU.
But that error will not prohibit anything regards to its ability to run
*different story on a CANBUS model i.e. Roadster or Touring.

So ignore the speed sensor error for now - it will be resolved when you reconnect working speedo gauge
And has nothing to do with ability to start or run.

When you say 'won't start' - what do you mean exactly?
Won't crank or won't fire?

If it is cranking over but won't fire, you need to look to whatever you might have done with your TPS & Stepper cal.
And also look to your hoses to the MAP sensor to be sure nothing leaking there.

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Kevin frazier said:

... can the speed sensor be bench tested ...

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