91 318i, pulled valve cover, is my timing ok? Pics enclosed...

[codyb]

1991 318i, 178k, recently purchased. Last night the car ran great for 9 miles, shut it down, started it up 15 minutes later, and it shakes very badly, sounds awful, hardly runs, but gets a little "better" over 3500rpm. Engine is missing significantly.

Guy in my other thread suggested I pull the valve cover and see if my timing chain jumped a tooth. Well I pulled the valve cover off, everything to me looks clean and in good condition. The teeth don't show hardly any wear...

I can wiggle the chain with my finger but not much. Another member said there should be arrows on the chain or sprockets that point to each other to tell you when the timing is on. Well I don't see any arrows or marks indicating where or what exactly needs to line up.

Here are the pictures:







What do you think???

[bmwman91]

Both cams look like they are off. Are the bolts holding the sprockets to the cams tight? Generally, the bolts are centered in the sprockets' slots. You will need to set the motor to TDC and check the alignment of everything before messing with that though as the PO may have done something sloppily.

Other than that, I would guess that the problem is the little gray connector on the wiring harness up on the firewall. Pull the black plastic cover and look for a single wire connector. If it is connected, unplug it and that should fix your issues. This only applies if you have a car with an O2 sensor & catalytic converter though (assuming you are in the US, where all cars do).

[codyb]

Both cams look like they are off. Are the bolts holding the sprockets to the cams tight? Generally, the bolts are centered in the sprockets' slots. You will need to set the motor to TDC and check the alignment of everything before messing with that though as the PO may have done something sloppily.

Other than that, I would guess that the problem is the little gray connector on the wiring harness up on the firewall. Pull the black plastic cover and look for a single wire connector. If it is connected, unplug it and that should fix your issues. This only applies if you have a car with an O2 sensor & catalytic converter though (assuming you are in the US, where all cars do).

Pardon my ignorance, but what exact bolts are you talking about? I don't know the names of everything in there... first time I've ever pulled a valve cover.

I didn't see a single wire connector with a grey wire up in my firewall... but I did see this wire, which is grey with a black strip. It was already not connected and tucked out of the way.



Is this the one you're referring to? What does it do?

[codyb]

I also tested my cam sensor, reads 1250 ohms, and my crank sensor reads 500 ohms...

[bmwman91]

Aah yeah just leave that disconnected. It hooks up a sensor to the ECU that is used on cars with no O2 sensor. A lot of people mistakenly connect it and it makes the ECU angry.

I was referring to the 4 bolts holding each sprocket/gear to the cams. You'll notice that they are slotted. Typically, the bolts sit in the middle of the slot, as opposed to all the way to one side.

[codyb]

Aah yeah just leave that disconnected. It hooks up a sensor to the ECU that is used on cars with no O2 sensor. A lot of people mistakenly connect it and it makes the ECU angry.

I was referring to the 4 bolts holding each sprocket/gear to the cams. You'll notice that they are slotted. Typically, the bolts sit in the middle of the slot, as opposed to all the way to one side.

I checked and those bolts are tight..

[thedguy]

Have you checked things like the plug wires and spark plugs?  possible you got a bad tank of gas, or put low octane in and urns getting mad?

[codyb]

Have you checked things like the plug wires and spark plugs?  possible you got a bad tank of gas, or put low octane in and urns getting mad?

The tank was pretty empty (on the red), I went to a fairly busy Shell station, filled with $20 worth of premium (their v power), and drive it 9 miles and it ran perfectly the entire time until I shut it down and restarted.

The spark plugs look good, the wires don't look all that old. But I'm not sure what the correct procedure test them are....   and is it possible to test them, and the coils, with the valve cover off?

[thedguy]

Use an OHM meter to check resistance on the plug wires.  I honestly don't know what the spec is, but if one is far off from any others, that could be your problem.
My #2 went bad and I couldn't tell until I had swapped it out with one I got from the yard and the car ran better (not great, but better).  These can be tested regardless of valve cover installation.

Hell I figured it out which one was the problem when I unplugged it while the engine was running and noticed #2 removed didn't cause the car to run any worse!

I doubt you have a coil issue, possible, but unlikely.  I have no idea how to test it wouth having an extra pack.  I now have 2 laying around the garage.

Perhaps the fuel filter is clogged, that could cause lean conditions and lead to misfiring.  If you happen to fill up just after the truck that refilled the tanks pulled out you can get a lot of the dirt and junk that was stirred up.

Since you still have the valve cover off, I'd get the motor to TDC.  IIRC there is a way to stick a bolt through an access hole at the back of the block and lock the motor at TDC.  From there you can check the cams are timed correctly.  I honestly don't recall what the marks look like.  It's been 6 years since I've tore open one of these.

[codyb]

Use an OHM meter to check resistance on the plug wires.  I honestly don't know what the spec is, but if one is far off from any others, that could be your problem.
My #2 went bad and I couldn't tell until I had swapped it out with one I got from the yard and the car ran better (not great, but better).  These can be tested regardless of valve cover installation.

Hell I figured it out which one was the problem when I unplugged it while the engine was running and noticed #2 removed didn't cause the car to run any worse!

I doubt you have a coil issue, possible, but unlikely.  I have no idea how to test it wouth having an extra pack.  I now have 2 laying around the garage.

Perhaps the fuel filter is clogged, that could cause lean conditions and lead to misfiring.  If you happen to fill up just after the truck that refilled the tanks pulled out you can get a lot of the dirt and junk that was stirred up.

Since you still have the valve cover off, I'd get the motor to TDC.  IIRC there is a way to stick a bolt through an access hole at the back of the block and lock the motor at TDC.  From there you can check the cams are timed correctly.  I honestly don't recall what the marks look like.  It's been 6 years since I've tore open one of these.

I put the valve cover back on. Started the car. Pulled spark plug wire from cylinder 1. No change in crappy idle. This wire was also sparking any time it got near metal.

I pulled wires from all the other cylinders one at a time. Engine ran much worse each time. Also none of these wires sparked when placed near metal.

So I have a problem either with the coil or the spark plug wire for cylinder #4. I looked in the tube that goes over the spark plug and it was filled with oil and a lot of gunk, while the others were clean. I cleaned it out with qtips as best I could, put it back on, and it ran noticeably better, but still misses pretty good.

Right now I'm not sure if it is a bad wire, a bad coil, or both. I think it's weird that only the wire in question sparked when near metal and the others didn't. Could the coil be shorting out or did my wire take a crap? Best price I can find on a new set of wires is $100, where a new coil is $50

What do you think is bad? Coil or wire?

[Geoff]

sounds like a bad wire..
                               Geoff

[romkasponka]

Do conversion to coil on plug instead of just replacing wires. Price would be almost the same...

[thedguy]

It's a wire.  I just got done dealing with that issue and just paid for the COP conversion.  Though it took 3 weeks for my cop kit to come in (it's something these guys do on the side).

BTW, I'd double check your valve cover gasket, or your torque on the bolts, sounds like you got a bad leak.

I've got a now useless to me set of wires (they are old ones from the yard but they worked the couple of weeks I needed them) and a good set of coils you can take off my hands for dirt cheap if you can't afford or don't have the time to wait for the COP kit.

[romkasponka]

Or you can do it without any kit, just enlarge holes for COP's. They are newer BMW.



You can also try to use audi COP's because they do not need any mounting hardware. Jus check diameter and length.

http://www.ebay.com.au/itm/AUDI-A4-ALT-ASN-BBJ-A6-ASN-BBJ-IGNITION-COIL-OVER-PLUG-077905115-077-905-115-NEW-/190587381045#ht_2574wt_905