The e30 developed a misfire on the final leg of our Sunday tour. It’s fixed now.


  • left the car parked
  • researched the issue on the e30 forums, came up with a million different ideas (see below)
  • for good measure sent an email to my mechanic


  • got up early planning to check the spark plugs
  • didn’t have the right socket, went to Pepboy’s and bought a 21mm spark plug socket
  • my mechanic emailed me to confirm that I should start with the plugs
  • blew out each port with compressed air and removed plug #1
  • looked dirty, though later my mentor and mechanic told me that it didn’t look that bad
  • left the job as it was, Trina went and picked up “Bosch Super Plus WR8LC+” spark plugs for me


  • got up early
  • methodically loosened each plug with the breaker bar
  • removed each plug with socket driver
  • labelled each plug
  • plug #4 was pretty black, #5 was totally clogged, #6 was blistered
  • plugs were pre-gapped but checked anyways, all were .30mm
  • applied anti-seize compound to the threads on each plug and re-threaded by hand
  • tightened to finger tightness with extension and socket
  • tightened to 22 ft. lbs. with torque wrench
  • discovered tips on plugs are larger than the plugs on HT wires
  • removed plugs again and removed tip with vise grips
  • re-installed plugs
  • after stalling 2-3 times managed to keep it alive long enough for a drive around the block
  • still mis-firing, stomp code 1222 (“Lamda Control 1”, umbrella code for too much o2)
  • checked HT wires, #1 seemed just ever so slightly mis-seated at the distributor cap
  • car ran just fine after that


Wrap Up

My mechanic says based on the buildup that the problem was plug #5 and the miniscule amount that the #1 HT wire was out by would have no effect. I’m not 100% sure with that diagnosis but the car is running and I’m happy. I will sand blast my old plugs and save them for spares as I will need to replace #5 in 3,000 miles. Or less.

His sound advice is not to put any more money into this m20 engine, which could run for a long time in it’s current state. And save for an engine swap, specifically a 3.2L e36 M3 motor a.k.a S52. If I get lucky I may get the engine for $2K, but install will be a whole other matter. If I do an engine swap then I may paint the engine bay at the same time.


Photos of the worst two plugs, #5 (gap filled with buildup) and #6 (blistered):

Technicals Spec List

e30 M20 Spark Plugs: NGK ZGR5A or Bosch Super Plus WR8LC+
Spark Plug Socket Size: 21mm
Spark Plug Torque: 15 – 22 ft. lbs. 

Misfire Information

For reference, diagnosing a misfire includes (but is not limited to) the following systems / parts:

  • spark plugs
  • spark plug wire set
  • distributor cap & rotor
  • ingition coil
  • fuel pressure / fuel pump
  • fuel injectors
  • AFM (air flow meter) & related hoses 
  • vacuum leaks
  • timing belt
  • coolant temperature sensor
  • o2 sensor

October 31, 2012 mechanical, repairs

This post aggregates a few recent fixes and updates into a single post. Went to the junkers today, found some good stuff including an uncracked dash which would probably fetch $200 if I was willing to ship it to a buyer. I left the dash behind but may go back tomorrow I’m not sure.


Door Trim 

  • removed all the old door trim
  • removed any damaged clips, some which the PO crazy glued on when they broke (they are $0.35 each, I have found this to be his typical fix for things)
  • touched up the paint around the trim, clips
  • installed new trim, clips

I’m glad the broken and peeling trim is gone but this didn’t make the car look any better. I am going to consider painting the trim, along with my bumper trim, at some point in the future. For now it’s fine even if one peice of trim is not as shiny as the rest (because I had to assemble the complete set of trim from 3 different cars).

By the way, these bits are $1.00 from most suppliers but BMW of South Atlanta sells them for the list prince, usually less than $0.50 each.


BMW of South Atlanta (link)
e30 325i > Vehicle Trim (link)

Part Numbers:

Clip: BMW Part Number 51131876128 (x1 Per Door)
Grommet: BMW Part Number 51121867907 (x1 Per Door)
Cap Nut: BMW Part Number 41335480120 (x1 Per Door) ! This Part Doesn’t Fit !
Clamp: BMW Part Number 51131829904 (Sedan x2 Per Front Door, x1 Per Rear Door)

Accessory Fusebox 

  • like most e30s the small accessory fusebox next to the main fusebox had no lid
  • this box has two wires: red is always hot, green is hot when key is on
  • i’ve seen these boxes full of water, mine was full of dust
  • lid clasp was broken, had to replace the whole box
  • with another box I was able to just yank the wires out, that didn’t work this time
  • tore the box apart with needlenose pliers
  • discovered that if I had a long, thin, narrow peice of metal I could have gotten it apart properly
  • installed new box, lid



e30 325i > Fusebox Diagram (link)

Part Numbers:
Fuse Box: BMW Part Number 61131382196
Lid: BMW Part Number 61131382197
Boot: BMW Part Number Unknown

Smoke Test

  • sent the car to Bavarian Motorsport for a smoke test and pre-CCC checkup
  • vacuum leaks from breather hose, intake manifold to purge valve and idle control valve
  • they replaced those
  • had front brakes and rotors replaced



Bavarian Motorsport (my shop of choice) (link)


  • not something I did today, just an on-going issue: swapped my AFM a few days ago
  • ordered a remanufactured AFM from Advance Auto Parts a few weeks ago
  • had pretty bad luck with another “brand” of remanufactured AFMs in the past but this was cheap
  • part arrived but has no mounting bolts
  • got some 6mmx18mm flange bolts from Home Depot to mount it
  • disconnected the battery for a few hours to reset ECU (supposedly)
  • car bogs a bit on cold start, hunts then seems to run o.k. sometimes, other times losing power but RPMs are fine
  • everytime I disconnect that battery it seems to start all over
  • not sure I’m going to keep the AFM, may return it and go back to my old AFM or have it refurbished, I’m not sure what’s next with this issue


Python Remanufactured AFM at FCP Groton (link) – My Review (link
Remanufactured AFM at Advance Auto Parts (link)

Cabin Lights 


  • replaced all the door switches
  • cabin lights suddenly work!!
  • open a door, lights come on. close the door, lights stay on, then go off. How modern!

Photo update: 


October 28, 2012 photos, repairs

Picked up and installed some used sidemarker sockets and new bulbs (part number 63217160797). All but one of the car’s sidemarkers has been disconnected and burned out since I got the car. Some day I’d like to put clear lenses (read: make) in my markers and front turn signals but that will have to wait.

On that note, here’s a few of my non-mechanics rules to buying a used e30:

  • if someone can’t be bothered to replace a burned out bulb they probably couldn’t be bothered to do the required maintenance either. burned out bulbs are a sign of neglect.
  • avoid custom painted cars: replacement body parts cost extra because they will always need to be painted and fasteners and clips may be painted over or missing entirely.
  • almost any car looks good wet. be suspicious if someone hoses down their car before you look at it.

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October 7, 2012 mechanical, repairs

I’m going to point-form this rather than add a whole lot of narration that no one really cares about. Basically, since I replaced the thermostat the second time the car has been running hot, especially at idle. This is probably caused by one of three things:

1 – Coolant circulation problem:

  1. Radiator is clogged – doubtful, rad is only 2 months old
  2. Water pump is broken – doubtful, water pump is only 2 months old
  3. Air is in the system – doubtful, new thermostat has a hole in it and bleeding the system produced no air bubbles just coolant
  4. Coolant is low, coolant system is losing pressure – checked frequently, level holds steady. A pressure issue is unlikely without a leak.

2 – Air circulation problem:

  1. Mechanical fan is not working
  2. Auxiliary (electric) fan is not working

3 – Ignition or Valve Timing problem:

  1. Let’s not even go there… drive belt is 2 months old and car was professionally tuned.

My attention turned to the second set of possible causes for the overheating since it’s easy to test the air circulation system. From what I’ve read and been told, the mechanical fan should run all the time but run faster as coolant gets hotter and engages the fan’s clutch. At 80C the thermostat opens and allows coolant into the engine. If the coolant gets really hot the aux (electrical) fan will engage low speed mode at 91C, then go into high speed mode if the temperature continues to climb to 99C. That shouldn’t even happen because the mechanical fan should be sufficient to cool the rad and keep coolant below 91C. The mechanical fan would require parts but the electrical fan might be easier to fix so I checked that first:

GOOD: aux fan comes on when A/C is on, at least it runs as listed in the Bentley manual I jumpered the thermostat switch and found:

  • GOOD: fan high-speed works
  • BAD: fan low-speed did not work. Possible causes:
    1. could be the resistor, which comes in two variants and is very difficult to replace without removing the radiator
    2. fan relay is blown
  • GOOD: Replaced relay K1 and low and behold now both low and high speed modes are working when jumpered


  • BAD: visually, the fan was turning a speed I would describe as “slow” even when hot
  • VERY BAD: at operating temperature I was able to stop the fan blade using a single piece of cardboard (a rolled up newspaper could have been used too)
  • GOOD: belt seems tight when depressed with my finger, less than 1/4 of deviation
  • BAD: both upper and lower hoses coming from rad were hot (only indicates a problem, not necessarily a clogged radiator)

I checked with my friend and mechanic (who will remain nameless so he will not be inundated with after hours petitions like mine) for guidance. He didn’t offer any alternative theories so I decided to go ahead with the fan clutch replacement. He hooked me up with a new fan clutch and most importantly a 32mm fan clutch wrench (which is long and thin) and a pulley retainer. If you ever do this job I cannot overstate the value of having the right tools especially the pulley retainer not sure of the quality but you can buy both from Amazon for under $30.00. You can use a regular 32mm wrench but there will not be room for a pulley retainer as well, therefore the special thin versions are required. Here’s how this went down:

  • removed the old fan using the 32mm wrench by loosening the reverse threaded nut (when standing in front of the car righty loosey lefty tighty, or clockwise to loosen)
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  • didn’t need the pulley retainer here because the belts were nicely tensioned
  • didn’t need to whack the wrench with a hammer, nut loosened easily probably because it hadn’t been on for long
  • turned the fan mostly by hand until the last couple turns where the wrench was
  • used the wrench and my spare hand to grab the fan but still almost dropped it
  • there is only millimetres of extra space between the rad and the fan once it’s removed
  • tried to remove the fan blade from the fan clutch
  • my fan had regular bolts, not M6 (hex) bolts so there was little room for a socket between the bolt and the clutch
  • fan kept wanting to spin out of my grip while trying to loosen the bolts
  • vice grips couldn’t get good purchase anywhere
  • breaker bar didn’t help, just aggravated the problem
  • posted on facebook e30 group looking for either:
    • A) a bench mounted vice to use
    • B) a replacement fan
  • thankfully someone (thanks, Vivek) was able to provide both but I had to remove the fan from a clutch myself and also the vice was not on a bench
  • went to get fan
  • needed pulley retainer in order to remove fan from donor vehicle
  • noticed this fan had M6 bolts, was able to remove all of them by using my socket wrench and leveraging my grip against the edge of the fan directly across from the bolt I was removing
  • did the same trick on 2 of the bolts on my fan
  • used the vice clamped onto 2 screwdrivers stuck through the tines on the clutch to hold it in place and remove the last 2 bolts
  • amazingly, the clutch will not come apart from the fan blade! no explanation for this. locktite?
  • thankfully I had the fan blade from the donor vehicle
  • paid vivek $5 for the fan blade
  • went home, cleaned the fan and attached it to the new clutch (torqued M6 bolts to 80 +/-5 in. lbs.)
  • carefully threaded new clutch onto water pump bolt by hand until the pulley and belt started moving
  • used the pulley retainer again to finish the job and tighten the bolt with the wrench (guessed at how tight it should be… it’s reverse threaded so it shouldn’t fall off)


Mina really wanted to go for a drive in so we all piled in, got coffee and gas, went to Campbell, then back home, then to Los Gatos to drop off the tools at my friend’s place and back home again. When we were getting coffee I noticed this couple standing next to a BMW X3 who were smiling and nodding at me. His name was Will and he just wanted to say how great it was to see someone in an e30 with the whole family. It was cool to chat even for a couple minutes and it turns out he’s in the BMW Club so maybe I’ll see him again. Car was either running a little cool in traffic or just a tick warm at idle, but totally within allowable ranges. E30s are known for having jumpy, analog dials so this is fine. I’m really happy that my car is running properly again as I’ve been limiting myself to short trips and eyeing the temperature gauge nervously all week so I am glad that I can go for long morning drives again.


Addendum I:

What caused all this? I think the fan clutch probably didn’t like being jostled so violently when I was hammering away on the thermostat two weeks ago. That’s the only explaination I have for it’s sudden failure.

Addendum II:

Got the clutch off the fan blade. Hit it a few times with the hammer. Now I have a spare.

August 19, 2012 mechanical, repairs

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