Any LT1/impala ss engine experts?

8

87 Pete

Member
Joined
May 25, 2001
My brother has a '95 9C1 caprice with about 55k miles on it. It occasionally has a crank but no-start condition. The fuel pump went out a couple months ago, and we replaced that and the filter, it seems to be getting fuel. It also does not die once it's started. We also replaced the battery and had the alternator/charging system tested, and they look good.

Oddly enough the body is in mint shape, but the engine area and underbody are rustier than I would expect. Are there any power junctions/grounds/fusible links we should check for corrosion? Any other areas to look at?

Thanks.

Pete
 
when you get a no-start, what do you need to do for it to run again?

Mine used to foul plugs in the winter.

Bob
 
TurboBob said:
when you get a no-start, what do you need to do for it to run again?

Mine used to foul plugs in the winter.

Bob
Click to expand...

It seems like if you give it a couple days it will re-start. I've also tried putting a charger w/a 50-amp start setting on the battery when cranking, sometimes that would work, sometimes not.

My brother also mentioned smelling gas, I wonder if he's flooding it. That's interesting about fouling plugs in the winter, the problem started about a month ago. Maybe we should put some new plugs and wires on it.

Thanks,

Pete
 
Mine used to be the worst if I "marshalled" it. i.e. start it, move it in the driveway, and shut it off. The short runtime wouldn't burn off the start-up fuel and leave the plugs wet. Next try would be a no-go.

I was running cold plugs and 36 lb injectors due to the turbo I put on the car.

You opti-crap might be getting weak also.

Bob
 
If it's a 95, it should have the vented opti (I believe, the fbods had them), so it shouldn't have as much problems as a nonvented one.

That being said, even vented optis can fail from moisture, so you might pull it off and check it out.
 
With him saying the engine bay is rustier than he would expect would lead me to believe its had a lot of moisture in the engine bay for some reason, or was by the coast where there's lots of humidity in the air, corrosion on the engine would lend itself to corrosion in the opti-spark.
Almost anything on the LT1's ignition related can be traced back to something wrong with the opti 9 times out of 10. May want to break out a spark tester when its not wanting to start.
 
optispark was the first thing that came to my mind. they are very finniky, not to mention expensive. MSD has an improved one out, dont know how much better it is, but they claim to have fixed all the problems that the OEM one had. Id replece it with the MSD one.
 
Thanks for all the ideas guys. He is supposed to bring the car home this weekend. We will check all the power and ground wires and opti. He does have the newer vented style, but I know they are always suspect.

I also found out the factory battery cables and early-design junction block are poorly designed and subject to overheating and fire. Nice work GM, always trying to save $.02 on wiring :rolleyes:

Pete
 
the plug that plugs into the top of the opti is prone to loose pins and corrosion..... check that also.
 
The opti-spark on my 95 Roadmaster is going on 300K miles and is still running strong. I bought it with 125K on the clock and it appeared to be the original. Anybody who replaces one just because, deserves to throw their money away. And my best Corvette shop, who BTW agrees with me, will say the same thing. Double check the coil while you are in there. Most of the time a marginal coil will cause that problem. Lots of perfectly good optis have been replaced just because somebody read somewhere on the internet that they are crap. BS. The only fault the opti-spark has is that nobody makes a dependable and long lasting water pump for the LT1.
 
Is the IAC working. Have you tried holding the accelerator pedal down a little bit to open the throttle. If the IAC is closed it will just crank when cold, once the engine is warmed up it will work fine. Had this happen to me a few years ago on my 96 Caprice.
 
tap on the tops of all the relays while running. The only trouble with the opti I have seen was croos firing due to dust in the cap from the carbon on the rotor. Sure if the pump leaks its not going to be good.
 
also, if you pull the opti you can disassemble it to check for carbon like mentioned above, and see if the bearing is worn out.
 
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