Help! Dodge Colt won't run.

OK, lets start with the basics.

Disconnect the battery for at least 30 seconds. This causes the ECU to reset itself.

Turn on the IGN. The check engine light (CEL) should come on, then go off after about 10 seconds. There should not be any error code output. There may still be one (non-critical) if the CEL is off.

Try to start. It probably won't. You should hear a click from the MPI relay (probably behind the radio).

Now to check for fuel at the engine. CAREFULLY undo (but not remove) the two M6 bolts that secure the fuel hose to the fuel rail. Wiggle the hose: there should be some residual fuel pressure that leaks out. I suspect you have low to none. do the bolts up again.

Lets say yes, no fuel pressure. There's several possibilities:

1. the fuel filter (the can on the firewall end of the fuel hose) is blocked. To check, take if off (the input pipe fitting will be a bear to undo), and give it bang or two and reverse blast with compressed air. Can't hurt, and often unblocks the filter until you can replace it.
2. There's crud in the fuel tank thats blocking the pump filter. As a last resort, you can drain the tank from the drain c*ck on the underside of the tank.
3. The fuel pump is not running, either because its not getting power or it worn out. You get access to the pump from a plate under the rear seat or in the trunk (depends on the car model). The MPI relay is what provides power to the pump. When you turn to START, the relay provides power to the pump, and once the engine is running, the ECU controls the relay. So ... put a multmeter on the wires going into the pump. You should be able to hear the pump whirring, even from the driver's seat. If you don't have power on the pump, trace the wires back. There's another connector block somewhere under carpet near the B pillar. You 'll probably have to take the radio out to check the output of the MPI relay. MPI relays do fail.

Stewart DIBBS

Thanks for the speedy reply. It does have fuel pressure. But I only checked it at the top of the fuel filter on the firewall. I'll check at the fuel rail and let you know what happens. Eric

I have fuel pressure. It comes out pretty fast. Still won't run. I put some gas, a couple tablespoons or so, into the intake manifold. THe thing won't even pop. Now I'm really starting to suspect the spark. Even though the plugs spark blue in open air, and even though the plugs are new, and even though the ignition timing seems correct it must be spark related. Is there any way to test that? Eric

When everything looks right, a primary assumption is wrong. I advise taking the cam belt cover off and verify that the cam is correctly aligned. Its not impossible that the belt has jumped a tooth. The engine will still try to run as the ECU will do its best to set the timing back (waaaay back).

You could also check that the coolant temp sensor (on the thermostat housing AFAIK) has good connections to the wiring harness. Also, the sensor is driver by either +12V or very close to +5V (I'm not sure which for the 92), so check the wires to the sensor. This temp sensor output is critical to getting the engine to start, esspecially when cold. On a warm day, or in a heated garage, you can take the wires off the sensor and the engine should start quite easily. If the sensor is shorted out (happens sometimes) the engine can be a pig to get started.

You also need to verify that the injectors are getting power. The ECU drives these by grounding the circuit. That is, when the IGN is ON, and certainly on START, you should be able to detect +12v on on the larger of the injector wires. If there's no +12v, then I'd suspect the MPI relay, as this is where the power comes from. As said previously, it usually behind the radio, but may be in the dash near the A pillar.

Stewart DIBBS

Greetings Stewart, You are absolutely correct about me missing something. I will have time saturday to do another diagnosis. It will probably show me where I goofed when making the first. Thanks for all the help. Eric

Greetings Stewart, Thanks again for the advice. I checked again all the thing suggested. It turns out that the car would not run with the old air flow sensor, but one from the wreckers was OK. But that wasn't the only problem. I was stymied because it had spark. And the timing light was triggered OK, showing the timing was OK. However, the spark seemed a little weak. I remember the first time I changed the plugs after buying the car new was about 60,000 miles. The plug gap had increased from .030 to ,060! Yet the car still ran fine. Just hard starting at 32 degrees. To jump the .060 plug gap meant that the spark must be pretty healthy. And a spark like that should make noise in the open air. When the plugs were pulled and the spark tested it was blue but not really powerful. Not wanting to replace stuff willy-nilly and never know the actual problem I started with new plugs and then replaced the rotor. That did it! Putting the old rotor back in would make the car un-startable. Putting the old air flow sensor has the same effect. So it seems that I had two problems at the same time. Your help, and pointing out that if I find nothing wrong I must be doing something wrong made me look closer at that spark. Thanks, Eric R Snow