[icingdeath88]

Originally Posted by ddmd

To All,
Any help with this will be appreciated since my engine knowledge is limited. My son was in an accident with my LSi in November where he rear ended someone at low speed. Their rear bumper rode over our front bumper and crushed the radiator into where it was barely touching the engine. The air bags didn't deploy. I removed the damaged parts, had a new radiator support put in, and tried to start the car. It cranks but doesn't start. I can hear the fuel pump running if I'm underneath the car. Tomorrow I'll spend some time trying to figure this out. Any ideas will be appreciated.
1. I'll pull the fuel line off after the filter to see if there's pumping gas.
2. I'll pull a spark plug to see if they're wet (injectors) and if they have spark.
3. Is there an "accident relay" or "after emergency mode" that turns
something off in the ignition circuit when in an accident? I don't think so.
-Does the "fuel rollover switch" have a role? maybe. never had to mess with this myself. I think this would just turn off the fuel pump though.
-Does the security system have to be reset? not if it's cranking. the security system can interrupt the signal to the starter to prevent the car from running, but that's the only way it can, AFAIK.
4. I'll check for vacuum hoses that came off (didn't see any) and harness
connectors that may have come off. The harnesses, at least in the
damaged area, seemed to be undamaged. Look for wiring that's between body panels and such that might be pinched. Most of the wiring for the engine is confined to the back of the engine bay, however. The body harness that goes through the driver side fender, across the front of the car is for the headlights, some A/C, etc, but not for the engine. So if it's damaged, it might not be causing this issue, but might cause others.
5. I'll look at ground connections.
6. The "ambient air temp sensor" looks OK but doesn't the ECU uses this
for air mixture? I assume I can just check the temp gauge in the car
to see if this works. The ECU doesn't use this. I think only the A/C system uses this.
7. Are there parts that may break with impact that wouldn't allow the
car to start at all? -Mass Air Flow Sensor Connections in the MAF might break in a collision. They sometimes break and need to bre re-soldered just due to age, so an accident could do it.
-ECM
-Crank Sensor
Thanks in advance,
Dennis

Some answers in red above. Might be a good idea to post some pics of the damage. Also, do any ECU codes come up? That should be the first thing to check on the list if you haven't already.