chevygirl85 Posted January 25, 2011 Report Share Posted January 25, 2011 Hello again to all :) so I finally have got my little truck running ('84 Nissan z24 720 4x4) after my very long and tiring problem with trying to wire up the newer style dizzy instead of the older vacuum advanced one (previous thread posted on here). I finally got ahold of a donor truck and installed the older vacuum dizzy and gear on and got the truck running. Now I am having a problem with trying to get this truck to idle correctly and just run right over all. Here's what's going on.. I installed the older vacuum dizzy and got the truck to where it'll run on it's own but now I cannot get it to idle correctly (either goes down to about 700-800 RPMs and spits and sputters till it finally dies or stays up anywhere from 1500-2000 RPMs and will not drop to save it's life) Truck has almost no power at all. Tried a highway run and I was not able to get it up about 3000 RPMs to even try to hit highway speeds and hitting any type of hill I have to get a running start no matter what and still loose speed very fast. I have looked over the truck many of times to see if a vacuum line is broken or missing or something plugged but cannot find anything that would make it run this poorly. Then again I really have no idea on where each and every vacuum line should be ran other than all the manuals I have looked thru which don't give very good pictures anyways..I hooked up a smoke tester to see if any vacuum leaks are there and the only place the smoke comes out of is from the carb. Ran a vacuum test and at idle (1500 RPMs) it is sitting about 15 Hg's. What is the correct vacuum specs for these engines?? Again no where I have looked gives me a guesstimated spec or anything on what the vacuum should be... I am not new to the mechanic world but am new to the 80's gen vehicles and don't really know much about them and all of these wonderful vacuum lines that are apparently needed! Any and all help or advise is greatly appreciated!! Thank you in advance :) Quote Link to comment
Sealik Posted January 26, 2011 Report Share Posted January 26, 2011 (edited) Ya...that 15lb is a little low.....should be around 19-21Lb If you are planning on keeping the truck...and have no smog testing.....I would pull the Hitachi and replace with a Weber. Then you can eliminate all the emissions/hoses etc. Plus....you'll have a little more snap in the 'throttle'..... :) Edited January 26, 2011 by Sealik Quote Link to comment
Sealik Posted January 26, 2011 Report Share Posted January 26, 2011 Here are some diagrams. http://720world.ning.com/forum/topics/vacuum-diagrams-1?commentId=2016119%3AComment%3A26057 Quote Link to comment
chevygirl85 Posted January 26, 2011 Author Report Share Posted January 26, 2011 Yes I am definitely leaning towards throwing on a weber to get rid of all that useless junk as I call it and yes thankfully no emissions around here! Yay me lol. But as far as the vacuum problem..do you think that it could just be that..the wonderful carb it has on it? Quote Link to comment
Sealik Posted January 26, 2011 Report Share Posted January 26, 2011 (edited) You have a vacuum leak somewhere......or the engine is very tired....? This will help..... http://www.secondchancegarage.com/public/186.cfm Edit.... No smog testing......replace the carb then. I believe there are couple of them for sale in this forum. Edited January 26, 2011 by Sealik Quote Link to comment
chevygirl85 Posted January 26, 2011 Author Report Share Posted January 26, 2011 I am really hoping that it's not the engine..it was fine before the swap. I am going to do a compression test on it tomorrow when I have daylight. What is an ok range for compression on these engines? Thanks for your help :) Quote Link to comment
chevygirl85 Posted January 26, 2011 Author Report Share Posted January 26, 2011 Also what size carb would be a good size to put on this truck? Don't really want over kill and don't want something that will dog it down more ya know lol. I live in a higher altittude and have a lot of hills around me so definitely need some power to this little guy :) Quote Link to comment
Sealik Posted January 26, 2011 Report Share Posted January 26, 2011 (edited) Also what size carb would be a good size to put on this truck? Don't really want over kill and don't want something that will dog it down more ya know lol. I live in a higher altittude and have a lot of hills around me so definitely need some power to this little guy :) 32/36 is the carb to go with.....the DGEV model will have an electric choke. Not sure of the compression readings on a good/used Z24 engine....150ish? Edited January 26, 2011 by Sealik Quote Link to comment
chevygirl85 Posted January 26, 2011 Author Report Share Posted January 26, 2011 ok awesome :) thank you for your help and quick responses! Quote Link to comment
Sealik Posted January 26, 2011 Report Share Posted January 26, 2011 No problemo.... :D If you do buy a Weber....make sure it's an actual..... Weber. Quote Link to comment
Sealik Posted January 26, 2011 Report Share Posted January 26, 2011 Oh....and pics are somewhat mandatory.....of the truck that is.... :) Quote Link to comment
Buzzbomb Posted January 27, 2011 Report Share Posted January 27, 2011 Kudos to you for using a vacuum gauge! It's an overlooked tool that can really be of great use. FYI- What altitude are you at? When I lived at 1800 ft, my 720 had around 20 inches of vacuum. Now that I'm at a much higher altitude, I'm somewhere around 16. In other words, if you live at a higher altitude, it's not unheard of to have vacuum that is less than stock. To some extent, it's normal. However, 1500 RPM is not a normal idle speed. That being said, it's best to check out all the hoses, carb connections, etc. as previously stated to eliminate that from the equation. I'm no sure if that year truck had the fuel cut-off solenoid, but one of those that doesn't function can make it where it won't idle under 1000. Quote Link to comment
chevygirl85 Posted January 28, 2011 Author Report Share Posted January 28, 2011 lol pics will be coming soon! I am living at around 5000-5600ft so yeah I can see how vacuum could be lower but so far with all my other cars vacuum has always been around specs but then again this is my first run with a smaller truck or just a 4 cylinder for that matter...and yes 1500 is too high for me..I could see around 1000 maybe if that's as low as it will go and I would just have to learn to deal with it but do not like it at 1500 and will not drive it until I can get it lower! I was fortunate and was able to find a rebuilt weber carb the next day so fingers crossed I will have it by next week! I do have a question regarding the conversion tho..I am getting ahold of just the carb nothing else so will I need any adapters as far as linkage to mount it up correctly? I am going to order the adapter plate and air filter this weekend but don't wanna do so until I know everything that I will need As far as the fuel shut off I do believe the truck has one or at least I am able to find testing procedures for it thru alldata. It gives me the procedure but does not tell me where it's located? I would love to verify if it does or not and test it so where the heck is it..? lol Thank you again for all the help and advise! Quote Link to comment
Sealik Posted January 28, 2011 Report Share Posted January 28, 2011 (edited) lol pics will be coming soon! I am living at around 5000-5600ft so yeah I can see how vacuum could be lower but so far with all my other cars vacuum has always been around specs but then again this is my first run with a nissan...and yes 1500 is too high for me..I could see around 1000 maybe if that's as low as it will go and I would just have to learn to deal with it but do not like it at 1500 and will not drive it until I can get it lower! I was fortunate and was able to find a rebuilt weber carb the next day so fingers crossed I will have it by next week! I do have a question regarding the conversion tho..I am getting ahold of just the carb nothing else so will I need any adapters as far as linkage to mount it up correctly? I am going to order the adapter plate and air filter this weekend but don't wanna do so until I know everything that I will need As far as the fuel shut off I do believe the truck has one or at least I am able to find testing procedures for it thru alldata. It gives me the procedure but does not tell me where it's located? I would love to verify if it does or not and test it so where the heck is it..? lol Thank you again for all the help and advise! Ya...you are way up there.....elevation wise....1 Lb less for every 1000 ft above sea level....I think? The fuel shut off.... ?????..is the idle cut solenoid.....in the Hitachi....don't worry about it. You might also need a fuel regulator set at 2.5 lb.....should run okay without it.....but should consider. You also need the adapter and air cleaner....I just bought a Weber air cleaner. Was delivered today.....29 bucks delivered to Canada....(ebay)...pretty good deal You might also have problems with your jets...???..I believe anything over 4200ft is of issue Edited January 28, 2011 by Sealik Quote Link to comment
Sealik Posted January 28, 2011 Report Share Posted January 28, 2011 You will also utilize the trunnion from the Hitachi....that's the piece that operates the throttle. Remove whatever is on the Weber and replace....this will enable you to use your stock throttle cable. Might also consider pulling the EGR and cap....could be somewhat NFG and leaking. Quote Link to comment
chevygirl85 Posted January 28, 2011 Author Report Share Posted January 28, 2011 yeah I have priced out the adapter plate kit and air filter kit and am looking at around 100 or so for just those 2 items but will I be able to hook it up with the stock springs, cables and brackets I have now or is there some special weber linkage kit I have to buy to hook it all up? The carb that is in it now ran fine back home where this truck ran at about 5000ft to 7500ft daily so I would hope that nothing is wrong with them, and the weber I am getting is jetted for the elevation back home but is the same elevation here so fingers crossed there aren't any problems! Quote Link to comment
chevygirl85 Posted January 28, 2011 Author Report Share Posted January 28, 2011 NFG? Quote Link to comment
datzenmike Posted January 28, 2011 Report Share Posted January 28, 2011 Have someone turn the ignition to on (not start) off,on, off. If the idle cut solenoid is working you will hear a clicking sound at the rear of the stock carb. The idle cut not working will not cause a high idle by itself. What happens is it won't idle, so the owner turns the idle speed up above the idle circuit where the primary barrel is supplying the fuel air. Fast idle could be the cause of the lower vacuum. Fast idle causes are: Throttle shaft worn and sticking, not returning to idle position. Throttle cable too tight and not allowing the throttle to close. Idle speed screw turned in too far. Choke not warming up and shutting off... fast idle cam stays engaged. Fast idle cam dirty and stuck on, not releasing. When fully warmed up take the top off the air filter and look inside. The choke plate should be in a vertical position like this: It should not be closed (or partially closed) Take a look at the fast idle cam... it's the ivory colored plastic thing with tiny steps on it located just above where the throttle cable attaches to the carb. If the choke does not open fully, a linkage will hold the fast idle cam on and the throttle will close on one of the steps speeding it up. If the linkage or cam is dirty it may stick in the on position. Judiciously spraying with carb cleaner or WD-40 will clean and lube the linkages. Hold the throttle partly open to dis-engage the fast idle setting and work ALL the linkages back and forth. If the choke is fully open, the linkage should freely fall of it's own weight and the fast idle cam move out of the way of the fast idle set screw pictured above. Now the throttle can close fully and the regular idle speed adjusted. A can of carb cleaner is easier and cheaper than a new carb. . Quote Link to comment
Sealik Posted January 28, 2011 Report Share Posted January 28, 2011 yeah I have priced out the adapter plate kit and air filter kit and am looking at around 100 or so for just those 2 items but will I be able to hook it up with the stock springs, cables and brackets I have now or is there some special weber linkage kit I have to buy to hook it all up? The carb that is in it now ran fine back home where this truck ran at about 5000ft to 7500ft daily so I would hope that nothing is wrong with them, and the weber I am getting is jetted for the elevation back home but is the same elevation here so fingers crossed there aren't any problems! 100 bucks is a little high for the adapter plate and filter.....but here nor there. You will need the Hitachi trunnion for the Weber. NFG...no fuck'n good....pardon my 'French' :D The Weber was re-jetted for the elevation.....that is good. Quote Link to comment
chevygirl85 Posted January 28, 2011 Author Report Share Posted January 28, 2011 Wow awesome pics thank you! I will spray it all down and give er a good cleaning tomorrow and see what happens :) Haha that's all good sealik! What exactly is the trunnion? Ha wow I sound like a total newbie..never really had to dig into the carb world this much before.. Quote Link to comment
Sealik Posted January 28, 2011 Report Share Posted January 28, 2011 Wow awesome pics thank you! I will spray it all down and give er a good cleaning tomorrow and see what happens :) Haha that's all good sealik! What exactly is the trunnion? Ha wow I sound like a total newbie..never really had to dig into the carb world this much before.. This is the Hitachi trunnion on the 32/36.......'closest' in pic/ side of carb, for stock throttle cable Quote Link to comment
chevygirl85 Posted January 28, 2011 Author Report Share Posted January 28, 2011 Oh ok gotcha! Looks simple enough to do now that I know what I am looking at and what it should look like Quote Link to comment
Sealik Posted January 28, 2011 Report Share Posted January 28, 2011 Oh ok gotcha! Looks simple enough to do now that I know what I am looking at and what it should look like That carb is on a L20B manifold.....you might want to rotate the trunnion 180 degrees.....so the throttle cable pulls from the right...? Quote Link to comment
chevygirl85 Posted January 28, 2011 Author Report Share Posted January 28, 2011 Yeah the throttle cable is on the right/pass side of the engine compartment but still all very helpful pictures :) Quote Link to comment
Buzzbomb Posted January 28, 2011 Report Share Posted January 28, 2011 Have someone turn the ignition to on (not start) off,on, off. If the idle cut solenoid is working you will hear a clicking sound at the rear of the stock carb. The idle cut not working will not cause a high idle by itself. What happens is it won't idle, so the owner turns the idle speed up above the idle circuit where the primary barrel is supplying the fuel air. Fast idle could be the cause of the lower vacuum. Fast idle causes are: Throttle shaft worn and sticking, not returning to idle position. Throttle cable too tight and not allowing the throttle to close. Idle speed screw turned in too far. Choke not warming up and shutting off... fast idle cam stays engaged. Fast idle cam dirty and stuck on, not releasing. A can of carb cleaner is easier and cheaper than a new carb. . You're right, Datzenmike! With the idle cut solenoid, it's the cure not the actual problem that IS the problem :) There is another cause for high idle that has snagged me a few times, and I've seen you mention it too. The secondary gets hung up a little and it needs to be "jiggled" back in place so it is at its stop. That's something to look at too when she cleans her carb. Lots that can be checked while cleaning. Quote Link to comment
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