Fixedit
04-02-2015, 09:35 AM
Okay, I'm sorry for taking up this entire forum with my crap, but I realized I never posted anywhere about an issue my engine has.
I tried to explain it in my "Cylinder Head Bolts BT Engine" thread, but didn't spend the time to give the big picture. This is an '86 Automatic EFI LXi.
I'll start with these issues;
1. Anytime the engine is started when cold, it revs to 1500-2000RPM for a good minute to warm itself up. Once it is out of that cycle, it'll try to idle at 900-1000RPM. It soon starts to constantly rev and drop for a good ten minutes, ranging from 1000 to 1800RPM. It's a quick pattern, revving and dropping about every second. It stops once the temp gauge reads about a quarter from the bottom, and will idle at about 1100 to 1200RPM, depending on the day (who knows what). Some days it'll idle rough at 1000RPM, pittering and puttering, it sounds like I have a mild cam in a V8. After driving for a good trip, the temp gauge wont ever really reach much further than a 1/4 from the bottom, maybe 1/3. Idling in park after a drive it will sit at a less rough, nicer 1000RPM, maybe even dropping to a splendid 850-900.
2. For a total of maybe THREE times I've owned this car (since September 2014), I've "Blown my head gasket". The car drives great, and then I'll come to a stop, put it park, and it starts running real rough, like 3 cylinders firing, with tons of white puffy coolant smelling smoke from the tail pipe. I come back to it after a few hours, starts right up and runs great. No problems other than #1, which happens on cold start ups anyways.
I've done so much research about issues, enough to confuse myself. MAP sensor is good. Adjusted EACV. Smoked intake: no vacuum leaks. So I tried burping the cooling system; bubbles constantly --> Exhaust gasses entering cooling system. Visual inspection of jungle of coolant hoses above transmission shows at least one has a pin hole leak, and the back of the engine block looks like someone puked down the side of it. So I have a coolant leak, a really small one. Maybe cause by the exhaust gasses? Are the hot gasses screwing with the EACV? How do the exhaust gasses escape the system?
I could possibly have a cracked head; but wouldn't that be evident EVERY time I get up to operating temp? This has happened just a few times. I think the head gasket is blown in a way that it's only letting exhaust into the cooling system, and somehow I have a cracked head that doesn't open up every time the engine is hot.
The only reason I have not done a compression test is solely because Cylinder #2 Spark plug is in a thread repair sleeve. I replaced the plugs when I first got the car, and that one broke in the head, and I had to drill it out. The sleeve went in crooked, and I'm too scared to take the plug out for a compression test because it pulls the sleeve out with it, and this is my only daily driver right now, I can't park it and take the head to the machine shop to be checked for a crack or repaired.
To sum it up; What causes a surging cold idle, rough warm idle, and coolant to enter a cylinder extremely infrequently?
I tried to explain it in my "Cylinder Head Bolts BT Engine" thread, but didn't spend the time to give the big picture. This is an '86 Automatic EFI LXi.
I'll start with these issues;
1. Anytime the engine is started when cold, it revs to 1500-2000RPM for a good minute to warm itself up. Once it is out of that cycle, it'll try to idle at 900-1000RPM. It soon starts to constantly rev and drop for a good ten minutes, ranging from 1000 to 1800RPM. It's a quick pattern, revving and dropping about every second. It stops once the temp gauge reads about a quarter from the bottom, and will idle at about 1100 to 1200RPM, depending on the day (who knows what). Some days it'll idle rough at 1000RPM, pittering and puttering, it sounds like I have a mild cam in a V8. After driving for a good trip, the temp gauge wont ever really reach much further than a 1/4 from the bottom, maybe 1/3. Idling in park after a drive it will sit at a less rough, nicer 1000RPM, maybe even dropping to a splendid 850-900.
2. For a total of maybe THREE times I've owned this car (since September 2014), I've "Blown my head gasket". The car drives great, and then I'll come to a stop, put it park, and it starts running real rough, like 3 cylinders firing, with tons of white puffy coolant smelling smoke from the tail pipe. I come back to it after a few hours, starts right up and runs great. No problems other than #1, which happens on cold start ups anyways.
I've done so much research about issues, enough to confuse myself. MAP sensor is good. Adjusted EACV. Smoked intake: no vacuum leaks. So I tried burping the cooling system; bubbles constantly --> Exhaust gasses entering cooling system. Visual inspection of jungle of coolant hoses above transmission shows at least one has a pin hole leak, and the back of the engine block looks like someone puked down the side of it. So I have a coolant leak, a really small one. Maybe cause by the exhaust gasses? Are the hot gasses screwing with the EACV? How do the exhaust gasses escape the system?
I could possibly have a cracked head; but wouldn't that be evident EVERY time I get up to operating temp? This has happened just a few times. I think the head gasket is blown in a way that it's only letting exhaust into the cooling system, and somehow I have a cracked head that doesn't open up every time the engine is hot.
The only reason I have not done a compression test is solely because Cylinder #2 Spark plug is in a thread repair sleeve. I replaced the plugs when I first got the car, and that one broke in the head, and I had to drill it out. The sleeve went in crooked, and I'm too scared to take the plug out for a compression test because it pulls the sleeve out with it, and this is my only daily driver right now, I can't park it and take the head to the machine shop to be checked for a crack or repaired.
To sum it up; What causes a surging cold idle, rough warm idle, and coolant to enter a cylinder extremely infrequently?