Could this be the Optispark?
Thread Starter
On The Tree
Joined: Jan 2009
Posts: 127
Likes: 0
From: Sebring, FL
Could this be the Optispark? Stock 1994 Formula. Usually the car will start very easily. Sometimes this car takes about 10 seconds to crank, but has recently randomly shut off going down the road and will take a lot of cranking to start. Other times I will go out to start it and it just refuses to start. When I come back later, it cranks up like a champ. Cycling the key does not seem to help, so I kind of doubt it is my fuel pump. It has retained power in high rpms until today when it cut out badly on two consecutive first gear pulls.
Plugs, wires, and Opti were all replaced about 8K miles ago. I have tried wiggling connectors and wires with no results. A fresh fuel filter was also installed last week.
I went to get it scanned and apparently there is a loose connection somewhere under the dash because the man said that "it won't let the scanner into the computer and it appeared to be ignition related." I figured that my next step was to check power to the Opti and coil when it won't start and then find the loose connection under the dash. Anyone got ideas? I really don't have the money for another damned Optispark.
Plugs, wires, and Opti were all replaced about 8K miles ago. I have tried wiggling connectors and wires with no results. A fresh fuel filter was also installed last week.
I went to get it scanned and apparently there is a loose connection somewhere under the dash because the man said that "it won't let the scanner into the computer and it appeared to be ignition related." I figured that my next step was to check power to the Opti and coil when it won't start and then find the loose connection under the dash. Anyone got ideas? I really don't have the money for another damned Optispark.
Thread Starter
On The Tree
Joined: Jan 2009
Posts: 127
Likes: 0
From: Sebring, FL
What about the V.A.T.S.? I switched to my spare key and so far it has been starting for me. Only three times so far, but what happens when the V.A.T.S. triggers? Any chance at all this is related?
On The Tree
Joined: Jun 2005
Posts: 105
Likes: 0
From: Wyoming
My camaro did the same thing after it would warm up it would die, then you would have to let it cool down before it would start. turned out to be a bad optical sensor.
It could also be a bad icm, autozone can test them, I would start there.
It could also be a bad icm, autozone can test them, I would start there.
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On The Tree
Joined: Jan 2009
Posts: 127
Likes: 0
From: Sebring, FL
Well I checked my fuel pressure, the Haynes manual I have says 41-47 psi with the key on motor not running and 3-10 lbs less with motor running. I am getting about 35-37 psi in both cases. The pressure spikes to about 42-44 lbs when the key is first turned on, the motor is started, or if I give it some throttle.
I am going to go ahead and replace the fuel pump and see what happens. My new question is, if I get the Walbro 255 lph in tank pump for the LT-1, will it support the 55-60 lbs of pressure needed if I swap over to a LS based motor? From what I have heard, these pumps can support about 500hp, is that true?
I am going to go ahead and replace the fuel pump and see what happens. My new question is, if I get the Walbro 255 lph in tank pump for the LT-1, will it support the 55-60 lbs of pressure needed if I swap over to a LS based motor? From what I have heard, these pumps can support about 500hp, is that true?
On The Tree
Joined: Jun 2005
Posts: 105
Likes: 0
From: Wyoming
I'm running a single walbro in my camaro...seems to be working fine. Also have you checked if you if your plugs are sparking? The first thing i do when my car dies is take out a plug, hook it back up the the plug wire and lay the plug on the headers. Then i have someone crank it over while I watch for spark. If no spark then I pull the coil wire off of the opti and have someone crank it over and see if it archs. The past three times my car died there was no spark at the plug, but the coil was sparking, indicating the cap and rotor were trashed.
If the coil doesn't spark then it could be the optical sensor.
If the coil doesn't spark then it could be the optical sensor.
Teching In
Joined: Mar 2009
Posts: 41
Likes: 0
From: Butler, PA
http://www.mainstreamtopics.com/foru...p?showtopic=78
Try the above link. Its a step by step write up to help you diagnose the problem.
Try the above link. Its a step by step write up to help you diagnose the problem.
