Hard Starting

1996 Geo Metro 1.0L/5spd, 200K miles,

Red, with a black hood due to an encounter with an upside down dead flying deer.

I have a puzzling problem: When I turn the key, the engine immediately fires up and shuts down after less than 1 second. Subsequent cranking sounds different, and is faster, as if the spark plugs had been removed,and doesn’t even pretend to fire up. If it is left to sit for 15 minutes, you can repeat the process- turn key, vrooom- squat!

The only way to start the thing is to turn off the fuel injector (with the switch I installed for that purpose, (otherwise it will flood hopelessly) adjust the TPS all the way lean, crank; all the way rich- crank; (repeat three or four times) then halfway- crank; a little more to rich- crank; repeat as needed and eventually it sounds like normal slower cranking again, then turn on the fuel injector for 1 second and crank; a little more to rich- crank; repeat as needed and it will eventually reluctantly start and idle.

(Helps to pull off a vacuum line sometimes…)

Once it is warmed up, it starts and runs perfectly, and gets 40 MPG on the highway.

If you let it cool more than two hours, it is time to start the whole ritual over again.

Here’s where it gets interesting: This has been going on since April, the same whether it is 100 degrees or 14 below. The entire engine was replaced with a rebuilt, including TBI, manifold, ditributor, and all parts and sensors hanging on them.

ECM has been replaced twice, as have all the sensors, coils, noise filters, etc.

This thing has eaten my life, and is still chewing.

The factory Service Manual is nearly worn out from flipping pages while I run through all the diagnostic tests.

The only clue I have is a lot of RF noise coming from the harness wire connecting the coil, ignitor and noise suppressor, which is probably part of a school of migrating Crimson Herring.

Do you think painting the hood red might cure the problem?

There is a slim to none chance changing the hood color will fix the problem. Since it does not appear to be a fuel delivery problem, it must be a spark problem. The rf noise might be a good place to start if you can isolate the source to say a bad coil wire. Bad coil wire or connection is my guess. If you can get it to fail at nighttime looking under the hood while someone else tries to start the engine you may be able to hear and see the source of the errant spark. Replacing the distributor cap and rotor may be helpful also if you have one, treat the wires GENTLY!

Igniter feeds the ignition trigger signal to the coil, and the Noise Suppressor is supposed to dampen RF interference from the ignition pulses so they don’t drown out the radio reception.
A timing light hooked up while cranking in the dead zone shows good spark, and wires, cap, rotor and plugs are new, although perhaps not premium quality. I just noticed while adjusting TPS that moving the wires going to the TPS connector with the ignition turned on causes the Idle Speed Motor to move, so I may have a lead on where the bogus sensor inputs are coming from. The only inputs to ECM during Open Loop are the Throttle Position Sensor, Idle Speed Motor, Manifold Absolute Pressure sensor, Intake Air Temperature Sensor, Engine Coolant Temperature sensor, Camshaft Position Sensor (distributor pickup coil) and the Crankshaft Position Sensor. Since the IAT, MAP, ISM and TPS are interconnected, it is likely the problem is somewhere in that circuit. If it just wasn’t so darn cold I’d spend some time metering the harness between them, but I have no garage…

Coincidentally a 92 metro problem.

spray wd40 into the intake and then try to start it if you use enough wd40 the car should run off of it for a few seconds