 __Volume 30| March 9th, 2010 _____ About VanAgain | VW Accessories | Vans for Sale | The Community |
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How to troubleshoot a Vanagon that won't start
Help my 2.1l Vanagon has fallen on it's face and it can't get up! A Vanagon Stalls and Won't Start. I have had people email me with this problem about a million times so I finally decided to do a write up about the proper proceedure to get your van up and running again.GOT GAS? First of all, do you have gas in the tank? Please, you don't know how many times people call me, I ask them this question and they get really quiet for a minute. Don't overlook the obvious! If you know you have gas in the tank the next thing you want to do is to start to troubleshoot the reasons for the engine not starting. You are looking at six possible causes. 1. Lack of Spark 2. Lack of Fuel 3. Lack of Compression 4. Lack of Fresh Air (Intake Blocked) 5. Lack of Exhaust flow (Exhaust Blocked) 6. Improper Timing If your van was running just a short time ago, and died suddenly, you can almost certainly rule out number 6. Really that is only a possibility if you have just disturbed the timing in some way. If you haven't please DON'T TOUCH the distributor and change the timing. If you do you will be sorry! Now you have just "muxed up" (technical term for bollocks) something else that you will have to fix before the engine will start. Also lack of compression (3) is a very rare thing to happen without plenty of other bad things happening before the van will no longer start. Again this is something you should investigate as a last resort after you have checked everything else. 1. Lack of spark: Let's start then with Lack of Spark as the normal, number one culprit to vans stalling and not restarting. This can be caused by a number of reasons however we first want to confirm that this is what is happening and then we can looking into why. Remove all of your spark plugs and visually inspect them. Do they look damaged or really sooty? Is the center electrode worn down to the same level as the edge of the threaded part? If so you should either clean or replace your plugs and see what happens. Your plugs can become fouled by a rich running condition or oil filled oil (don't do this either!) and the van will never start. If your plugs look good, then move on to the next step which is to test for spark. You can check your spark by unplugging all of the fuel injector plugs and then removing a spark plug, grounding this plug to the engine while the wire is attached and cranking the engine over. This will allow you to test spark without the injectors spraying. You want to see a bright white spark several times in a row. If you have spark then you can test the injectors by grounding the center coil wire to the engine and plugging all of the fuel injector plugs back in. Remove the small 10mm bolts between the injectors and they will lift out of the intake. Put a small pan under them and either have someone crank over the engine or use a remote starter but be sure that your ignition key is in the "on" position or the injectors will not spray. You want to see a cone shaped pattern. If you aren't seeing any spray remove the bolt that closes up the test port on the fuel lines (by the distributor on the center of the top of the engine). Clamp a hose to this test port and put one end of the hose into a jar that way you are safe from gas spills.Now just turn the key and see if you get gas out of here. 2. Lack of Fuel If you aren't getting any gas then you need to check your fuel pump and filter. Causes for no spark: ECU Hall Effect Generator (in distributor) Coil. Of the three I have ranked them in their order of most failures to least. If you aren't getting any spray at the injectors but you do have fuel pressure then it could be: ECU Hall Effect Generator Injectors clogged. Again in order. If your fuel pump isn't working it could be: Hall Effect Generator Fuel Pump Relay for Fuel pump Ignition switch Wiring to pump. 4. and 5. Lack of Intake or Exhaust flow If you are getting spark and fuel and everything seems fine that way, check your cataytic convertor. I have seen these become so clogged that they will not allow any exhaust to leave the engine and thereby not let the engine run. You can have someone crank the engine over and put your hand by the tail pipe to see if you feel any air coming out while the engine is cranking. If not remove the three bolts between the cat and the connector pipe and try to start the van that way. If it starts then remove and replace the cat with a new one. Overfilling on oil or bad rings can cause this problem. Also check your intake by inspecting your air filter. There is a cardboard (you heard me right) tube that comes down from the plastic vent that is in the upper rear corner of the van on the same level with the rear window. This tube can collapse and block the intake air. Unhook the air box from it if you think it might be the culprit and if the van starts up then you know this is bad. You can either remove it or replace it with some drier hose from Home Depot (aluminum not card board please!). 3. Lack of compression. I know this is number 3 and now it is the last to be considered but it is not common for you to lose compression and the engine to not start at all. Usually you will lose one cylinder and the engine will still start but run roughly. However it is possible so if all else fails, do a compression test on your engine You can buy a compression tester from Advance Auto or Auto Zone for not much money. Now disable the spark and unplug the injectors as we have already discussed. Screw the compression tester into a spark plug hole. Get someone to crank the engine over for 10 seconds while you watch the gauge. Draw a square on a piece of paper. That represents your engine. Now write down the compression numbers on the area of the square that corresponds to the cylinder you are testing. The lower limit of compression in a Waterboxer is around 119 psi. However I have seen good running engines with around 95 psi so if you are getting a low reading don't jump to the conclusion that this is your problem. If compression is the culprit you will see zero compression. That is the cylinder or cylinders that is causing the problem, investigate further. This troubleshooting guide should help you narrow down the problem until you get down to just one or two choices of what the problem could be. Many times you can narrow down the problem to either the ECU or the Hall Effect Generator and it is difficult to figure out which one of these two is the culprit. I know that Bentley has a proceedure for the Hall Effect but I have never been able to get an accurate Pass or Fail out of this test. My normal test when I am confronted with these two choices is to swap in a known good ECU and see what happens. Many times it is the ECU that has failed and needs to be replaced. Any ECU from 86-91 will work in any other 2.1l Vanagon so if you have a friend nearby that is willing to let you borrow his ECU this is the best way to test. If you have to guess I would say that most of the time it is the ECU. However if the plug is broken off of the side of the distributor, I would lean more toward the Hall Effect generator as this is the failure mode for that part. I have rebuilt ECUs on the shelf for $250 plus $100 core charge. I also have new Hall Effect Senders for $125 or rebuilt Bosch Distributors with new cap and rotor included for $259 plus a $77 core charge. If you really appreciate this troubleshooting guide please make an effort to support Van-Again with your parts purchases. Nothing says "Thank You" like buying your parts from us! We sincerely appreciate your support. At Van-Again we're out to prove that we're not only your VW parts source but also the place to go to get your VW Van questions answered. Go to the homepage. |
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