Update, disconnect battery over night, security seems to have reset as light goes out while inserting key. Still crank/no start, but finally got my scanner back from a buddy that was borrowing it, vehicles starts with scanner hooked up and dies when unplugging it. Any Ideas? Thanks

 

A while back member posted some odd behavior when the obdII was connected and I vaguely remember it being a ground [or lack of ground] at the back of the plenum. Check the ground connections at the top back of the engine. But usually it happens after some one has worked on the vehicle.

There are multiple discrepancies/odd_observations.

Vehicle runs with ether [that has nothing to do with obdII plugged in or not. [this can not be ground problem]
Blinking security while imobilizer is not killing spark. [this could be the ground problem]

Are we missing some information here?

Salim

 

There is a grounding wire to the passenger side of the intake manifold. If that’s loose the car will crank but not start, and stall if the car is running and ground is removed. Is it possible that plugging in OBD tester provides anouther route to ground?

 

It's starting to turn into a fun thread and so many great posts even tho the OP doesn't think it's important to give details.

"Car runs only when scanner is plugged in".
What we don't know:
How long it ran?
Codes present?
How well it ran?
Exhaust smell?
Exhaust smoke?
Revs properly?
Etc, etc

What I hope we can assume:
Compression ok
Crank shaft sensor and camshaft sensors ok
Timing belt hasn't slipped
Fuel injectors pulsing properly with precise fuel delivery
Ignition coils are pulsing/plugs sparking properly
Wire harness not damaged or chewed up

I like the idea of checking grounds as mentioned above.
Engine ECM as ya'll know is a frame ground and the engine ECM's sensors & peripherals have engine ground.
Both need to be good or unpredictable problems and issues can happen.

-> I am also wondering about a possible dying Engine ECM but too early to know.

 

Update, replaced ground wires in wire loom back of engine. Seems to be fine for now. Thanks for suggestions

 

Thank you for the update.

Our mind has been trained to think logically and in this case we [at least I] took the random action of starting with ether as a consistent action.

Thank you bordenj for the right diagnosis.

The ground point is not directly visible too.

Salim

 

Umm, thanks? My post reiterated what you posted previously just with a tad more detail.

But what remains unexplained is that having the OBD tester plugged in also was a “fix”. Which must mean that plugging in the tester provides an alternate path to ground?

Yes/no?

 

A member had posted such an observation [OBD connector enabled starting].

For sure the connector has signals, power, ground and shielding. Typically the ground and shielding are connected together. Very likely that is what is happening.

Salim