[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]
Peter Legault, Someone had a similar problem. This is an old e-mail from last month. For some reason I cannot find it on the archive I guess only selective year 2000 stuff applies. So instead of having you look for it I am resending it. This e-mail mentions how to troubleshoot the pump relay problem even though instead of not working relay it is a buzzing relay problem. You must have the Bently scats to understand this. The numbers on the relays: 86 and 85, power to relay and 87 and 30/51 are the switched connections. The pump relay is switched on by power from the brain relay positive and the negative side of the pump relay is energized by the brain. Follow the message at bottom using a Bently scat. If you have no source for a scat I can Snail/mail you one big one. I hope for no typos. I hope not to confuse you, I am not the most coherent writer. If you have any specific questions please e-mail me. LEON MARTINEZ -----Original Message----- From: Martinez, Leon Sent: Monday, April 30, 2001 8:34 PM To: 'type3@vwtype3.org' Subject: FW: 69 notchback help Getting to your buzzing relay, do you have a bently manual ? Go to page 18 in section 4 in the fuel system chapter in the book and look at the schematics. Please follow me. I will be using the scat that is for the 1970 to 1972 car, this one is easier to follow. It seams that all EFI cars are hooked identically at the fuel pump and it's components. At the bottom of the scat you can see the pump labeled as number 9. Just above right is the relay labeled number 15. Look at your relay, it should have the numbers exactly the same as in the picture in the book. The numbers on the connectors should read 86 and 85 and 87 and 30/51. In case you do not have a 30/51 get a double blade adapter from an auto parts store, this is to connect two wire on that blade connector on your relay 30/51; the 30/51 siginfies that it is for two connectors or one connector with two wires crimped in. You wanted to know what the relay is for ? All relays in a car or electronic equipment is to remove the load on the switching wiring and the switches. If they are not installed you may have heated melted wiring and burned out switches. It increases the amount of wiring but makes the wiring shorter where it counts. The relays activate it's internal switch when pin 85 is negative and 86 is positive 12v across them. This will magnetize a metal core that is wonded by copper wire that is connected by pin 85 and 86. The magnetism pulls the metal switch closed for the big power/current item like a pump. That is how relays work. For troubleshooting, you will need a multimeter with a continuity tester beep. If you do not know what this is and do not know how to use it, ask me because my instructions will not be very useful if you cannot verify good connections and voltages you will be out of luck. Back to the relay problem. When you turn the key the brain relay is activated by the fuse box and a ground that is attached permanently to the chassis ground. This relay is located under the rear set (I think that is the location) Look at your scat, this relay is located at top left and is labeled as number 12. The connector labeling is similar to the pump relay. When key is turned positive voltage goes to pin 86 on this relay from the fuse box, negative ground is hooked up to pin 85 on the brain relay. When this relay is activated, the battery positve on the battery (shown as a square top left with a positive sign (+) and a negative sign (-)) will come in through pin 30/51 and pass through the now connected pin 87 that is hooked up to the brain at pins 16 and 24 at the brain connector. Additionally at pin 87 of this brain relay, the positive voltage moves power to pin 86 of the winding part of the pump relay. This is the copper wonded part that needs the negative side at pin 85 to cause a magnetic field at the core thus pulling the switch inside across pins 87 and pins 30/51. Once this relay is activated pins 87 and 30/51 connect together and let power from the fuse box (30 amp fuse that is always connected to the positive of the battery). This will make the pump turn on and no buzzing should exist. What happened to the negative part of the pump relay ? Well pin 85 wich is supposed to be negative is connected to the brain at pin 19. The brain turns the pump on this way. If you turn the key you should hear the pump on for a few seconds then it turns off, this is a saftey feature that prevents the pump from turning when engine is not turning. Now lets trouble shoot, verify with a continuity tester every connection mentioned and make sure nothing is loose and and continuity is good when testing in the off position. Check voltages in the on position at the pump relay and the ground wile buzzing is occuring. Let say you want to check the relay and pump directly; make sure connection between the pump and the relay is good. Check the ground to pump is good. Get a wire and hook it up to a keyed (hot when key on ) positive in the fusebox and the other side to pin 86 . Ground the relay with a wire at pin 85 you should hear the pump on when the key is turned, buzzing should not exist. Turn engine on, does it turn on nicely ? Connect back together. If this is successful then the problem lies between the positive pin 86 and brain ground at pin 85 . Check for a good solid voltage with a meter if this is difficult use a small light bulb (12v) attached to 2 wires, attach the one side to pin 86 and the other side to ground. Make it buzz , does the light buzz too ? No? if not the voltage is good . Yes? bad wire connection or funny brain relay (unlikely). Disconnect bulb, hook one side to power at the fusebox and the otherside to pin 85. Is it buzzing (light) ? No. If no then computer and wiring is good. If yes (light is buzzing) then the wire and/or brain is defective .If wire proves good and brain seems defective hook up pin 85 to ground, problem should go away. replace brain when you can or test one out from a friend. Take pump off dissasemble front driver part and check for junk inside where the fuel moves make sure its clean, do this if you suspect the pump only, several of us had this problem I doubt this is your problem. If I missed something and you need clarification on something specific, e-mail me. I will answer. You must develop some creative troubleshooting after understanding this scat, that way it will become very easy to figure problems out. Don't forget to e-mail me if you get stuck or do not understand some of my rantings. I probably made some mistakes I hope somebody finds them or maybe I have no mistakes ? LEON MARTINEZ 1969 SQUAREBACK EFI/AUTO SAN DIEGO AND TIJUANA ------------------------------------------------------------------- Search old messages on the Web! Visit http://www.vwtype3.org/list/