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96 CORROLA COLD STARTING PROBLEM
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* August 21, 2009, 03:56:18 PM
96 CORROLA 1.6 MPI (GEO PRISM) COLD STARTING PROBLEM
ONCE I RESTRICT AIR FLOW BY HAND THE ENGINE WILL START THE REST OF THE DAY.
PLEASE GIVE ME SOME IDEAS ON WHERE TO START
THANKS

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* August 26, 2009, 03:10:48 PM
#1
Need a bit more information.  What\'s the mileage on the car?  Maintenance history - what has already been done, tune-up / repairs?

What exactly do you mean by restricting airflow?  Blocking the intake by your hand while someone cranks the car or similar.

One thing that strikes me off the bat - by restricting the airflow to the engine to help it start - points at a possible issues with the cold start injector, the throttle body (could just need a good cleaning), or a potential fuel pressure / fuel supply issue on cold starts.  

By restricting airflow as you crank the engine, you effectively \"choked\" it down - enriching the mixture to help it ignite readily.  Same effect as older carburated engines - they had a choke that restricted airflow to enrich the air/fuel mixture as well help \"pull\" fuel into the cylinders.

Excessively worn sparkplugs and/or worn ignition components (plug wires, cap, rotor, etc.) can cause a hard start issue as well.  If they are not up to spec, i.e., spark is not \"hot\" enough or even a misfire issue, they would have a very hard time igniting the air/fuel mix on cold starts.

Dirty and clogged injectors are another possibility - by choking the induction system - you could have temporarily \"flushed\" dirt and grit out of the injectors when there was a stronger vacuum present.  This could also point at other potential culprits - like:  a dirty fuel filter, dirty or worn injectors, fuel leak (bad seal in injector log, hardlines, etc.), bad fuel pump, bad pressure regulator, etc.

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* August 28, 2009, 12:50:22 PM
#2
Thanks for the info;

You are right about hand choking the engine...
This engine is MPI so I didn\'t see a cold start injector.
This morning was a little colder than average (55-65 range) and seemed to start Better !
One suggestion that has been offered to me is the temp sensor....(But gauge works fine...are they sepperate?)

Once the morning cold start has been done there seems to no trouble with the rest of the day....
It can set all day @ work and no problems..... thats why It\'d driving me Nuts !

Any more thoughts would be appreciated

Dan

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* September 01, 2009, 05:25:41 PM
#3
Temperature sensor could be potential culprit.  The temp gauge does run off the same sensor, but its resolution is not fine enough to see small temperature issues that could affect cold startup.  But the temperature sensor generally gets worse at the temp extremes (ie. colder/hotter weather should make it worse - not a cold startup).

I agree - kind of weird that it only does this once a day, then be fine several hours later.  Sounds like it needs a cold soak before the problem manifests itself.  Sounds like an intermittent problems, which in itself is hard to diagnose.  Problems could be anything from a vacuum leak to fuel issues.  

I\'d start with a good tuneup, if one hasn\'t already been done - just to start from a clean slate.  Then go from there.

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* September 19, 2009, 05:07:23 PM
#4
It Looks Like the problem has been resolved>>>>

Replaced the cap and rotor after seeing a pretty big Spark show flowing over the Coil Bridge (built into Cap)
Never would have suspected it unitl the show....Because of No misfires after it started


Thanks for all your help

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* September 21, 2009, 08:36:51 PM
#5
Good to hear that it got resolved!  Thanks for posting a resolution to your topic.

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