Jumped timing?

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Chula Vista, CA
#1
Is this a common occurence among the earlier E21s? Mine's a 1982 320i.

It all started last monday, August 2nd, around 8pm. I was driving on the Interstate 8 westbound, after coming off the 805->8 junction. The cars was revving normally, all of the sudden I feel an irregularity in the engine's rhythm and then the car skips a beat, I hear a whirring and then a "clacking" noise and I have to keep the RPMs really high just to keep in motion. Mind you, I nearly lose my cool, because this is on a San Diego freeway, where the average speed is 75+, so people are coming at me fast (normally, I'm passing THEM). So, it's making this kind of whirring and pinging noise, then I think to myself: "Oh shit, clutch plate." So, I try downshifting-- no, clutch is fine, engine is not however.

Anyway, I manage to limp it to my dad's place in Point Loma, and I have to keep it in the 2500 range just so it won't die. The cop sitting next to me is now leering (oops). After being followed home by a cruiser, I let the car die in the car-port.

After the longest 2 minutes of sweating and explaining myself to the officer he wished me luck and went about his business. See, because I am still young, I am public enemy number one, regardless of the fact that I have no criminal history or any traffic or parking violations whatsoever.

Anyway, I pop the hood, try to start the engine, it starts and then dies. It does this several times, I figure it to be misfiring, so I check all the plugs (mind you, I bought the vehicle used). They appeared to have been severely warn, and not replaced in sometime. So, I think to myself, no big deal, it's just a misfire, go buy some plugs. I walk to Kragen, while I'm there, I buy new plugs, new distributor cap, new rotor, some injector cleaner and a Chilton's guide. Walk back, replace everything, make sure the firing order is good, the cap is good and, still, no love.

So, I call my friend over who is a bit more knowledgeable than I about engines, and he brings his timing gun wiht him. We get the engine running, but we notice that it's running on only 2 or 3 of 4 cylinders. I think, "crap, headgasket." So, we pull everything apart, check for water, and there's no abnormal exhaust discoloration. No, not the gasket.

Anyway, I manage to get it running steady enough to limp it home back down to Chula Vista, on Thursday evening. Since then, I've tested the alternator, the distributor, replaced the spark wires, checked under the valve cover. None of the valves are stuck, but I can't get to enough of the timing chain and cam shafts to see if the mark is set properly.

We know it's not a thrown rod, because all of the pistons move. Also, for some reason it seems cylinder 3 doesn't spark. I've replaced the wires, the plugs, the dstributor cap/rotor, everything. However, it seems it's a compound problem, the timing is off plus the 3rd cylinder not sparking.

Has anyone had similar problems or know enough about this vehicle's design to hint as to what the problem could be. Also, has anyone had any experience setting the timing on these machines? Because, it appears I have to pull-off half the engine components to get at the timing chain.

I'm so throroughly assed-out if I can't get this car running by next Monday, because I start class again and I go to two different campuses, in addition to working a job. So, the car is a vital necessity, for me.
 
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Location
Oregon
#2
I am not convinced that the Timing chain jumped a tooth. You should be able to pull the fan off, and then get to all the bolts holding the front cover of the engine on. Its a two piece set up I believe. You will have to pull all the belts off too. Once you get the front cover off then you just need to get the engine on top dead center and check to see if the marks of the crankshaft pully and camshaft sprocket is lined up.

It may be the pulse generator(i think tahts what its called) inside the distributer. Its basically BMW's version of a magnetic pickup inside the distributer. Its a piece of circular plastic thats got copper wire wrapped around the inside of it, and its got a two prong connecter... wich is where the ignition module plugs in.

Now I am going off the early 83-85 318i engine, but its the same as your 1982 320i. They both have the 1.8 liter M10 engine. I have owned two of the 318i's and done lots of work one them so I know the M!0 four cylinder pretty well.

Thats my thought, later.
 
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Location
Chula Vista, CA
#3
Hmm, pulse generator? Would I be able to get that at any parts place, or would I need to go to a dealer for that?

But, if it were something inside the distributor, wouldn't that keep the other cylinders from firing?

I noticed that the fan assembly and the pulleys were in the way, but it also looks like the water pump is in front of the timing chain cover.
 
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Location
Oregon
#4
The dealer will for sure but not sure about the common part stores. I have a local parts guy that can get about everything for a bmw and only charges me 25% over his cost. I did not think about the water pump but yes it is in the way I believe.

Is your timing chain loose on the pulley? These engines do have an automatic chain adjuster on them. I know on the older Kawasaki four cylinder motorcycle engines the cam chain adjuster can get clogged with sludge overtime and cause the chain to loosen up, and of course jump a tooth on either camshaft. I had two M10 engines go over 250,000 miles and never had one jump timing.

If No.3 does not have any spark then it would be causing these problems. So I say its ignition related. I take back my thoughts on the pulse generator, if it wasnt working all pulgs would not fire. Check the igition module. The early 318i has two different types, a Siemens unit(I think) and a Bosch unit. I am not sure really how to check the igition module as I have never had one go out. Test the coil also.

Just curious have you done a compression test? Thats one good way to make sure the head gasket is still good. Best of luck.

Later
 
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Location
Oregon
#5
Duh

You dont have a 318, you have a 320. I dont know what ignition modules they used on the 320's or even where its located. Its probably on the firewall though. Later.
 
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Location
Chula Vista, CA
#6
I appreciate all of the help, letting you know that.

However, I went back out to the car, had my friend look at the distributor, specifically the number three plug and the distributor is throwing spark, but the wire and plug are not. Like I said, the wires on there are brand new, but could that be it? I mean, it's almost as if maybe it's not throwing enough spark.

I also called some mechanics, one will take a look at the timing chain, but it's going to cost two and a half hours worth of labor to do so, putting the price tag at $120 (which I know isn't much, but I only have 500 to live on, right now and I still gotta finish paying for my books this semester). I'd go ahead and do it, but there's no guarantee that's the problem.

How do I tell if I have a bad coil?

Another mechanic suggested that it could be my valves. Which would be easier to fix than the timing, as you can access them from the valve cover (duh). However, he didn't really explain to me what he meant by "valves," like whether they were stuck, burned/misshapen or something.

My friend suggested I hire a mobile mechanic and have him come out here and diagnose the problem, that way I can put together a plan of action to have the car fixed, without having it sit in a mechanic's lot and rack up a bill.
 
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Pgh
#7
always follow the simplest line of reasoning first. It's running on 3 cylinders and one cylinder is not getting spark. Then why on earth are you looking for jumped timing and bent valves? Track down this problem through your ignition system.

Unplug your #3 wire and use a different wire (one of your old ones or whatever) to see if it's something about the #3 wire or the #3 sparkplug.

Don't make this any harder than it has to be. Start at the very simplest of problems. I had a similar problem in my '89 Accord and started to think jumped timing and all sorts of horrible things myself, when, eventually, I replaced the distributer with a junkyard unit, sheerly on the advice of someone at PepBoys. Miraculously, it worked.

If you're not getting spark at a cylinder, start there. The simplest answer is probably the correct one.
 


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