Badly fouled spark plugs |
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Badly fouled spark plugs |
andreic |
Sep 15 2016, 08:43 AM
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#1
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Member Group: Members Posts: 172 Joined: 21-December 15 From: Madison, WI Member No.: 19,479 Region Association: Upper MidWest |
Hello,
I have a problem on my newly rebuilt 1.8L engine, with L-Jet. Yesterday as I was driving home the car simply quit about 5 blocks away from home. Until this point it was running very well. I had to have it towed home and now I started trying to diagnose it. So far I've checked that the fuel pump operates when opening the flap in the AFM, so I suspect I got fuel pressure right. The starter spins the engine well. I have strong spark on the main distributor cap wire (coming from the coil), and putting a brand new spark plug into one of the spark plug wires I have spark at that too. (Originally I was too lazy to pull an actual plug from the engine.) But this morning I tried pulling a spark plug from the engine, and it is completely black and covered in carbon. Not wet, just covered in a thick layer of solid black material. I can't check right now whether the spark plug from the engine is fouled badly enough to not give a spark at all, or if it still is OK. (I need to wait for my son to come back in the afternoon to help me, this is a 2-person job.) But assuming the spark plugs are the problem, can somebody offer a guess as to what could have caused the engine to foul the spark plugs so badly and so quickly as to stop the engine while driving? Before that there was no indication something was wrong. Other slightly strange things. a) I've noticed the car burns a lot of gas. I barely get 20 mpg in mixed city/highway driving. b) I have about 600 miles since the rebuild, engine ran well all along. c) The only other issue with the car is that I can not get the idle right: it seems to idle at 1800 rpm most of the time, but if the engine is well warmed up (after about 1/2 hour of driving) or if I hold off the clutch as I come to a stop until the rpm's come down to 900, it'll idle at 900. I've tried two different throttle bodies, thinking it may be the throttle that sticks, but it behaves the same way with both. I started to suspect that the distributor is sticky and does not retard the idle sometimes. Any suggestions, highly appreciated. Thanks, Andrei. |
Bulldog9 |
Sep 24 2016, 11:29 AM
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#2
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Senior Member Group: Members Posts: 705 Joined: 21-August 13 From: United States Member No.: 16,283 Region Association: MidAtlantic Region |
Reading through the thread, you have:
1. Black sooty plugs 2. Blue smoke out the tailpipe when running 3. Increasing oil level in crank case 4. Occasional no run situation. 5. 125# on compression test 6. Bad gas mileage The sooty plugs could be many things, incorrect heat range on the plugs, bad wires, bad plugs, weak spark/coil/rotor. As many others have said, when a plug is fouled, it needs to be replaced. I've even filed the firing points and for whatever reason fouled plugs rarely work right. Could also be as has been said many times too much fuel due to too high fuel pressure, or your cold start valve continues to spray creating a super rich run situation. This is further supported by your increasing oil level. Either you have too much fuel spray or not enough spark. You need to correct/eliminate one or the other or both. Blue smoke? RINGS...... FIrst get rid of that Castrol Crap, put in the proper Oil. Valvoline V1, Joe Gibbs, or Brad Penn. Castrol used to be a solid product, now is unreliable. I also think that this is a new motor? It could be that they havent been seated properly, but my guess is you have trashed them with a too rich environment. What do I mean?? Well you have so much fuel in the cyls that it is seeping past your rings and getting into the oil raising the oil level and because of this the rings/cyls, maybe pistons (unlikely at this early stage) are shot........... YUP, I'm saying that I think that even once you fix your fuel/spark issue you are looking at a ring job/rebuild. Now once you sort out the fuel/spark issue, I would change the oil and go beat on it, see if you can get the rings to seat/reseat and start working properly once they have proper lubrication and oil film on the cyls. But if I may, you have largely ignored or rebuffed most of the input people have given you. Why bother asking? Either way good luck! |
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