engine and drivetrain Replaced spark plug wires, 20 miles later engine runs rough wont start

[pmg]

In a parking lot right now.

A few weeks ago, the wire tab on my cylinder 1 spark plug cable broke free causing the cable to come loose and fry itself on the headers. I lost spark on 1, patched it up again with some electrical tape while I waited for new wires from IE (https://www.iemotorsport.com/bmw/2002-ignition/02wires8.html)

I installed them today. Everything was great for 20 miles, then I pulled off the freeway and the engine started running very rough, knocking, and had a big loss of power. Made it to a parking lot and shut everything off. Now I can't start again.

I though maybe a loose connection but that doesn't look to be the case. I replaced all four wires and kept the old set in the trunk. I just put the old wires back on and still no go.

Any ideas?

[pmg]

Video here:

I also replaced the radiator last week, maybe that is contributing factor but the temps have been normal from my instrument cluster.

[GoFaSSter]

Check the basics. Do you have fuel getting to the engine? Do you have spark at the plugs? Is the air filter plugged? It sounds a little like the timing slipped. Is the distributor loose?

[pmg]

Fuel, yes.

Spark, yes.

Air filter is fine.

Fuel filter is dirty but still working.

Distributor is on tight.

Loosened it and advancing it a little helped get it started.

Turn idle up to 2000rpm and wiggle it around to where it sounds the best and it ends up where I started before I loosened it. Tightening it down again. Starts if I hold the accelerator down. Does not start without my foot on the accelerator.

Plus side. Got it started and limped 2 miles home. Down side, it's positively weak. Maybe 20% power. Sounds very diesel-ly if I apply any load to the engine whatsoever.

Sound:

[Buckeye]

Confirm spark plug wires connected to distributor cap correctly. Inspect inside distributor cap for tracking. Confirm distributor components (rotor, contact breaker) are not worn-out

['76mintgrün'02]

... and replace that dirty fuel filter you mentioned... as well as the dust cap on your strut mount(s)  

 

After the fuel filter, the first thing I would do is connect a dwell meter and timing light and make sure the points and timing are set correctly.

 

If you do not have these tools yet, I suggest getting an 'all in one' gun.  It is very useful having both in one tool as well as a volt meter and tachometer.  $100 +/- well spent.

[Hans]

Could you have disturbed the dist. and/or cap when changing wires? If it ran fine before wire change, then I'd be looking at dist. related issues: timing being one.

[Danz3]

If it ran fine for 20 miles and your plug wires are OK then I wouldn't think it's the wires. Sounds simple but did you make sure the plugs are tight? Assuming you changed plugs with wires.

[Dev02]

Any chance you timed the car when you changed the wires, then forgot to tighten things back down and the timing got knocked off?

[Mike Self]

Agree with the others...something slipped in those 20 miles...either the timing, the points, or...could the vacuum advance hose have come loose at either the dizzy or carb end?  That would account for the weak running and reluctance to start...

 

An intriguing problem...let us know whatcha find.

 

mike

[pmg]

• I took apart the upper half of the distributor and cleaned things up. Some mild copper oxidation on the contacts but nothing clearly wrong (or from what I can tell) that should prevent it from working. The rotate-y bit was a minorly pitted but cleaned up. I didn't see any evidence of carbon tracking. The shaft has a bit of axial wiggle (maybe 1/16th" of an inch) which isn't ideal but not terrible? Dizzy is on tight, and has been since before this trouble started when it was still working.
• I replaced the old fuel filter with a new one. There was a lot of particulate in the old filter that looks like cigarette ash. Running the engine for a bit, I've seen a small but noticeable amount collect on the new filter pretty quickly. 
• Prior to these engine troubles, when I've taken my antiquated timing light to it in the past, I've noticed the steel ball through the observation slot has enough vibration to it that I can still "line it up with the edge of the slot" but it's bouncing back and forth enough that I question that being the optimal point. From this FAQ article I gather that's due to the axial play mentioned above. If I advance the distributor by ear a bit more (widdershins I think?) then it sounds better. This is at 2000rpm with the vacuum disconnected from the distributor and plugged by hand.
• Replaced the old spark plugs (NGK BP5ES)  with new ones today (NGK BP6ES). No reason to switch from the 5's to the 6's, just what I had in my desk. Old ones had some carbon fouling. Reading up on this it means I might have rich mixture, clogged air cleaner, or some kind of carb problem? Running a Weber 38/38.

If I remove ignition wires to cylinders 3 or 4 while the car is running nothing happens. Engine continues to sound equally rough. If I remove the ignition wires to cylinder 1 or 2 the engine sputters and stops.

 

I've confirmed I'm getting spark and all four cylinders, but the above observation leads me to believe that I'm not getting ignition on cylinders 3 and 4. At this point the next thing to check may be obvious to others here but totally eludes me.

 

If it's not spark than it must be fuel or air. Should I see if my intake to cylinders 3 & 4 is blocked up? Do I need to take a boroscope to the spark plug holes and inspect the cylinders? Should I remove the cylinder block head? This kind of engine debugging is virgin territory for me and I'm not sure how to intuit my way to a solution from here.

 

p.s. I did not know I needed dust covers for the strut mounts. Now I do. Thank you for the sharp observation MintGrun!

[Simeon]

If it seems to affect two cylinders next to each other (and you have ruled out spark) then you should do a compression test and consider a head gasket failure between 2 cylinders.

[Guest_anonymous]

Any chance that one of the intake manifold plugs came off on the last intake runner or the brake booster check valve or hose is cracked creating a vacuum leak?

[Hans]

Time for a compression test. When did you last adjust the valves?

[LimeySteve]

Head gasket blown between 3&4 is my 02c been there done that as most of us have at some point, compression check time, easy to do & conclusive evidence of problems .

 

Good luck