Post by Volktales on Oct 18, 2014 11:07:16 GMT -8
Ok it is kinda like this. It has been many moons now since I have owned my orange campervan. Once upon a time when I first restored it and started using it alot it featured an 1800 cc engine with the original dual carb setup. Although this always ran and drove just fine, I didn't like the transmission at the time which was from an early '68 bay. Later I acquired a project '77 Westy that never got finished (long story). I basically decided to swipe the 2 litre engine, trans, fuel tank, and entire fuel injection system from it. After rebuilding everything, I transferred it all into my '74 van. I took the time to swap ALL related components over and everything would work just like a stock '77 (or would it?). The one thing I forgot was the linkage under the throttle pedal was quite different and the original linkage wouldn't allow full throttle. Once this was attended to everything seemed fine and dandy in the world. .... But then a problem very slowly developed over the years... The bus always started instantly when warm, but often cranked excessively when cold. Originally this only happened if sitting for some time, but eventually occurred more and more often. I tested different things over the years but every time I did something it seemed to "cure" it for a while. Finally I had enough and decided to get serious about looking for the problem. And after lots of looking, this is what I found....
This is the ignition switch taken apart; that shiny spot in the center of half the switch assembly is the main contact that supplies battery power to the rest of the switch. It looks shiny because I filed the crap out of it as it was nice and burnt looking. At the same time I soldered on a new thicker wire to replace the black wire shown in the photo. This wire feeds ignition power to the fuse box and seemed kind of wimpy. Checking the diagrams carefully showed that fuel injected buses had a larger gauge wire for this purpose and mine was puny and intended for carbs (injection system has more things to power up via ignition power). Guess I should have thought about that sooner. One thing is for sure, I picked up over 1/2 of a volt in supply power to the coil by doing this. Will find out tomorrow if I really fixed it however.. I also suspected that my Pertronix ignition might be drawing too much juice. The draw was the same on my other bus and it always starts right up even after sitting for eons... If this one still won't start I might just cry all day....
Incidentally, removing the ignition switch is not high on the fun factor. The official manual says to remove the steering wheel, switches, upper bushing, and remove the entire housing to extract the switch. The samba has a very good how to that says the same thing. That looked like effort and it is most definitely possible to remove the electrical part of the switch without doing any of this. You will be lying on the floor and the brake pedal isn't very comfy on the head, but it can be done from below without too much effort. It is necessary to unplug the wiring to the ignition switch only, remove 4 phillips headed bolts, slide column assembly to the back a bit, then undo a very tiny set screw and the switch can be removed with a bit of poking with a screwdriver. The switch itself comes apart easily with a small screwdriver to pry it apart. Cleaning the contacts should restore function and last for a long time. And you just know it will be better than a crappy new switch from who knows where. Note this info applies to baywindows up to around 1975-ish. Later bays used a cheapo switch that is totally different in design as is the plastic column assembly that surrounds it. The earlier housing is all metal. Also if you need to replace the mechanical key portion of the switch, then you have to completely remove the assembly from the van!
This is part 5261 of this thread..... I haven't said anything more about this for a while because quite simply the problem was still there!!!! After repairing the ignition switch and related wiring without success, I had to dig deeper to find a cure. If only I knew how deep it would be.... The problem was poor cold starting, and MANY different tested were carried out. The fuel pressure was tested first (remember this 1974 bus has a later 1977 2 litre fuel injected motor installed with aftermarket Pertronix electronic ignition). The electric fuel pump worked properly with both pressure and flow within specs. The cold start injector electrically worked and registered a drop in fuel pressure while operating as required (we will come back to this later). The main relay that controls the injection system and fuel pump is a combined unit (called the double relay(duh!)) was tested and worked fine. So did the other injection parts including the air flow meter, auxiliary air regulator (adjusted for a faster cold idle), and main temperature switch. The various related grounds were tested as well and were fine. Testing all the ignition wires revealed the coil wire seemed to have more resistance then it should. Swapping this made a big difference in spark output( I had rigged up a remote starter button by this time and watched the spark from the coil wire). Although replacing the wire helped, the starting problem persisted. I decided to look at the cold start injector again and this time removed it and watched its spray pattern. Instead of a nice cone shape, fuel dribbled sickly out the injector. I replaced it with a tested used one and was sure this would solve my problem. Nooooooooo it was not to be..... I then went through the electrical system that supplies power to the coil and found some less then perfect connections causing voltage drops. Cleaning this connections raised my available voltage to the coil by almost 1 volt. Joy?
Nooooooooooo!... I was still suspecting a poor spark because when compared to my 1972 van, the spark was definitely not as strong. Switching coils made no difference, neither did the rotor or cap. I even stole the Pertronix earmarked for the Ghia and tried that in case the original was faulty, but again no dice. Getting desperate I borrowed some other injection parts (Thanks, Steve) and swapped out the starter and air flow meter. Of course there was no difference...... Later I ran giant jumper wires from the battery to the fuse box and from the fuse box directly to the ignition coil. Also bypassed the ignition switch and anything else related to the circuit. Oh and disconnected everything not required to start the engine. Did it work??? NOOOOOOOOOOOOO! But I did find something.... If I ran a large diameter wire (10 gauge) directly from the battery to the coil, it would start immediately. So what was the solution?? Simple yet with a weird twist at the same time......
Getting thoroughly pissed off by this stage, I decided to do a cheat. Knowing that the problem was definitely a lack of juice getting to the coil, I decided to add a relay into the circuit. Electrical relays perform a simple purpose, allowing a small current flow to control a much larger current flow. If your not really comfy with electricity, compare it to water flowing in your garden hose. Voltage is similar to the pressure in your hose. Even if your not spraying the hose and no water is coming out the nozzle, the pressure is still there, just like the 12 volts sitting in your battery waiting for something to do. Amperage (current flow) can be thought of water actually flowing through the hose when you are spraying it. Resistance (measured in Ohms), can be equated to a kink in your hose which restricts the water flowing through it. Basically excess resistance somewhere in an electrical circuit will cause a lack of current flow causing what you want to work to NOT work correctly! Just like my effen bus! Testing for excess resistance with your digital multimeter on the Ohms scale is useless anyway as even a single tiny strand of wire will show a circuit pathway exists even if the other 99 strands are broken in the wire. To test properly for excess resistance involves doing voltage drops which can be time consuming and difficult on your own. This is why I bypassed suspect wires with long jumper wires but was unable to isolate the exact point of failure. (Patience was long gone by this stage). Anyway back to the relay... Basically by installing this relay I could supply the coil with current direct from the battery and control it using the original supply wire from the ignition. See picture below for explanation. This works because now the original wiring in the bus only has to turn on the relay which requires much less juice then powering up the original coil and electronic ignition system. The relay once turned on supplies battery power to the coil directly through large diameter wires. The bus now started instantly to my delight, but was reluctant to stop running!!!!
Yes the engine did not want to stop running when the key was shut off! Checking for voltage at the original coil wire, now attached to the relay showed that with the key off, 1.0 volts was still at the wire with the engine running. This was enough juice to keep the relay engaged, therefore power was still being supplied to ignition system hence the running. Turning on the turn signals or hazard lights was enough to kill the engine however. The 1.0 volts was being generated via the charge light on the dashboard due to the way in which the alternator's regulator works. This is common on old vehicles converted to relay controlled ignition systems and is known to effect MSD systems as well. MSD supplies a diode for this purpose and one of my Hot Rod friends gave me a spare he had. You can see the diagram of how it is installed in the bottom of the first photo and the black blob in the wire in the picture is the diode itself. Installing this cured the running on problem instantly. The installed relay in the second photo looks unsightly but as I was so happy to have it running right, that I stopped caring by this stage!
And I know it is from a TOYOTA but at least you know it will continue to work forever! The relay is actually a headlight relay from a 1991 Tercel so it is vintage in its own right now! Anyway the bus starts instantly hot or cold and is better then it ever has been. Idle is smoother too and pulls away from low rpm better than ever. In the end this project gobbled up hours and hours of time but the only cost was I replaced the 11 year old battery early on, just in case. Everything else was stuff I had lying around or "borrowed" from dear old dad. So the moral of all this is... well I don't have a clue but at least Karma is restored once again in the VW...
This is the ignition switch taken apart; that shiny spot in the center of half the switch assembly is the main contact that supplies battery power to the rest of the switch. It looks shiny because I filed the crap out of it as it was nice and burnt looking. At the same time I soldered on a new thicker wire to replace the black wire shown in the photo. This wire feeds ignition power to the fuse box and seemed kind of wimpy. Checking the diagrams carefully showed that fuel injected buses had a larger gauge wire for this purpose and mine was puny and intended for carbs (injection system has more things to power up via ignition power). Guess I should have thought about that sooner. One thing is for sure, I picked up over 1/2 of a volt in supply power to the coil by doing this. Will find out tomorrow if I really fixed it however.. I also suspected that my Pertronix ignition might be drawing too much juice. The draw was the same on my other bus and it always starts right up even after sitting for eons... If this one still won't start I might just cry all day....
Incidentally, removing the ignition switch is not high on the fun factor. The official manual says to remove the steering wheel, switches, upper bushing, and remove the entire housing to extract the switch. The samba has a very good how to that says the same thing. That looked like effort and it is most definitely possible to remove the electrical part of the switch without doing any of this. You will be lying on the floor and the brake pedal isn't very comfy on the head, but it can be done from below without too much effort. It is necessary to unplug the wiring to the ignition switch only, remove 4 phillips headed bolts, slide column assembly to the back a bit, then undo a very tiny set screw and the switch can be removed with a bit of poking with a screwdriver. The switch itself comes apart easily with a small screwdriver to pry it apart. Cleaning the contacts should restore function and last for a long time. And you just know it will be better than a crappy new switch from who knows where. Note this info applies to baywindows up to around 1975-ish. Later bays used a cheapo switch that is totally different in design as is the plastic column assembly that surrounds it. The earlier housing is all metal. Also if you need to replace the mechanical key portion of the switch, then you have to completely remove the assembly from the van!
This is part 5261 of this thread..... I haven't said anything more about this for a while because quite simply the problem was still there!!!! After repairing the ignition switch and related wiring without success, I had to dig deeper to find a cure. If only I knew how deep it would be.... The problem was poor cold starting, and MANY different tested were carried out. The fuel pressure was tested first (remember this 1974 bus has a later 1977 2 litre fuel injected motor installed with aftermarket Pertronix electronic ignition). The electric fuel pump worked properly with both pressure and flow within specs. The cold start injector electrically worked and registered a drop in fuel pressure while operating as required (we will come back to this later). The main relay that controls the injection system and fuel pump is a combined unit (called the double relay(duh!)) was tested and worked fine. So did the other injection parts including the air flow meter, auxiliary air regulator (adjusted for a faster cold idle), and main temperature switch. The various related grounds were tested as well and were fine. Testing all the ignition wires revealed the coil wire seemed to have more resistance then it should. Swapping this made a big difference in spark output( I had rigged up a remote starter button by this time and watched the spark from the coil wire). Although replacing the wire helped, the starting problem persisted. I decided to look at the cold start injector again and this time removed it and watched its spray pattern. Instead of a nice cone shape, fuel dribbled sickly out the injector. I replaced it with a tested used one and was sure this would solve my problem. Nooooooooo it was not to be..... I then went through the electrical system that supplies power to the coil and found some less then perfect connections causing voltage drops. Cleaning this connections raised my available voltage to the coil by almost 1 volt. Joy?
Nooooooooooo!... I was still suspecting a poor spark because when compared to my 1972 van, the spark was definitely not as strong. Switching coils made no difference, neither did the rotor or cap. I even stole the Pertronix earmarked for the Ghia and tried that in case the original was faulty, but again no dice. Getting desperate I borrowed some other injection parts (Thanks, Steve) and swapped out the starter and air flow meter. Of course there was no difference...... Later I ran giant jumper wires from the battery to the fuse box and from the fuse box directly to the ignition coil. Also bypassed the ignition switch and anything else related to the circuit. Oh and disconnected everything not required to start the engine. Did it work??? NOOOOOOOOOOOOO! But I did find something.... If I ran a large diameter wire (10 gauge) directly from the battery to the coil, it would start immediately. So what was the solution?? Simple yet with a weird twist at the same time......Getting thoroughly pissed off by this stage, I decided to do a cheat. Knowing that the problem was definitely a lack of juice getting to the coil, I decided to add a relay into the circuit. Electrical relays perform a simple purpose, allowing a small current flow to control a much larger current flow. If your not really comfy with electricity, compare it to water flowing in your garden hose. Voltage is similar to the pressure in your hose. Even if your not spraying the hose and no water is coming out the nozzle, the pressure is still there, just like the 12 volts sitting in your battery waiting for something to do. Amperage (current flow) can be thought of water actually flowing through the hose when you are spraying it. Resistance (measured in Ohms), can be equated to a kink in your hose which restricts the water flowing through it. Basically excess resistance somewhere in an electrical circuit will cause a lack of current flow causing what you want to work to NOT work correctly! Just like my effen bus! Testing for excess resistance with your digital multimeter on the Ohms scale is useless anyway as even a single tiny strand of wire will show a circuit pathway exists even if the other 99 strands are broken in the wire. To test properly for excess resistance involves doing voltage drops which can be time consuming and difficult on your own. This is why I bypassed suspect wires with long jumper wires but was unable to isolate the exact point of failure. (Patience was long gone by this stage). Anyway back to the relay... Basically by installing this relay I could supply the coil with current direct from the battery and control it using the original supply wire from the ignition. See picture below for explanation. This works because now the original wiring in the bus only has to turn on the relay which requires much less juice then powering up the original coil and electronic ignition system. The relay once turned on supplies battery power to the coil directly through large diameter wires. The bus now started instantly to my delight, but was reluctant to stop running!!!!
Yes the engine did not want to stop running when the key was shut off! Checking for voltage at the original coil wire, now attached to the relay showed that with the key off, 1.0 volts was still at the wire with the engine running. This was enough juice to keep the relay engaged, therefore power was still being supplied to ignition system hence the running. Turning on the turn signals or hazard lights was enough to kill the engine however. The 1.0 volts was being generated via the charge light on the dashboard due to the way in which the alternator's regulator works. This is common on old vehicles converted to relay controlled ignition systems and is known to effect MSD systems as well. MSD supplies a diode for this purpose and one of my Hot Rod friends gave me a spare he had. You can see the diagram of how it is installed in the bottom of the first photo and the black blob in the wire in the picture is the diode itself. Installing this cured the running on problem instantly. The installed relay in the second photo looks unsightly but as I was so happy to have it running right, that I stopped caring by this stage!
And I know it is from a TOYOTA but at least you know it will continue to work forever! The relay is actually a headlight relay from a 1991 Tercel so it is vintage in its own right now! Anyway the bus starts instantly hot or cold and is better then it ever has been. Idle is smoother too and pulls away from low rpm better than ever. In the end this project gobbled up hours and hours of time but the only cost was I replaced the 11 year old battery early on, just in case. Everything else was stuff I had lying around or "borrowed" from dear old dad. So the moral of all this is... well I don't have a clue but at least Karma is restored once again in the VW...
