>> ... Today it won't even try to start. No matter which mass air flow sensor
>> is connected. The
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>Stewart DIBBS
>www.vysor.com/lancerproject
> 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.
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
Eric R Snow - 17 Mar 2005 16:14 GMT
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
>> 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
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>
>Stewart DIBBS
Eric R Snow - 27 Mar 2005 18:57 GMT
>> 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
[quoted text clipped - 25 lines]
>
>Stewart DIBBS
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