420A Crank no spark no start

[amir kade]

I have a 2g 97 that I fully built bottom up new motor but it is currently getting no spark.
I had put in a new crank sensor and cam sensor. It’s getting fuel and air but no spark at all, I was thinking it’s the PCM since I’m not getting 12v constant to the coil pack when key turned.

My compression is good, anyone have suggestions?

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[Bud92gsx]

Fuel, spark, compression.

This is a very common problem that is usually the ecu.. Ive had this happen myself, so u know I'm not just blowing smoke up your you hooo rofl

 

[amir kade]

Fuel, spark, compression.

This is a very common problem that is usually the ecu.. Ive had this happen myself, so u know I'm not just blowing smoke up your you hooo rofl

So what was your symptoms were they the same as mine?

 

[BLACK'98DSM]

Missing a valve cover bolt is not great. That's why the side of your cylinder head has a thick layer of oily residue. I fail to see what's new about this engine.

Anyway, what's going on with that ECU? Why has the name plate been scratched off and scribbled over with marker?

The harness isn't looking great, either. There could be damaged wire(s) floating around.

First, check the continuity and resistance of the coil power supply wire from end to end. There should be continuity and very low resistance. If that wire checks out, do the same for the crank trigger signal wire. This will narrow it down to being a faulty component and not faulty wiring.

Also check your engine ground straps, as I see many parts are missing. Hopefully you aren't trying to run the engine this way.

 

[amir kade]

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[amir kade]

Missing a valve cover bolt is not great. That's why the side of your cylinder head has a thick layer of oily residue. I fail to see what's new about this engine.

Anyway, what's going on with that ECU? Why has the name plate been scratched off and scribbled over with marker?

The harness isn't looking great, either. There could be damaged wire(s) floating around.

First, check the continuity and resistance of the coil power supply wire from end to end. There should be continuity and very low resistance. If that wire checks out, do the same for the crank trigger signal wire. This will narrow it down to being a faulty component and not faulty wiring.

Also check your engine ground straps, as I see many parts are missing. Hopefully you aren't trying to run the engine this way.

Yeah so I built this motor meaning I put all its parts together timing chain piston heads rods, cranks, etc it’s not “new” like ordered the dsm was just a shell so they’re gonna be some bolts missing cause i need to order a bolt kit for it, but the harness is just fine. I accidentally grounded he alternator wire on the frame a blunder I’ve made. That’s why I feel the ecu is cooked, it’s gonna look rough, i understand you feel as if a car is supposed to be perfect by I’m doing this by myself, just need a little help from people that have the same car check out the vid I posted

 

[BLACK'98DSM]

I wasn't implying that anything should be perfect. It is a 27 year old car after all. Just making some observations.

It's possible that you fried the voltage regulator, which is within the ECU. You need to conduct further diagnostics though before getting a new ECU that you may not need. It's not very common for the 420A ECU's to go bad.

 

[amir kade]

I wasn't implying that anything should be perfect. It is a 27 year old car after all. Just making some observations.

It's possible that you fried the voltage regulator, which is within the ECU. You need to conduct further diagnostics though before getting a new ECU that you may not need. It's not very common for the 420A ECU's to go bad.

I’m gonna post 2 videos that rule out the components the crank position sensor works but it’s getting only 8 volts from the power supply wire
and the ignition coil’s continuity is perfect

 

[amir kade]

I wasn't implying that anything should be perfect. It is a 27 year old car after all. Just making some observations.

It's possible that you fried the voltage regulator, which is within the ECU. You need to conduct further diagnostics though before getting a new ECU that you may not need. It's not very common for the 420A ECU's to go bad.

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