Problem with Roadmaster.

[Hijinx]

I have a 1994 Roadmaster Buick. It has 180,000 miles on it but runs like a top--when it starts.

90% of the time it starts fine. turn the key and she's off.
10% of the time the motor turns over but won't start.

Grind on it for 5 minutes--no start.

Leave it set for a day and it starts right up

I have had 2 mechanics look at it and they cannot tell what's wrong since it does this intermitently.
One kept it for a 2 weeks started every day no problem, I brought it home and it wouldn't start, let it set a day and it started right up.
This car is too nice to send to the junk yard, but I cannot be left in the lurch without knowing when it will start.

Has the LT-1 engine.

 

[Chris0nllyn]

When was the last time the Optispark system was checked out? Those things are a PITA.

 

[glhs837]

Yep, crank but no start equals lack of fuel or spark, intermittent fuel delivery being much more rare than intermittent spark, I think chris is onto it.

https://answers.yahoo.com/question/index?qid=20140124175923AARQztF


Ya know, the more I learn about GMs, the more I wonder if they just intermittently drop acid in random water coolers around the engineering spaces....... "Of course Bob, placing the ignition module behind the water pump is a brilliant idea!!!!!! Now lets frixxlewap the wotzlemups some more"

 

[Hijinx]

When was the last time the Optispark system was checked out? Those things are a PITA.

I had to Google that one, I never heard of Optispark but after reading about it I remember not too long ago having the water pump replaced.

Thanks I will get someone to look into it.

Just looked into price for the system: about $319.00 add labor for removing the water pump and replacing it and I guess I am looking at about $500 to see if that is the problem, is there any way to test it before replacement?

 

[MMDad]

I had to Google that one, I never heard of Optispark but after reading about it I remember not too long ago having the water pump replaced.

Thanks I will get someone to look into it.

Just looked into price for the system: about $319.00 add labor for removing the water pump and replacing it and I guess I am looking at about $500 to see if that is the problem, is there any way to test it before replacement?

When it won't start, pull a plug wire. Stick it on your tongue and have someone crank it. If you don't feel anything there's no spark.

 

[glhs837]

When it won't start, pull a plug wire. Stick it on your tongue and have someone crank it. If you don't feel anything there's no spark.

Is this car repair or marriage counseling?

 

[Chris0nllyn]

I had to Google that one, I never heard of Optispark but after reading about it I remember not too long ago having the water pump replaced.

Thanks I will get someone to look into it.

Just looked into price for the system: about $319.00 add labor for removing the water pump and replacing it and I guess I am looking at about $500 to see if that is the problem, is there any way to test it before replacement?

Unfortunately, since your problem is intermittent, so will the testing. You'd have to get a spark tester and wait for it to happen again.

Or after cranking and cranking, pull the plugs and turn the motor over by hand. If fuel squirts out of the cylinders, the fuel is being delivered and filling up the combustion chamber. This means the motor is getting air and fuel, but no spark.

BTW, don't get a cheap OEM replacement. Get an aftermarket one that fixed the issues GM made in the first place. The main one being the weep holes at the bottom of it. That, plus the location (on the front of the motor) allow water to enter the optispark and foul the points.

Also, depending on how long ago the water pump was replaced, it may be worth changing it at the same time. :shrug:

 

[Hijinx]

Unfortunately, since your problem is intermittent, so will the testing. You'd have to get a spark tester and wait for it to happen again.

Or after cranking and cranking, pull the plugs and turn the motor over by hand. If fuel squirts out of the cylinders, the fuel is being delivered and filling up the combustion chamber. This means the motor is getting air and fuel, but no spark.

BTW, don't get a cheap OEM replacement. Get an aftermarket one that fixed the issues GM made in the first place. The main one being the weep holes at the bottom of it. That, plus the location (on the front of the motor) allow water to enter the optispark and foul the points.

Also, depending on how long ago the water pump was replaced, it may be worth changing it at the same time. :shrug:

Thanks for the advice, I somehow feel this is the problem. Will definitely test the spark next time it happens.
Not with my tongue though , maybe with a screwdriver held just a little way from the manifold.

 

[Chris0nllyn]

Thanks for the advice, I somehow feel this is the problem. Will definitely test the spark next time it happens.
Not with my tongue though , maybe with a screwdriver held just a little way from the manifold.

Anytime.

Or you can just get a spark tester for under $10 at Autozone.

 

[glhs837]

I'll admit, I just stick a screwdriver in there myself.