I got it running!, But...... Options

[Cjllong]

Hello all,

So, a new fuel pump, double relay, computer, and other stuff, I finally got my 914 running. I replaced the throttle valve switch with another I just happened to have around, and it started up. But, it died a few minutes later when I moved some wires. AH HAAA! I thought, a bad ground. I found the bad ground in terminal 85 of the double relay. (I had suspected it prior.) I spliced the wire just outside the relay box and wired in a small jumper cable, but also wired the original back together. I connected the jumper to a ground, (metal portion of the vehicle) and the car roared to life again! Here's where it gets weird. I followed the original ground wire to one of the three ground wires located on the passenger side, below the intake. I disconnected it and the motor died. I reconnected it, and it lived. Then I disconnected the jumper, and it died. I reconnected it, and it lived. In short, both grounds need to be connected in order for the engine to run. I tested the original wire with an ohm meter it tested good. (IMG:style_emoticons/default/WTF.gif) Any ideas on what's wrong here? Also, the engine wants to die when I push the throttle only a little bit. If I push it far enough, it kicks in and then I can slowly bring it back down again. The motor also idles rough. Is there a way to fine tune the idle? You guys have been a great help so far, keep the ideas comming!

Chris

[por73914]

(IMG:style_emoticons/default/welcome.png) As my avitar say "I don't know what the hell I am doing" But I am glad you got her running I am sure someone on this board can help you out! (IMG:style_emoticons/default/welcome.png)

[BMXerror]

Which engine and fuel system? On D-jets after I think 71 (I'm not sure because I have a 70) there's an idle mixture adjustment screw on the ECU. There's also the bypass valve on the throttle body that controls idle speed. That's the only idle adjustment that I know of.
With the electrical problem, it's hard for me to help from here, especially not knowing the vehicle. It's a wierd one, for sure. What reading do you get with the ohm meter on that ground wire? Also, have you checked to make sure the jumper wire you're using is in good shape? The only thing I would suspect is that you have two weak, but not totally open connections, and the two of them collectively make up the ground. The fault could also be corrosion at the ground connection. Make sure it's clean. I'm not the best of help when it comes to these things, but nobody else chimed in, so I'm who you've got. (IMG:style_emoticons/default/biggrin.gif) Like I said though, tell me your type of vehicle, and maybe I can help you work through it. Meanwhile, I'll let my mind chew on it and see what I can come up with. Don't lose hope.
Mark D.

[Cjllong]

My car is a 1975 with a 2.0 from a 1973. The kicker is, it's got the L-Jet fuel injection modified to it from the original 1.8L motor. Everything ran great until it just died one day. I'm pretty sure this ground is the issue, but I can't figure out why I need it grounded in two places. The Ohm meter read less than one when I tested the ground wire. I hope that helps!

Chris

[BMXerror]

Sorry for the slow response. Running in an AX yesterday and was busy. Anyhoo, you've prettymuch got me stumped on the electrical thing. I'm pretty bad with electrical anyway, and that's just weird. I would venture to guess, though, that since your problems all started at once, there's probably one common electrical problem that is causing the rough idle and odd behavior. Now as for what that problem is.... (IMG:style_emoticons/default/confused24.gif) But anyhow, I'd chase that exclusively and not worry about the idle and throttle problems right now, as they may be one in the same. Hopefully we can get an L-jet guru to chime in here and offer a hand.
In the meantime, I would just get a wiring diagram (sounds like you've got one) and start tracing every suspect wire with a multimeter. Make sure to study the diagrams thoroughly, because there are some really wacky arrangements as far as power distribution goes. I'll look through my L-jet diagrams and see what I can find, but without seeing it, I can't make any promises. Sorry I can't be more help, but you'll get it.
Mark D.

[highways]

The only thing I would suspect is that you have two weak, but not totally open connections, and the two of them collectively make up the ground. The fault could also be corrosion at the ground connection. Make sure it's clean. Mark D.

(IMG:style_emoticons/default/agree.gif) for the first round of trouble shooting. Not a bad idea to 'rebuild' your ground connections (of which there may be several on the car?). Get a small brass wire brush and some medium coarse steel wool. Polish all the ground terminals (battery disconnected!) really really well. Use sand paper as well if needed. If the wire itself is in bad shape- replace (make sure you use plenty off gauge, more then it had before can't hurt). Make sure old crimped terminals didn't break any wires. Go to radio shack and get their TV pot cleaner. It's an electro mechanical spray cleaner in a small can that cleans corrosion and leaves a conductive lubricant on the part. Lubricate the connection and use some new washers to make a fat contact.


This is just a guess but maybe something is partially shorting out.. establishing an unwanted ground path and drawing current away from where you need it? Some wires taped together somewhere?