theboraxkid

The guy at the shop says the egr passageways need to be cleaned in the intake manifold. Is that a big job?

GOOD NEWS! I took my truck in to a local shop, and they made it idle so beautifully I cannot believe it. All it needs now is the EGR lines cleaned. How do I do that?

My Datsun 720 electrical nightmare- help!: http://youtu.be/M3Zen44_0uU Video showing my ridiculous wiring- let me know if the link works

The fuse that goes to the brown wire was surprisingly not blown. I have current going to both coils now with ignition ON and kill switch OFF. The kill switch is hooked up to the idle cutoff valve in the carb. My truck will not start if there is current going to the idle cutoff valve. I definitely hear the click of it working when I apply current to it, but when it is working, the truck just doesn't run. And if it's off, I have no idle once the truck warms up enough to come off the high idle cam. If I try turning the switch to the cutoff valve ON with the engine running, it immediately kills the engine. Why does my engine only run with no current to the cutoff valve?

Both of my coils do work, I know because I switched the wiring on them and they do the same thing hooked up either way. I just tried starting is with the kill switch hooked up only to the idle cutoff, and it was a no go. Only starts with kill switch off and the wires for it touched to the junction that is supposed to power the intake coil (but doesn't) now for some reason. The electrical is a complete mess, the white wire that comes off one of the coils stops at a dangling plastic connector. There's also a blue wire, red wire, and brown wire, with ignition and kill switch on they read around 12 volts. With engine running, and kill switch off but connected to the junction for the intake coil, it reads 12 volts everywhere except that really annoying junction, which reads an amazing (and confusing) 20 volts. This really is defying all logic now.

Also, I did check the EGR and all related components, they all function as they should

The other posts aren't really that important now, I guess. Anyway, I spark tested both of my coils, and found out that only my exhaust side had power going to it, and somebody had linked both the positive sides of the coils together. The same junction that should power my intake coil also powers the idle cutoff valve. My truck has a kill switch, and it was hooked up to the junction that worked on my powered coil, so it was useless. I hooked the kill switch up to the junction for the intake coil and idle cutoff valve, and with both coils powered it will not start. It also will not start if I remove the wire that links the two coils together. (This electrical system is heavily ruined by the P.O. who tried to install a stereo). I'm basically at the point where I'm just gonna try stuff until it starts to idle. Basically, my questions are: 1. Why doesn't my truck start unless the coils are linked together? (+ to +) 2. There's supposed to be current going to the idle cutoff switch in the carb when it's running, right? 3. I apparently timed my truck on one coil, is that why it won't start on both?

I checked timing today,just had someone hold the engine running as low RPM as possible. Timing was WAY off, it was 20° btdc. Now it's set properly, and I still have no idle, but it runs much better. The carb gasket thing has been repaired and it no longer leaks. I'll check my EGR today, also do more poking around for possible vacuum leaks.

And my carb has the mixture screw sealed where it's supposed to be from the rebuilder, everything I see in the manuals states that I basically should not touch that. Should I dare break the seal loose to try adjusting it?

And it's not like a rough idle issue or something, it just sputters like crap at anything below whatever speed the high idle cam holds it at, and it dies anytime I don't have my foot on the throttle. And in order to pass California smog, my timing needs to be 3° BTDC at idle. Since I have no idle, I have no way of really checking this. Also have no way to check the actual engine speed

UPDATE: I replaced my vacuum advance and it still runs exactly the same. I'm running out of ideas here

It does have a cutoff valve and it does work, I don't get dieseling or anything. It runs a lot better at higher RPMs now than it did with the old carb, but it still dies out when I let off the gas pedal

Here's a link to a video of my truck running... It sounds real bad. It has a new carburetor, just set valves to factory specs, new plugs, plug wires, cap, rotor, all vacuum hoses hooked up exactly as the FSM states. After I took this video, I found my distributor vacuum advance was completely shot, and leaks quite a lot of vacuum. Could that cause all that horrible sputtering/no idle? Please do help!

I'm gonna try to patch mine I think, it's just the area around a bolt hole. It's less broken than I thought. Still waiting on a new carburetor, so I have time

Thank you very much, please let me know if you do find it. Still have not been able to find one anywhere