Skulptr Posted January 2, 2012 Report Share Posted January 2, 2012 Well I'm sitting on the side of the freeway posting this, since im 70 miles from nothing. I can't go over 30. Simple as that. I can get going, but once I hit 30mph, the truck just dies like its ran out if gas. Sometimes it will buck like a bull first, or it will just give up. It makes no sense to me. The things I did to it today, had no tail lights or interior lights, found a blown fuse fixed it. Had no left turn signal, found a bulb missing in the tail light, fixed that. replaced my gauge cluster for the one from my other truck with a clock and functioning guages. Found a broken wire behind the fuse panel, fixed that its the one that shorted the lights. All these fixes were me trying to figure out why I have no brake lights now. and I put what was left in my gas can in the tank, drive for 3 miles fine. I stopped to fix the lights and stuff, the fuel pump ran while I was doing it but you could hear the fuel cycling back into the tank. I've gone through everything I changed. Nothing has changed drivability, still chokes once i hit 30 or so. It will idle just fine, I can rev it to redline and no choking, can hold the throttle at 3k rpms for several minutes and it stays steady, but once I drive and reach speed it has problems. I'm starting to lean toward water in the gas, from that gas can. But would watered gas run fine with no load, but suffer once it comes to a load? I'm stressed to no end right now as I just finished a small roof job and the thousand pound load of old roof is in my truck and now I can't dump it. any input is appreciated. I would love to get a fresh opinion on where to look for something else. truck is an 85 kc z24 5 speed with weber 32 36. on another note, there is a black relay on the passenger side that was replaced by a previous owner, and doesn't appear to be working. I unplugged and put it back while the truck was running, nothing changed, and the relay didn't click or buzz. Its not the mystery black box as far as I know, which I think I'm seeing mounted further up behind the dash on the passenger side. Quote Link to comment
Big Schlink Posted January 2, 2012 Report Share Posted January 2, 2012 Any history of clutch or transmission maintenance/problems? Quote Link to comment
Guest kamakazi620 Posted January 2, 2012 Report Share Posted January 2, 2012 What about your coil??? The Z24 720s have 2 coils 1 for idle to 1500?? the 2nd for higher rpms Quote Link to comment
wayno Posted January 2, 2012 Report Share Posted January 2, 2012 Is there a fuel filter in the weber near the inlet? I had an engine that kept cutting out because of a plugged internal carb filter, I would just get up to speed, then it would cut out. Quote Link to comment
Skulptr Posted January 2, 2012 Author Report Share Posted January 2, 2012 Only filter is the oem back by the tank. The throw out bearing is dying but not enough to do this. I drove it 70 miles at 65 with no problems. Once I did the above it did this right away. checked the coils too, both are sparking fine. Though I did pull the #1 exhaust boot, it sparked against a ground, but pulling it didn't change how the truck was running, not even a hiccup. I checked both sides with the truck running. I just can't wrap my head around it idles and revs smooth as butter, but under load.... Quote Link to comment
Skulptr Posted January 2, 2012 Author Report Share Posted January 2, 2012 Kamakazi, both coils run full time, one is exhaust side, other intake side. Quote Link to comment
Wide14u Posted January 2, 2012 Report Share Posted January 2, 2012 thinking its the choke Quote Link to comment
datsunaholic Posted January 2, 2012 Report Share Posted January 2, 2012 That really sounds like a clogged fuel filter. It'll rev to redline with no load, because unloaded doesn't use much fuel. Quote Link to comment
datsunaholic Posted January 2, 2012 Report Share Posted January 2, 2012 thinking its the choke Unless the choke is jammed shut, it won't do that, and you'd know by the smoke cloud. The choke will open at 1/4 throttle even if it's not electrically wired in. Quote Link to comment
datzenmike Posted January 2, 2012 Report Share Posted January 2, 2012 Sounds like fuel delivery.... almost plugged filter. If you can replace do so, doesn't even have to be the right one, just has to fit and let gas through. Failing that take out and shake the shit out of it and try again. Quote Link to comment
Skulptr Posted January 2, 2012 Author Report Share Posted January 2, 2012 Choke and fuel cut solenoid seems to be working properly. I'm going to drain my tank tomorrow, which really sucks since I just put gas in it this morning. I'm also going to change the filter since this truck sat for years. The engine and tranny is from my 86 daily driver, if something is wrong I'm almost 100% its going to be with something on this truck. And fuel loaded or not, the weber only needs 3.5psi of fuel to run, and I have no regulator installed, never have always ran fine. Quote Link to comment
wayno Posted January 2, 2012 Report Share Posted January 2, 2012 I just went out to my L20b with a webber on it and looked at it, it does have a fuel filter/screen in it, below where the fuel line connects to the carb, there is a nut on the bottom center of that connection, you need to loosen that nut, remove it and check the screen. Sometimes if you shut the engine down and tap on the carb in that area, it will knock some of the debris off the screen, but the problem will come back right away. Quote Link to comment
Skulptr Posted January 2, 2012 Author Report Share Posted January 2, 2012 Mine does not. I rebuilt it. I know for fact that there isnt one. Quote Link to comment
wayno Posted January 2, 2012 Report Share Posted January 2, 2012 Mine does not. I rebuilt it. I know for fact that there isnt one. So your webber carb doesn't have this big flat nut on it under where the fuel line connects, that would be a first for me, but I have not been looking. Quote Link to comment
thetimanator Posted January 2, 2012 Report Share Posted January 2, 2012 I have a 510 with an L20b so this may or may not apply but that buzzing relay sounds similar to my choke heater relay that caused all my battery drain issues. I got rid of it. Quote Link to comment
datzenmike Posted January 2, 2012 Report Share Posted January 2, 2012 ... I'm going to drain my tank tomorrow, which really sucks since I just put gas in it this morning. I'm also going to change the filter since this truck sat for years. Filter first. Then check regularly. If it keeps plugging then yes pull the tank (maybe when closer to empty) Quote Link to comment
Guest kamakazi620 Posted January 2, 2012 Report Share Posted January 2, 2012 Kamakazi, both coils run full time, one is exhaust side, other intake side. uhhh, No,thats NOT how it works,i'll +1 on me cuz i'm not stranded on freeway :lol: 1 Quote Link to comment
HRH Posted January 2, 2012 Report Share Posted January 2, 2012 Kami, both coils fire for the same ignition event. One fires at 3 degrees btdc, on 3 degrees atdc. The result is a larger and longer lasting spark, similar to an MSD box using multiple sparks below 3000 rpm. Skulptr: Fuel filter fits all of those symptoms. Quote Link to comment
Siempreloco Posted January 2, 2012 Report Share Posted January 2, 2012 I MAY BE ABLE TO HELP! I hope im not too late.. But when I was test driving my 620 before buying it to bring home i was having a problem the SAME as you are describing, turns out the distributor was loose, All i had to do was move it with my hand(that loose) into place, tighten it down, and BOOM power. I HOPE ITS THE SAME THING, such an easy fix. Theres an obvious bolt that you can see, and one up underneath that which was a size 8, thats the one that was loose on mine, no idea if this applies to your truck or not. Crossing my fingers for you, man! Though while re-reading this, my solution may be not a solution at all, since im not really sure if your truck has a distributor, because im kind of a noob..and my idea probably wont help you. shit. I tried. Quote Link to comment
Skulptr Posted January 2, 2012 Author Report Share Posted January 2, 2012 I'm not going to pill the tank, just the fuel line and let the pump do the work. There wa snt much to start with, I just hate wasting gas Quote Link to comment
datzenmike Posted January 2, 2012 Report Share Posted January 2, 2012 I think there are a lot of misconseptions on the dual plug design on the NAPS engines. Both plugs fire together, simultaneously. This provides two ignition sources and shortens the burn time thus you can run much less advance. A shorter burn time also reduces the time during peak pressure and temperatures when oxides of nitrogen (a pollutant) are produced. Dual plugs can also more effectively burn large amounts of EGR with no effect in performance and actually improve mileage. (EGR is not present at idle or full throttle or a cold motor, so keep in mind when thinking of removing it to improve performance because it's a waste of time) On some Z24 engines there is a vacuum operated switch to disable the exhaust side plugs to reduce engine noise under full throttle. When in single plug operation, the distributor automatically advances the timing to compensate for the longer burn time so that performance is unaffected. Quote Link to comment
Skulptr Posted January 2, 2012 Author Report Share Posted January 2, 2012 uhhh, No,thats NOT how it works,i'll +1 on me cuz i'm not stranded on freeway :lol: Haha.. Quote Link to comment
Guest kamakazi620 Posted January 2, 2012 Report Share Posted January 2, 2012 Haha.. Hope you get it work out man!! Quote Link to comment
Skulptr Posted January 2, 2012 Author Report Share Posted January 2, 2012 I think there are a lot of misconseptions on the dual plug design on the NAPS engines. Both plugs fire together, simultaneously. This provides two ignition sources and shortens the burn time thus you can run much less advance. A shorter burn time also reduces the time during peak pressure and temperatures when oxides of nitrogen (a pollutant) are produced. Dual plugs can also more effectively burn large amounts of EGR with no effect in performance and actually improve mileage. (EGR is not present at idle or full throttle or a cold motor, so keep in mind when thinking of removing it to improve performance because it's a waste of time) On some Z24 engines there is a vacuum operated switch to disable the exhaust side plugs to reduce engine noise under full throttle. When in single plug operation, the distributor automatically advances the timing to compensate for the longer burn time so that performance is unaffected. is that what the vacuum advance line on my dizzy does? when I hooked it up tonight to the vacuum from the carb my idle rose almost 300 rpms Quote Link to comment
I'm BLUE Posted January 2, 2012 Report Share Posted January 2, 2012 Wild shot ... Mufflers can get plugged badly on older cars Jets in carb ,,, fuel filters ,,, bad fuel pump Quote Link to comment
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