Topic: Calling 8v guru's (Wiring content) (Read 1026 times)

Luckyy · « **on:** July 27, 2009, 07:40:23 PM »

While wiring a stereo system from scratch in my super secret 92 8v gti project, I was in search of an ACC 12v power source and ended up probing my fuse box with a voltage meter to find it. Somehow during that probing, I knocked, pushed, or poked something that I shouldn't have in my Fuel Pump fuse, and now it won't turn on when the key is turned.

Does anyone have any insight as to how to fix this, or even just how to remove the fuse box so I can dig around?

I can get the pump to run by prodding around in one of the holes on the box, and the car starts up just fine... But if I were to place something in the hole to complete that circuit then my fuel pump would just run until my battery died. Unfortunately I don't know enough about fuses and relays to figure out how to fix this.

Any help would be greatly appreciated, Thank you all in advance.

armydub01 · « **Reply #1 on:** July 27, 2009, 07:48:22 PM »

in doing this you may have blown a fuse, pull your fuel fuse out check there isnt any broken to burnt ares

Luckyy · « **Reply #2 on:** July 27, 2009, 08:02:01 PM »

Yeah, I went ahead and checked those out first. Car had all of the sweet oldschool fuses and a lot of the tabs broke off when I was first checking them so I just replaced all of the fuses with some newer ones.

I'm almost positive that it is the fuel pump relay, but I have no idea how to check for it or replace it once I know its busted. Ah well, it is raining now so I guess I'll call it a night. At least I got my sweet $80 wal-mart deck working!

101stvet · « **Reply #3 on:** July 27, 2009, 08:05:50 PM »

it sounds like you knocked/pushed one of the wires out the backside of the fuse block and now it's loose and wont make contact with the fuse/relay i'd drop the fuse block and make sure all the wires are pushed in the block and not hanging out the backside i've had this happen to me before , aslong as you didn't smell or see smoke i think this might be the issue.

the relay is on the bottom all the way to the right if i rember right bap geon is the place toget it every other parts store in town will take a couple days

Luckyy · « **Reply #4 on:** July 27, 2009, 09:18:49 PM »

Yeah, that sounds about what I was thinking happened, just can't articulate it. Any tips or tricks on getting the damn fuse block off?

Smokestack · « **Reply #5 on:** July 27, 2009, 09:42:54 PM »

Quote from: Luckyy on July 27, 2009, 09:18:49 PM

Yeah, that sounds about what I was thinking happened, just can't articulate it. Any tips or tricks on getting the damn fuse block off?

There are two white "clips" that hold it in place on either side of the fuse block. Rotate them 180* (you'll have to lift them off of the block an 1/8 of an inch to clear the stop to rotate them) and then pull them out strait down. Now you can lift the fuse block off of the bracket and fight with the wires that have molded themselves to how they've sat for the past 20 years.

It's always a good idea to carry a spare relay, so pick one up anyways and use it to test with. Sometimes you can get a touch more life out of a failing relay by tapping it on a hard surface and plugging it back in so that you can test the system, but that doesn't always work.

Luckyy · « **Reply #6 on:** July 28, 2009, 08:02:35 PM »

Got the fuse block off this afternoon thanks to Smokestack, and all of the relays looked good. I wasn't sure which was the fuel pump relay, I'm pretty sure it is 32 but I have no idea what the part number is. I'll be heading to Bap Geon first thing in the morning to pick up a new relay and I hope that will solve the problem. I'm a little concerned because of this: If completing the circuit in an area PAST the fuse and BEFORE the relay still turns the fuel pump on, that means the signal is still making it through the relay. Which, to my limited knowledge of how relays work, means that the unit is still good?

Bah I dunno. Thanks for the help thus far guys, hate to bother people over such a simple issue.

101stvet · « **Reply #7 on:** July 28, 2009, 08:16:47 PM »

u can have relays that do either i.e -won't let a signal thru or will allways let a signal thru if i had i thought about it i could have swung by with the relay out of 89 jetta seating in my driveway to test to see if it is in fact the relay

mjohnson · « **Reply #8 on:** July 28, 2009, 08:46:23 PM »

If the fuse is good, that means power should be getting to the relay. If the relay is good, it will close the circuit when the key is on and open the circuit when it is closed. When you are 'probing' around you are making the circuit think the key is on.

I think you might be chasing the wrong thing. You really need to get a multimeter in there to check things out. If your fuse is good then there should be 12v (or whatever the fuel pump draws) all the way to the relay. You also need to know what you're jumping. A relay has two different circuits running through it. It is simply just an electronic switch that controls a high voltage circuit with a low voltage signal. One side will have the main load (12v) and the other side, which I like to use a technical term and refer to it as the 'control'

(much smaller voltage which runs through the coil). Since the only purpose of the relay is to tell the pump to turn on or off, it is going to be a SPST (single pull single throw) relay (switch). When the key is turned on, it is supposed to send a signal to the control side, flipping the switch (closing the main load circuit). The relay is either going to fail open, or closed.

Assuming your fuse is good, then that means you have 12v going to the relay, which also means that you jumping the fuse on that circuit makes no difference. That means that your probing is happening on the 'control' side of the relay, which puts the problem on that same circuit. Since you said you jumped a wire before the relay causing the pump to work, that means your relay is still good.

Provided all the info you gave is correct and that I interpret it right, the problem is not the relay, but instead an open somewhere in the circuit from the key to the relay. Take note one where you jump from/to and narrow the area down.

Smokestack · « **Reply #9 on:** July 28, 2009, 09:59:43 PM »

The fuel pump relay should be the one on the bottom row on the far right. It should have a 80, 67 or 167 on it. If not it's just not a factory relay. There will be two very large copper spades on the back of it and at least one very small spade for the control and maybe another small one for ground. The control comes right off of the ECU, so if the car starts and runs with the fuel pump jumpered that pin should be fine. Try placing a wire across the two slots the large spades fit into (I believe the powersource for the pump is hot, but try it with the key on anyways). If the pump turns on either the relay is bad (more than likely. It's actually very common for them to go out) or you cut into the control wire. The control wire comes from the ECU (or the ignition control module next to the ECU if so equipped) in the engine compartment with the rest of the engine harness into the fuse block. Unless you delved into the big bundle of wires going straight from the firewall to the fuse block, I doubt the control wire is bad from you wiring the stereo in. You can check out this page for info on the fuse block and where the wires are supposed to go http://www.a2resource.com/electrical/CE2.html. The control wire should be on plug G1, pin 03 (G1/03) and is red w/ yellow stripe. Unless the engine is actually running, that pin will only power up for a few seconds after the key is turned on, but before you start delving that deeply into the wireing, test the relay. I just recently spent a lot of time going through the wiring of a certain Alpine White 92 GTI that just moved to Maryland just to find that the fuel pump relay was causing the problem.

BTW, there's a small brown wire with a red stripe coming off of the steering column that makes for a good switch power for stereos. It turns on when the key is inserted into the ignition.

Luckyy · « **Reply #10 on:** July 29, 2009, 12:15:47 AM »

Karma to all three of those excellent posts! I'll check out (if I can find) the ignition to fuel pump fuse wire and make sure it is getting juice, as well as test out the two spades on the relay plug.

sad_rocc · « **Reply #11 on:** July 29, 2009, 06:17:04 AM »

All I can add is that the pump relay is hot. You should hear the pump turn on as soon as you jumper it. Those relays go out often enough that many mk1 and mk2 guys have made a jumper with a couple spade connectors and a bit of wire to keep in the car at all times.

Smokestack · « **Reply #12 on:** July 29, 2009, 07:38:47 AM »

Quote from: Luckyy on July 29, 2009, 12:15:47 AM

Karma to all three of those excellent posts! I'll check out (if I can find) the ignition to fuel pump fuse wire and make sure it is getting juice, as well as test out the two spades on the relay plug.

There is no ignition to fuel pump wire. It comes from under the rain tray at the ECU. Best way to check is to pull the fuel pump relay and either jumper the two connectors for the main power. You can try finding a small spade you can stick into the control wire slot (the hole in the relay plug that gets a signal to turn the pump on), attach a multi meter to it and watch it when you turn the key to the run position. Once again, the likelihood of that wire being the problem is slim to none. Don't worry about it unless you install a new relay and the pump still doesn't work.

Quote from: sad_rocc on July 29, 2009, 06:17:04 AM

...Those relays go out often enough that many mk1 and mk2 guys have made a jumper with a couple spade connectors and a bit of wire to keep in the car at all times.

That's also why many mk1 and mk2 owners carry spare fuel pump relays.

mjohnson · « **Reply #13 on:** July 29, 2009, 09:19:08 AM »

Quote from: Smokestack on July 29, 2009, 07:38:47 AM

...Don't worry about it unless you install a new relay and the pump still doesn't work.

Good point Chris. I suppose I was getting ahead of myself. I'll be honest, I have zero experience with anything other than mk4. I was just running circuitry through my head trying to help shed some light. It's usually best to start with the easy/cheap/probable solution and go from there.

sad_rocc · « **Reply #14 on:** July 29, 2009, 12:05:00 PM »

Quote from: Smokestack on July 29, 2009, 07:38:47 AM

That's also why many mk1 and mk2 owners carry spare fuel pump relays.

I think the mk1/2 motto is "Why pay money for something when you can build a crappier, cheaper and almost as effective version yourself?"

Luckyy · « **Reply #15 on:** July 29, 2009, 07:45:24 PM »

So, the fuel pump runs just fine when the connection is jumpered, and the car fires up... I'm going to try Bap Geon in the morning for a new relay.

While the connection was jumpered and I had the car running (Maybe 2 minutes), I was hearing a pretty damn loud ticking noise tied to my RPM from my bay that was undoubtedly not there before this fuel pump deal. I have no idea where it was coming from, but it was in the spark plugs/head/timing chain area

Basically, before I run to the parts store I want to know if anyone has any ideas on what would have caused this? I don't mind the noise, just want to know if it could be anything particularly destructive.

Thanks for all the help thus far guys, I wish I knew more about 8v's but I figure this is a pretty good way to learn.

Smokestack · « **Reply #16 on:** July 29, 2009, 09:48:47 PM »

Sounds like the typical 8v lifter noise. They get sticky after time and make noise. Tends to be louder when the engine is cold. You can fix it by changing out the lifters, but it's not hurting anything.

Best way to learn is to buy a Bentley manual and dive in. Damn things are worth their weight in gold.

Luckyy · « **Reply #17 on:** July 31, 2009, 06:36:22 PM »

Indeed, I'm downloading one right now

So here is an issue update: Finally got off work early enough to go down to Bap Geon today and got myself a new fuel pump relay. Got home and popped it in, turned the key in the ignition, and was greeted by a few quiet pops and some curling smoke from the new relay.

So either I got the wrong PN and it couldn't handle the 12v coming through, or something else went wrong. I am trying to think out the circuit path and what would have caused that..

Any more (Hopefully last) suggestions?

101stvet · « **Reply #18 on:** July 31, 2009, 08:40:37 PM »

u might want to go thru the wires and make sure nothing is grounded since i am a mk1/mk2 owner i can't tell ya how many times i've had smoke come from my dash and a relay go up in smoke and yes i've had flames before also, the last time it was a wire that had rubbed thru in the engine bay down behind the motor but i was getting smoke in the dash . other then that i'd would have to look at it to tell ya

the last problem i had was this past wednesday i got a water leak (which i didn't know about) coming from my windsheild which leak water allover my fuse block , taking out my wiper relay , fuel pump realy, and few fuses , all while i'm going down the hwy in the pouring rain good time let me tell ya

so moral of the story go to the junkyard and yank all the fuel pump relays you can find and just put them in the glovebox, it's like riding a motorcycle it's not if , but when is it going blow

Luckyy · « **Reply #19 on:** July 31, 2009, 10:04:17 PM »

Haha indeed. Well I'll finally have a day off tomorrow to actually check the car out in some daylight, hopefully I'll get everything figured out. Thanks for everyone's help!

Luckyy · « **Reply #20 on:** August 07, 2009, 12:40:07 PM »

Bah, two brand new relays later and still no love. Guess I'm going to be tracing wires all weekend!

If anyone for some ungodly reason enjoys a challenge or wants to help, just lmk

sad_rocc · « **Reply #21 on:** August 07, 2009, 01:35:07 PM »

Quote from: Smokestack on July 29, 2009, 09:48:47 PM

Sounds like the typical 8v lifter noise. They get sticky after time and make noise. Tends to be louder when the engine is cold. You can fix it by changing out the lifters, but it's not hurting anything.

Best way to learn is to buy a Bentley manual and dive in. Damn things are worth their weight in gold.

A bottle of Marvel Mystery oil usually will clear that up. Sucks about the relay. Wiring is such a pita.

Luckyy · « **Reply #22 on:** August 07, 2009, 03:10:12 PM »

Sweet, thanks for the tip

Luckyy · « **Reply #23 on:** August 07, 2009, 07:30:36 PM »

Tonight's discovery, my problem is indeed the control wire. I am getting no voltage to the relay from the control wire when the key is turned. From the diagrams I have looked at, the control wire from the ECU to the fuse block is Red/Yellow and at G1/03. So should I just chop that open and see if I'm getting power, and if not just re-rout the whole line with my own wiring? Not entirely sure how the best way to fix this is.

Smokestack · « **Reply #24 on:** August 07, 2009, 10:37:07 PM »

Trace the wire through the wiring harness and see if there's anything tying into it or if it's cut. Do you think you tied into it when you wired your stereo? Remember that the control wire will only power on for a few seconds after the key is turned to the on position unless the computer receives firing signals from the distributor.

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