So I know I have bad valve seals. 86 GT V6 4spd. Have had the smoke on cold startup for at least a year and haven't bothered with it. But it has had a misfire/lack of power issue that has been getting increasingly worse after a cold start lately. Now when I pull out of the driveway in the morning, it will sputter to the point that it almost stalls unless I let the clutch out extremely slow. All the ignition components are new or in good shape. Timing seems to be OK. New plugs, good gaps. Once it warms up and I've been driving a bit, the power is back. Anyone else have these issues just caused by valve seals?
------------------ My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual
Run some cleaner through the fuel system. The best one I have found is a product called Guaranteed To Pass, That's right sounds stupid! But I've used this product numerous times when you have a cat converter code at inspection time. Pour it in your tank at about 1/4 tank and drive it, add another 1/4 tank and erase the code. Every time I did this the code doesn't return! So it's cleaning a lot more that just the cat converter. At Autozone and maybe Advance too.
Only the startup smoke is bad valve seals. The other symptoms are something else.
But could be a result of bad valve seals over time. Oil in the cylinder means more carbon buildup. If that carbon ends up sticking to the valve seat, it could cause the valve to not seat properly, and there could be enough of an opening to result in more of the air/fuel mixture being pushed out of the chamber prior to combustion, and could cause a misfire and decreased power.
It probably needs at least a valve job now, along with new valve seats, after having the issue neglected for so long.
Been there, done that with the cleaners. Done the whole seafoam treatment from the vacuum intake, fuel and oil. New fuel filter too.
My guess is that the plugs are getting really fouled from all the oil, and it's starting to use more oil than it used to as well. When I put new plugs in recently, she ran like a champ with excellent power- for about 2 days. Then went back to the cough, cough miss miss.
------------------ My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual
Try a quart of lucas oil stabilizer. Had a very similar issue on startup on my 88 formula.. Didn't believe my boss it would help with oil consumption and car running better. Most people don't like fixes in a bottle bit Lucas is great stuff. I was amazed. Now all of my cars get a quart with every oil change......the wet dry compression test will give you a great idea of what's up with the motor!!! Best of luck Brian
Originally posted by FieroCat: My guess is that the plugs are getting really fouled from all the oil, and it's starting to use more oil than it used to as well. When I put new plugs in recently, she ran like a champ with excellent power- for about 2 days. Then went back to the cough, cough miss miss.
The "old school" way to clean carbon buildup out of the combustion chambers and valves is a squirt bottle full of water. That might sound funny, but it works.
Anyway, it sounds like you have a substantial amount of engine oil getting into the combustion chambers. Since you have the puff of smoke at startup, I think it's safe to say your valve seals are toast. Your piston rings may be worn, too. A compression test should help determine that. Check compression normally, then squirt a little engine oil in the spark plug hole and test again. If the compression goes up noticeably, you have worn piston rings.
Well I figured out one thing, it only has the bad misfiring condition after it's rained or been sitting in the rain overnight. Here in Florida it basically rains every day over the summer, and occasionally there's a dry day. Today was dry, and it started without any of the missing. Full power! Something to do with moisture on the ignition components?
------------------ My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual
Originally posted by FieroCat:Something to do with moisture on the ignition components?
That's a good possibility. Having experienced this problem myself (I'm also a Floridian), I decided to use silicone grease on all electrical connections in the engine bay. That includes the spark plug boots, ignition coil electrical plugs, even the pickup coil connection. Also, you want to make sure none of the spark plug wires have cracked or damaged insulation.
Ironically, you can visually check the spark plug wires at night. Wait until it's dark outside, start the engine, then look in the engine bay. If a spark plug wire is leaking current, you'll see a strange "aurora-like" effect on the plug wire.
One of my engines had the start up smoke of bad valve seals almost from rebuild date. Never got any worse, never affected performance, used less than a pint of oil between 7500-10,000 mile changes. It ran perfect for over 100,000 miles/ 7 years. One of my SLs started burning a bit from valve seals, fouling out plugs within 1,000 miles (once a month). I just changed to Castrol Syntec oil, upped the plug heat range a bit and it all stopped.
I actually did replace my plug wires recently for that reason, they were arcing badly. But it hasn't helped much. There is the space left between the spark plug wire boot and the plug itself that seems to be where water can accumulate, is that what the silicone grease in the boot helps with?
------------------ My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual
