sage691

Hi folks, OK, time to report back my results with the "relay". This may be a long winded post as I want to be as thorough as possible with all the details. So on Thursday I had a friend remove the relay black box. It was a PITA to remove and he had to use a rachet with a phillips screw head inside as those 35 year old screws feel like they are welded shut ! But he got it off and we took a look at it, and LO AND BEHOLD there was immediate evidence of moisture/water damage !! I took 2 photos to show you guys and here are the Dropbox links: https://www.dropbox.com/s/vmp6ixvyljahv9t/DSC00117.JPG?dl=0 https://www.dropbox.com/s/y8cya29j1qcg9o1/DSC00120b.JPG?dl=0 The first photo shows what appears to be some type of paper cover that sits over the circuit board, I guess to protect it from moisture ? You can see how it seemed to shrink back and also that greenish mildew from water/moisture. Then the 2nd photo shows a line of black bubbly goo that looks to be evidence of some component overheating on the other side of the circuit board. This is definitely NOT solder flux either. My guess is that on the other side there is a burnt out resistor, capacitor, or diode. And now I feel a little stupid. Why ? Because when I first posted I forgot to mention the LEAK that just so happens to be right over where this relay switch is located. Yep, when it rains hard I have been seeing some water on the carpet by the passenger seat. And when I traced it a few days ago (after a HARD rain) I saw evidence that water is getting in by the bottom corner of the front windshield. I had no idea that crucial electronic components would be placed in such a precarious position, so I figured the leak was no big deal. So I took "Datzenmike"s advice and made up a little jumper wire from two 24 gauge phone cable wires twisted together, and I stuck each end in where the diagram showed. Remember that I had already tested the fuel pump and it was pissing out fuel like a drunken sailor. Here is what I noticed in chronological order: 1) When I turned the key to the pre-start position I immediately noticed a sound (by the carb) that I hadn't heard in a LONG time ! This is a rapid fire "clicking" sound (32 or 64 per second), like the speed of a machine gun. The fuel pump makes a buzzing type sound, and that was the only sound I had been hearing since the truck started really acting up. Heck, it's been so long I had forgotten about this sound. But the moment I heard it I remembered it, and when the truck ran good that sound was always there. 2) The truck started up easily and immediately had a nice smooth idle. Before I would have to keep my foot on the gas for at least 1 minute, revving the engine pretty high just to get it where it wouldn't sputter and kill out. It had been a LONG time since the truck started up and idled this easy from a cold start ! 3) I was able to rev the engine VERY high without it sputtering, making fire cracker sounds, etc. It felt a lot smoother for sure, and then when releasing the gas it came back down to a smooth sputter-free idle. 4) So I took her for a ride and WOW -- she hadn't run this smoothly in a long, long time ! So long in fact that I realize this must have been a problem going on for years now. That day I drove her around De Saix Ave. (a close street with a straight run for about 1.5 miles in each direction) for about 30 minutes. Every time I got to the end of the street I would turn around and start from 0mph and get her up to 50mph until the next turn around. I must have done that 15 times before pulling back in to the garage. I was in disbelief that a defective little relay switch could reek so much havoc on the performance of a vehicle, rendering it almost dead ! I let her sit for another 10 minutes and we adjusted the idle on the carb down as it was WAY too high ! Then I took her out on the highway and got her up to 60mph with no problems. The truck was on for over 1 hour all in all, and NOT ONCE did it have anything close to the symptoms it had before ! 5) Another thing I noticed is that the largest fuel hose attached to the carb was significanty less hot than it was before ! I mean, this hose was so HOT before that if you tried to squeeze your fingers around it you would have to remove them in 1 second or you would get burned badly. But now, after running for over 1 hour it is just very warm and I could grab it and hold it for as long as I want and not get burned. I am not sure what this hose is so I took a photo of it for you guys. In Photoshop I made a red line in the middle of it. Here is the Dropbox link to that: https://www.dropbox.com/s/5l0r5dzkxjclzml/DSC00122.JPG?dl=0 I have been running the truck now for several days and it hasn't missed a beat ! It runs better now then it has in years, and also the temp gauge stays lower and never even makes it to halfway before the thermostat opens up -- before the temp needle would go to the halfway mark, then back down a bit once the therm kicked in. So I assume the engine is running cooler as well which was a surprise; I didn't know that a fuel starved carb would cause an engine to run hotter. I am still convinced that the catalytic converter is clogged and needs replacement, but it was definitely not causing the the engine to lock down like it was. So my "to do" list now is: 1) Order a new Relay, or possibly even try to fix the old one myself. It looks as though I can de-solder those pins and access the guts on the other side. If a diode, cap, resistor burned out I can probably get a replacement for pennies. And it's GOOD to know I can remove the relay completely and still run the truck -- so thanks "Datzenmike" for that tip !! I won't leave it like that for more than a week or two at the most. 2) FIX THE LEAK ! I guess I will need to look on Ebay for the full weatherstripping set that seals the front windshield, and maybe the two front doors as well. Any tips on WHAT to buy and WHERE to look for that stuff guys ? 3) Replace the Catalytic Converter. We looked at it closer, and it does appear to be the removable kind -- it has old rusted out bolts and nuts at the inlet and outlet sides. I bought some deep penetrating lube for those, so my buddy said he would like to give it a go. I saw new ones on Ebay for $40 so the cost is no big deal. 4) Re-attach the fuel pump. Right now it is "rigged" in place with wire as the bolt broke off inside the threaded hole upon removal. We are going to have to think outside the box to try and get that re-attached securely. 5) Buy a new gas cap. The old one is in pretty shabby shape and is likely letting moisture into the gas tank. 6) Probably get new hoses from the gas tank to the fuel filter, filter to pump, and pump to carb. Those hoses look as old as the hills to me ! Well, that's about it for now folks. I am so, so grateful to "datzenmike" and "Charlie69" for all of the help you guys provided. It would have been IMPOSSIBLE to figure this out without your help, and I am deeply appreciative. If you have any tips on my "to do" list above I would appreciate that as well. This baby only has 285,000 miles and so I am hoping she is good for another 500k at least !

OK I get it ! So just to be clear, I first remove the screws attaching the relay so I can access those wires in that plastic connector more easily. I leave the plastic white harness connected to the black relay box. Then I take a small copper wire (16 or 18 gauge) and stick one end in the hole for the Blue terminal, and the other in the White/Black terminal. Then start up the truck and take her for a long spin and see if she is suddenly starts running consistently better. And if she does, then I know the RELAY is the problem. Sounds not too hard, and hope I didn't get anything wrong. I'll do that and report back. BTW, yes it is a long process but I am actually enjoying the challenge !

OK, so you're implying that there still might be a problem with the fuel pump even though it passed the first test (output volume) ? Like maybe once the engine is running it starts to output less and starve the carb ? I am just a bit confused, so sorry if I sound ignorant -- which essentially I am when it comes to car mechanics (lol)😄. I am not sure what that relay actually does, but I thought it might somehow control the flow of fuel to the carb POST the fuel pump output line. Is that correct ? And so, if the relay is malfunctioning then even though the pump is good the carb will still be starved of fuel ? And the "jumper wire" test will reveal something different than the other test I did ? 😟

Hi guys, We tested the Mr Gasket fuel pump today and it seems to be working properly. A buddy of mine got under there and removed the hose on the output side (which was a real PITA), and then we let the pump hang down angled into a 1 gallon empty water jug cut in half. We used a timer and I turned on the ignition half way to get 12v of power to the pump. It started pumping out a nice continuous healthy looking stream of fuel and stood that way for a full 1 minute. Then when the clock showed 1 minute there was over 1/3 of a gallon of fuel in the jug. I assume this means that BOTH the fuel pump and fuel filter are OK ? So I guess the next thing to check would be the fuel pump RELAY ? I found an article about this online, and I also was able to locate it on my truck. Here's a link to that article: https://axleaddict.com/auto-repair/The-Datsun-and-Nissan-Pickup-Fuel-Pump-Relay-What-the-Haynes-Automotive-Repair-Manual-Wont-Tell-You So I am going to test for that next. But if it is NOT that, then I am wondering could the Catalytic Converter being clogged up alone be the cause of the problem ? In other words, since I KNOW that is clogged up should I try to address that first and then see how the truck runs ? And if a new Catalytic Converter doesn't fully fix it, here's my next list of things to check for: 1) pinched/clogged fuel line hose from fuel pump to carb 2) clogged carb inlet 3) float or needle valve set too low 4) bad o2 sensor Now, can you guys give me any tips about WHERE that fuel line hose (from the pump) connects to the carb ? Any pics maybe of it you can post ? I am assuming I do the same thing here that I did with the pump, testing to see that over 1 liter per minute shoots out of the end of that hose ? Then, HOW do I go about testing the carb inlet with the banjo fitting ? Any tips on WHAT I am looking for there ? And the same with the float/needle valve being set too low. Any pics of WHERE those things are and WHAT they look like ? And then HOW to tell if they are set too low ? And HOW to set them higher ? You guys are pretty much my life line here, and I really appreciate it ! There are NO mechanics in my area that know about these quirky Nissans/Datsuns. So the advice you guys are giving me is pure GOLD brothers !!

OK, here are links to 2 pics of the fuel pump: https://www.dropbox.com/s/8u9m8acpr5lcuny/DSC00119.JPG?dl=0 https://www.dropbox.com/s/6pu9br0wa398afh/DSC00120.JPG?dl=0 It's hard to make out the brand name, but it is definitely not anything stock. You guys ever see any one like this before ?

Wow, I must have a different pump altogether as mine does not look like Charlie's picture. And my fuel filter is separate from the pump -- it is housed in a clamp and has a hose coming out of it that attaches to the fuel pump.

That fuel filter was changed about 1 month ago. But I'll go ahead and get another new one put in there since they are so cheap !

Thanks Charlie ! Yeah, I think it is definitely clogged up. I started up the truck today and let it idle for about 5 minutes, and when I walked by the exhaust pipe in the rear I felt some mist with dirt on my bare leg. Stuck my hand there and got some more of this wet mist with brownish dirt mixed in. And then the same thing again -- when you rev the engine the air pressure output from the exhaust pipe goes down and gets really hot. BTW, I am 99% sure the cat is welded on the pipes. I need to check again, but when I had my head under there (for a few seconds) it looked like it was welded. This is REALLY hard for me to do because I recently had spinal surgery to my neck, and so I need to lay down on my back so as not to trigger bad neck/arm pains. But I am determined to get this baby moving again. I think I may have the Double Whammy going here: 1) a clogged cat on the exhaust side and 2) a starved carb. I know it may sound crazy, but I was thinking about getting somebody to cut the exhaust pipe right before it reaches the cat. Is that feasible ? Here in New Orleans we don't have to worry about yearly emissions tests. I'm just not sure if I could run the truck like that before having somebody weld a new pipe in there to connect to the exhaust pipe in the rear.

Well, to be honest when I did that test I am not sure that I turned off the ignition in a nanosecond, so maybe a little fuel got in there post stalling. Also, I REALLY had to get my eye right up on that little glass just to make out that line which seemed to be 1/32" of an inch to from the bottom. So yeah, there was virtually nothing in it from my memory of that moment. I will run the fuel pump test tomorrow to see if it is putting 1.4 liters per minute and report back my findings.

OK, and thanks ! So I guess since there was almost no fuel in that little glass when the truck stalled/killed, that means we can rule out the ECC system being faulty ?

Question for Charlie69: I was trying to locate the fuel pump and was wondering is it somewhere near the carb or under the chassis ? Any clues on what to look for ? Since the carb had almost no fuel level in that little glass when it killed out, I was wondering if the fuel pump might be going bad. A mechanic told me they start leaking fuel when malfunctioning. I can't remember if I ever changed the fuel pump in the 13 years I have owned the truck.

Hi guys ! OK, I ran all of those tests today you guys recommended. Datsenmike: I found that little glass with the dot in the middle on the carb. Before I started the truck up toady I noticed it was empty. So I started it and let it warm up for 10 minutes before taking it on a nearby street where the speed limit is 40mph. Once I got up to about 25mph she started acting up again, and so I did what you told me and gave it more gas attempting to accelerate. Then she sputtered out and stalled (making some popping sounds), and I immediately turned off the ignition and pulled over. When I looked at the carb glass there was VERY little gas in it -- nowhere near the dot in the middle. The gas level was pretty much to the bottom of the glass, hard to even see it really. Charlie69: I tried your suggestion of letting a friend rev the engine while feeling the exhaust pipe output. What I noticed is that when the engine was reving higher the heat increased but the air pressure output seemed to drop. In other words, at normal idle I could feel some air pressure on my hand at about 4" from the exhaust pipe hole; BUT when my friend started pressing the gas pedal and reving the engine higher the pressure output seemed to drop but got significantly hotter. Heck, I was afraid my hand might get burned if it was too close -- that's how HOT it would get ! I haven't tried disconnecting the 6 wires at the back of the carb yet because I wanted to wait and see what you guys say about these tests first. Btw, the truck has 285,000 miles on it and has had this issue for a while, but now it is a LOT worse. No it has never been sitting up and I have been using it everyday for 13 years ! I just don't drive it much (about 15 miles a day), but she has always run GREAT for the most part and been very reliable. Changing the fuel filter didn't really make any difference, and I am not really sure what fuel pump I have. Well, I hope you guys can give me some more insights now as to what the culprit may be ? And thanks again SO MUCH for your help -- it is sincerely appreciated !!! We are in New Orleans where the Covid 19 is pretty bad, and so we really need the truck working to get thru this.

OK, Thanks again Charlie69 and Datzenmike ! I am going to do all of what you both recommended and report back the results ASAP. I will do what Datzenmike recommended first as he described very well what the truck is doing -- lurching forward when giving gas, then stalling. Yep, "lurch and stall, lurch and stall" !! Btw Datzenmike, the truck has an automatic transmission. Checked the trans fluid and it is nice and healthy. And a question for Charlie69: Any tips on how to remove those 6 wires without ruining anything ? Are there any "tricks" to it ? If the problem is the ECC system I was hoping I could just disconnect it for a little while and use the truck to survive in the meantime.

Thanks Mike !! Yes, it is indeed the ECC version. It has 1 wing nut in the center of the air filter cover, and I also noticed that "mystery electrical box" under the seat. Today I cleaned and taped up that sketchy part of the cable and gained a false sense of confidence. So I took her for a ride from my house to my studio downtown -- BIG mistake ! What is weird is that from a cold start (after being off for several hours) the truck will run sorta OK for the first 5-7 minutes or so. The total distance of that trip was about 10 miles, and for the first 3-4 miles (cruising at about 25-35mph on side streets) she was able to handle that OK with just a little locking up when trying to go faster. But man oh man, after about 10 minutes she started locking up BIG TIME and I barely made it to my studio. So I let the truck sit for about 6 hours and then decided to try and make it back home -- another BIG MISTAKE ! And the same thing happened again. She ran OK at 25-35mph for the first 7 minutes/4 miles and then started acting up the worst I have seen her do yet. It felt like a MIRACLE that I actually made it home. I had to keep going back and forth with small movements of my foot on the gas pedal just to keep her going, and my speed went from 25mph down to about 15-10 mph by the end of the trip. The thing is, if you try to give it gas to go any faster it locks up right away and will kill on you. So I had to keep lightly (and quickly) pumping the pedal just to putter along at 15mph to avoid killing out. WHAT DO YOU GUYS THINK ? I am REALLY praying that it can be fixed because I need the truck pretty badly right now. I never imagined that a faulty sensor could make a truck run this bad, but I am truly glad I made this post as I am gaining an education for sure ! I was thinking about looking at the 1 month old plugs to see if maybe they are carbon fouled already. Maybe the "over rich" condition is causing them to foul up quickly ? But I just can't believe that alone would be causing the truck to run this bad. Honestly, this is the worst she has ever run in the 13 years that I have had her. So it seems the wire is probably not the problem, but instead the 02 sensor or something inside that "mystery box" under the seat ? You are right that the wire is hard and seems to be a co-axial type, so it is probably just fine because it is not broken or severed anywhere. Oh yeah, and I did jiggle those 6 wires (round electrical plug) in back of the carb while the truck was running and it did nothing to change the idle -- so I assume those are OK as well.

Hi datzenmike, Man, thanks a MILLION for the quick response. This forum is truly awesome !! YES, my mechanic friend had mentioned "sensors" as possibly being the culprit. I just assumed (wrongly) that my truck probably didn't have one ! So I went digging after reading your reply and I found what you are talking about, and also a SKETCHY looking splice job of the wire that runs from the carb to that sensor. There was some old dry rot electrical tape around the splice section that just crumbled off when I squeezed it, exposing BARE silver looking stranded wires. Here are some dropbox links photos that I just took of all this: https://www.dropbox.com/s/pq2t5oyoza1tzt0/DSC00618.JPG?dl=0 https://www.dropbox.com/s/x2iwrlobc78sj1a/DSC00620.JPG?dl=0 https://www.dropbox.com/s/w4aw8stpzl2l80b/DSC00621.JPG?dl=0 Sorry, but I could not figure out how to attach pics here, so I used my dropbox account. Just click on each link and a photo should come right up. In the 1st photo you can see that sketchy looking splice with EXPOSED wires !! I can't imagine that is anything good. In the 2nd and 3rd photo you can see that O2 sensor from two different angles. It looks just like what you (datzenmike) posted to me. The 3rd photo has my finger pointing at it. So now I am wondering if that sketchy splice with exposed wires is the culprit causing the engine to lock down when giving it gas ? It seems that might explain WHY when it is crazy HUMID that the problem gets a lot worse; those exposed wires likely get very moist and may start shorting the sensor out ? What do you guys think of that ? Also, is it possible to simply CUT that wire and disengage the O2 sensor completely until I get a new one ? I was hoping I could at least use the truck for a little while in the meantime. OR, should I just try to clean that splice area up really good and then thoroughly seal it off with some electrical tape so moisture cannot get to the wires ? Maybe THAT will solve the problem temporarily ?