Diagnosis on air intake oil leak and timing question
03-12-2011, 12:51 PM
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Diagnosis on air intake oil leak and timing question
Hi,
I have a 1984 928 S2 Automatic.
I noticed a pool of oil sitting in the air guide housing when I refitted the Mass Air Flow meter assembly recently. I've attached a picture to show where I mean. Has anyone seen this before - any likely / common causes?
Secondly, I checked the timing because I was getting an occassional backfire / popping and typically under load in slow speed or/and when cold e.g. pulling away up a hill at fairly low revs. The car seems fine at higher revs.
The ignition timing was nearer 36 degrees BTDC at 3000 revs - the owner manual and workshop manual say 23 degrees. So looks like I need to adjust it a bit - but I couldn't work out how to undo and rotate the twin distributor assembly?
It's like they are set - which is probably the case and I've just asked a dumb question! But there was nowt in the manual about that?!
Thanks in advance (no punn intended
) for your ideas/help
Dave
I have a 1984 928 S2 Automatic.
I noticed a pool of oil sitting in the air guide housing when I refitted the Mass Air Flow meter assembly recently. I've attached a picture to show where I mean. Has anyone seen this before - any likely / common causes?
Secondly, I checked the timing because I was getting an occassional backfire / popping and typically under load in slow speed or/and when cold e.g. pulling away up a hill at fairly low revs. The car seems fine at higher revs.
The ignition timing was nearer 36 degrees BTDC at 3000 revs - the owner manual and workshop manual say 23 degrees. So looks like I need to adjust it a bit - but I couldn't work out how to undo and rotate the twin distributor assembly?
It's like they are set - which is probably the case and I've just asked a dumb question! But there was nowt in the manual about that?!
Thanks in advance (no punn intended
) for your ideas/helpDave
03-12-2011, 12:55 PM
#2
Puddle of oil there is quite normal, generally caused by crank case pressure ventilation back to the intake.
As for the timing, get a wrench and have some fun. If I recall, the 4.7 Euro has a differnt timing setting than the US version. So double check your numbers.
As for the timing, get a wrench and have some fun. If I recall, the 4.7 Euro has a differnt timing setting than the US version. So double check your numbers.
03-12-2011, 01:00 PM
#3
Oil in the air guide is typical. The oil comes from the oil seperator at the front of the engine. It's the same place where you add oil.
There should be a wire mesh "basket" where you add oil. If the basket is gone, an excessive amount of oil can be sucked into the plenum, air guide and throttle body.
There should be a wire mesh "basket" where you add oil. If the basket is gone, an excessive amount of oil can be sucked into the plenum, air guide and throttle body.
03-12-2011, 01:10 PM
#4
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You can check what the CO is set at currently by measuring the ohms between terminals 14 and 25 at the LH connector. Range is 0-1000, 382 is the factory 'zero'. Higher is richer. (EZF_LH22_16V.pdf)
03-12-2011, 02:03 PM
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Much different. '84 ROW has digital EZF ignition.
Could be intake backfire from running too lean. S2s are sensitive to MAF aging as they don't have an O2 sensor. You may be able to adjust the MAF CO screw to compensate.
You can check what the CO is set at currently by measuring the ohms between terminals 14 and 25 at the LH connector. Range is 0-1000, 382 is the factory 'zero'. Higher is richer. (EZF_LH22_16V.pdf)
Could be intake backfire from running too lean. S2s are sensitive to MAF aging as they don't have an O2 sensor. You may be able to adjust the MAF CO screw to compensate.
You can check what the CO is set at currently by measuring the ohms between terminals 14 and 25 at the LH connector. Range is 0-1000, 382 is the factory 'zero'. Higher is richer. (EZF_LH22_16V.pdf)
I feel reassured about the oil at least
Dave
03-12-2011, 02:23 PM
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The only spec I can find for 16V EZF in the WSM is 10±3° @ 700±50 rpm.
Below is the cruise map for the 16V EZF (x418 EPROM).
Dot is 3000 rpm at part throttle, ~37°.
Below is the cruise map for the 16V EZF (x418 EPROM).
Dot is 3000 rpm at part throttle, ~37°.
