Wednesday, April 4, 2012

Sky Carp

I am going a bit off topic today but this is just one of those things that has annoyed me for a while and has seemed particularly bad with the early arrival of spring and the arrival of one of the most annoying animals, Canadian Geese. They are big, aggressive, and make a lot of poop. The other day I was out driving on the freeway and there were a couple of them in the center lane honking and trying to scare away cars going down the road at 70mph. It was tempting to to hit them with my car but I figured hitting one of them would probably damage my car. Had it been my Jeep where I don't really care about the aesthetics it would have been a different story. Normally I would't try to hit critters because I am more than willing to let them go about their business but Canadian Geese seem to be more problem than they are worth. When I have been going through a parking lot and one comes up honking and flapping while idling down the lane I have opened the door into one to get it out of the way, I have chased them with a car but they still seem to think that they are in charge. Its not like they are deer where they go stupid when they see headlights, deer in general don't act aggressive towards vehicles, I have heard of the buck in rut charging a vehicle but that is rare compared to those stupid geese.

Thursday, March 29, 2012

Failed Coil Pack, or How to Make a BMW V8 Run Like a Worn Out 4 Banger

Recently my BMW 540i decided that it wanted to run the garbage. I was heading home accelerating hard onto I494 (you know merging into traffic at highway speed) when the car started running really bad. It was definitely misfiring on at least one cylinder possibly more as it seemed to really lack power, it seemed to have the same power as my old Bronco II. So I parked it and didn't want to deal with it right away because I was pissed and didn't want to get more pissed at the moment if I found out I blew the head gasket or cracked the block or head or some other expensive to fix issue. So the next day (Monday) I stopped on my way home from work at  O'reilly Auto Parts to borrow their scan tool to see what codes are being thrown. I pulled the codes and got P0300 (random misfire), P0307 (misfire cylinder #7), and P0420 (catalytic system below threshold bank 1). So what do these codes mean, well P0300 is kind of meaningless as there it means there isn't a consistent misfire so it will usually get set first then when a complete failure happens then another P030X code specific to the problem cylinder will get set. Once a code is set it will remain until erased by a scan tool so seeing both P0300 and P0307 shouldn't be unexpected.  The P0420 makes sense as I was dumping raw un-burned fuel from cylinder 7 into the exhaust and catalytic converter (drivers side which is bank 1).

So now armed with this info the possible causes could be:

  • failed spark plug, cylinder #7
  • failed spark plug boot,  cylinder #7  (this car uses a coil on plug setup so it doesn't have plug wires)
  • failed ignition coil, cylinder #7
  • Failed fuel injector, cylinder #7 (stuck open or leaks like a sieve)
  • Failed head gasket at cylinder #7
  • Burned exhaust valve on cylinder #7
  • Cracked head on cylinder #7
  • Cracked block on cylinder #7
At this point in my head I start fearing that it is a failed head gasket as I am a pessimist and the failure happened when I was accelerating hard (blocks and heads don't tend to crack any more unless you are doing really stupid stuff). So now to start trying to better diagnose the problem. Always start with the easiest things so I played musical coil packs and switched the one on cylinder 7 with the one on cylinder 6. No I turned the key to the run position (everything has power but the car isn't running) and used the scan tool to clear all the codes. I am really hoping to see a P0306, but a P0307 wouldn't necessarily be bad at this point either. So I start the car and let it run and then press the re-scan button. Low and behold I get only 2 codes, P0420, and P0306. Now this could have been better as now I know I need to replace the coil pack that is now on cylinder #6 as the car is now shooting cylinder #7. At this point I can pretty much rule out everything else as the misfire moved with the coil pack. Granted coil packs are more expensive than spark plug boots and spark plugs but are cheaper than a head gasket replacement, valve replacement, head replacement, or engine replacement. They are also a lot easier to replace than fuel injectors even if the cost is about the same.

I went and talked with my mechanic neighbor and he suggested replacing all the coils as well as boots and plugs since I am in there anyway and the Bosch coil packs aren't exactly know for their reliability so might as well do all of them instead of potentially having this problem in the future again. This is what I as planning on doing anyway as once you are in there might as well do everything so you don't have future problems. This is still cheaper than any of the catastrophic failures, and the remaining 7 reasonably good coils can be kept as spares in case one of the new ones fail some time down the road, I do the same thing with belts too. 

Also for piece of mind (that OCD thing I got going on) I also did the following:
  • checked to see if the oil was milky. It will look like chocolate milk if you get coolant in your oil and they get hot and mixed up real good. This is a sign of a problem with the head or block, usually a head gasket.
  • Checked to see if there was an oil film in the coolant, oil leaking into the coolant.  This is a sign of a problem with the head or block, usually a head gasket.
  • Checked to see if there were bubbles in the coolant, combustion gases in the coolant.  This is a sign of a problem with the head or block, usually a head gasket.
  • Checked the oil filler cap for moisture, some cars like my wife's VW have a problem with this but my BMW doesn't so I didn't want to see any. Often this is a PCV problem but it could also be a small bit of coolant mixing with the oil, evaporating, and then condensing on the oil filler cap. Might be a sing of a small head gasket leak.
  • Did a compression test on cylinder #7. This rules out cracks in heads, cracks blocks, head gasket failures, and burned valves.
As all of these checks passed so it is definitely not one of the catastrophic failures which is good. So now I was just waiting for my parts that were on order from the auto parts store. Once received I went and change out the old spark plugs, spark plug boots and coil packs. I cleared the codes and the car fired right up and the sluggishness and misfire has gone away. It was a good idea to also change out the plugs as all but the one from cylinder #7 showed signs of lean burning. This wasn't really a surprise as the emissions system detected unburden fuel (the misfire) and to try to correct it leaned out the fuel air mixture. So with new plugs, boots and coils the care is running great again.

Thursday, March 22, 2012

My Used Car Buying Guide

One thing people frequently ask me about is advice on buying a used car. I would like to think it is in part because I know a lot about vehicles and also it doesn't hurt that I have bought good used vehicles. Below is what I do when buying a vehicle and what I look at.
  1. Don't plan on buying a specific vehicle and then try to find one that you can afford instead figure out what you want to spend and then find the best vehicle that meets your needs in that price range. This opens up a larger selection of vehicles and when you get it narrowed down to a few you like then you can pick the one you want based off of model or type. Almost always I have a few choices and personally I have a preference for BMWs so once narrowed down to a few choices I tend to pick those.
  2. Have realistic expectations for your price range. The general rules I follow for what to expect from a vehicle are:
    1. $500 or less - If it moves under it's own power it is a good deal
    2. $500-$1,000 - Decent engine, decent transmission (still not great) but expect a lot of other issues some may be major
    3. $1,000-5,000 - Good engine and transmission, expect a number of minor issues but there shouldn't be any major issues
    4. 5,000-10,000 - There should only be minor issues, no major ones. Mileage should be around the average of 12,000 per year. Reasonably new vehicle.
    5. More than $10,000 - It should run great, no major issues, few if any minor issues, mileage should be around the average of 12,000 per year.  Reasonably new vehicle.
  3. Find out what you need. Too many times to I see people buy cars they don't like because they thought they wanted/needed something else. If you just need to transport people and have never driven a truck or SUV then don't buy a SUV to haul people around because you probably won't like how it drives (this happened to my sister). 
  4. See what is available. Go get a news paper or better yet go online and use sites like,,, or any number of other vehicle sites. Select the style of vehicle you are interested in, set your price range (be reasonable), and set your search area. Now you have a list of potential vehicles so start deciding what ones might be worth going to see.
  5. Determining the actual cost of a vehicle. Private sellers have a tendency to either undervalue or over value their vehicles while dealerships will generally be more correct. Good sources for info on this would be sites like or as these can give you a ballpark idea of what a vehicle should cost. Remember just because someone else paid too much or threw too much money into a vehicle doesn't mean you have to. Why should you care what they paid or how much they spent on fixing it.
  6. You should now have narrowed down the vehicles to a few that would be worth going to see and drive. The inspection and test drive are probably the greatest indicators of quality. I check the following:
    1. The dipstick - It shouldn't be varnished or covered in soot, also the oil level should be correct
    2. The oil - If they haven't just changed it it shouldn't smell burned and defiantly should never have metal shavings in it
    3. The coolant - shouldn't have any oil film on top, if you have a coolant gravity tester check the quality
    4. Check the fuel filter - If it looks cleaner than the rest of parts around it it has been changed
    5. squeeze the hoses - they should be somewhat firm and shouldn't show surface cracks
    6. Check the automatic transmission fluid - It should be at the proper level and bright red and shouldn't smell burned
    7. drive the car - Take it out on the highway and when going down the on ramp run it through its paces hard. Problems will show up first at the extremes any noises, misses, hesitation or other abnormal things are an indicator of problems as are long or incompetent shifts in an automatic transmission. 
    8. take it into a parking lot and do a couple of tight circles listen for creaks, squeals, grinding noises, or clunks.
    9. Check the power steering fluid - If it uses regular power steering fluid it should be clear, if it uses ATF it should be bright red
    10. On a manual see that it shifts smoothly and that the clutch holds when accelerating hard
    11. Make sure that the car drives straight.
    12. when going over bumps listen for clunks or other noise from the suspension.
    13. make sure that all 4 tires match
    14. check for even tread wear
    15. Find out common problems on the vehicle you are looking to buy and check for those as well
    16. Check in the wheel wells and door seams for signs of rust
    17. If you are really motivated and buying form a dealership see if you can get them to put the car up on the lift and check it out. I have only managed to get one dealership to do this and that was the one where I bought my current BMW from. Here you can check a lot of the suspension and drive train stuff like axles, suspension, wheel bearings, tie rods, drive shaft, and a bunch of other stuff 
    18. Turn the steering wheel to see if there is excessive play in the suspension, then turn it to the extremes to make sure that the power steering pump isn't making tons of noise. It will make some but shouldn't get really loud
    19. If you don't want to do this get a mechanic you know to check it out, there is a charge for this but it will give you piece of mind.
  7. Never buy the vehicle the day you first look at it. Go home find out specific things to look at more closely, and common problems. Sleep on it and then go checkout the vehicle again and take it for another test drive. If you still like it then buy it, otherwise walk away.
I have used this method for every vehicle I have ever owned and haven't been let down, even with the beater vehicles I have bought that were well under $500.

Friday, March 16, 2012

Google Knows How to Fix Your Car

As I have gotten more experienced working on vehicles I have been tackling more difficult jobs. For a lot of these jobs something like the Chilton or Haynes manuals are great but frequently I find them to have poor images (why do they take black and white pictures of gray and black stuff in poor lighting instead) tiny diagrams, and sometimes are too general and don't cover the topic I am interested in. Also they don't have the best diagnostics section. When you start to run into these limitations you basically have 3 options:

  • Official Factory Service Manual
  • Random people on the internet
Factory Service manuals are great (I have the one for my MG Midget that I got from a friend) but they can be on the spendy side (start at about $100 and go up from there) but they will tell you everything you need to know to fix your problem. Problem is you either need to order them online or buy them from the dealership, online is cheaper but still don't expect to be paying less than $100 and you have to wait at least a day for it so show up.

For those of you who don't know ALLDATA is an online resource that covers all makes and models of vehicles and basically has all the info in the respective factory service manuals. This is a pay service but if you are lucky enough that your local library has access (I think most in Minnesota do, and I know the Dakota County ones all do) so you can go use it there. If you wanted access from home it gets pretty spendy (currently $26.95 per year for the first vehicle) but might be worth it if you have a car that needs lots of repairs. Typically this is the service that professional mechanics use.

This leaves the 3rd option of people on the internet. Now this may not sound like a very good option but it has worked really well for me in the past. Most of the time you are not the first person to try and do something and there are others like me who are really into their vehicles. As such these people tend to post DIYs online with some really good large color pictures and write-ups. Frequently there are entire sites designated towards a specificy vehicle that have lots of info on them. Add in message boards and there is probably more info online for free than there is in ALLDATA for your vehicle. The hard part is finding it and knowing what to put into Google. So how do you find the data:
  1. Go to a search engine like google, yahoo, ask, ...
  2. Enter some basic info but don't be too specific as maybe no one made reference to a green 2003 version of your vehicle. 
    1. make
    2. model
    3. problem or question
  3. check out the results, if you have a lot of results for different vintages of your vehicle you may want to try and trim them by being a bit more specific. With BMWs you can usually eliminate stuff not relevant to your vehicle by putting in the engine type (M62) or body type (e39). I haven't done it with my jeep yet but then I haven't had to search for much. If you don't know these values I might suggest checking out Wikipedia for your vehicle make and model as there you can probably find these values.
For example in the past I have used these sites for various vehicle info:
  • - Ford Ranger/Bronco II site. This page is the technical section for the site and has lots of detailed fixes and modifications
  • - BMW 3 series hatch back (my previous BMW)
  • - BMW 7series site that has a BMW e39 section since a lot of things are shared between those vehicles
  • - A BMW message board covering all models
  • - This specific page has a whole ton of e39 BMW DIYs linked from across the web in one spot. The site covers all BMW models.
  • - This page has details on replacing the valley pan on a BMW M62 engine.  The site covers all BMW models.
There are a number of additional sites I have gone to but those are just some of the gems I have found but searching the internet. The other nice thing is that if you want to do some vehicle modifications again you probably aren't the first one to want to do that so you can find all sorts of info and see where others have had issues or know what you are getting your self into. Sometimes you never find what you are looking for and have to settle for what info you can find. Personally I think I am the first person who want to have a supercharged alcohol burning MG Midget. I can find some info on converting a vehicle to run on alcohol but most of the info on doing that is from really goofy alternative energy people who basically just want to make moon shine and aren't doing it right (they don't even bother to adjust the fuel air ratio) but I have had some luck in poking around on the various sprint car, and midget racing (not the MG kind) as those cars are all alcohol burners and they actually know what they are doing. The supercharging part is easy as there is a kit for the A-series engine, as well as an optional high boost kit for the supercharger.