The curse of the 914

[silver2.0]

Well, it sure seems I have put in about 10 times as much wrenching as driving, and my car just broke again. This time it has something to do with the fuel pump. No more buzz when the key gets turned. Can anyone tell me where the "relay" board is that the positive wire from the pump goes to? I haven't had a chance to dig into the car yet, but I can't remember seeing a realy board. Is it where the alternator plugs in on the left side of the engine compartment? Thanks for help guys. Here is a picture of my time and money black hole. I guess I should get used to wrenching on it, it will take me years to finish, but jeez, it sure would be nice to get in some seat time!!

[SGB]

yep. Thats it. Under the black plastic top there are about four round black relays. there is a diagram on the PP electrical diagrams link about which does what. If yer car is carburated it might not use the stock relay.

[Dave at Pelican Parts]

Yup. If it has D-jetronic FI (stock for 1.7 and 2.0), Brad Anders has a flowchart on his D-jet website (http://members.rennlist.com/pbanders) for troubleshooting the pump control circuit. There is also an article on Tim's 914 Fan Page, http://www.914fan.net/fuelpump.html .

--DD

[jamcleod]

you should post your location. i'm sure some local 'teeners would be able to help you get more seat time.

[lmcchesney]

From my reading and confirmation on my relay board, these relays are all the same units, (C-615-109-01). If you think your fuel pump relay is out, try switching say number 5 which is for the rear defoger for the pump unit. This will eliminate or correct the relay. I also found I could check the function of the relay by confirming continuity of post 85 and 86 as well as 30/87a. Then I connect a small 12v source to 85/86 and hear the relay click and see continuity between 30 and 87.
Agree DD.
L. McC

[Dave at Pelican Parts]

Actually, I like to swap one of the headlight motor relays for a suspect relay. Then I can cycle the headlights and that will test the suspect relay, as well as having a known tested good relay (assuming you've used your headlights recently) in the "trouble" spot.

--DD

[silver2.0]

It's a D-jet 2.0. A 70 body and a 74 motor, and various other bits. Thanks for all the great advice guys. I wish there were some locals, none I know of. I live in Fairfield Washington, near spokane. If any of you know of anyone, let me know, and I will buy them a beer.

[Dave at Pelican Parts]

There are a few up that-a-way... At least, within a few hours drive! Geoff (Bleyseng) is one of the BBS's D-jet "experts" and lives up in WA state. Not sure what part, though.

--DD

[silver2.0]

I think I have found the problem. It was just the 25 amp fuse on the relay board. It was heavily corroded. I plan on replacing them all with the newer glass style. Does anyone have any thoughts on wether the fuse could have just blown because it was crusty? I can't find anything else wrong, and it's working great. Thanks for the great advice, at least I learned a few more things about my car. I think I am far more intimate with it than any car I have ever had before, and I have only owned it a few months!!

[WOODPIE]

Yeah, Silver, a crusty fuse area can cause problems. I've had the spring/clamp part get so hot, the plastic on the relay board started to melt before the fuse gave up. Whenever I have fuel pump problems, that's the first place I look. Clean the contact areas real good, and keep them clean.

Ed

[silver2.0]

Nevermind, thought I had it, left me stranded half way to work. Damn it. I'll keep you posted, and probably have more questions before I am done.

[914GT]

Silver - is there a possibility you have a bad ignition switch with intermittent contact? That would drop the 12 volts out to your fuel pump as well as the ignition coil. Maybe you could put a voltmeter between the fuse and ground, then turn the key back and forth several times (or jiggle it) to see if 12 volts repeatedly comes up and stays up solid in the on position.

[silver2.0]

Well, maybe you guys have an idea. If I disconnect the fuel pump, the fuse won't blow, even when I turn the motor over for 10 seconds or so. When the pump is connected, it blows the fuse within 2 seconds. So, Just to be sure it was the pump, I ran a wire to ground, and One to my battery with an inline fuse. It worked great for my 45 minute drive home. It must be the wiring then huh? Any suggestions on where to start first??

[robinaube]

The problem must be between the relay board and the fuel pump. I would look carefully at all of the engine wireharness to ensure there isn't any chafed wires. Most likely you have a spot on the harness where the insulation is worn off and its grounding to the engine or tin.

As a last resort, you can run a pair of wires from the coil are to the fuel pump. Run the positive wire from the coil + to the pump + side. Then run the second wire from the engine block (-) to the pump (-) side. This will run the pump when ever the ignition is on. For safety, I would put a fuse in-line on the plus wire.

Rob

[robinaube]

Sorry for the double post. The problem is not your fuel pump itself or you would not have been able to drive home. It would have blown your fuse. The problem must be the wiring itself.

[WOODPIE]

IIRC, a faulty auxilary air regulator heater wire will blow the fuel pump fuse.

Ed

[Biggy72]

yup, or if the aar isn't working at all it just won't work. I had the problem right before the engine went in mine.

[silver2.0]

I have a question about that. Is the AAR The part with 3 inlets for vacuum hoses located near the oil fil tube? Mine is not fully hooked up I don't think, and there are no wires going to it. Where is the AAR heater? Is it that part that just sits on top of the block, more twords the passenger side, with just one wire going to it? I am conisdering running a new relay to my pump. I would like to have it actuated with the coil as suggested, but, I don't want to have it running when the motor is not running, in case I crash. Should I tap into my oil pressure sending unit for that? Any suggestions are greatly appreciated as always. I just don't like the idea of having so many trivial things such as my heater, and rear defogger on something that will keep me from getting to work. Don't you agree? I think I want to run a relay to the pump though, just to be on the safe side.

[Dave at Pelican Parts]

Don't run it off the coil, or the oil pressure switch, or any of that. Those are band-aids, IMHO, and OK only for testing. Fix the thing correctly--sounds like you may need a new wire from the relay board to the pump. (But check other things first.)

The AAR is just to the left-front of the manifold, it has two hoses going into it. Check my hose diagram, the AAR is labeled. The wire goes into the bottom of it, where the heater is contained.

--DD

[Bruce Allert]

Here's a picture of a 2.0 that Bleyseng (Geoff in Seattle) did for those of us that need refreshing of our minds! It shows location of the AAR.

..........b