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Dead And 30 Lbs Compression - Now Running?!?

1K views 6 replies 5 participants last post by  E36_318_is 
#1 ·
Hello all - I too am a new BMW Owner/Forum Memeber. I bought a '97 318is with 108,000 miles a couple of months ago, and have been amazed by the driving experience. A couple of weeks ago my idle started being very rough. It still ran fine ( and got 32 mpg). I went to start it Monday, and it fell on it's face. I tried to re-start, but it sounded like the engine was turning over with no spark plugs in it, and would not fire. :cry
To date I have changed the air filter, oil (Mobil-1) and oil filter (the filter in the car when I bought it was the dirtiest filter I have ever seen in a car), and spark plugs (Denso Iridium - could not find NGK)
I had to travel all week, so I started troubleshooting it today. First I made sure the cam was turning with the crank by looking through the oil fill hole - it was. I then pulled the plugs out 1 at a time and checked compression from cyl 1 to 4. 1 - 30lbs, 2 - 40 lbs, 3 - 70 lbs, 4 - 110 lbs. By now it started sounding like there was compression. I re- checked Cyl 1, and there was now over 100 lbs. I put the plug back in, cranked several times for 20 seconds or so. After a couple of minutes, it kept sounding more and more like it had compression, and it eventually started.
Runs better than ever, and while the idle isn't perfect, it is much better than before.
Any thoughts? Would hate to have it happen again while travelling and have it not recover...
Is VANOS hydraulic? could the condition of the oil when purchased and subsequent changing have broken some "crud" loose and temporarily screwed up VANOS?
I'm reaching - but I have never seen an engine lose almost all of it's compression, and then magically have it restored. :banghead Thanks all - sorry for the VERY long expanation...
 
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#2 ·
Sorry to ask a stupid question, but are you sure that everything was put back in it's place and the test ect was done correctly? Because that does sound really weird. No clue as to what could cause it unless it was operator error some where along the line.
 
#3 ·
Originally posted by thekid@Apr 3 2005, 04:01 PM
Sorry to ask a stupid question, but are you sure that everything was put back in it's place and the test ect was done correctly? Because that does sound really weird. No clue as to what could cause it unless it was operator error some where along the line.
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Not to sure, you should prolly take it to the dealer or someone really good...
 
#4 ·
Originally posted by thekid@Apr 3 2005, 05:01 PM
Sorry to ask a stupid question, but are you sure that everything was put back in it's place and the test ect was done correctly? Because that does sound really weird. No clue as to what could cause it unless it was operator error some where along the line.
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I wish I knew...The plugs were all tight before the test, and it really cranked over before and during the compression test as if there was no compression...running ok now. Called my mechanic before the test, and he was similarly baffled. I'll call him this week to tell him what happened and let everyone know what he thinks it was.
 
#6 ·
Originally posted by bitcore@Apr 4 2005, 07:22 PM
Extremely strange, did you use a torque wrench on the spark plugs and whatnot?
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Dont worry about Vanos, the 1.8l Engine does not have vanos, rather it has dual intake runners with different lenghts.
 
#7 ·
Originally posted by victorgallas+Apr 6 2005, 02:43 PM--><div class='quotetop'>QUOTE(victorgallas @ Apr 6 2005, 02:43 PM)</div><div class='quotemain'><!--QuoteBegin-bitcore@Apr 4 2005, 07:22 PM
Extremely strange, did you use a torque wrench on the spark plugs and whatnot?
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Dont worry about Vanos, the 1.8l Engine does not have vanos, rather it has dual intake runners with different lenghts.
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yeah - I used a torque wrench (Tried for 20 ft lbs), and all plugs were still tight when I removed them for the compression check. Still running well.
Thanks for the clarification on the VANOS issue. Just more confused now. I keep getting sent out of town for work so I have not made it to my mechanic yet for his assesment/guess.
 
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