# BMW e30 won't start! What happened and what should I check next? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [June 7, 2013, 8:58pm UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423 "2013-06-07T20:58:26Z")\ **Posts on this page:** 18\ **Page:** 2
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [June 12, 2013, 3:46am UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/21 "2013-06-12T03:46:30Z")
Did you check to make sure the rotor is turning when you crank the engine? Do you have spark? ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [June 12, 2013, 5:25am UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/22 "2013-06-12T05:25:42Z")
> [@Rick](#): > > Did you check to make sure the rotor is turning when you crank the engine? > Do you have spark? Rotor turning, _STRONG_ spark! (never seen one like it! Bright, white flash. Has nice NGK plugs, which I swear by) But like you point out- spark in the wrong order is pretty worthless! **Rick** , help me out with my thinking here. I’m questioning my compression test. I pulled all six plugs for the test. Lets assume either scenario: 1. Blown head gasket- Would an inline six suck air from a blown head gasket across the whole head, with plugs out, and give consistent low readings across all cylinders? (First time I’ve used the compression tester, a Snap-on, ran it for about 3 compression cycles) Should I seal up the other 5 and crank for about 6-8 cycles? Scenario 2: Timing belt skipped a tooth or two. Would that throw off _all_ 6 cylinders compression? Looking at the cam and the rocker action, I would think that at least one or two would have the valves in the proper position to build up some compression. But simple math, even to a Beer Drinker says that 360 divided by 6 equals an even, equal, exact number. Are all my valves (either exhaust or intake, depending on firing order) open _just enough_ to prevent an accurate compression test assuming a skipped tooth or two? I got readings of around **40 psi** :eek:, consistently _across all 6 holes_. Keep in mind, this thing _ **ran** _ the day before! My next plan is to dig into the timing belt. I’m reluctant to replace that (and the H20 pump, which should be done at the same time) on an engine that is wore out and produces 40psi compression. I’d rather spend the $500 on the reman the guy has for sale. (If he still has it, 200 miles away) Not being able to trust my diagnosis bothers me. I absolutely **detest** part-swapping. Am I even thinking clearly here? Should I be concentrating on some electrical/sensor failure? Brain? The Dreaded CPS? (I’ve swapped out pretty much all the relays and unplugged/plugged every connection I could find) Thanks, all! ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [June 12, 2013, 5:30am UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/23 "2013-06-12T05:30:15Z")
> [@Gatopescado](#): > > I absolutely **detest** part-swapping. Ah, The Irony! Too cheap to replace a timing belt, so I’ll toss in a whole engine! :smack: Y’all know what I meant… I hope. 😃 ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [June 12, 2013, 5:52am UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/24 "2013-06-12T05:52:57Z")
> [@Gatopescado](#): > > Rotor turning, _STRONG_ spark! (never seen one like it! Bright, white flash. Has nice NGK plugs, which I swear by) But like you point out- spark in the wrong order is pretty worthless! > > **Rick** , help me out with my thinking here. I’m questioning my compression test. I pulled all six plugs for the test. Lets assume either scenario: > > 1. Blown head gasket- Would an inline six suck air from a blown head gasket across the whole head, with plugs out, and give consistent low readings across all cylinders? (First time I’ve used the compression tester, a Snap-on, ran it for about 3 compression cycles) Should I seal up the other 5 and crank for about 6-8 cycles? > > Scenario 2: > > Timing belt skipped a tooth or two. Would that throw off _all_ 6 cylinders compression? Looking at the cam and the rocker action, I would think that at least one or two would have the valves in the proper position to build up some compression. But simple math, even to a Beer Drinker says that 360 divided by 6 equals an even, equal, exact number. Are all my valves (either exhaust or intake, depending on firing order) open _just enough_ to prevent an accurate compression test assuming a skipped tooth or two? > > I got readings of around **40 psi** :eek:, consistently _across all 6 holes_. Keep in mind, this thing _ **ran** _ the day before! > > My next plan is to dig into the timing belt. I’m reluctant to replace that (and the H20 pump, which should be done at the same time) on an engine that is wore out and produces 40psi compression. I’d rather spend the $500 on the reman the guy has for sale. (If he still has it, 200 miles away) > > Not being able to trust my diagnosis bothers me. I absolutely **detest** part-swapping. > > Am I even thinking clearly here? Should I be concentrating on some electrical/sensor failure? Brain? The Dreaded CPS? (I’ve swapped out pretty much all the relays and unplugged/plugged every connection I could find) > > Thanks, all! 40 PSI? Holy fuck me sideways! You said low, not non existent. 120 is low. 40 PSI is DOA. Dead, a non starter (but you knew that). If the belt is on right, you have an ex-engine. Your engine is pining for the fjords. yeah the belt probably jumped. Pull the front cover and line up the timing marks by rotating the crank, I would bet the cam gear is 2-4 teeth off. for right now, just reposition the belt and make sure the car will start when the belt is right. ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [June 12, 2013, 1:22pm UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/25 "2013-06-12T13:22:28Z")
> [@Jake\_Jones](#): > > Jesus, dude. He’s got a 25 year old BMW that his neighbor gave him after it was beaten on for 20 years. The shit broke. He’s looking for some help, not a BMW dealer. Lighten the fuck up. Oh you all lighten up. Even the OP understood it to be a joke. But I guess it came across more harsh than I intended. I have no problem helping the OP fix his priceless antique automobile. Well, except that I know jack shit about fixing cars. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [June 12, 2013, 2:01pm UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/26 "2013-06-12T14:01:43Z")
No! No! It’s just tired after ‘avin’ a long squak! I guess I’ll be tearing into the timing goodies. I simply _love_ draining coolant. Especially with the dogs hanging around. I’ll “have fun”! 😃 ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [June 12, 2013, 11:59pm UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/27 "2013-06-12T23:59:39Z")
Didn’t get to work on it today. Its about a million degrees outside, with 90 mph wind. So, naturally, the wife has me put up the Above-ground pool. :rolleyes: Because _she_ wants the kid out of the house. :smack: I had to park the truck up-wind and strap the top frame-rail to it to keep it from blowing away. Having “fun”! 😃 ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [June 13, 2013, 9:41pm UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/28 "2013-06-13T21:41:13Z")
Update: Torn it all apart! Belt was shreaded completely down one side. Barely a belt at all! **Rick** called it: 2 teeth off! Parts be here tomorrow. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [June 14, 2013, 1:53am UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/29 "2013-06-14T01:53:51Z")
> [@Gatopescado](#): > > Update: Torn it all apart! Belt was shreaded completely down one side. Barely a belt at all! > > **Rick** called it: 2 teeth off! > > Parts be here tomorrow. 😃 ::: Wanders out of thread whistling Nobody Does it Better::: ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [June 14, 2013, 4:12am UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/30 "2013-06-14T04:12:37Z")
Almost forgot. Make sure you replace all the idlers and rollers. Might need a tensioner or jockey pulley also. Ps what caused the belt to shred? ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [June 14, 2013, 5:59am UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/31 "2013-06-14T05:59:40Z")
Funny you should ask! My guess is it never been done! The lower timing cover was broken. You could see right in and see the belt’a’spinnin’! Decades of grime had accumulated in the near vicinity. No evidence of this little procedure having ever been done. Recommended at 60k, this thing has 180k! (I’ve only put 10k, maybe, waiting for the head gasket manifestation to show itself) I pulled the lower timing cover, and it was broken. Started cleaning up the area, and found a piece of metal imbedded in a heap of “old car amber” and damn if it wasn’t the piece of the timing cover! JB it, Don’t Scrap It! It’ll be good as new tomorrow morning! 😃 Somebody along the chain of ownership decided it would be a good idea to secure the passenger side of the radiator to the front clip with a WOOD SCREW! Wait. … … What did I just type? A Fucking _Wood Screw_. Yes. someone drilled thru the plastic side of the radiator and then into the sheet metal and installed a **WOOD SCREW.** I’ll post an update for you in the next day or two. But I’m so confident in this beast running again that I replaced the old, sun-rotted speakers in the rear deck with some fresh Cerwin-Vegas the fit perfectly in the holes and sound not-too-bad! Got 'em from the junk yard. Hey, **Rick** , do you drink beer? If so, I think I owe you one to two. ---
**Author:** ![sisu](https://avatars.discourse-cdn.com/v4/letter/s/df705f/32.png) [@sisu](https://boards.straightdope.com/u/sisu)\ **Post date:** [June 14, 2013, 6:07am UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/32 "2013-06-14T06:07:26Z")
Well I have a 1985 325e and a very similar thing happened to me after about 250,000 miles, I just swapped the engine for a reco one for about $1,000 and well all good now. It was worth spending the money as it is a rare TC Bauer and they are worth about $10k for a really good, which this one is. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [June 15, 2013, 1:21am UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/33 "2013-06-15T01:21:01Z")
Got it fired up and it ran pretty good for a while. Once it warmed up, it started hicupiing and sputtering. There is a massive sucking sound on the intake side. The boot from the air flow sensor is totally FUBAR, most likely from me jacking the engine up and down (which I did, big time!) to install the new motor mounts. (The sensor is mounted to the fender!) Tore that boot all up! There is a pretty clean 325 up in the junkyard locally. Maybe I’ll get lucky and snag a usable boot. Heck, I even have “junkyard bucks” to the tune of $20! The symptoms seem to indicate a vacuum or other similar issue. No knocking or ticking from the head, so I’m hopeful on getting it back to where it was, at least. I’m real confident I got the timing correct. I ran it thru probably 12 times by hand, and another 30-40 with the starter (checking compression- another story!\*) and the marks always hit spot-on. It fired and ran with just a touch of the starter, also. But I have to accept the fact that some other, possibly major damage occurred when the belt jumped. And I suspect that head gasket is really blown, but _ **how the hell did it run this long?** _ \*I either don’t know how to use the tool, or it is wildly inaccurate. Still got real low readings, but it fired up immediately. 😕 ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [June 15, 2013, 10:53pm UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/34 "2013-06-15T22:53:43Z")
No boots at either junkyard! Local autoparts place doesn’t list it. Grabbed one on ebay instead. I’ll post an update next week. I’m pretty sure this is gonna get it back running at least as good as it was. It runs when you disconnect the air flow meter connecter. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [June 21, 2013, 8:28pm UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/35 "2013-06-21T20:28:37Z")
“Fun” update: Installed the new intake boot (after some mods to some hoses) and it still don’t run right! It runs “better”, but not right. I must have missed something, broke something or screwed up somewhere during the belt change. Bugger! ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [June 22, 2013, 12:36am UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/36 "2013-06-22T00:36:17Z")
**Success!** Stuck Air-flow meter! Having run out of options, I decided to “Punt”. Took a big screwdriver and pryed off the black top of the air-flow meter, not knowing what to expect. Hey look! A little thingy that moves in a half circle and makes electrical connections! A quick inspection reveals that _it does not move_. So, I try to move it by hand. Stuck! Give it a little more mustard, and BOING! It snaps back to the other side, and moves smoothly by hand. Well, now we have Goulet! I plug shit back in, fire it up and WEEEEEE! Running BMW e30! Just under $100, including $30 for the intake boot that I probably could have avoided wrecking if I was a little more careful. Thanks to everybody who gave advice and good wishes! ---
**Author:** ![ducati](https://avatars.discourse-cdn.com/v4/letter/d/cc9497/32.png) [@ducati](https://boards.straightdope.com/u/ducati)\ **Post date:** [June 22, 2013, 1:38am UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/37 "2013-06-22T01:38:13Z")
Good. Should have been in the " check this" rotation, but you’re here. [Now clean it properly!](http://www.youtube.com/watch?v=vPT8rL0noYg) ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [June 22, 2013, 4:03am UTC](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423/38 "2013-06-22T04:03:38Z")
**WOW!** Cool vid! That guy is sprayin’ that stuff like he’s getting paid for it! 😃 Thanks for the link! [Previous page](https://boards.straightdope.com/t/bmw-e30-wont-start-what-happened-and-what-should-i-check-next/660423.md?page=1)