My car cranks but won't start. New ecu, new relay. There appears to be no spark at the plugs confirmed by pulling one out and grounding it. Map sensor has 5v going to it but don't know how to test the sensor itself(? $235 to replace). If ECM, relay and others are all replaced, what else could cause the no fire situation (cap, plugs, wires all new too).

. Check all under-dash and under-hood fuses with a test light or multimeter. Here's how:

https://www.askmehelpdesk.com/cars-t...tml#post252145

. Test Ignition Control Module (igniter) and coil. Many AutoZone stores can do this for free.

Does your Civic pass the 3 basic diagnostic question tests?

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Originally Posted by txgreasemonkey

. Check all under-dash and under-hood fuses with a test light or multimeter. Here's how:

https://www.askmehelpdesk.com/cars-t...tml#post252145

. Test Ignition Control Module (igniter) and coil. Many AutoZone stores can do this for free.

Does your Civic pass the 3 basic diagnostic question tests?

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I have now additionally checked the igniter (bench tested at auto parts store- it passed bench test, additionally the old coil (was replaced) was tested and it was good...
Prior to me getting involved, the kids replaced distributor cap, rotor, plugs and wires - a wire to the igniter was left off. Unfortuately this was not caught until after the ECU and relay were replaced (although a shop diagnosed the ECU originally based on codes). All fuses are known good, fuel pump engages, FUEL Filter replaced and getting fuel.

Car is turning over and nearly (but not) engaging and cranking.
All Fuses checked. Coil wires getting voltage, now getting spark @ plugs. Just can't get it to turn over and engage. Any suggestions, or should I get it into a shop?

. If you have a tachometer it may be shorting out. Therefore, remove the BLU wire from the ICM and try starting the car.

. Ensure all connections going to the ICM are clean and tight. They loosen, over time, due to heat.

. There may be a problem with the CKP, TDC, or CYP sensors in the distributor, which feed necessary data to the ECM for starting. If even one of them is bad, the housing must be replaced.

. MAP Sensor may be bad, which will prevent starting.

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Originally Posted by angusmstep

my car cranks but won't start. new ecu, new relay. there appears to be no spark at the plugs confirmed by pulling one out and grounding it. map sensor has 5v going to it but don't know how to test the sensor itself(? $235 to replace). if ECM, relay and others are all replaced, what else could cause the no fire situation (cap, plugs, wires all new too).

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/txgm- there is no tach.
Any way to test the map sensor without the vehicle being able to run? I understand you can vacuum test at the bottom but it takes idle or running to check the vacuum.
Where is the icm?