Start up problem

[majorghn]

I have a a 1996 Caprice classic 4 door 5.7 LT1 engine

Have had this issue a long time, have problems with it starting up when it is hot and humid, more so with the humidity, winter is no problem at all even if it's raining out, summer and early fall forget about it, won't start in high humidity even when it's 65 degrees out, when it rains or even a few days after a rain with no sunshine car may not start until whatever the moisture got into dries out.

I did some checking around on the Internet and it said most likely cause was a crack in the distributor cap, so I had it replaced a few days ago, 2 days later it rains overnight and the next morning it was 63 degrees out and the car was barely was able to start, after several seconds of it running it's fine, runs smooth.

Would ignition coil and module be the next likely culprit?

[Blue Bowtie]

If the OptiSpark distributor was replaced the plug wires should have been replaced at the same time. At the very least they should have been tested. Presuming the wires are serviceable and the Opti repair was done properly, the next and easiest component to check is the ignition coil. It is mounted on the front of the left head and is reasonably easy to access.

Incidentally, I've slid this thread over to the Caprice Forum. Even though it's pushing 20 years old, it doesn't quite fit into the loosely defined "Classic" forum just yet. It's likely to get more and better attention here anyway.

[Tech II]

For those out there that don't know what an opti spark system is, in a 5.7 engine, it is one pain in the ass......

I remember a guy, who had a Firebird, and he decided to just do a tuneup, since the car had 100K on it.....when he found out how much a tune up cost, he traded the car in......

first the wires are hard to remove and new wires are hard to install....the plugs are not easy to get to....in order to remove the distributor cap, you have to remove the water pump....I am not kidding.....and if that water pump was never replaced before, you are going to be recommended to replace it, because if it decides to leak later, that weep hole is right on top of the distributor, and that can take the distributor unit out(the optispark electronics)....now you are paying for a whole distributor and not just a cap/rotor......customer's are shocked that a water pump is part of a tuneup on these vehicles...and then you have to check that the air line to the distibutor is working properly so that ozone is removed from the distributor(creates corrosion)....

I lucked out one time....Firebird came in with a misfire....naturally, you are thinking the worse....plugs or wires or dist cap......I was recommending a tuneup because of the mileage and condition of cap and wires.....luckily, the first thing I did was remove the coil wire from the coil to the distributor......I found corrosion where the wire attaches to the coil.......I cleaned the corrosion and I installed just the coil wire, and the misfire was gone......gave the guy the option of doing the rest of the job, or just the wire....he took just the wire.....SM was not happy.....But I didn't escape the job......a couple months later, he traded the vehicle in....one of the Salesmen, wanted to use it as his dealer car, because he knew he could sell it in his town, just driving around.....two weeks later the vehicle had a misfire.......we ended up fixing the vehicle, or rather I did......SM was happy again.....but Sales Dept wasn't....

[majorghn]

Originally Posted by Blue Bowtie

If the OptiSpark distributor was replaced the plug wires should have been replaced at the same time. At the very least they should have been tested. Presuming the wires are serviceable and the Opti repair was done properly, the next and easiest component to check is the ignition coil. It is mounted on the front of the left head and is reasonably easy to access.

Incidentally, I've slid this thread over to the Caprice Forum. Even though it's pushing 20 years old, it doesn't quite fit into the loosely defined "Classic" forum just yet. It's likely to get more and better attention here anyway.

Changing the spark plug wires cost way too much, upwards of $400 for labor, if the coil does not fix it, will have to wait until next summer, out of money for further repairs. Wish their was a quick fix to get the car started when this happens, like something I could spray onto a part to dry the moisture up. Thnks for your reply though.

[Blue Bowtie]

The plug wires can be replaced on a cold engine with only time and good access to the top and bottom side of the engine compartment. The biggest cost is the labor. The wires route through various clips, loom covers, and shields out of necessity.

Tech II is correct about the Opti. It is a very good time to replace the water pump and possibly timing cover seal(s) depending upon which of the three Opti drive system is involved. I personally have two LT1 vehicles and have replaced one of the Opti cap/rotors after the cap internal insulation breakdown which is so typical. I've replaced Optis on various other vehicles as well. The Caprice is by far the easiest since there is so much room at the front of the engine to work.

Since the Opti was replaced and it ran well for a short time, it is possible that internal moisture is an issue. After checking out the coil, if that does no solve the issue it may be worthwhile to look over the Opti vacuum lines and check valves just to be sure it is getting ventilated properly.

[j cAT]

when you have hard cold starting when damp out the plug wires could be the problem.

however being a 1996 OBDII LT1 you did not state any codes ????

so I would check the fuel pressure key on eng off. 41-47 psi. wiring issues are common now on these especially if you run it on less than 1/3 of a tank of gasoline.

miss fires on bad wires or a bad opti will show when driving it . also you will get CEL flashes and codes like P0300 etc..

on the water pump weep hole best install the weep hole drain tube

for some reason the ECT wiring gets damaged . this is in front of the water pump. if this connection is bad/wires it will hard start and no codes.

I have owned this 96 impala 21 years now time fly's quickly ..

[Blue Bowtie]

Good point on the drain tubes. Hopefully the new Opti is not wet and the coil solves it.