theboraxkid Posted January 10, 2015 Report Share Posted January 10, 2015 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! 1 Quote Link to comment
wayno Posted January 10, 2015 Report Share Posted January 10, 2015 Are all the wires connected to the carb, some carbs have a fuel cutoff for when the engine is shut off so it will not diesel, and the engine will not idle when this cutoff circuit has no power. I don't know a lot about the Z22 carbs, so sorry if it doesn't have this cutoff devise. 1 Quote Link to comment
theboraxkid Posted January 10, 2015 Author Report Share Posted January 10, 2015 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 1 Quote Link to comment
Lockleaf Posted January 10, 2015 Report Share Posted January 10, 2015 Cap your vacuum advance line real quick, see what happens. A vacuum leak definitely creates idle issues that seem to disappear at higher RPM. It could be done with a finger if necessary, just to see if everything smooths out at idle. 1 Quote Link to comment
datzenmike Posted January 10, 2015 Report Share Posted January 10, 2015 You have three other posts on the same problem. http://community.ratsun.net/topic/64968-z22-engine-hitachi-carb-spacerinsulator/ you never said if this was fixed... http://community.ratsun.net/topic/64925-82-720-wont-idle-runs-like-crap/ http://community.ratsun.net/topic/64847-82-720-mixture-adjustment-and-other-problems/ Can we expect another post on this next week? Why not post in the original thread so all the things that are wrong (symptoms) and all attempts at fixing are recorded together? There's history here that readers need to know about. 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! There should be no ported vacuum advance at idle so a bad vacuum advance diaphragm or cracked hose leading to it shouldn't affect it. However for best mileage economy above idle, you seriously need vacuum advance, so get it fixed. Did you adjust the idle mixture screw???? Set idle speed as low as possible. Turn mixture in till idle quality drops, then out until it drops and pick a spot roughly in between where it idles best. Presumably, the idle speed has gone up, so turn the idle speed back down around 700. Turn mixture in then out and set in the middle where it idles smoothest and adjust the engine speed. Repeat over and over until you can't improve the idle quality and the idle speed remains about 700-800. In order to do this, timing must be adjusted properly first. I suggested this earlier but you never replied about it Timing. Z series are very tolerant of too much timing advance and it might not be noticeable at idle. Set timing to 5 degrees BTDC with the vacuum advance hose disconnected. Before adjusting the mixture screw the valve lash must be set or confirmed and timing at 3-5 degrees BTDC The EGR valve should be closed at idle or it will disrupt it. Normally it is, but exhaust deposits can block it's closing and leak gasses in. Only way to fix, is remove and wire brush it. 1 Quote Link to comment
theboraxkid Posted January 11, 2015 Author Report Share Posted January 11, 2015 UPDATE: I replaced my vacuum advance and it still runs exactly the same. I'm running out of ideas here 1 Quote Link to comment
theboraxkid Posted January 11, 2015 Author Report Share Posted January 11, 2015 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 1 Quote Link to comment
theboraxkid Posted January 11, 2015 Author Report Share Posted January 11, 2015 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? 1 Quote Link to comment
wayno Posted January 11, 2015 Report Share Posted January 11, 2015 Check your PCV valve, unplug the hose and cover it with your finger and see if it changes anything. 1 Quote Link to comment
datzenmike Posted January 11, 2015 Report Share Posted January 11, 2015 I was afraid of that. California does have sealed mixture adjustments to prevent owners tinkering. UPDATE:I'm running out of ideas here Well.... The EGR valve should be closed at idle or it will disrupt it. Normally it is, but exhaust deposits can block it's closing and leak gasses in. Only way to fix, is remove and wire brush it. Since I have no idle, I have no way of really checking this. Also have no way to check the actual engine speed Two things... 1/ pull each coil wire off and confirm that there is spark from BOTH. Put an old plug in the end and lay on a grounded surface. 2/ All engines like more advance at idle so loosen the distributor adjustment set screw (but notice where it is now so you can return it)and turn the distributor slightly clockwise. If this doesn't work try counter clockwise. This may get your idle back then it can be checked properly. You also didn't get back about the leaky damaged carb gasket you were going to fix. 1 Quote Link to comment
theboraxkid Posted January 11, 2015 Author Report Share Posted January 11, 2015 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. 1 Quote Link to comment
Charlie69 Posted January 11, 2015 Report Share Posted January 11, 2015 Mike is there any chance to merge all these threads into 1? I am lost and confused. Quote Link to comment
datzenmike Posted January 11, 2015 Report Share Posted January 11, 2015 Don't forget to check for spark on both coils. This affects how it will run. One coil needs more advance, two needs way less. They have to both work in order to run 3-5 degrees. You have three other posts on the same problem. http://community.ratsun.net/topic/64968-z22-engine-hitachi-carb-spacerinsulator/ you never said if this was fixed... http://community.ratsun.net/topic/64925-82-720-wont-idle-runs-like-crap/ http://community.ratsun.net/topic/64847-82-720-mixture-adjustment-and-other-problems/ How about it Mr. Boax? Want these other posts added into this one? Quote Link to comment
theboraxkid Posted January 12, 2015 Author Report Share Posted January 12, 2015 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? Quote Link to comment
theboraxkid Posted January 12, 2015 Author Report Share Posted January 12, 2015 Also, I did check the EGR and all related components, they all function as they should Quote Link to comment
datzenmike Posted January 12, 2015 Report Share Posted January 12, 2015 Jezus friggin previous owner bastards.There should be two power wires, one for each coil. The White/Yellow stripe wire is from the ignition switch. The Brown wire is powered by the second fuse over from the left side of the fuse box. It's probably blown and also supplies the auto choke heater and the idle cut solenoid. To get running it's not that important where the power comes from.*Still haven't hear you say there is spark at both coils. Both must be firing for a proper idle. 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? 1/ Maybe one coil is dead and you are disconnecting power to the only good one.2/ The idle cut is powered any time the ignition is in the ON position. The choke heater is only on when the engine is running.3/ No, but the correct timing will only work best if both coils are firing. See * above. Also, I did check the EGR and all related components, they all function as they should You can't know it's working unless you remove and verify that the valve is clean. Only way to be sure. Quote Link to comment
theboraxkid Posted January 12, 2015 Author Report Share Posted January 12, 2015 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. Quote Link to comment
datzenmike Posted January 12, 2015 Report Share Posted January 12, 2015 Never assume!!!! Pull the wires from the cap. Stick an old spark plug in the end and lay on a grounded surface. Crank engine over. DO YOU SEE SPARK????? This is the only accepted method. Only way to be sure is seeing the spark. 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. Jezus friggin previous owner bastards. There should be two power wires, one for each coil. The White/Yellow stripe wire is from the ignition switch. The Brown wire is powered by the second fuse over from the left side of the fuse box. It's probably blown and also supplies the auto choke heater and the idle cut solenoid. To get running it's not that important where the power comes from. Quote Link to comment
theboraxkid Posted January 13, 2015 Author Report Share Posted January 13, 2015 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? Quote Link to comment
theboraxkid Posted January 13, 2015 Author Report Share Posted January 13, 2015 My Datsun 720 electrical nightmare- help!: http://youtu.be/M3Zen44_0uU Video showing my ridiculous wiring- let me know if the link works Quote Link to comment
datzenmike Posted January 14, 2015 Report Share Posted January 14, 2015 Check the valve by putting 12 volts on the red wire. This should energize the solenoid and open the valve allowing idle mixture fuel. If this does not work remove the valve and take the guts out... this removes it as a problem. Save the parts for later. With the solenoid solved try turning the idle mixture screw in. It may be set too rich. Get rid of that kill switch! It's likely causing problems. Clicking on the video says This video is Private 1 Quote Link to comment
xsdg Posted January 19, 2015 Report Share Posted January 19, 2015 Just a thought: maybe the person altered the internals of the anti-dieseling solenoid to make it a more effective theft-deterrent device? Because otherwise, there's no way that the truck should run when it's unpowered, and then stall when it's powered. Actually, one thing that comes to mind: if you switch the spring location, and wire the solenoid reverse polarity, that would cause it to be normally-open (passing fuel), but closed while powered, no? Quote Link to comment
theboraxkid Posted January 21, 2015 Author Report Share Posted January 21, 2015 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? Quote Link to comment
datzenmike Posted January 22, 2015 Report Share Posted January 22, 2015 Hoses? Just replace. EGR? remove and wire brush EGR metal tube to the exhaust manifold? Because of the S shape there's not much you can push through. Blow in one end if it's open I'd leave it. Quote Link to comment
theboraxkid Posted January 22, 2015 Author Report Share Posted January 22, 2015 The guy at the shop says the egr passageways need to be cleaned in the intake manifold. Is that a big job? Quote Link to comment
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