the_tool_man

I bought an N42 intake from a local forum member for future use. It has a CSV on it that I can use to plug my intake while I test mine for correct function and leaks. Anyone know approximately how much fuel is supposed to come out during a cold start? Sent from my XT1254 using Classic Zcar Club mobile

I like that answer. Also, I STILL haven't checked the CSV. It may be leaking. I do have a spare now, which will make checking easier. Sent from my XT1254 using Classic Zcar Club mobile

One of the "loose ends" was removing the fuel pressure gauge I'd had in there for a year, . I thought I might put it back and run it through the passenger side hood vent. I have to remove and repair that piece anyway at some point. And I don't have a go-pro or spare phone. Regardless, the fuel gauge isn't working right. The sender will have to come out for cleaning/replacement. And I noticed in the last week the fuel pressure drops to zero pretty quickly after shutdown. So I should probably replace the check valve. I might as well do the tank while I'm doing all the other stuff. Then I'll have confidence in the fuel system. Sent from my XT1254 using Classic Zcar Club mobile

Over the weekend I changed fluids, set the timing and tied up a few loose ends in the engine room. Vacuum holds at 15 at idle. Still a tad low (I'm just gonna have to replace all the vacuum hoses and be sure). It would hesitate at times under acceleration. But it's been running fairly well. Then tonight I took it out for a longer drive. After a few miles it started to bog really badly around 3k rpm. It would occasionally backfire out the tailpipe too. It only does it while driving. It revs fine in the shop. I figure it's rust from the fuel tank getting sucked up while in motion. So I guess it's time to drop the fuel tank and have it cleaned and coated. On to the next layer of the onion. Sent from my XT1254 using Classic Zcar Club mobile

I washed mine. For the first time. Since buying it a year ago. Why so long? Because it didn't run until yesterday! So glad it's running finally! Sent from my XT1254 using Classic Zcar Club mobile

No video. But a few photos after a fluid change and wash. I drove it around my neighborhood for about 15 minutes and it runs pretty good. I need to do a thorough tune up and bleed the brakes before I drive it much. But I couldn't resist a shakedown drive. The only thing I can find wrong is a burned out license plate bulb and the power antenna is inoperative. Sent from my XT1254 using Classic Zcar Club mobile

I'd be concerned with building pressure if the seal is too good. I removed the AFM, leaving the rubber hose to the intake in place. I used the big end of my yogurt cup with a few wraps of electrical tape to plug that. I'd already blocked off the EGR passage and associated vacuum line. All I had to do at that point is pull the brake booster line off the hard line on the intake, and clamp the tube from the fog generator to it. I could have used the barb on the booster check valve. But the tubing I used was too big, and there wasn't much room around it for fiddling with a hose clamp. I suspect you can leave the exhaust (and even the EGR) open, and it will still be effective. Even with some leakage around the tubing and yogurt cup, there was plenty of fog coming out around the injector boss to see the leak. I need to do a write-up on this, I guess.

Soon. With all the mixture excursions and sitting, I want to change the fluids first. I also want to bleed and inspect the brakes before I trust them. Maybe a low speed pass around the neighborhood wouldn't hurt, lol.

Good question. I suppose some does escape. But the fog machine I borrowed is pretty big, and puts out a large volume of fog (it traversed the 10 foot tube in a second or two). So there's plenty to go around. In fact, I had to be pretty meticulous sealing up the intake with my yogurt cup, and even making sure the hose clamp on my vinyl "fog tube" was tight enough to seal it against the vacuum port pipe in the intake. Otherwise, fog would seep out where I didn't want it to, and obscure things pretty quickly. Once I fixed the injector leak, I ran the machine a couple more times to verify it and look for others. At that point, the leakage around the yogurt cup and vinyl tube were still enough to send faint tendrils of fog here and there. So I had to fiddle some more to eliminate the leaks. Even my sealed connection at the fog machine leaked a little. Thinking about this, you don't want this to build any pressure. It might damage vacuum diaphragms and such. So having the exhaust pipe be a safety valve is probably a good thing.

I tried out the fog machine tonight. It worked spectacularly well. I found a huge vacuum leak around the #5 injector. I must have not gotten the sealing ring lined up when I installed it a while back. I disassembled the rear half of the fuel rail and redid everything. Another fog test showed no leaks. I turned the key and it started right up. It's smooth as silk. I set idle speed and timing once it had warmed up. It revs freely with no hesitation or popping. I am SOOOOO HAPPY right now! Thanks to all of you for your help, advice, encouragement and patience. I can be an idiot sometimes. But with your help I've made a big step forward tonight. Thank you. . Sent from my XT1254 using Classic Zcar Club mobile

I disconnected it at the booster side of the check valve. In fact, that's where I later measured the idle vacuum from. Whether open or hooked up to my vacuum gauge, the engine behavior didn't change.

I'm not comfortable with the propane torch method, especially right over the exhaust manifold. I didn't think about the gasket being upside down. It lined up with all the contours of the head, so I don't really see how it could be. The gasket is visible in the photo I took of the valve train. Can you tell?

I tried pulling the dip stick, removing the oil cap and pulling the vacuum line to the booster (at different times). The idle didn't change. This supports the vacuum leak theory. I'll spend more time on it this weekend with a stethoscope and a noid light to investigate the injectors. I think I'm getting close. Sent from my XT1254 using Classic Zcar Club mobile

I didn't know noid lights existed. I'll pick up a set. I didn't check the distributor. But I've already set the static timing. Would it run with the distributor 180 degrees off? Sent from my XT1254 using Classic Zcar Club mobile

FSM spec is .037-.041 for a '77. Five of the new ones I bought were at .038. so I gapped the sixth one the same. Sent from my XT1254 using Classic Zcar Club mobile

Tonight I pulled the plugs, cleaned them and gapped them to .038". I pulled the valve cover and checked the valve lash. All were in spec. While I had it open, I rotated it to put #1 at TDC and verified the cam timing was correct. I checked the torque on the head bolts. They were all tight. Does the red on the camshaft mean anything? Then I buttoned it all back up and started the engine. I pulled each plug wire in succession to see if the idle changed. The idle is so rough that it was hard to tell. But it seemed as though #2, #4 and #5 made a difference and the others didn't. I confirmed with a timing light that all plugs are getting spark. Fuel pressure is good. That leaves injectors and vacuum, right? I don't have a stethoscope (I'll pick one up this weekend). And my hearing is shot. So I've decided to just replace all the injector connectors. I already have new ones, since I'd planned on swapping them anyway (boots are disintegrated). As I said, the injectors are brand new. I practiced connector pin removal tonight at the kitchen table. I also borrowed a fog machine to test for vacuum leaks. I'll play with that this weekend. Sent from my XT1254 using Classic Zcar Club mobile

Thanks for that. I went to Harbor Freight and bought a ready-made remote start switch for $8 (with coupon). Worked great for re-starting while diagnosing running issues, looking for leaks, etc. I also used it for compression testing. But it never occurred to me that I could have left the key off to disable fuel, saving me the trouble of disconnecting the injectors. I was in the habit of turning the key on every time. I guess I deserve to be treated like an idiot, when I act like one.

I'm not sure whether to find this line of discussion funny or insulting. I assumed a photo of the mysterious box was sufficient. For the sake of brevity, I didn't develop an elaborate verbal description. Again, knowing what to call it would have been helpful. But I didn't have that information. I have every intention to resolve the fuel pressure issue at the earliest possible opportunity. I am quite familiar with the fuel pump test you mentioned, and will certainly perform it. But in the event the fuel pump doesn't operate, I will be looking for possible causes, starting with most likely ones. For example, what electrical connections might I have disturbed? Since I touched the junction box, I wanted to know what it does, so that I can assess whether or not it might be related to the issue. The time to ask is now, while there is time for someone to answer, not at 8:30 this evening when I need the answer at hand. I can see how my questions might appear random or spontaneous if they don't correspond with your paradigm of a logical troubleshooting method. But there is an underlying reasoning, nonetheless. Disconnecting the fuel injectors was so that I didn't get sprayed by fuel while performing the compression test. Because I wanted to minimize cooling down during the test, I took out all of the plugs at the same time to get compression readings quickly.

I have tried to identify the mysterious black plastic thing that is screwed to the driver side inner fender forward of the coil. See yellow circle in photo. I haven't found it through searching, since I don't know what to call it. I tried to open it last night while working on the car, thinking it might be a junction box of some sort (trying to avoid having to unplug all of the injectors). I figured out it's potted, and can't be opened. But what is it? If it has something to do with the fuel pump, it might explain why mine quit working. Unfortunately, during the compression testing, I paid no attention to the fuel pressure. So I don't know exactly when it quit.

It's detailed in my intro thread linked in post #1. But the fuel system has been gone through from the filter outward. Fuel pressure was verified. 44psi dead headed to test check valve. 35psi with engine off. 32psi with engine at idle. New FPR. New injectors. New hoses. I haven't replaced the CSV. But I'll check it.

Load test is a good idea. I'll try that. Plugs are new with correct heat range. I'll check gap. Water temp circuit has been verified. I will test CSV. Air filter was removed on day one. FPR has been replaced. Fuel pressure was good. Leakdown was in spec. Fuel check valve tested good. AFM came from running car.

Good idea. I'll check the plug gaps. I still have the old, conventional plugs, though they're really dirty. I could swap those back in if you think they'd be better. Once again, the car will start and idle, albeit roughly, when cold. Once warm, it won't really idle for very long, maybe 15 seconds or so. At any temperature, when I attempt to rev the engine, it will hesitate and pop a few times in the intake. Then it will rev. If I hold it at 2000 rpm or more, it seems to run pretty smoothly, with a slight tremble. I don't know if that's normal or not, since I've never owned one of these before. I have not attempted to drive the car, other than driving it off the trailer and into my shop. The driveway is very steep. And the thought of trying to back it up that hill with it sputtering and dying doesn't appeal to me. I verified spark on all six cylinders with my timing light.

I have lots of pics. The only overall engine photo is from the day I bought the car (below). The coil of wire around the AFM was what I stuck in it to hold the flap open and let the car run well enough to drive it off the trailer and into my shop, lol. That AFM ended up having an intermittent fuel pump contact, and had been "adjusted" by someone. I replaced it with a known good one from a running car. I've included a couple of closer shots of the sides of the engine in case they help. I've got close-ups of just about everything. So just ask if you want more detail.

The boot looks like practically like new. No tears. All the soot has made me think it's running rich. But the popping in the intake has everyone telling me it's running lean. I don't know what to believe. Photo of boot right after I got the car. I've replaced the coil and plug wires since this photo was taken. So disregard the beat up coil wire.

I got one end of the PCV hose loose, so I could give it a good inspection. No apparent issues. I've come up with a plan to use smoke to look for vacuum leaks. But I couldn't do that until a friend brings me his fog machine. So tonight I did a compression test. After warm-up: 1:152psi 2:152psi 3:158psi 4:155psi 5:155psi 6:150psi An 8psi range (5℅) seems pretty good. Here's a pic of the plugs (in order 1-6 left to right): They probably have about fifteen minutes of total run time on them. No time for more than that. So I put everything back together and checked the firing order for the fourth time. Of course there's always something that goes wrong. I have no fuel pressure now. Not sure how since I didn't touch the fuel pump circuit. Sent from my XT1254 using Classic Zcar Club mobile