Engine will not start after upgrades**help**

[east302]

P0336 is the code.

We did the test again.. no pulse

P0336 is the code.

We did the test again.. no pulse

No pulse from the ICM or no pulse from the VCM?

So you do have voltage to the coil?


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[Denali_high]

With the new coil, I would make sure you have power going to the coil. A new coil won't send power to the distributor if it's not getting power to itself.

This might be frustrating, but another engine swap won't necessarily fix it. There's a reason why this engine isn't firing and it can be found with enough time and patience.

Thank you so much for your response! The coil is getting power.

Also have the tahoe computer i pulled the motor from. Swapped it out.. still nothing

 

[Denali_high]

Which white wire on the vcm do I probe? The white plug is the only one that doesn't have a white wire.

 

[Denali_high]

So..we probbed all the wires..no pulse period..just dims from current draw

 

[east302]

If the coil is not getting a signal from the ICM, you'd probe the white wire at the connector to the ICM. It should have four wires:

Pink: voltage
Black with white stripe: ground
White with black stripe: signal to coil
White: signal from VCM, this is what you'll probe with the coil and ICM connectors all connected.

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[Denali_high]

If the coil is not getting a signal from the ICM, you'd probe the white wire at the connector to the ICM. It should have four wires:

Pink: voltage
Black with white stripe: ground
White with black stripe: signal to coil
White: signal from VCM, this is what you'll probe with the coil and ICM connectors all connected.

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We have already done this..still nothing

 

[east302]

Oops, just saw where you posted the P0336 code. Fix that and it'll probably solve your issue since the VCM won't be able to signal the ICM. The VCM isn't seeing a signal from the Crank sensor.

Here's the diagnostics for a 1998 350, maybe it will help:

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This link may be a more user-friendly test...

http://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/how-to-test-the-crank-sensor-1






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[skylark]

The crank sensor gets 12v or so w the key off..but as soon as the keys on it drops volts drastically. Is this normal?

Nope, not normal. Put 12v directly to the pink wire from the battery and try to fire it. I bet it works.

 

[Denali_high]

Nope, not normal. Put 12v directly to the pink wire from the battery and try to fire it. I bet it works.

Already tried

 

[skylark]

Already tried

How about the ground side?