So....once again in 5 months time my fuel relay has gone bad. So what I'm thinking about doing instead of purchasing a new relay every 5 months, is jumping the 2 fuse relays - numbers 5 and 7.

My idea is to leave the fuses and relay inplace, but run a wire from each fuse up to a toggle switch in my dash. Not in the center console but in the blank spot used for the fog light accessory between the dimmer switch and the lights switch for the dash and head lights. My thought is if I do that, then I'll put the key in position 2 flip the switch and then turn the key to position 3 to start it, thus turning it into a 2 stage starting process. Upon reaching my destination, I'll turn the switch and the key off simutaneously, or the switch first then the key second(I don't think it'll matter how I turn it off as long as the fuel and electrical supply are cut).

Do I have to bite the bullet and wait until I can afford a new relay? I'm excited about this neat and new idea but I would really like some input from you guys on this?

 

Bad idea. That's too much juice to run through a dash switch without...you guessed it...a relay. A temporary fix is to jumper the connection at the relay but even that's risky. You can't imagine how much juice runs through that circuit. As a jumper, you need to use 12 gauge wire at a minimum and keep it as short as possible. Such a fix is good enough to get you off the road or even home; certainly not something you want to do on a regular basis. You may very well have gotten a bad fuel pump relay. Because they are obsolete it seems only companies like ScanTech are making them anymore and while good, they are not as durable as Streibel or Hella. First, I'd do a post mortem on the relay and see what I could see...burned contacts or a break in the solder.

 

The older relay I replaced was the brown cased one and the "new one" i put in was green. I was thinking about pulling a few of the green ones from the yard

 

Yeah, KJet in 82 ran the green relay....3523639. Be advised there's any number of relays that will fit that socket but the color is the quick check. The wrong relay can fit but not work...or work but run extremely hot...I've done both so trust me...be sure to get the correct one. If you're just pulling relays at the jy, that's fine but note that age is as big a factor as use is in failures so...when you can, I'd spring for a new one.

 

I figured that I'd just pull the big fat green relays from the older models and the white ones from the newer models, use the older ones for my old one and the newer ones from my new 240s. What would happen if I stuck a white one in place of a green one?

 

Well, that's what I was talking about. Specifically, if you disassemble the white one used with LH electronic injection, you'll find it actually contains 2 relays...one controls the fuel pumps and the other controls the fuel injectors. The old green ones for KJet are constructed differently as it is constant, mechanical injection...two totally different beasts all together. I've done it in the past...don't remember if I tried to crank it or not...just remember the wrong relay got REAL hot real quick!!

 

Ok thank you. Is it the same with the blue and white od relays?

 

There's actually 3 od relays. Blue is only for the M46 manual, orange for the older AW70/71's (81-84) and the white used for AW70/71's from 85 on. These are absolutely not interchangeable...again...I've tried!

 

Just for kicks. What would happen if I threw an AW relay in my M46? I mean would it fry everything or just no response?

 

I have done exactly this! I am currently laughing because i pulled this fix off more than two years ago with little to no problem. it IS true that there is alot of current running through this fuse as i have replaced 2 15amp switches over the years (from melting, yikes) but i changed over to a 20 amp and all's well! i do suggest a switch with a little auxilliary light that turns on when you flip it, to remind you to turn it off AND IF for some reason the switch failed (or melted) the light will turn off because the circuit is interupted and you will know that the switch is the culprit of the problem! *warning* this fix is not very appealing to women that you take out on date. ALSO!!! REMEMBER to turn the switch off!!!!

 

I did the switch idea only as a temporary fix mainly, but how would I properly wire in the light without running the risk of shorting out loads of stuff?

I was hearing both pumps, but now after two weaks I think I can only hear one pump - the in-tank one I believe. And now the car won't run, and it has trouble turning over, but runs extremely rough when turning the key and if I let the key go it shuts off immediately. What do you think this is? I put this in another post if you'd take a look?