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. |
andreic |
Sep 24 2016, 12:52 PM
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#2
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Member Group: Members Posts: 172 Joined: 21-December 15 From: Madison, WI Member No.: 19,479 Region Association: Upper MidWest |
PROBLEM SOLVED!!
Sorry for the many posts, and I apologize if this has brought out some anger in some people, leading them to troll. Trust me, I was probably the most frustrated of all. The trouble turns out to have been the ECU. After changing the oil with fresh one, and putting in new spark plugs I tried running it again, with no change whatsoever -- very rough running, no idle, blue smoke coming out. Then I replaced the ECU as a last hope measure. And lo and behold -- suddenly running perfectly. It was still spewing a bit of blue smoke, but that corrected itself after driving it hard for about 5 minutes. I also did the "lugging" procedure recommended by Len, just in case it was needed, but the car now runs perfectly, no smoke coming out of the exhaust, exhaust smells normal, etc. So warning to others: even though I myself had never heard of the L-Jet ECU's failing, they apparently can fail in rather weird ways (I suspect it kept some or all of the injectors wide open all the time). At this point I only have one last question. The previous oil got fouled with gasoline; I did change the oil, but not the filter, so a small amount of fouled oil still is there in the engine. The questions are: a) Is it OK to drive the car with this oil in for another month (I'll be putting car in storage mid-October, and usually I do an oil change just before that), or should I change the oil right away? b) Many people said that Castrol 20W50 is not ideal for this engine. What is a recommended oil? Brad Penn 20W50? Or a straight weight oil? Thanks a lot again for the support, especially the experts (Timothy, Len, etc.) CAR IS RUNNING AGAIN! HURRAY!! |
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