I am chasing a few engine problems with my 1986 328. The vehicle engine was misfiring badly at high rpm and underload. plugs very dry fouled. I have found and replaced 4 plug extenders. 2 with burn thru and 2 with brittle and cracking material. Spark Plugs were replaced, extenders replaced and a few minor ignition wire repairs made. The cat was melted and restricted. It was replaced and a new O2 sensor. No miss at high RPM but there still exists a lack of full power. I have 11in of vacuum at idle(1000-1050rpm). I dont think this is adequate but I cannot find any specs for vacuum reading anywhere. I checked the engine visually, with pliers pinching lines and propane but cant find a vacuum leak. The engine does NOT idle as though it has a vacuum leak. Question 1: Can anyone supply a normal reading at idle on a 328? Secondly, the engine feels as though there is no advance on the timing. runs fine and smooth but just wont rev and lack of power. I will check with a timing light tomorrow but if there is no advance at higher rpm this points to a bad vac hose, disconnected vac hose, or inoperable ECU. Question 2: Where is the ECU on a 1986 328? Thirdly, there was excessive oil in the intake, just before the throttle butterfly valve(with rubber intake tube off). I though it might be a bad PCV or related to my low vacuum. Technical info shows the "valve" on the crankcase system, inline silver valve, drivers side of the engine, as an oil splash and not a check valve at all. Question 3: Can any one supply info on the correct functioning of this valve or suggest other diagnosis for the excessive oil in the intake?
ecu is in the trunk on the right side - passangers side under the luggage area. there are 4 bolts that hold it onto a plate you have to remove then turn the plate over to reveal the ECU... the left side also houses the Marelli "computer" .... good luck have now idea why you would have oil in the intake....
Oil residue in the butterfly area is 100% normal, as the "output" of the vapor separator goes back into the air filter housing, then thru the sensor plate...then on to the throttle body. A good shop, will as part of a comprehensive major service, clean all of the accumulated oil residue from the throttle body assembly and the sensor plate area. I have had a few 328's in for service with "sticky" throttles, or slow to return to idle concerns, only to find years of built-up oil residue in this area. Lack of comprehensive services by pros, or excessively high oil levels can exacerbate this problem... David
~15 in Hg @ sea level; maybe ~13 in Hg @ 5000 ft elevation. Do put a timing light on it and confirm that both banks are actually firing on all cylinders. One explanation for "no power" and low intake vacuum is if you are only running on one bank -- i.e., if only on 4 cyls, to get the 1000 RPM idle, the throttle would be more open than "normal" which would lower the vacuum level. Good hunting!
+1! Make sure you have both coils firing - must test each one. Another hidden item is the 02 protection relay on your ECU board - it's the one with the fuse; make sure the fuse is ok and shake the relay to ensure nothing rattles. Good luck!!
I have a multimeter and am waiting for an attachment to view secondary patterns. In the meantime, I did put an ohm meter to the coils. little resistance between the four primary connections but no continuity between secondary any any of the four primary connections. Is there a proper way to test the coils without a scope? Ken
I am at sea level so 11in is definitely a problem. thanks for the data. I will test both banks and report back. Ken
Quick and effective test: Put a timing light on each high tension coil lead; If the light flashes, you've got spark, if not...you don't.
I believe it is more than just residue. I cleaned it thouroughly before a 150 mile run. will inspect again and take a picture if it has not improved. thanks for your insight. Ken
I would start looking for vacuum leaks - I recently found oneon my 328 in the long vac line that runs from the plenum to the ECU (which is in the floor of the trunk on the left side in my 89 328). Its fixed a while bunch of issues.
I lost power on my '86 328...(lost a bank).. I had FoD work on it & they cleaned the contacts on the coil connection...she has been running fine. also no worries about the oil in your intake b-4 the butterfly.... but still a compression check won't hurt
You said you had burned wires and extensions,shorted out coils can fail under load and will not charge and collapse fast enough for high revs or load.Just because it sparks does not mean it's good.try this nad let us know.Have a Happy! Gilligan
I put a light on all cylinders...all are firing. I adjusted the mixture and got 2 more inches of vacuum and 200 rpm before idle readjusted. road test tomorrow.
I put a timing light on it and all cylinders are firing. I double checked the firing order and plug wires. all correct. Whast you describe fits exactly what i am experiencing. I was an automotive tech for five years...a long time ago. the performance problem "feels" like bad/floating points or secondary ignition breaking down at high rpm. the coils on the car are different. Must have been replaced at some time. is there any way to test the coil?
Get two fresh coils and try it out . It may only be one bad one. It is weird as the coils wiil work at lower power. See if you can find a parts store that will let you take them back if unused or put two on just for the Idea that you know their good. I've had three in 30 years.Good Luck and let me know.
The "bad wires" had poor connections between the screw in pin and the wire core. Wires seem good as a whole. cant test mag resistance wires with ohmeter. A few bad extenders were found but I did order and replace all 8. Thanks for the suggestion
Brian, I don't think doddk....has modified ignition to accept standard coils on his 328.....correct me if I'm wrong Mike
